Articles
Events in early embryonic development and importance of early pregnancy diagnosis
AK Balhara, SK Phulia, Jerome A. and Inderjeet Singh
An early and accurate diagnosis of reproductive dysfunctions or aberrations is crucial to better reproductive management in livestock. In fact, high reproductive efficiency is a pre-requisite to realization of high life-time production from dairy animals. In this respect, early pregnancy diagnosis is important for shortening the calving interval through enabling the producer to identify open animals in order to treat and/or rebreed them in time for maintaining a short postpartum barren interval, ideally close to 60 days.
Buffalo, the most important dairy animal of the Indian subcontinent, is often blamed for sub-optimal reproduction especially relating to late puberty, long calving intervals and a high incidence of anestrus. Lack of reliable early pregnancy diagnosis method further aggravates the situation. Various direct and indirect methods of pregnancy diagnosis being practiced in bovine species, with their inherent merits and demerits, are discussed here.
An ideal dairy breeding programme outcome: a healthy calf per year .The early embryonic period in bovine lasts for approximately 42 days post insemination (Committee on Reproductive Nomenclature, 1972), encompassing a series of crucial events starting with fertilization and culminating in implantation (Table 1). It is also during this period that the maximum reproductive losses are encountered, attributed to embryonic or maternal causes consisting of chromosomal, physiological and endocrinological aberrations or infections to which the developing embryo is susceptible. Post-implantation, embryonic losses due to non-infectious causes are rare and the pregnancy becomes more secure. The early embryonic development in mammals has been shown in figure 1.
Figure 1. Development of the conceptus from fertilization to elongation of the chorionic vesicle (A)Fertilization (B) First cleavage, occurring about 24 h after fertilization, producing an embryo with two cells or blastomeres still contained within the zona pellucida (C) Second cleavage, within 12 h of first cleavage, producing four blastomeres (D) Third cleavage, within a few more hours, resulting in eight blastomeres within the zona pellucida (E) Subsequent cleavages produce the morula with 16 to 64 blastomeres, still within the zona pellucida (F) Continued cleavage results in a blastocyst with a distinct inner cell mass (ICM) and a layer of trophectodermal cells (T) surrounding a fluid filled central blastocoelomic cavity (BC) (G) Outward pressure from the growing blastocyst ruptures the zona pellucida (hatching) so the conceptus can now increase in size (H) The conceptus grows rapidly into and through the spherical blastocyst stage (I) blastocyst elongates quickly into a filamentous form that grows to fill much of the uterine lumen. Table 1 narrates the gestation lengths in different dairy animals.
Table 1. Important events during early embryonic period
| Day of Pregnancy | Event |
| Day 0-1 | Fertilization, single-cell embryo (zygote) in oviduct |
| Day 2 | Early cleavages in the oviduct (upto 8 cell stage),
Activation of embryonic genome |
| Day 3-4 | Embryo enters the uterus |
| Day 5-6 | Zona-enclosed embryo progresses into compact morula stage (Bovine)
Blastocoele formation begins (Bubaline) |
| Day 7-8 | Formation of a blastocoele with differentiation of embryonic cells (Bovine)
Expanded blastocyst hatching from zona pellucida (Bubaline) |
| Day 9-10 | Blastocyst expansion and hatching from zona pellucida (Bovine)
Embryonic cells concentrate at ICM (inner cell mass) |
| Day 11-15 | Rapid blastocyst elongation from tubular to a filamentous structure |
| Day 14-19 | Filamentous blastocyst communicates with dam (by secreting IFNτ) for maternal recognition of pregnancy to tide over cyclic luteolysis |
| Day 19-20 | Implantation begins |
| Day 21 | Caruncles–cotyledons appear, embryogenesis starts |
| Day 22-41 | Implantation and embryogenesis progress further |
| Day 42 | Implantation and embryogenesis completed |
A pregnancy diagnosis method has to rely on one or more of the embryonic developmental profile associated changes in dam’s physiology. Accordingly, measuring peripheral concentrations of progesterone, pregnancy associated glycoproteins (PAGs) and early pregnancy factor are some of the commonly practised pregnancy detection methods in bovines, and each has its own benefits and limitations.
Table 2. Gestation lengths for different dairy animals
| Species | Range (days) |
| Cow – Bos taurus | 278–290 |
| Cow – Bos indicus | 285–295 |
| Water buffalo – Bubalus bubalis | 302–317 |
| Goat – Capra hircus | 142–154 |
| Ewe – Ovis aries | 143–153 |
| Arabian camel – Camelus dromedarius | 345–395 |
| Asian camel – Camelus bactrianus | 370–440 |
| Llama – Lama guanicoë glama | 320–345 |
| Alpaca – Lama guanicoë pacos | 325–366 |
| Reindeer – Rangifer tarandus | 210–240 |
| Yak – Bos grunniens | 250–270 |
Ideal pregnancy biomarker
In order to qualify as a suitable marker for pregnancy, the candidate molecule should be able to determine the pregnancy status as early as possible, with 100 % accuracy and with no false positives or false negatives. Additionally, desired characteristics of a biological marker for pregnancy should include the following characteristics:
- Specifically up-regulated or down-regulated during pregnancy.
- Expressed over a considerable period of time to give ample time for diagnosis.
iii. Present in easily accessible body fluids like serum, milk, urine, vaginal discharges etc.
- Preferably to have the ability to reflect age as well as viability of the conceptus.
- Least affected by non-animal factors like feed, environment and drug interactions.
- Testing method to have the ability to reveal the result immediately.
None of the present day methods qualifies as an ideal diagnostic due to limitations of accuracy, later stages of applicability as well as the requirement for elaborate instrumentation and laboratory set-up. Further investigations on developing novel early pregnancy diagnostics for livestock species, especially buffaloes, are in progress and hopefully, very soon we should have a suitable marker / diagnostic test for early pregnancy in livestock species including buffalo.
Buffalo under Heat Stress
AK Balhara, Jerome A and Inderjeet Singh
Amongst different environmental conditions, it is the hot weather that ubiquitously compromises the productive and reproductive performance of livestock species. The plains, coast-line and foot-hill regions of the Indian subcontinent, home to over 90% of the worlds’ buffaloes, experience varied and extreme weather conditions, with temperatures reaching up to 48°C in summers and as low as minus 2°C in winters. The presence of large buffalo population in such diverse climatic conditions indicates that buffaloes are well-adapted to such climatic extremes. Yet, it is generally believed that buffaloes are sensitive to heat stress, owing to:
Ø Thick black skin color that absorbs more solar radiations, which are high in the region.
Ø Sparse hair coat, considered inadequate to insulate the buffalo from high temperatures.
Ø Buffalo skin has fewer (almost 1/6th) sweat glands in the skin than Zebu, situated deep in the skin, compromising heat dissipation through evaporative heat loss.
These peculiar morphological and anatomical characteristics make buffalo poor thermoregulator, thereby tending to increase the internal body heat, which in turn, takes its toll on food intake, productivity as well as reproductive performance of the animal. Thus it is no surprise that there is a scarcity of milk in this region during summer months, while most of the calvings are concentrated during rainy and winter months of the year.
Inspite of these facts, which tend to suggest susceptibility of buffalo to heat stress due to its unique thermoregulatory mechanisms, the presence of large population of buffaloes in such harsh hot climates could possibly be due to some of the special anatomical, behavioral and morphological features of the skin in this species. Such features include the characteristic black skin that contains numerous melanin granules, which provide protection against UV rays component of sun light. UV rays are abnormally high in the typical hot climates of the tropics. Further, buffalo dermis has well-developed sebaceous glands and their oily secretions make skin slippery for water and mud. This possibly acts as a defence against harmful ingredients present in mud and water while wallowing. The oil secretions from skin make it more lustrous during summer to reflect solar radiations more effectively.
Common terms associated with heat stress
Ø Heat wave: Long period of excessively hot climate.
Ø Heat Cramps: Muscular pain and spasm due to heavy exertion in hot climate.
Ø Heat Exhaustion: Excessive loss of body fluids (usually through sweat) leading to fatigue.
Ø Heat-stroke / Sun-stroke: Break-down in thermoregulatory system of the body leading to increased internal temperature with no sweating and death, if not immediately treated.
Adaptive changes in response to heat
In response to heat-stress, numerous physiologic changes occur in the animal system including altered acid-base chemistry and endocrine glands activity, in response to compromised thermoregulation as well as reduced nutrient intake. Nevertheless, many changes occur as a result of stress in the animal.
Neurons, which are temperature sensitive, are located throughout the animal’s body and send information to the hypothalamus, which invokes numerous physiological, anatomical or behavioural changes in an attempt to maintain heat balance. During heat stress, buffalo exhibits reduced feed intake, decreased activity, seeks shady and airy places, increases respiratory rate, peripheral blood flow and sweating. Table 1 lists different physiological adjustments in the animal’s body in response to heat stress.
Table 1. Physiological effects of heat on buffalo
| Effect | Implications |
| Hemodynamic effects | Increased blood flow to skin and peripheral tissue resulting in:-
– increased hydrostatic pressure – increased capillary permeability – leucocytic and antibody infiltration – analgesia |
| Neuromuscular effects | Increased nerve conduction velocity, decreased firing rate of motor neurons resulting in muscle relaxation and increased pain threshold |
| Metabolic effects | Stimulation of hypothalamus resulting in increased metabolic rate, oxygen uptake and accelerated healing |
| Soft tissue extensibility | Increased collagen extensibility for maintaining greater length after stretching for:
– decreased elasticity – less force required to increase length – decreased risk of tissue tearing |
These responses have deleterious effect on both productive and reproductive status of the animal. Fig. 1 illustrates different physiological adjustments in body of a buffalo in response to heat stress.
Fig. 1 Physiological mechanisms during heat stress in buffalo
The negative effect of heat stress on milk production is due to the decreased nutrient intake and decreased nutrient uptake by the portal drained viscera of the buffalo. Blood flow shift to the peripheral tissues for cooling purpose alters the nutrient metabolism and contributes to lower milk yield during hot weather. Hormonal alterations associated with heat stress include decline in plasma somatotropin and thyroxine concentrations in an attempt to reduce metabolic heat and consequently, milk production. Heat-stressed buffalo exhibits altered blood acid-base chemistry as a result of the shift in thermoregulation from conduction, convection and radiation mediated heat-loss to evaporative cooling. Heat-stressed animal has elevated rectal temperature and respiration rate accompanied with diurnal variations in blood pH and bicarbonate values. Wide swings in acid-base chemistry, from alkalosis to compensated acidosis, result in metabolic acidosis during the cooler evening hours. Reduced concentrations of blood bicarbonate compromise the buffering capability associated with the bicarbonate system, which may be critical during summer. During hot season, the dry matter intake of buffalo is decreased and the ratio of forage to concentrate intake is also decreased. In other words, the decline in milk yield at higher temperature is more marked in a buffalo that produces more milk. There is a significant relationship between the level of milk yield and the decline in milk yield associated with increase in daily mean environmental temperature.
Changes in gene expression associated with heat stress
The central dogma of life (DNA-RNA-Protein) suggests that changes do occur at the gene level, which percolate to altered protein milieu in the body. The heat shock proteins (HSP) are one of the fundamental groups of molecules that have been used to study the stress physiology at molecular level. The changing profile of these proteins at the gene and protein level in different tissues, including muscles, is a useful indicator of the damage caused by stress at the molecular level. Study of antioxidant enzyme systems, especially in erythrocytes, has also been used to investigate the oxidative changes in the animal body.
How to recognize heat stress
Ø Changes in consciousness: Rapid and weak pulse, rapid but shallow breathing;
Ø Abnormal vital parameters: Elevated heart rate, respiration rate, rectal temperature;
Ø Unusual salivation: Capillary refill is very fast
Ø In case of heat stroke – very high body temperature – sometimes as high as 106 – 108°F.
Heat stroke is life-threatening, so immediate veterinary attention is a must while moving the animal to cooler place, giving bath with cold water or wrapping in wet sheets and providing fan.
Ø Signs of heat exhaustion: Dizziness / unconsciousness; Skin becomes dull and may be cold too.
Management of heat stress
Modification of the micro-environment / Use of cooling system
Careful management is important to alleviate heat stress and maintain high production levels in lactating buffaloes under hot environmental conditions. Good management practices include modification of the surrounding environment to reduce the impact of environment and at the same time promote heat loss from the animal. Combating heat stress in buffaloes can be through various management practices such as provision of shade, increasing air movement and repeatedly wetting the animal with cold water for greater evaporative cooling.
Shade: Simple shade is the basic method of protecting animals from direct solar radiation in day-time during summer. The most effective source of shade is the trees and plants. They provide not only protection from sunlight, but also create a cooling effect through the evaporation of moisture from their leaves. Shade has a beneficial effect on the physiological response of buffaloes to heat as the body temperature, heart rate and respiration rate all decreased when shade is provided during summer. These practices shall reduce the impact of solar heat while maximizing heat dissipation from the animal.
Air movement: Air movement becomes more important during hot-humid climate for providing cooling and comfort to the animal. Apart from shifting animal to shaded airy place, fans or dairy fans and different types of coolers can also be installed for making the place airy. Air movement increases the rate of heat loss from animal’s body surface, only as long as the air temperature is lower than the animal’s skin temperature.
Evaporative Cooling: For this, various cooling systems have been developed such as holding-pen cooling, exit-lane cooling, and free-stall cooling. These systems are applicable for the animals maintained in covered pucca sheds. An evaporative system which uses water mist with fan is more effective and economises water use in comparison to repeatedly bathing the animals. Some farmers prefer sprinklers or mister, installed on the roof or at various places in the barn. The use of a combination of evaporation and air movement such as ‘mist fans’ are more effective, economical and useful than fans and wetting alone. Water sprinklers generate a large volume of waste water.
Feeding strategies in hot environment
There are several key areas of nutritional management which should be considered during hot weather. These include special formulation to account for reduced dry matter intake with corresponding greater availability of key nutrients and to compensate for dietary heat increment while avoiding nutrient excesses. The energy requirements of lactating buffaloes also increase under high temperature conditions, but this increase is apparently caused primarily by the increase in metabolic energy.
Water intake: Water is arguably the most important nutrient for buffalo during hot climate. Water intake is closely related to dry matter intake and milk yield, but regardless of the rate of increase, it is important that abundant water must be available at all times under hot conditions. Hot weather, declining dry matter intake and high lactation demand requires increased dietary mineral concentration. The primary cat-ion in bovine sweat is potassium. Sharp increases in the secretion of potassium through sweat occur during hot climatic conditions Alterations in mineral metabolism also affect the electrolyte status of buffalo during hot weather. So it important to supplement minerals during hot climate.
Night Grazing: Buffaloes kept in a shed maintain rapid heartbeat during the night. However, when the animals are allowed out into a pasture at night, these physiological responses decrease immediately. This is the result, both of a reduction in radiation heat from the surrounding buffaloes, as well as increased heat loss from the animal itself.
Feeding High-Energy Diets: Low-fibre, high fermentable carbohydrate diets lower dietary heat increment compared to high fibre diets. Although the metabolic energy of dairy buffaloes increases in a hot environment, heat stress depresses feed intake. For this reason, it is important to increase the energy content of the diet of dairy buffaloes, in order to maintain their energy intake under hot conditions. The heat increment, which is an internal heat stressor in hot environments, is lower in highly metabolizable diets. So it is imperative to use fatty feeds, or calcium salts of fatty acids, as the means of improving energy supply for buffaloes in summer. Buffaloes fed on such diets have higher milk yield, and a lower body temperature and respiration rate.
Feeding by-Pass Protein: Dietary protein degradability is also critical under heat stress conditions. It is well known that excessive protein intake increases heat production and decreases reproductive performance. However, the protein requirement of buffalo increases and dry matter intake decreases in a hot environment, consequently, the protein supplied to lactating buffaloes during summer is not always sufficient. By using fish meal, which is a by-pass protein, the milk yield and protein content of buffalo milk increases but the ruminal ammonia production decreases.
Genetic selection
There are many aspects of genetics that influence the animal’s response and endurance to heat stress. Accordingly, wide variations in the same are evidenced among different breeds of livestock. The maintenance of body temperature is heritable through characteristics like coat structure and color, sweating competence, low tissue resistance etc. So selection of animals through specific genetic markers for heat tolerance will help to address the problem of heat stress in buffaloes by identifying the heat stress tolerant animals.
Conclusion
In hot-humid climates, although buffalo attempts to acclimatize through physiological changes including cutting down on feed intake and heat production, but this does not come without sacrificing part of its productivity. In order to prevent this economic loss to the farmer, there is need to understand and effectively combat heat stress by minimizing its impact on animal body and its productivity. Over generations, continued genetic selection for improved dry matter intake and milk yield under adverse climates, will pave the way for producing buffaloes that are better equipped for heat tolerance. In the short term, there is no substitute to good management practices to ameliorate heat stress, which include nutritional management and infrastructure facilities for providing comfort to the animal in the event of harsh hot climate. There is little doubt that a buffalo shall repay the investment in due course of time through continued high milk productivity and maintaining good reproductive efficiency for higher life-time productivity.
Buffalo Stem Cell
What are stem cells?
- Stem cells are cells which are capable of dividing symmetrically and renewing themselves for long periods.
- These are unspecialized cells but can give rise to specialized cells in response to specific signals.
Stem cells are generally of three origins
Embryonic stem cells: Derived from the inner cell mass of the blastocysts – are pluripotent.
Fetal stem cells: These are from placenta, and fetal adnexa, such as umbilical cord blood, umbilical cord matrix, amnion, amniotic fluid (AF), fetal fibroblasts and are multipotent;
Adult stem cells: Isolated from most postnatal tissues and are either unipotent or multipotent.
Stem cells types
Totipotent
The fertilized egg is said to be totipotent-from the latin totus, meaning entire. Because it has the potential to generate all the cells and tissues that make up an embryo and that support its development in utero. All of these cells are generated from single, totipotent cells- the zygote or fertilized egg.
Pluripotent
Most common term used to describe stem cells that give rise to cells derived from all three embryonic germ layers-mesoderm, endoderm, endoderm and ectoderm. Source of pluripotent stem cells are either inner cell mass of blastocysts or embryonic germ cells from the genital ridge
Multipotent
Can differentiate in more than one type of cells but not capable to differentiate in all germ layer cells eg. hematopoietic stem cells from bone marrow and mesenchymal cells from the fetal origin
Unipotent
Unipotent stem cells is usually applied to adult stem cells. These cells can differentiate in only one lineage. Adult stem cells in many differentiated tissues are in typically unipotent and just give rise to only one cells type in normal conditions.
Applications of ES cells in buffalo and other farm animals
- Veterinary regenerative medicine: Tissue injury repair, wound healing etc
- Transgenesis: Stem cells have long life and it is easy to transfect these cells for transgenic animal production through SCNT. To produce eco-friendly, bio-medically important animals
- Assisted Reproduction: Obtaining germ cells to treat infertility. Stem cells can be transformed in sperm or egg. Repopulation of endangered threatened breeds/conservation. More suitable donor cells for cloning
- Studies on early development: The differentiation studies in three germ layers can suggest the steps in early development
- In vitro meat production: Stem cells can be differentiated into muscle cells and can be an economical, environmental friendly and ethical source of meat.
- Rapid drug testing: On Uniform cells
Institutes engaged in stem cell research on buffaloes:
| Sr. No | Institute | Project Title- funding source |
| 1 | CIRB, Hisar | Isolation Culture and characterization of adult stem cells in buffaloes-DBT |
| 2 | NDRI, Karnal | Establishment and maintenance of buffalo embryonic stem cell lines- DBT
Characterization and Differentiation of Embryonic, Adult and Spermatogonial Stem Cells in Cattle and Buffaloes- NAIP |
| 3 | Veterinary University Chennai | Establishment of buffalo embryonic stem cell lines- DBT |
| 4 | IVRI, Izatnagar | Development of embryonic stem cell lines from early stage parthenogenesis embryos and their comparison with IVF derived embryonic stem cells in buffaloes- DBT |
Characterization procedures:
- Alkaline Phosphatase staining
- Immuno-histo-chemical tests
- Surface markers based on specific antibodies
- RT-PCR amplification of selected transcripts
- Relative quantitative PCR
- Differentiation potential in response to specific signals
Opportunities and challenges
The features and the potential therapeutic properties of stem cells from various sources needs to be studied in more depth and then implemented at the clinical level following international guidelines. Stem cells derived from these fetal sources, mostly of the mesenchymal type, have the advantage that they rapidly expand to adequate numbers. Most of these cells don’t require feeder that reduce the chances of mixing the cells from other animals. These cells display negligible immunogenicity and no teratoma formation, while presenting no ethical concerns. Cell-based therapies with embryonic, fetal, adult, or induced pluripotent stem cells generated by reprogramming are thought to have great potential for the treatment of several degenerative diseases, which currently are without effective therapy. However, the ideal cell type is still undetermined. The attempts to establish ES cell lines of domestic animals have been unsuccessful in part due to the inability to develop suitable culture conditions for these species. It is likely that lack of cellular as well as molecular markers for validation of pluripotency and species-specificity are yet to be identified.
contributed by Prem Singh Yadav
Mastitis in Buffalo: Risk Factors
Varij Nayan, Anuradha Bhardwaj, A. Balhara, Jerome A, S K Phulia and Dheer Singh
Introduction
The water buffalo (Bubalus bubalis), also called the ‘Black Gold’ of India, contributes immensely to the Indian economy. India remains first in milk production in the world, thanks to contributions made by buffalo milk. However, mastitis remains the most expensive production disease of buffaloes. The economic damages in terms of decreased/ altered milk production and quality spans different seasons of the year and cannot directly or is easily visualized. An association between reproductive stress and clinical mastitis is also found. Mastitis (Greek, mastos- breast; itis- inflammation) is inflammation of parenchyma of mammary glands or udder and is characterized by physical, chemical and usually bacteriological changes in milk and pathological changes in glandular tissues (Radostits et al., 2000). It is the reaction of udder tissues to injury produced by physical force, chemicals introduced into the gland or most commonly from bacteria, their toxins and other microorganisms and to prepare the way for healing and return to normal function. Mastitis incidence is an outcome of interplay between the infectious agents, poor management practices, genetic and environmental factors stressing the defense of udder. Subclinical mastitis was found more important in India (varying from 5–20% in buffaloes) than clinical mastitis (1–10%) (Joshi and Gokhale, 2006). It not only affects the physical, chemical, bacteriological, technological and organoleptic properties of milk but also affects quantity/ production of milk. Mastitis is responsible for heavy economic losses due to reduced milk yield (up to 70%), milk discard after treatment (9%), cost of veterinary services/ care (7%) and premature culling (14%) (Bhikane and Kawitkar, 2000). Apart from its economic importance it also carries public health significance (Vasavda, 1988). Mastitis exists wherever there are dairy animals like buffaloes. It is frequently said that every buffalo develops mastitis before she dies. Indeed, it is doubtful that there is a single herd of buffaloes anywhere, regardless of size, which is truly free of the disease.
Risk Factors
- Host Factors
- Age/Parity:As the parity increases, an increase in the incidence of mastitis is seen (Kavithaet al., 2009). Sharma et al. (2007) also found higher prevalence of subclinical mastitis in 5 to 9 years old animals and in 3rd and 4th parities.
- Stage of Lactation:Buffaloes in the first stage of lactation (1-4 months) and the last part of dry period (10-12 months) are found to be more prone to mastitis (Kavithaet al., 2009).
- Milk Yield:High milk yielding animals are more prone to mastitis when compared to low milk yielding animals (Kavithaet al., 2009).
Figure 1: Risk Factors associated with Mastitis in Buffaloes
- Immunity of Udder/Mammary Gland
The dry period and the period soon after parturition are generally accepted as the most critical periods with respect to mammary health. During this period the mammary gland undergoes marked biochemical, cellular and immuno-modulatory changes to accommodate involution, to prepare for parturition, to withstand the stress of parturition, to transform colostrum into milk and then for the attainment of peak milk production. Additionally, the early dry period and peri-parturient period have been promoted as the times of highest incidence for new intra-mammary infections. Buffaloes possess a powerful defense mechanism against mastitis due to their tight teat sphincter (Hogberg and Lind, 2003) and long narrow teat canal, which can be expected to effectively prevent micro-organisms from invading the udder (Uppal et al., 1994). Therefore, the chances of infection during the dry period are low. But once the buffaloes are milked after parturition, loosening of the teat sphincter occurs due to continuous synthesis and removal of milk. These physiological changes alter immunity of the gland, thus making the buffaloes most vulnerable to new intra-mammary infections one week after calving (Dang et al., 2007).
- Injury to udder and teat:Healthy teat skin is the first line of defense against mastitis. Lesions on teat skin frequently harbor bacteria that may cause mastitis. Changes to teat tissue, particularly the skin of the barrel, teat-end, and teat canal may favor penetration of bacteria into the udder and increase the risk of new mastitis infections (Hamannet al., 1994). The cause of teat injuries should be quickly identified and eliminated. Tramped teats and udder injuries are the most serious risk factors for clinical mastitis.
- Udder quarters position:Incidence of mastitis is higher in hind quarters vs front (Rasoolet al.,1985). The reasons for higher hind quarters involvement might be due to more frequent exposure to dung and urine, larger capacity and mass, greater vulnerability to direct trauma and relatively more closeness to the floor as compared to fore quarters. Ramachandraiah et al. (1998) also found that the prevalence of mastitis was highest in the left fore quarters (29.3%) followed by left hind (28.0%), right hind (22.0%) and the right fore (20.7%) quarters. The higher prevalence of left side quarters was ascribed due to the common practice of milkmen milking the animals, while sitting on the left side of the animals; while they exert pressure on the left side of quarters.
- Udder shape:The prevalence of mastitis in buffaloes is the highest in double-leveled udder and lowest in spherical shaped udder
- Teat Shape and Size:According to Shukla and coworkers (1997), maximum prevalence of mastitis was recorded in case of animals with funnel shaped teat tip and was attributed to the retention of some milk which facilitates the microbial growth to establish mastitis. However, the results of the total somatic cell counts showed the round shaped teat tips to be equally susceptible to infection as they are more frequently exposed to environmental contamination and are also more likely to be injured. They also opined that plate type teat tips should be preferred over funnel and round shaped teat tips in breeding programmes to decrease the incidence of mastitis. Smaller teats were more prone to mastitis (53.66%) than medium (35.29%), larger (18.33%) teats. It may be due to the shorter teat canal enabling the microbes to move upward without much hindrance in comparison to large teat canal.
- General Immune Status and physical conditions of buffaloes:The lowered immune status and poor body condition of buffaloes due to lack of nutrients/ poor nutrient status, metabolic and infectious diseases can also lead to increased incidence of mastitis. A relation between milk fever and mastitis is also evident.
- Genetic Factors:Hereditary/ Genetic factors influence susceptibility to mastitis. The different buffalo breeds and different buffaloes are not equally susceptible. Selective breeding that focuses solely on milk production is undoubtedly an important factor in higher rates of mastitis.
- Environmental and Managemental Factors
- Season:Heat and humidity may increase the pathogen load in the environment (field or housing) (Goddenet al., 2003), resulting in a greater incidence of mastitis in warm weather. Shathele (2009) reported that, the incidence of mastitis decreased with increasing ambient temperature but increased with decreasing ambient temperature. Dhakal et al (2007) showed that 37.3% of buffaloes had clinical mastitis during the summer season followed by the autumn season (31.7%) and minimum (7.83%) during spring season (February, March and April) in Nepal. Incidence of staphylococcal mastitis was found to be significantly higher during summer than winter in Chennai (Thennarasu et al., 2009). According to Chand et al. (1995), the season of calving had a significant effect in the incidence of mastitis in buffaloes. The animals calved in rainy season had the highest incidence of mastitis.
- Udder and Milker Hygiene:A combination of simple hygienic measures like udder washing with disinfectants and drying with a clean towel and effective antibiotic therapy results in great reduction in the incidence of mastitis. Milking personnel good hygiene is equally important.
- Poor Management Practices:Housing facilities and management practices on farms contribute to the contamination of environments and the exposure of teats to the environmental pathogens. Poorly designed facilities can contribute to increased incidence of environmental mastitis. In all housing systems, high stocking density, dirty bedding or ground, infected utensils, poor ventilation and high humidity are important risk factors. Housing increases the risk of mastitis because the confinement of the animals and the multiplication of micro-organisms in the various litters elevate teat challenge, and consequently mastitis (Sudhan and Sharma, 2010).
- Milking Methods:Incidence of clinical and sub-clinical mastitis is observed to be high when knuckling was practiced rather than stripping on comparison with the full-hand method (Kavithaet al., 2009).
- Number of buffaloes milked by a milker:In general, as the number of buffaloes milked by the same milker increase, so does the prevalence of mastitis.
- Feed Factors:Feeding and diets of buffaloes can influence the resistance of cows to intra-mammary infection. Incorporation of vitamins E, A, and β-carotene and the trace minerals selenium, copper, and zinc, probiotics, choline and conjugated linoleic acid (CLA) can improve udder health and their deficiencies in diet may be associated with increased incidence of mastitis. Contaminated water is also related to mastitis.
- Bedding Material:Incidence of mastitis was found to be less on sand flooring than concrete, and that when soil was used as the bedding material, the incidence was found to be high (Kavithaet al., 2009).
- Micro-organism/ Pathogen Factor
Important pathogenic risk factors include presence of number of organisms on teat skin and their virulence factors, presence of minor pathogens, blind treatment and poor veterinary care. The incidence of mastitis is related to the number of organisms on the teat skin and teat end (McDonald, 1977). With habitat destruction, new and emerging pathogens are coming in picture. Poor veterinary care and indiscriminate use of antibiotics are also compounding or complicating the mastitis scenario. Incidence of MRSA (methicillin resistant Staphylococcus aureus) mastitis is also coming in light.
Amongst different environmental conditions, it is the hot weather that ubiquitously compromises the productive and reproductive performance of livestock species. The plains, coast-line and foot-hill regions of the Indian subcontinent, home to over 90% of the worlds’ buffaloes, experience varied and extreme weather conditions, with temperatures reaching up to 48°C in summers and as low as minus 2°C in winters. The presence of large buffalo population in such diverse climatic conditions indicates that buffaloes are well-adapted to such climatic extremes. Yet, it is generally believed that buffaloes are sensitive to heat stress, owing to:
Ø Thick black skin color that absorbs more solar radiations, which are high in the region.
Ø Sparse hair coat, considered inadequate to insulate the buffalo from high temperatures.
Ø Buffalo skin has fewer (almost 1/6th) sweat glands in the skin than Zebu, situated deep in the skin, compromising heat dissipation through evaporative heat loss.
These peculiar morphological and anatomical characteristics make buffalo poor thermoregulator, thereby tending to increase the internal body heat, which in turn, takes its toll on food intake, productivity as well as reproductive performance of the animal. Thus it is no surprise that there is a scarcity of milk in this region during summer months, while most of the calvings are concentrated during rainy and winter months of the year.
Inspite of these facts, which tend to suggest susceptibility of buffalo to heat stress due to its unique thermoregulatory mechanisms, the presence of large population of buffaloes in such harsh hot climates could possibly be due to some of the special anatomical, behavioral and morphological features of the skin in this species. Such features include the characteristic black skin that contains numerous melanin granules, which provide protection against UV rays component of sun light. UV rays are abnormally high in the typical hot climates of the tropics. Further, buffalo dermis has well-developed sebaceous glands and their oily secretions make skin slippery for water and mud. This possibly acts as a defence against harmful ingredients present in mud and water while wallowing. The oil secretions from skin make it more lustrous during summer to reflect solar radiations more effectively.
Common terms associated with heat stress
Ø Heat wave: Long period of excessively hot climate.
Ø Heat Cramps: Muscular pain and spasm due to heavy exertion in hot climate.
Ø Heat Exhaustion: Excessive loss of body fluids (usually through sweat) leading to fatigue.
Ø Heat-stroke / Sun-stroke: Break-down in thermoregulatory system of the body leading to increased internal temperature with no sweating and death, if not immediately treated.
Adaptive changes in response to heat
In response to heat-stress, numerous physiologic changes occur in the animal system including altered acid-base chemistry and endocrine glands activity, in response to compromised thermoregulation as well as reduced nutrient intake. Nevertheless, many changes occur as a result of stress in the animal.
Neurons, which are temperature sensitive, are located throughout the animal’s body and send information to the hypothalamus, which invokes numerous physiological, anatomical or behavioural changes in an attempt to maintain heat balance. During heat stress, buffalo exhibits reduced feed intake, decreased activity, seeks shady and airy places, increases respiratory rate, peripheral blood flow and sweating. Table 1 lists different physiological adjustments in the animal’s body in response to heat stress.
Table 1. Physiological effects of heat on buffalo
| Effect | Implications |
| Hemodynamic effects |
Increased blood flow to skin and peripheral tissue resulting in:- – increased hydrostatic pressure – increased capillary permeability – leucocytic and antibody infiltration – analgesia |
| Neuromuscular effects | Increased nerve conduction velocity, decreased firing rate of motor neurons resulting in muscle relaxation and increased pain threshold |
| Metabolic effects | Stimulation of hypothalamus resulting in increased metabolic rate, oxygen uptake and accelerated healing |
| Soft tissue extensibility |
Increased collagen extensibility for maintaining greater length after stretching for: – decreased elasticity – less force required to increase length – decreased risk of tissue tearing |
These responses have deleterious effect on both productive and reproductive status of the animal. Fig. 1 illustrates different physiological adjustments in body of a buffalo in response to heat stress.
Fig. 1 Physiological mechanisms during heat stress in buffalo
The negative effect of heat stress on milk production is due to the decreased nutrient intake and decreased nutrient uptake by the portal drained viscera of the buffalo. Blood flow shift to the peripheral tissues for cooling purpose alters the nutrient metabolism and contributes to lower milk yield during hot weather. Hormonal alterations associated with heat stress include decline in plasma somatotropin and thyroxine concentrations in an attempt to reduce metabolic heat and consequently, milk production. Heat-stressed buffalo exhibits altered blood acid-base chemistry as a result of the shift in thermoregulation from conduction, convection and radiation mediated heat-loss to evaporative cooling. Heat-stressed animal has elevated rectal temperature and respiration rate accompanied with diurnal variations in blood pH and bicarbonate values. Wide swings in acid-base chemistry, from alkalosis to compensated acidosis, result in metabolic acidosis during the cooler evening hours. Reduced concentrations of blood bicarbonate compromise the buffering capability associated with the bicarbonate system, which may be critical during summer. During hot season, the dry matter intake of buffalo is decreased and the ratio of forage to concentrate intake is also decreased. In other words, the decline in milk yield at higher temperature is more marked in a buffalo that produces more milk. There is a significant relationship between the level of milk yield and the decline in milk yield associated with increase in daily mean environmental temperature.
Changes in gene expression associated with heat stress
The central dogma of life (DNA-RNA-Protein) suggests that changes do occur at the gene level, which percolate to altered protein milieu in the body. The heat shock proteins (HSP) are one of the fundamental groups of molecules that have been used to study the stress physiology at molecular level. The changing profile of these proteins at the gene and protein level in different tissues, including muscles, is a useful indicator of the damage caused by stress at the molecular level. Study of antioxidant enzyme systems, especially in erythrocytes, has also been used to investigate the oxidative changes in the animal body.
How to recognize heat stress
Ø Changes in consciousness: Rapid and weak pulse, rapid but shallow breathing;
Ø Abnormal vital parameters: Elevated heart rate, respiration rate, rectal temperature;
Ø Unusual salivation: Capillary refill is very fast
Ø In case of heat stroke – very high body temperature – sometimes as high as 106 – 108°F.
Heat stroke is life-threatening, so immediate veterinary attention is a must while moving the animal to cooler place, giving bath with cold water or wrapping in wet sheets and providing fan.
Ø Signs of heat exhaustion: Dizziness / unconsciousness; Skin becomes dull and may be cold too.
Management of heat stress
Modification of the micro-environment / Use of cooling system
Careful management is important to alleviate heat stress and maintain high production levels in lactating buffaloes under hot environmental conditions. Good management practices include modification of the surrounding environment to reduce the impact of environment and at the same time promote heat loss from the animal. Combating heat stress in buffaloes can be through various management practices such as provision of shade, increasing air movement and repeatedly wetting the animal with cold water for greater evaporative cooling.
Shade: Simple shade is the basic method of protecting animals from direct solar radiation in day-time during summer. The most effective source of shade is the trees and plants. They provide not only protection from sunlight, but also create a cooling effect through the evaporation of moisture from their leaves. Shade has a beneficial effect on the physiological response of buffaloes to heat as the body temperature, heart rate and respiration rate all decreased when shade is provided during summer. These practices shall reduce the impact of solar heat while maximizing heat dissipation from the animal.
Air movement: Air movement becomes more important during hot-humid climate for providing cooling and comfort to the animal. Apart from shifting animal to shaded airy place, fans or dairy fans and different types of coolers can also be installed for making the place airy. Air movement increases the rate of heat loss from animal’s body surface, only as long as the air temperature is lower than the animal’s skin temperature.
Evaporative Cooling: For this, various cooling systems have been developed such as holding-pen cooling, exit-lane cooling, and free-stall cooling. These systems are applicable for the animals maintained in covered pucca sheds. An evaporative system which uses water mist with fan is more effective and economises water use in comparison to repeatedly bathing the animals. Some farmers prefer sprinklers or mister, installed on the roof or at various places in the barn. The use of a combination of evaporation and air movement such as ‘mist fans’ are more effective, economical and useful than fans and wetting alone. Water sprinklers generate a large volume of waste water.
Feeding strategies in hot environment
There are several key areas of nutritional management which should be considered during hot weather. These include special formulation to account for reduced dry matter intake with corresponding greater availability of key nutrients and to compensate for dietary heat increment while avoiding nutrient excesses. The energy requirements of lactating buffaloes also increase under high temperature conditions, but this increase is apparently caused primarily by the increase in metabolic energy.
Water intake: Water is arguably the most important nutrient for buffalo during hot climate. Water intake is closely related to dry matter intake and milk yield, but regardless of the rate of increase, it is important that abundant water must be available at all times under hot conditions. Hot weather, declining dry matter intake and high lactation demand requires increased dietary mineral concentration. The primary cat-ion in bovine sweat is potassium. Sharp increases in the secretion of potassium through sweat occur during hot climatic conditions Alterations in mineral metabolism also affect the electrolyte status of buffalo during hot weather. So it important to supplement minerals during hot climate.
Night Grazing: Buffaloes kept in a shed maintain rapid heartbeat during the night. However, when the animals are allowed out into a pasture at night, these physiological responses decrease immediately. This is the result, both of a reduction in radiation heat from the surrounding buffaloes, as well as increased heat loss from the animal itself.
Feeding High-Energy Diets: Low-fibre, high fermentable carbohydrate diets lower dietary heat increment compared to high fibre diets. Although the metabolic energy of dairy buffaloes increases in a hot environment, heat stress depresses feed intake. For this reason, it is important to increase the energy content of the diet of dairy buffaloes, in order to maintain their energy intake under hot conditions. The heat increment, which is an internal heat stressor in hot environments, is lower in highly metabolizable diets. So it is imperative to use fatty feeds, or calcium salts of fatty acids, as the means of improving energy supply for buffaloes in summer. Buffaloes fed on such diets have higher milk yield, and a lower body temperature and respiration rate.
Feeding by-Pass Protein: Dietary protein degradability is also critical under heat stress conditions. It is well known that excessive protein intake increases heat production and decreases reproductive performance. However, the protein requirement of buffalo increases and dry matter intake decreases in a hot environment, consequently, the protein supplied to lactating buffaloes during summer is not always sufficient. By using fish meal, which is a by-pass protein, the milk yield and protein content of buffalo milk increases but the ruminal ammonia production decreases.
Genetic selection
There are many aspects of genetics that influence the animal’s response and endurance to heat stress. Accordingly, wide variations in the same are evidenced among different breeds of livestock. The maintenance of body temperature is heritable through characteristics like coat structure and color, sweating competence, low tissue resistance etc. So selection of animals through specific genetic markers for heat tolerance will help to address the problem of heat stress in buffaloes by identifying the heat stress tolerant animals.
Conclusion
In hot-humid climates, although buffalo attempts to acclimatize through physiological changes including cutting down on feed intake and heat production, but this does not come without sacrificing part of its productivity. In order to prevent this economic loss to the farmer, there is need to understand and effectively combat heat stress by minimizing its impact on animal body and its productivity. Over generations, continued genetic selection for improved dry matter intake and milk yield under adverse climates, will pave the way for producing buffaloes that are better equipped for heat tolerance. In the short term, there is no substitute to good management practices to ameliorate heat stress, which include nutritional management and infrastructure facilities for providing comfort to the animal in the event of harsh hot climate. There is little doubt that a buffalo shall repay the investment in due course of time through continued high milk productivity and maintaining good reproductive efficiency for higher life-time productivity.
Knowledge of new technologies and products for optimising profit from animal husbandry practices
Dr. Mayukh Ghosh, Dr. Thanesh Oraon, Dr. Rajesh Kumar
Advancement of scientific knowledge and industrial development has improved our livelihood with a continuous pursuit. Similarly, it has also enriched the animal husbandry sector through development of feed and other allied industries imparting more values to animal resources. However the quest to find KAMDHENU is still going on. The changes in animal husbandry practices using newer techniques and products have enhanced per capita animal productivity through better breed selection, management and nutrient supply. Knowledge on these aspects of recent trends, applications and products is highly essential for an animal husbandry entrepreneur for maximum production and cost reduction to maximise the profit in highly competitive global market. Due to WTO agreement, entire world has become one market now. So our farmers and entrepreneurs must apply recent products and advanced techniques to maximize output through cost-effective animal husbandry practices for sustaining in globally competitive market.
Ration cost is one of the major running cost in animal husbandry practices, accounts more than 50-70% of total running cost. Balancing of ration is essential to get maximum productivity from animals so that farmers can get maximum profit. Ration includes feed, fodder and other biological products which improve the nutritive worth of feedstuffs. Formulation of ration is always done by a veterinarian according to species, production and milk yield potential of an animal, its physiological status and local availability of feed and fodder at competitive prices. But in the process there are some limitations, as there is a maximum limit of dry matter which can be feed to an animal in a day due to its limited intake capacity. Sometimes it also happens that some feed contain anti-nutritive factors (ANF) but are available locally in abundant and cheap. Some feed materials may have good nutrition value but due to inherent physiology of animal it cannot utilise the same. The requirement of new products and formulations are also increasing because presently we are facing shortage of green fodder by nearly 60%, concentrate feeds by 64% and nearly 23% deficiency in dry fodder availability. Therefore there is continuous increase in price of animal feeds and fodders. So, the technologies which aid to maximise the profit by increasing the utilisation of available feed and fodder resources at cheap price are the need of the hour.
To withstand in this challenging scenario and enhance production from animals, we need to provide ration which give them all essential nutrient on one hand and also provide the supplementation which help animals to extract nutrients from feed and fodder and improve the digestibility, immunity and production of animal in a cost competitive manner. The supplements may not add extra nutritive value to animals directly but by increasing the nutrient availability, digestibility of taken ration, enhancing immune status or by other associated ways may increase the production of animal in the same amount of given ration. These supplements can be divided into following broad categories: 1. Mineral supplements, 2 Enzymes, 3.Antibiotics and probiotics, and 4. Hormones. In next few series we will discuss about applications, advantages and limitations of these supplements one by one. However it is strictly advised to take suggestion of a local veterinarian before using these products.
Enzymes: Enzymes are biological catalysts which accelerate chemical reactions or biological processes. All animals use enzymes to digest feeds. Pigs and poultry cannot digest 15–25% of the feed they eat, because the feed ingredients contain indigestible anti-nutritional factors that interfere with the digestive process and/or the animal lacks specific enzymes that break down certain components in the feed. Choice and application of enzymes depend upon ration type and animal. Animals reared by farmer can be broadly divided into two types according to their digestive system one monogastric like pig, chicken, dog, duck and other birds and second ruminants like cow, buffalo, sheep, goat etc. Their feeding need and habits are entirely different from each other so supplementation of enzymes also varies accordingly. These enzymes in our country are manufactured by numerous companies at cost competitive prices.
Monogastric animals: In monogastric animals enzymes supplementation is done either (1) to supplement endogenous digestive enzyme for fast and better digestion, (2) to release of available phosphorus from phytate in feed, (3) to improve energy and amino acid availability in feed by removing encapsulating effect of the cell walls, (4) solubilisation of cell wall, non-starch polysaccharides (NSP), (5) hydrolysis of certain types of carbohydrate-protein linkages and therefore improved availability of amino acids, and (6) elimination of the anti-nutritive properties of certain dietary components,
1. Phytase: it is the enzyme which increases the bioavailability of phosphorus from feed. Feed generally contain 15-20% of phytate Posphorus in poultry and pig feeds. Giving phytase @500-1000 (FTU/kg feed) in general increases phosphorus availability upto 50% from same feed and thus better the FCR (feed conversion rate to meat/mass). The phosphorus is essential for formation of bone and egg production. Application of phytase in pig also reduces the cost nearly by 3% in pig.
2. Non-starch polysaccharides (NSP) enzymes: In plant based feed starch is major source of energy in monogastric animals. But feed also contain non-starch based energy sources which are not effectively utilised by the monogastric animals. Monogastric animals do not produce digestive enzymes to degrade NSP. Supplementing enzymes which make these non-starch based energy sources available to the animals will lead better utilisation of same feed, and provide more energy for growth and production in low cost. In addition this will decrease the management problems related to sticky droppings in poultry which is predisposing factor of many diseases like coccidiosis and other problems. Cellulase, Xylanase and Glucanase are example of such enzymes. Adding Xylanase and Glucanase enzyme @500 and 2000IU/kg feed can improve the feed conversion ratio (FCR) upto 1.5 to 7% and daily body weight gain upto 15%. The effect also depends upon the type of feed. In feed with high cell wall content will produce more effective yield (like the effect will be more pronounced in feed containing wheat which is rich in cell wall content than corn having low cell wall content). Further it had been found more effective in aged birds (layer) than younger ones. As a thumb rule β-glucanases are typically used in barley- and oat-based diets, whereas xylanases traditionally recommended for wheat-based diets. Cellulose is used in all class of plant feed having grain as major components. Addition of xylanase in older pig causes upto 11% efficient digestion of protein component of pig feed. They application of these enzymes depend upon type of feed in pig also, as enzyme supplementation have little positive effect in wheat grain and maximum effect in feed rich in bran. Application of carbohydrases (Cellulase, xylanase, glucanase, amylase, mannanase etc together) in pig also reduces the cost nearly by 8 % in pig husbandry.
3. Amylase: Cereal grains have an undigested starch fraction between 2%-8% at the terminal ileum while it is upto 19-28% in legume grain. Any increase in efficiency of the digestion of this starch will directly increase the bioavailability of starch which in turn yields better growth or production from same feed. Amylase enzyme is used for digestion of starch. These kind of ingredients like Corn and sorghum grains are predominant in Poultry feed. Amylase in poultry feed is mixed to about 800-1800 IU/kg of feed. Supplementation improves daily gain by 3 to 9.4% and feed conversion by 4 to 5%. It also plays important role in digestion of protein as carbohydrases improve the digestibility of cysteine compared to that of methionine in complete broiler diets by breaking carbohydrate-protein linkages. The carbohydrase can improve the overall digestibility of proteins upto 16% also.
4. Protease: Poorly digestible protein strongly decreases feed intake and body weight gain of broiler chickens. Proteases are used both in pig and poultry feed. They are protein digesting enzymes and increases the amino acid availability to animal from feed which is essential for growth and production. Proteases are of various types whose selection depends upon types of ingredients present in ration and age of the animal to be fed. Generally protease is added @ 200-300mg/kg feed. Protease along with amylase can lead to extra body weight gain in range of 5-15% in poultry, depending upon the type of feed. Supplementation of protease can increase the feed conversion efficiency upto 14% and hence lead better growth in pigs. Protease supplementaion yielded more pronounced effect on pigs of older group (60-90 day old) than younger ones (30-60 day old). Piglets fed with acid protease may gain more weight. Apart from direct effect, it shows indirect positive effect as it reduces the instance of E. coli count in poultry and allergen susceptibility in pig and lead to better health and survivability.
5. β-mannanase: Soybean meal, palm kernel meal, copra meal, sesame meal and guar meal based feed contain more mannose which prevent the proper digestion of such feeds to animals. Supplementing mannanase along with other enzymes help in better utilisation of these feeds. Soybean and guar meal are present in abundance and cheap in Madhya Pradesh and Rajasthan, are commonly used for preparing animal feed. They have various ANF like soybean agglutinin, proteinase inhibitors, urease etc. in soybean and β-mannan, saponins, trypsin inhibitors etc. in guar meal which are having negative effect in animal health and performance. Harmful effect of these ANFs can be reduced by enzyme addition and feed containing these ingredients can be used as cheaper source of feed for monogastric animals. It may be given at the rate of 1.5 to 110 million unit/ton feed depending upon feed content. This may lead to 3 to 6% improvement of FCR and upto 7% growth in poultry. Similar improvement by enzyme supplementation has been observed in swine in various form of diet like corn-soya based diet.
Pectinase : Pectinase is a term used for a class of enzymes that break down pectin, a cell wall polysaccharide of plants, functions in ripening process of fruits. Positive utilisation of feed has been found on application of pectinase in pectinase for full-fat canola seed or flaxseed based diet when it is supplemented @50-100 unit/kg diet.
Source, rate and method of proper mixing of these enzymes in feed is essential to get maximum benefit. So it is advisable always that feed formulation along with these enzymes must be done with the help of local veterinary personnel. This is essential because proper selection and mixing reduces the feed cost and the composition of same feed ingredient varies according to geographical location where it has been grown.
Ruminants: The ruminant production system is dependent on forage as main nutritional component. Forages (grass, rice and wheat straw etc.) are subjected to microbial digestion in the ruminant gut. The microbial mode of digestion allows ruminants to better unlock the unavailable energy in the plant cell wall components than other animals. In spite of that only 10 to 35% of energy intake by feed is available as net energy. This is because the ruminal digestion of plant cell walls is not complete. Mostly cellulase and hemicellulase are used in ruminants as major fibrolytic enzymes to improve fibre digestibility. Fibre rich fodders (rice and wheat straw, grasses etc.) are major component of ruminant ration hence increasing fibre digestibility increase the intake of digestible energy by the animal. As a result, less feed is required to produce per kg of milk or live weight gain or, alternatively, more milk or weight gain results per kilogram of feed consumed by the animal. These enzymes help in increasing dry matter intake (DMI), average daily gain and milk production of dairy cows. Supplementation of enzymes are most effective when added to diets fed to high producing ruminants with high energy requirements. The use of exogenous fibrolytic enzymes (EFE) to enhance quality and digestibility of fibrous forage is on the verge of delivering practical benefits to ruminant production systems. Exogenous feed enzymes are produced mainly from four bacterial (Bacillus subtilis, Lactobacillus acidophilus, L. plantarum, and Streptococcus faecium, spp.) and three fungal species (Aspergillus oryzae, Trichoderma reesei, and Saccharomyces cerevisiae spp.). The use of exogenous feed enzymes that are capable of breaking down carbohydrate linkages increase availability of nutrients such as starch, protein and fats etc. Enzyme feed specificity is one of the most important factor which reflects the effective enzyme application level such as:
1. Direct hydrolysis of the feed 2. Enhancement of microbial attachment 3. Changes in gut viscosity 4. Complementary action with ruminal enzymes 5. Improvement of nutrient digestion
In this regard, cellulases and xylanases are respectively amongst the two major enzyme groups that are specified to break joining of sugar molecules of cellulose and xylans found in plant cell wall components.
1. Fibrolytic enzymes (Cellulase and hemicellulase): Cellulose is most important component of grass and straw based fodder and is major source of energy to the animal for growth and production. Full digestion of cellulose can provide animal more energy for growth and production. For digestion of cellulose, cellulase enzyme is used. Maximum positive effect of this enzyme is found in early lactation followed by mid lactation. In early lactation milk yield can increase upto 15% while in mid lactation the increase can be upto 8% and DMI increase upto 8-12% . The fibrolytic enzyme is added @1.5-3.5ml/kg feed or cellulase enzyme at the level of 150 g/ton of forage.
2. Xylanases and β-glucanase: Xylan and glucuronic acid digestion in straw is essential for release of more cellulose for microbial digestion. This process is generally done by microbial Xylanases and β-glucanase but by adding these enzymes in feed will improve their digestion process more effectively. These enzymes help in breaking of bonds and release more energy substrate for growth of animals. It can be sprayed onto hay during cubing @1 or 4 g/kg DM, onto forages @2 to 5 L/ton forage, to concentrate @1.4 L/ton concentrate for optimum xylanase activity and feed digestion. Its supplementation with cellulase increases the body weight gain in high forage diet, but not so effective in high concentrate diet. In high yielding animals milk yield can increase upto 10% on supplementation and the effect is more pronounced in high forage diet.
3. Ferulic acid esterase: lignin and phenolic acids are inhibitory to the biodegradation of plant cell wall polysaccharides present in poor quality forage. Poor-quality forages like rice and wheat straw digestion can be enhanced by using these polysaccharidase enzymes. During silage feeding lactic acid bacteria which have ferulic acid esterase activity can be inocoluated , at the rate of about 10,000 lactic acid bacteria, so that indirectly administering the enzyme without additional cost.
4. Protease: It is generally used @1 -2 ml/ kg diet or 150-250g/ton concentrate. Protease activity and improvement in fibre degradation appears to depend upon the type of protease. Amylase and protease in high concentrate diet increases milk yield upto 10%.
5. Amylase can be obtained by mixing powdered Aspergillus oryzae, and is important when animals are fed on dry, cracked maize, steam-rolled maize and minimally processed barley grain kind of diet. Feeding of the powder @ 0.4 g/kg in high concentrate feed leads to 5% improvement in milk yield.
6. Phytase: Phytate, the principal form of phosphorus in plants, is not fully utilized by non-ruminants, and the resulting excretion of phosphorus contributes to phosphorus pollution. In contrast, the rumen is a source of highly active phytases, and thus ruminants can use phytate as a source of phosphorus.
Enzymes are used in combination to get maximum economic benefits. Furthermore, due to continuous shortage of feed of choice at optimum price, there is a diverging trend in animal growers to use the non-conventional feed or feed having some drawback as anti-nutritive factor but otherwise potentially very good source of nutrients. In these feeds along with other treatment enzyme supplementations can be very economical to remove their anti-nutritive factors in one hand and also increase digestibility and nutritivevalue to animals. Here are some examples of feed wise enzyme applications:
Soybean: Soybean yields 18.6% of oil and 78.7% of soybean meal with the rest being waste. The amino acid profile of soybean meal is close to that of fishmeal, except methionine corrected by using synthetic source of methionine in poultry feed, because of its high digestibility and metabolisable energy content compared with other vegetable fats/oils. But this high quality vegetable protein in animal feed cannot be fed raw because there are a number of anti-nutritive factors (ANFs) present that exert a negative impact on the nutritional quality of the protein. The main ANFs are protease inhibitors (trypsin inhibitors) and lectins can be destroyed by heat treatment. The trypsin inhibitors cause pancreatic hypertrophy/hyperplasia with consequent inhibition of growth, while lectins inhibit growth by interfering with nutrient absorption. .Apart from protease inhibitor and Lectins, it also contains other ANF like goiterogens, Anti-vitamin factors, phytate. These drawbacks can be overcome by applying heat treatment and enzyme supplementation of the feed containing soybean meal. It can be used as diet ingredient in various proportion in pigs (31%), broiler (27%), dairy cattle (17%), beef cattle (9%), layer (8%), aquatic (5%) and others (3%).
Wheat: It contains xylans that increases the viscosity of the gut material (digesta), thus reduces its full potential utilisations. This effect can be corrected by supplementing the diet with enzyme xylanases that digest xylans effectively.
Sorghum (milo) contains tannins that bind with various proteins, reducing their digestibility. Different sorghum varieties have different tannin levels, so the type of sorghum used in feed is important. Generally, the darker the outer seed coat of the sorghum variety, the higher the tannin content. Birds will refuse to eat grain with high levels of tannins. Protease and other enzyme supplementation can reduce this problem.
Barley contains moderate levels of trypsin inhibitors, but the major problem with barley is high level of beta-glucans. Similar to xylans, beta-glucans reduce the digestibility of nutrients. Again, the adverse effects of the beta-glucans can be reduced by using feed enzymes.
Canola meal contains sinapine, which causes problem only for brown-egg layers. When canola meal is used in the feed for these layers, the eggs have a fishy and offensive odour
Rapeseed meal: The utilization of rapeseed meal as a protein source in animal feed is limited due to the presence of glucosinolates.
However, potential use of enzyme supplementations is very high but it has its own limitation also. These are as follows,
1. Enzyme Activity- Many manufacturers make enzymes from different sources so the effectiveness of same enzyme with respect to your feed formulation can vary according to their source.
2. Enzymes are most active in a specific range of pH and temperature, so supplementation of enzymes should be done keeping in mind of pH of your feed formulations.
3. Enzyme needs adequate time to act on feed, so some enzymes are needed to be sprayed or mixed in feed 12-48 hour prior to feeding to get best result.
4. Not all enzymes are suitable for every kind of feed; depending upon feed composition you have to select best combinations of enzymes. A small indicative list of plants and respective enzymes applied is given in table.
So it is always advisable to get the help of qualified veterinarian and nutritionist to formulate combination of enzymes which suit to your animal and feed formulation in order to get maximum economical advantage. This can be done with the help of doctors in nearby veterinary hospitals and more appropriately by nutrition specialist from your nearby veterinary college or research centre. The application of enzymes in feed to get more efficiency from a given feed is more important now a days because of increasing price of conventional feed and fodder of animals. So any increase in efficiency of feed utilisation will reduce the cost of animal feeding thus enhancing the profit from animal husbandry practices.
Table: 1 list of plants containing anti-nutritive factors/nutrients and suitable enzymes applied to increase the digestibility
| Antinutrient/ nutrient | Major source | Problem | Enzyme used | commercial availability | Manufacturer | Dose rate |
| Phytates | All plant based feed and fodders | Decrease phosphorus availability | Phytase | Biophos-pFS | Neospark | @5-10g/kg feed |
| Exozyme-ps | @1g/10kg feed | |||||
| Fytazyme 2500 | Intercorp Biotech Limited | @2-3g/10kg in feed | ||||
| phytase2500 | Varsha Group | @1-3g/10kg feed | ||||
| Arabinoxylans | Fibre based plant and cell wall of plant | Decrease digestibility of plants | Xylanase, Arbinofurinosidase | Grozyme contains Amylase , galactosidase, ,cellulase, hemicellulose, lipase, pectinase, phytase, protease, xylanase, glucanase along with various probiotic | Zeus Biotech Ltd. | @10-20g/1000 birds/day |
| Glucans | In cereals like oats and barely | Decrease digestibility | Glucanase | Enziver contain Amylase , cellulase, pectinase, phytase, protease, xylanase, glucanase | Pfizer | @ 4-5 g/10kg feed |
| Mannans | Soyabean meal, yeast | Resistant to digestion | Mannanase | Ctczyme | CTC BIO INC. | @4-5g/10kg feed |
| Cellulose | All plant rich in fibre | Not digested by monogastric animals, largest source of energy for ruminants | Cellulase | Brozyme contain Amylase, cellulase, phytase, lipase, pectinase, protease, xylanase, glucanase enzymes and some probiotics | Zeus Biotech Ltd. | @4-6g mixed in 10kg feed |
| Synerzyme-P-FS contains Amylase, cellulase, hemicellulose, phytase, protease, glucanase | Neospark | @5-7g/10kg feed | ||||
| Starch | Cereal grains | Source of energy for monogastric animals, need full utilisation | Amylase | Anazyme-TM contain Amylase, cellulase, hemicellulose, lipase, pectinase, protease, xylanase, glucanase enzymes | Varsha Group | @10g/10kg feed or 10g/day/animal |
| Poultaze contains Amylase , galactosidase, cellulase, hemicellulose, lipase, pectinase, phytase, protease, xylanase, glucanase | zydus | @3-5g/10kg feed | ||||
| TT-Zyme contains Amylase , galactosidase, ,cellulase, hemicellulose, lipase, pectinase, phytase, protease, xylanase, glucanase | TTK | @5 g/kg feed | ||||
| Protein | Corn, milo, vegetable meals, legumes, beans oil-seed | Source of amino acid for animals, need full utilisation | Protease | Bvzyme contain Amylase ,cellulose, protease and xylanase enzymes | Venkys | @4-6 g/10kg feed |
| Lipid | oil-seed | need full utilisation | Lipase | Caplix bio feed contain Amylase, cellulase, hemicellulose, lipase, pectinase, phytase, protease, xylanase, glucanase enzymes | ventoquinol | @3-5g/10kg feed |
| Hemicellulose | Straw | need full utilisation | Hemicellulase | Enplus contain Amylase, cellulase, hemicellulose, lipase, pectinase, phytase, protease, xylanase, glucanase along with various probiotic | Novartis | @ 4-5 g/10kg feed |
| Pectin | Bean and plant fruits | Decrease digestibility | Pectinase | Enpowervet contain Amylase, cellulase, hemicellulose, lipase, pectinase, phytase, protease, xylanase, glucanase along with various probiotic | Iris | @ 4-5 g/10kg feed |
Use of Hormones to increase the productivity from Animal Husbandry
Dr. Mayukh Ghosh, Dr. Thanesh Oraon, Dr. Rajesh Kumar
Hormones: Hormones are chemical messengers produced and released by endocrine glands, transported through body fluids to act on specific target organs or tissues of animal body. These chemicals are essential for communication between tissues and organs to regulate several important biological functions like metabolism, growth and development, production and reproduction, stress responses including behavioural activities of animals. Any defect in hormonal level either excess or deficiency, may lead to disease and hamper the normal physiology of animals. Now a day after advancement of knowledge about hormonal functions apart from their applications as drug for disease treatment, they are also used for faster growth, better production and reproduction purposes. However inappropriate or indiscriminate use of hormones and antibiotics for enhancing productivity can be very dangerous for both animal and human life. Excess or inappropriate use of these chemicals can make animals infertile or very susceptible for other diseases. Not only this, but also it may lead to deposition of hormonal or antibiotic residues in meat (residual effect) and their secretion in milk or other animal products which is ultimately used for human consumption. As animal products like milk, meat and eggs are used by human for regular consumption so unknowingly human also consume these hormones and antibiotics along with them. This may lead to many diseases like cancer, infertility or predisposes human susceptible to other diseases. So these hormones and antibiotics must be applied very judiciously following proper guidance of veterinary doctors. Not only this after administration of these products, before final consumption, animal must be given minimum withdrawal time (time before which administration of drugs must stop) as per guidelines, which is generally 7days for milk and 45 days for meat. All government guidelines must be known by farmers and entrepreneurs regarding this, and must be followed strictly in public interest. Similarly, during purchase of animal feeds, buyer must ensure information regarding hormone supplementation in the feed and take appropriate action according to law. For example hormone supplementation as drug or growth promoter must be stopped 45 day prior to culling of food animals which are reared for meat purpose. This 45 days withdrawal period helps animal to remove hormonal residues from its body. Similarly a minimum of 7 days withdrawal period must be given to milk producing animals before using such animal milks for human consumption.
Hormone applications may be profitable for farmers when used judicially and scientifically. Following are the applications of hormones which can help farmers to enhance productivity from animal farming.
1. Induction of lactation: In field condition it has been observed that some animals in a heard remain in reproductive problems like anestrum or repeat breeding for so long period that they ultimately become dry animals and uneconomical for the farmers. Farmers have to feed them for long time without any production benefit along with treatment cost which reduces overall profitability. Such animals after hormonal correction can be induced artificially to lactate, even though they have not given birth to new calf. This can render animals more profitable and animal husbandry sustainable for farmers. The application is more important in buffaloes because there is tendency of long anestrum period in these animals because of several factors including seasonal effect. It must be kept in mind that help of expert veterinarian must be taken to artificially induce the lactation. Normal estrogen and progesterone level in these animals should also be checked before starting hormonal treatment along with proper feeding. But all animals may not respond equally and positively to yield desired result.
In cattle with administration of estradiol 17-β and progesterone @0.1 and 0.25 mg Kg body weight/day/animal respectively divided into two parts and administrated twice daily for 7 days, additionally 2 mg reserpine twice daily from 9 to 12 days may start milking on 10th days. This can provide upto 50-80% of peak milk yield of animals. Simultaneously chance of estrous is also seemed to be not affected. Second induction of lactation may be possible only by short administration period for 3 days only and average milk yield may be upto 3 to 9 kg/ day depending upon diet, breed and response of animal to treatment.
Buffalo and its heifer having reproductive problems can also be induced artificially to lactate. Administration of estradiol 17-β and progesterone @0.1 and 0.25 mg Kg body weight/day/animal subcutaneously, divided into two parts and administrated twice daily for 7 days may start lactation after 14-20 days and can yield milk upto 700 kg in 200 days lactation period. Different combinations which can be used for this purpose is given in Table.1. However it must be noted that animals must be treated by expert veterinary doctors for this purpose along with supply of balanced nutrition as per expected yield. Initially milk will be slightly yellow which become normal in next one week. First week milk should be discarded.
2. Oxytocin Injection for milk let-down: Oxytocin can induce milk let-down by contraction of smooth muscles of the udder if is in the proper physiological state. But use of this drug is restricted as per law neither by nor on the order of a licensed veterinarian due to health hazard by its residual effect in milk. However, it can be used in conditions like to precipitate labour and induce normal parturition, for postpartum evacuation of uterine debris, for postoperative contraction of the uterus after cesarean section and controlling uterine haemorrhage etc. in consultation of a veterinary clinician. It should not be used to treat dystocia due to abnormal presentation of the foetus until correction is made.
3. Growth promoter: Hormones can be used as growth promoter in animals reared for meat purpose. Before administration of these hormones, farmers must know local rule and regulations along with rule of the country where it is intended for export if any. These growth promoters can be administered as implant or given in feed as supplement. The hormones 17β-estradiol, progesterone, testosterone, zeranol, trenbolone and melengestrol acetate (MGA) promote growth in cattle/ buffaloes. These compounds must be given with extra care and farmer not willing to use such compounds must ensure that concentrate they are buying are free from such hormone supplementations. When given in excess, these hormones have adverse developmental, neurobiological, genotoxic and carcinogenic effects on people who consume them, either via the parent compound, or via metabolites. Implants of 20-30 mg estradiol-17β and its combination with other hormones like progesterone can lead to nearly 10-25% extra body weight gain in calf. Similarly, the lean/fat ratio in male castrated and female pig carcasses may be increased by the use of oestrogen/androgen combinations. There is a list of combinations of hormones given in table 2 used for animal growth.
4. Estrous synchronisation: Estrous synchronisation means making all mature female animals to come in estrus at a time by application of hormone or other method. This may also be helpful to treat anestrous animals to let them come in heat. Apart from this, it may also produce more successful response by animals to artificial induction of lactation. Estrus is the time when animal become receptive to male so that successful pregnancy happen. This is more commonly practiced in cattle and buffaloes but can also be used in sheep and goat. Estrous synchronisation may be done by administration of hormone PGF2-alpha alone or along with other hormones like gonadotrophin releasing hormone (GnRH) or progesterone. GnRH is sometimes also replaced by estrogen. The selection to choose combinations depends upon physiological condition of animal and cost effectiveness of the treatment. This hormonal treatment is also beneficial for herd management, as estrous synchronisation of all animals in a herd can reduce the management expenses, helps to plan offsprings in better way, and reduces the medical and other associated costs. For example if a farmer have 20 animals in his herd and 14 are open, then synchronisation of estrus will help to come all animals in heat at a time. This will lead to insemination of all animal on nearly same day and reduce the doctor visit cost, similarly when they become pregnant then management of feeding and other care like immunisation etc. will be easy, and this also will reduce cost in terms of drug wastage, feed procurement, doctor visiting cost, man-power rationalisation, cost associated with birth of calf etc. This reduction of cost ultimately will lead to increase in profitability from animal husbandry practices. Further, farmers can also time the season or month of calving as per their convenience. Another benefit is that cow nutrition can also be improved by grouping cows according to stage of gestation and feeding each group accordingly and nearly all calves will be of same age and weight, so their management will also be easy. There are several protocol for estrous synchronisation like, prostaglandin used alone in cattle during the late stage of the luteal phase (11 to 15 day of the estrous cycle), success rate is higher than those injected in the early part (6 to 9 day) of the luteal phase. However it must be kept in mind that if protocol is for heifer, it must have gained 50-60% of adult body weight, while in case of cow the body condition must be very healthy and should have 50 days Post-Partum period or have shown anestrum for more than 50 days. Controlled internal drug release (CIDR) technique can also be used for this purpose. In this technique progesterone or related hormone is implanted near ear or in vagina of the animal. In general CIDR®-PG protocol is recommended in heifers in contrast to the Select Synch+ CIDR®protocol in cows, however it depends on animal condition so doctor itself have to decide it. In Select Synch+ CIDR®protocol, GnRH is given on day 0 and then day 7 of CIDR followed by administration of PG on 7th day. Then heat is detected and artificial insemination (AI) is done between 7th to 13th day. While in CIDR®-PG, only 7 day CIDR implant followed by administration of PG on 7th day is recommended. Then heat is detected and AI is done between 7th to 13th day. To understand benefit in simple words, normally animal shows 3 cycles in nearly 66 days so we can get only 3 chances of service for the animal while if we apply estrus synchronisation we can get minimum 4 chances to AI the animal.
Apart from, other hormone like growth hormone is used for enhancing milk production in other countries like USA but presently is not allowed in our country.
Application of antibiotics: Antibiotics are those chemicals/ drugs which are used to kill or prevent the growth of microorganisms like bacteria, protozoa, etc. Antibiotic are applied for two purposes a) Therapeutic purpose and b) As growth promoter in animal feeds.
a) Therapeutic purpose: Numbers of antibiotics are administered either by oral or parenteral route for treatment of animals against infectious diseases depending upon the type of bacterial or protozoal infection. The choice of drug and its proper dose also depends upon species and age of the animal, body weight, pregnancy status, duration of infection and so many factors. So, only a veterinary doctor can judge the type and dose of an antibiotic to be used in a particular condition. Farmers must be aware of the severe consequences of improper and under dosing of antibiotics leading to emergence of antibiotic resistance globally which renders the antibiotic ineffective to treat the animal in future. Further clinicians prefer to use alternative antibiotics in one geography for same disease to avoid drug resistance. So, any antibiotic must be solely used after consultation with a skilled veterinary doctor, and adequate care should be taken to avoid drug resistance. However the under mentioned guidelines should be followed for good antibiotics therapy practice
1) The minimum course of antibiotics should be completed as prescribed by clinician to avoid under dosing and development of antibiotics resistance.
2) Disc diffusion test can be performed to decide proper antibiotics as per their sensitivity toward the causative microorganism.
3) Use of specific antibiotic or monotherapy is advisable to avoid side effects or antibiotics resistance.
4) Antibiotic hypersensitivity can be tested to know whether the drug is suitable for the patient or not.
5) Antibiotics like Metronidazole, Chloramphenicol, Aminoglycosides and Tetracyclines etc. are contraindicated in Pregnancy. Thus these drugs should be avoided in pregnant patients. Pregnancy safe antibiotics like Penicillin, Amoxicillin, Ampicillin, Clindamycin etc. can be used in that condition.
6) The antibiotic left over in the vial after use should be discarded and never store it for future use.
7) Prolonged antibiotic therapy can damage ruminal or intestinal microbes leading to gastro-intestinal disorders. Ruminal card transplant or probiotic therapy can be done to restore the eco-friendly bacteria of gastro-intestinal tract.
8) Prevention is better than cure. Thus proper vaccination schedule should be followed according to the guidance of a veterinary doctor to keep the animals free from microbial diseases and avoid antibiotic therapy.
b) Antibiotic Growth-Promoters: This can be termed as application of antibiotics at a low, sub-therapeutic dose in feed formulations to inhibit bacterial growth or kill micro-organisms. Antibiotic growth promoters are used to “help growing animals digest their food more efficiently, get maximum benefit from it and allow them to develop into strong and healthy individuals”. Although the mechanism behind their action is ill-defined, it is assumed that the antibiotics help to control the growth of certain intestinal bacterial population and divert the lost energy of microbial fermentation towards growth of animal. Although the practice of using antibiotics as growth promoter has been shown to be effective in food animal farming but associated with the risk of evolution of antibiotic resistance among microbial populations which renders the antibiotic ineffective in future antimicrobial chemotherapy. Apart from treatment of animals, it also creates health hazard to the human population who use to consume those food animals or animal products bearing the residual antibiotics came from antibiotic growth promoters. So farmers must avoid use of antibiotics for growth promoter in animal feeds and only use them for treatment purpose or prophylactic purpose. Moreover, the use of antibiotics and associated chemicals when needed must be done in consultation of a veterinary doctor. Thus an effective alternative is required to substitute or ban the use of antibiotic growth promoters which can enhance the efficiency of feed conversion and improve the growth of animals. It has been observed that the effects of antibiotic growth promoters are more distinct in sick animals and those maintained in overcrowded, unhygienic conditions. So, proper hygiene, management and healthy environment can reduce the requirement of antibiotics as growth promoters. Simultaneously feed supplementation with suitable enzyme additives or adding friendly microbes in animal feed or probiotics can increase the digestibility of feeds to improve animal growth and substitute the use of antibiotic growth promoters. Also it must be followed strictly that if antibiotics are used in any purpose, proper withdrawal period must be given before consumption of the animal products.
So in conclusion apart from treatment of diseases, antibiotics and hormones can be applied to obtain better profit by farmers and entrepreneurs. Judicial application of these chemicals under surveillance of veterinary doctor can enhance profitability of farmer without side effect on animal and human health. Although, government do not encourage the use of these drugs as feed additive, but it had been seen that some of large entrepreneurs and feed mills are using it as feed supplement to gain profit. So government must make and implement law strictly to prevent the misuse of such drugs by these rich people. If government is really serious on the issue then it must amend law to make mandatory discloser for all commercial feed manufacturers that their feeds are free from hormone, antibiotics or if they have added then in which product and in what amount. Otherwise this will be a discriminating step to allow profit to the big entrepreneurs whereas the small and marginal farmers will be the sufferer and may not be able to sustain in highly competitive market.
Table 1. Use of hormonal combinations for induction of lactation
|
Treatment protocol |
Milking start |
Milk yield |
|
estradiol 17-b and progesterone @ 0.1 and 0.25 mg/ Kg body weight/ day / animals subcutaneously, divided into two parts and administered twice for 7 days followed by 25 mg hydrocortisone acetate on 19 to 21 day |
21 day onward |
3-9 kg |
Table 2. Hormonally-active substances used in animal production
|
Substances |
Dose levels |
Form |
Main use – Animals |
Trade name |
|
Oestrogens alone: |
|
|
|
|
|
DES(diethylstilbestrol) |
10–20 mg/day |
feed additive |
steers, heifers |
|
|
DES |
30–60 mg/day |
implant |
steers |
|
|
DES |
|
oil solution |
veal calves |
|
|
Hexoestrol |
12–60 mg |
implant |
steers, sheep, calves |
|
|
Zeranol |
12–36 mg |
implant |
steers, sheep |
Ralgro |
|
Gestagens alone: |
|
|
|
|
|
Melengestrol acetate |
0.25–0.50 mg/day |
feed supplement |
heifers |
MGA® 100/200 Premixes; MGA® 500 Liquid Premix |
|
Androgens alone: |
|
|
|
|
|
TBA |
300 mg |
implant |
heifers, culled cows |
Finaplix |
|
Combined preparations: |
|
|
|
|
|
DES + |
25 mg |
|
|
|
|
DES + Methyl-testosterone |
|
feed additive |
swine |
Maxymin |
|
Hexoestrol + |
30–45 mg |
|
|
|
|
Zeranol + |
36 mg |
|
|
|
|
Oestradiol-17β + |
20 mg |
|
bulls, steers |
|
|
Oestradiol-17β benzoate + |
20 mg |
|
|
(Synovex H |
|
Oestradiol-17β benzoate + |
20 mg |
|
|
(Synovex S |
Table 3. Currently available implants, active ingredients and concentrations.
|
Trade Name |
Active Ingredient |
Concentration (mg) |
Marketer |
|
Ralgro |
zeranol |
36 |
Schering-Plough |
|
Ralgro Magnum |
zeranol |
72 |
Schering-Plough |
|
Synovex-C |
estradiol benzoate progesterone |
10 100 |
Ft. Dodge |
|
Component E-C |
estradiol benzoate progesterone |
10 100 |
Vetlife |
|
Synovex-S |
estradiol benzoate progesterone |
20 200 |
Ft. Dodge |
|
Implus-S |
estradiol benzoate progesterone |
20 200 |
Pharmacia-Upjohn |
|
Component E-S |
estradiol benzoate progesterone |
20 200 |
Vetlife |
|
Synovex-H |
estradiol benzoate testosterone propionate |
20 200 |
Ft. Dodge |
|
Implus-H |
estradiol benzoate testosterone propionate |
20 200 |
Pharmacia-Upjohn |
|
Component E-H |
estradiol benzoate testosterone propionate |
20 200 |
Vetlife |
|
Compudose |
estradiol |
25.7 |
Vetlife |
|
Encore |
estradiol |
43.9 |
Vetlife |
|
Finaplix-S |
TBA |
140 |
Intervet (Hoechst Roussel) |
|
Component T-S |
TBA |
140 |
Vetlife |
|
Finaplix-H |
TBA |
200 |
Intervet (Hoechst Roussel) |
|
Component T-H |
TBA |
200 |
Vetlife |
|
Revalor-G |
TBA estradiol |
40 8 |
Intervet |
|
Revalor-S |
TBA estradiol |
120 24 |
Intervet (Hoechst Roussel) |
|
Component TE-S |
TBA estradiol |
120 24 |
Vetlife |
|
Revalor-H |
TBA estradiol |
140 14 |
Intervet (Hoechst Roussel) |
|
Synovex-Plus |
TBA estradiol benzoate |
200 28 |
Ft. Dodge |
|
Revalor 200 |
TBA estradiol benzoate |
200 28 |
Intervet (Hoechst Roussel) |