Ram Singh Bibyan, Pramod Kumar, Sarita Kaushal, Antra Gupta, Vibhore Aggarwal, Jannat Saini, Priyanka Patir, Lovely Anant and Prajakta Kailas Sangale
India possesses 57% of the world’s buffalo and 16% cattle, having 13% of the global livestock population (FAO, 2013). Buffalo is prominent in Haryana, Punjab, Gujarat, UP and AP, where it contributes between 54-85 per cent to total milk production and is important contributor to rural household incomes. Nutritional management during transition period is extremely important to achieve not only maximum milk but also reproduction from the ensuing lactation.
Transition period: In buffalo, transition period is the most important stage during which there is change from one state to another. The transition period is often considered from 3 weeks pre-partum to 3 weeks post-partum where buffalo transit from non-lactating state to lactating state. During this period many essential processes undergo within the body of dairy animals preparing for the next lactation. The dry period, and in particular the late dry period, should be considered a critical period in which the quality of all inputs will directly impact the productive performance in the next lactation as well as the incidence of disease associated with calving and buffalo health. Various physiological, metabolic and hormonal changes occur during the transition period for metabolic adaptations required for the growth of the foetus and onset of lactation. There is dramatic change in nutrient needs that necessitates coordination of metabolism to meet requirements for energy, glucose, amino acids and calcium by the mammary gland following calving.
Reduced feed Intake: The most important physiological changes are the reduction in dry matter intake (DMI) around parturition and increase in nutrient requirements for the rapidly growing foetus and milk production. However, the reduction in DMI varies with the breed of the animals, quality of ration, stage of lactation, parity, body condition score (BCS) of animals and also the environmental temperature. The DMI declines during the last 3 weeks of gestation and can be up to 30-35%, especially in subtropical area, where the summer temperatures usually reach 35°C during the day time. About 89% decline in DMI occurred at 5-7 days before calving in Holstein cows. Reduction in DMI in transition Murrah buffaloes was also reported which ultimately recovered after few days of parturition. These changes occurring in the transition buffaloes further modify her metabolism drastically. During the last trimester of pregnancy, the growing foetus occupies larger part of abdominal cavity which reduces the volume of rumen resulting in decreased DMI. Proper feeding management during this period regulates both milk production in the proceeding lactation as well as the reproductive efficiency of the animal.
Body condition score (BCS): Most of the dairy animals at the onset of lactation experience negative energy balance (NEB) due to reduced DMI and increased milk production. So, excessive mobilization of body lipid stores take place to support synthesis of milk and milk fat and increased amounts of non-esterified fatty acid (NEFA) are released into the circulation, the level of which increases gradually in the transition prepartum period, resulting reduced BCS, rumen fermentation and milk production. Dairy cows that are over conditioned (BCS>4.0), have a much greater reduction in their feed intake immediately pre-calving, compared with cows with a lower BCS.
Increased nutrient requirements: Parturition leads to an increased (2.8, 4.7 and 2.0 times more glucose, fatty acids and amino acids, respectively) demand of nutrient requirements by mammary gland especially for synthesis of milk lactose, fat and protein, which were at lesser need at prepartum for foetus. Therefore, there are challenges to the animal to meet these requirements. Immediately after calving, the demand of glucose for lactose synthesis increases to match the rapidly increasing milk production. In Holstein cows, the mammary requirement for energy was reported to increase three times at 4th day of lactation than that of the gravid uterus. The transition dairy animals suffer a NEB postpartum due to rapid increase in milk production which reaches its peak at 5-6 weeks, however feed intake continues to lower up to 12-14 weeks. The propionic acid produced in the rumen during the fermentation of dietary carbohydrates is the major precursor of glucose in the liver. In a study with Holstein cows, the foetus uses 46% of maternal glucose taken up by the uterus in the last weeks of foetal development. Glucose demand in Holstein cows has been estimated at 1000-1100 g/d during the last 21 days of gestation, but it increases sharply after calving to approximately 2500 g/day at 21d postpartum. Therefore, the shortfall of glucose requirement is covered from gluconeogenesis from body fat mobilization, muscle protein, amino acids, lactate and glycerol, subjecting the liver for a great challenge. The muscle protein mobilization increases threefold during the first week after calving compared with prepartum values; fat mobilization is 300%. Other body tissues also adapted to the reduced availability of energy. Glucose is also an important energy source for the ovary, and its reduced availability in the beginning of lactation can negatively impact the reestablishment of ovarian activity after calving, which affects the subsequent production. About 900g metabolizable protein (MP) is required per day during late pregnancy in Holstein cow and heifer. About 120 g MP/d is required for an increased synthesis of mammary tissue, resulting in an overall predicted requirement of between 1000 and 1100 g MP/d. Therefore, supplementation of dietary proteins especially rumen undegradable protein (UDP) is required to meet out these requirements. However, feeding of high protein with more degradability (RDP) could be detrimental to animal, and may result in decreased milk yield and delay in both follicular development and luteal function in cow. Feeding of excessive RDP also resulted in elevated blood urea nitrogen (BUN), and elevated milk urea nitrogen (MUN); affecting the uterine pH in heifers, which has been associated with reduced fertility. The excess ammonia and elevated pH levels in the rumen causes Ca2+ and Mg2+ to form insoluble complexes with phosphorus making them unavailable for absorption encouraging both hypocalcaemia and hypomagnesaemia, which causes parturient paresis immediately after parturition in cows Existing feeding standards recommend additional allowance 20 and 10% of maintenance requirement, respectively for immature buffaloes in first and second lactation for maternal growth. Micronutrients viz. minerals and vitamins are essential for mammary gland development, growth of the developing foetus, and support of the antioxidative and immune functions. The mammary requirement for calcium to produce colostrum on the day of parturition is more than double than that for foetal growth in late gestation. The onset of lactation places such a large demand on mechanisms of calcium homeostasis that most cows develop some degree of hypocalcaemia at calving. In some cases, concentrations of plasma calcium become too low to support nerve and muscle function, resulting in parturient paresis or milk fever. Adaptations to increase the blood supply of calcium very soon after calving include increased intestinal active transport, increased resorption of bone stores and decreased urinary excretion of calcium.
Health disorders coupled to transition period: The transition changes favour the occurrence of health problems. The main disorders occurring during the transition period are fatty liver, ketosis, sub-acute and acute ruminal acidosis (disorders related to energy metabolism); milk fever, sub clinical hypocalcaemia, udder oedema (disorders related to mineral metabolism), abomasal displacement, metritis, and poor fertility which leads to major complicating factors for subsequent reproductive performance, resulting additional economic loss. Poor transitions also result in milk income losses through lowered peak yield. Moreover, the diet of most dairy animals changes sharply at calving from being mainly forage-based to concentrate-rich diets with high level of fermentable carbohydrates, the amount of VFAs produced exceeds the capacity of the rumen to absorb them, leading to decreased pH in the rumen environment. This situation leads to the phenomenon known as rumen acidosis and contributes to reduced DMI and feed digestibility in the early postpartum period. The increased level of NEFA (>0.3 meq/l) in the circulation due to NEB during the transition can be oxidized either completely to carbon dioxide to provide energy to the liver or incompletely, resulting in the formation of ketone bodies (>1200 µmol/l, BHBA concentration) causing a metabolic disorder, ketosis. The liver also re-esterifies NEFA into triacylglycerol (TAG). To release TAG from the liver, it is packaged into very low density lipoproteins (VLDL). Fatty liver develops when the liver uptake of lipids exceeds the oxidation and secretion of lipids by the liver. Excess lipids are stored as TAG in the liver and are associated with decreased metabolic functions of the liver. Raised blood ketones are associated with a 3-8 times increased risk of a displaced abomasums, double the risk of retained placenta, three times risk of metritis and six times increase in the risk of developing cystic ovaries. Subclinical ketosis causes reduction in milk yield, lowered fertility and longer to return to oestrus.
Nutritional strategies during transition period:
Improvement of voluntary intake: Maintenance of feed intake in transition buffalo, especially just after parturition is very important to minimise chance of health disorders and improvement in performance. The feed additives viz. yeast extracts and flavouring agents could be used to improve feed intake in ruminants. Recently, phytogenic substances such as essential oils, herbs, spices etc are being used to improve intake and milk production in bovines. Feeding of composite feed additive to lactating Murrah buffalo during 30d of lactation was reported to improve feed intake.
Dietary Energy-Protein Manipulation: Energy and protein are required for the maintenance, growth, and reproduction and production performance of animal. It is demonstrated that high fibre diet during the dry period decreases the size of the rumen papillae, which are responsible for the absorption of end products of digestion in the rumen. On the introduction of high energy diet after calving, the size of rumen papillae increases, resulting in higher and faster absorption of nutrients. But, if a diet rich in soluble carbohydrates and low in fibre is offered few days prior to calving, the desired papillae size can be achieved immediately after calving. The diet of such cows must provide the required 10 MJ ME/kg DMI with 16% CP. Daily requirement of ME (Mcal) of 29.76 and CP (g) of 1460 for buffalo having 500 kg BW with 10 litre (7% fat) of milk production has been reported. However, care should be taken to check excessive intake of high-energy diet in dry period, especially during last 3 weeks of gestation, to avoid peri parturient complications. Higher plane of nutrition during transition period was reported to improve body weight, parturition and expulsion of placenta with heavier birth weight of calf. Occurrence of 1st post-partum oestrous and conception were also reported better in crossbred cows fed higher plane of nutrition. Increasing energy density of diet by introduction of grains in the diet of transition cows and heifers at least 3-5 weeks prior to calving may stimulate rumen papillae growth and increase VFAs absorption from the rumen, adapt the microbial population to higher starch diets and increase feed intake. The energy density should be between 1.56 and 1.62 Mcal NEL/kg DM intake. It was demonstrated that when energy density of the diet increased from 1.3 to 1.54 Mcal NEL/kg DM and CP increased from 13 to 16% at about 3 weeks prior to calving, feed intake was increased by 30%. Increasing the energy and protein density up to 1.6 Mcal of NEL/kg and 16% CP in diets during the last month before parturition improved nutrient balance of cattle prepartum and decreases hepatic triglyceride content at parturition. Generally, the roughage to concentrate ratio recommended for high yielder is 50:50. But as the DMI is the major constraint, the alternative is either to increase the energy density (by feeding additional grains or adding oil seeds or protected fat) or by reducing roughage to concentrate (R:C) ratio. Formulation of any ration with density beyond 13 MJ ME/kg DM is quiet impossible. The total starch contents in the diet of high yielder should be between 20-25%. Molasses is an easily fermentable source of energy and included to increase the palatability as well as level of soluble sugars in the diet. The energy density of a ration can also be increased by dietary supplementation of oils and improve milk yield, fat per cent as well as birth weight of Murrah buffalo. But, addition of oils beyond 4% of total diet may adversely affect the feed intake and fibre digestion.
Buffaloes should be fed to support 750-900 g average daily weight gain during last 2 month of pregnancy and about 700g average daily weight gain during the last 3 month of pregnancy. In pregnancy of adult buffaloes, CP requirement increases by 3, 8.4, 16, 26, 43 and 64% of maintenance requirement on 5th, 6th, 7th, 8th, 9th and 10th month of pregnancy, respectively. The corresponding increases in TDN requirements are 4.3, 7.2, 18.8, 22.2, 39.0 and 67.4% of maintenance requirement, respectively. Pregnant dry buffaloes (at >5 month of pregnancy) should be fed with 30 kg green fodder and 2 kg concentrate mixture (20% CP and 70% TDN) and ad libitum wheat straw. With decrease in availability of green fodder 1 kg concentrate mixture should be additionally fed to replace every 10 kg green fodder. This ration will meet protein requirement for entire pregnancy and energy requirement up to 9.5 month of pregnancy but will fall short of energy requirement on the last 2 weeks of pregnancy when additionally 1-1.5 kg grain has to be fed. For pregnant immature buffaloes, in additional 1 kg grain or 5.5 kg cereal fodder or 7.5 kg legume fodder should be fed to support 300-350 g average daily maternal growth. Similarly, buffaloes in their 2nd pregnancy should be fed additional 0.5 kg grain or 2.7 kg cereal fodder or 3.7 kg legume fodder to support 120-200 g average daily maternal growth. Challenge feeding of buffaloes with good quality fodder and concentrate mixture during last three weeks of pregnancy helps in priming the rumen for increased concentrate feeding in early lactation and build up body reserve for lactation. Dietary protein content and quality in terms of rumen degradability and amino acid composition is very important to meet the requirement of transition buffaloes. Natural protein supplement with high UDP content viz. corn gluten meal, cotton seed cake, coconut meal can be supplemented. Supplementation of condensed tannins (CT) through leaves of Artocarpus heterophyllus, Ficus infectoria, Ficus bengalensis and Ficus glomerata at 1.5-2.0% levels was observed to reduce the rumen degradability of groundnut cake to 60-75% from the normal value of 92%, demonstrating improvement of its utilization at lower digestive tract. Efficient utilization of protein supplements would not only improve the productivity and reproduction of the animal, but may also help in reducing the global warming by decreasing the enteric methane production especially from animals fed low quality roughages. The efficiency of rumen fermentation depends upon the amount of microbial biomass synthesized, which in turn depends on the synchronization of protein and carbohydrate breakdown.
Supplementation of bypass fat: High-yielding buffalo and crossbred cattle usually remain in negative energy balance during late gestation and early lactation due to energy deficiency. Under field conditions crossbred cow and buffalo often lose 75-90 kg BW after calving. Ovarian cycle ceases when buffalo loose 15-24% of BW. Such animals do not come in heat, unless the loss of BW is at least partially recovered. Fat plays an important role in the performance of lactating animals. Usually the extra energy required by the high yielding dairy buffaloes cannot be fulfilled by conventional ration. So, to increase the energy density of the ration, fats can be added. As fat degraded in the rumen may adversely affect the rumen microbes and feed intake; it should be given in rumen protected form. The level of total dietary fat in ration should not exceed 6-7% of diet. Mixture of cereal grains and forages usually contain about 3% fat, so up to 3 or 4% of dietary DM can come from supplemented fat. Inclusion of bypass fat up to 13% in the diet with continual increase in milk production in dairy Holstein cow has been reported. About 100-150g bypass fat/d could be supplemented to increase milk production performance in buffalo. Thus, supplementation of bypass fat in crossbred cows and Murrah buffaloes during the transition phase/early lactation improved the milk yield and fat content. Supplementation of bypass fat at 2.5% of DMI in multiparous crossbred cows from −40 days to +90 days of parturition resulted an increase in birth weight of the calves, while time taken for expulsion of foetal membranes, involution of uterus, onset of cyclicity, service period and number of inseminations per conception were reduced (P<0.05). Supplementation of 15g bypass fat per kg milk yield increased milk fat and yield in buffalo, however, there was no effect on cyclicity and pregnancy rate.
Protected amino acids supplementation: Methionine (Met) and lysine (Lys) are the two most limiting amino acids for milk production. Dietary supplementation of Met and Lys (1:3) can be an effective approach to improve amino acid balance for milk production. Met also has an important role in the formation of very low density lipoproteins which are necessary for the export of stored fat in the liver and helps in preventing fatty liver. Met and Lys easily gets degraded in rumen. A source of ruminally-protected methionine (RPM) and lysine (RPL) are available commercially. Incorporation of 10g methionine and 30g lysine in the ration has improved milk production and milk composition of lactating buffalo. Choline, a component of phospholipid and methyl donor, plays an essential role in very low density lipoprotein synthesis and contributes to fat export from the liver. Choline is also required for biosynthesis and secretion of milk. Fat metabolism can be improved with the help of choline for better energy production which helps in improving milk production. As dietary choline is rapidly degraded in the rumen, it must be supplemented in rumen protected (RPC) form. Supplementation of 54g of RPC 40d before and 120d after calving improved milk yield and milk composition in dairy cattle. The combined effect of supplementing ration with RPM, RPL and RPC on the performance of preparturient crossbred cattle revealed improved BCS on the day of parturition, duodenal supply of Met and Lys, plasma TG, VLDL and phosphatidyl choline levels on the day of parturition in cows. Transition Murrah buffaloes fed basal diet (BD); BD+7g RPM+15g RPL; BD+50g RPC; BD+7g RPM+15g RPL+50 g RPC for a period from -3 months to + 3 months post partum, demonstrated that feed intake and BCS remained comparable among the buffaloes, however, milk fat per cent and 6% FCM yield were increased (p<0.05) in all supplemented animals.
Vitamins supplementation: Niacin supplementation is common in transition diets for its role in the prevention of ketosis through reduced body fat mobilization. Dietary 14g/d niacin supplementation was reported to increase milk production in early lactation of dairy cows. However, a meta-analysis of 27 feeding studies involving niacin supplementation to dairy rations showed no improvement in lactation performance when niacin was given at 6-12 g/d. Supplementation of niacin at high doses to the transition dairy cows has given inconsistent results. Biotin has a proven ability to stimulate glucose synthesis in the liver, which is the main energy source for milk production. The feeding of high concentrate diet during early lactation reduces rumen pH, which in turn decrease the biotin synthesis, leading to laminitis, which adversely affects milk production. The biotin supplementation demonstrated reduced claw lesions and also improved milk production and reproductive performance.
Buffers supplementation: Buffers combat acid production in the rumen and help to reduce digestive upsets or to maintain milk fat percentage when high grain diets are given to the lactating dairy animal to meet out energy deficiency. A mixture of sodium bicarbonate and magnesium oxide (3:1) gives a better response than either fed alone. Buffers should be fed at the rate of 0.6 to 0.8% of DMI or 1.2 to 1.6% of concentrate mixture. Sodium or potassium buffers should not be fed during dry periods, because it elevates dietary cation-anion balance (DCAD) which predisposes the dairy buffalo to milk fever.
Rumen modifiers: Rumen modifiers act directly on rumen microbes, altering the microbial population balance and the proportions of volatile fatty acids (VFAs) produced. As such, they play a part in adapting the rumen. Ionophore rumen modifiers include sodium monensin and lasalocid. Antibiotic rumen modifiers include virginiamycin and tylosin. The effects of sodium monensin are primarily increased ruminal propionate balance, reflecting an increase in propionate producing bacteria compared to those producing formate, acetate, lactate and butyrate. The increase in both milk yield and milk production efficiency with decreased risk of ketosis, displaced abomasum, retained placenta and metritis was reported on supplementation of monensin to transition cows. Recently, various plant secondary metabolites are used to modify rumen environment to increase propionate production and reducing methanogenesis in the rumen. An increased milk production with sustained feed intake in early lactating buffalo fed a composite feed additive containing rumen stimulant and methane inhibitors at 30 days post-partum was reported.
Minerals supplementation: Buffalo milk is rich in calcium, phosphorus, potassium and magnesium. Most of the B-complex vitamins are present in milk. A marginal deficiency of the vitamins and minerals may not have significant impact on milk quantity and quality. However, calcium is one of the crucial elements in the ration to be considered more carefully in transition buffalo. At the beginning of lactation, the sudden demand of calcium for milk production increases dramatically, leading to fall in blood calcium levels resulting in hypocalcaemia. This stimulates the secretion of parathyroid hormone (PTH), which stimulates the bone resorption. It takes 2-3 days for the PTH cycle to become fully functional. It also activates vitamin D3, which increases absorption of Ca from intestine and mobilized bone Ca. But this process requires 24-48 h, and cannot prevent animal from milk fever/parturient paresis as more than 60% of cases of milk fever occur within 24 h of parturition. To avoid incidences of milk fever, the best feeding management practice is to provide low Ca (<50g/day) diet during last 2-3 weeks of gestation, which should be increased to about 100g/d at least two days before parturition. The diet, after parturition, should have sufficient Mg, an essential activator of vitamin D3 in liver. An optimum requirement of Ca and P by 0.53 and 0.34%, respectively in the total dry matter intake in buffalo was reported. Buffalo milk contains about 1.8-02.0g Ca and 1.1-1.2g P per kg milk. Daily requirement of Ca is at around 5.2-5.8g and of P is 2.1-2.3g for per kg milk production. Good quality mineral mixture should be supplemented (50- 60 g/d) to buffalo for proper foetal growth and milk production.
Dietary cation-anion difference (DCAD): DCAD refers to the numerical difference between the sum of certain dietary cations (positively charged minerals) and certain dietary anions. Primarily, the cations to consider are sodium (Na) and potassium (K) while the anions are chloride (Cl) and sulphur (S). Reducing DCAD in the prepartum transition period dramatically reduced the risk for milk fever and subclinical hypocalcaemia by improving calcium dynamics for the buffalo. A diet having 330 mEq/kg DM DCAD has promoted feed consumption, water intake and resulted in greater milk yield and milk fat in early lactating buffalo and occurrence of hypocalcaemia was reduced by feeding diet containing -110 DCAD level, for last four to six weeks before parturition. Feeding of 90g anion salt (-749 mEq) from -21 days up to calving and 125g cation salt (Sodi bicarb., +1473 mEq) up to 21d postpartum improved milk yield and fat per cent in Murrah buffaloes with simultaneous improvement in reproductive health of animals. Provision of adequate quantity and quality nutrients as required by buffaloes during the transition period generates positive effects on animal health; milk and reproductive performance.
Nutrition of transition buffalo plays an important role in improving production and reproduction performance not only in the current lactation but also in the ensuing lactation. Reduced dry matter intake during transition period is the main factor for depressed performance of buffalo. Estimates of the demand for glucose, amino acid, fatty acids, and net energy by the gravid uterus at three weeks prepartum and the lactating mammary gland at postpartum indicated approximately a tripling of demand for glucose, doubling of demand for amino acids, a five fold increase in fatty acids and four fold increase in calcium. Therefore, proper feeding management should be practiced to fulfil nutrient requirement for improved production and reproduction performance of buffalo.