Augmentation of productive and reproductive performance in dairy animals by prilled fat supplementation

1. V.R.Upadhyay

PhD Scholar (Animal Physiology Division)

ICAR-NDRI Karnal

Introduction

We have seen remarkable advances in animal productivity in the last 75 years which is greatly desired with increased human population without increasing much dairy animal populations. The primary source for this historic gains relates to management, body condition of animal, feeding and lastly on the individualanimal variation in nutrient partitioning during transition period.There are some periods of time when this feeding management have long-term impacts on metabolic function, nutrient portioning and ultimately on lactation. As parturition approaches, there is a progressive decrease in dry matter intake (DMI)with an overall decrease of almost 1/3^rdin the last 3 weeks of gestation and about 3/4^th of the decrease occurring a week before calving.Therefore it is very much clear that the stress of high production and long lactations are stressful on the cows and minor changes through supplementation may be somewhat inefficient if the goal is to improve energy status and counteract negative energy balance (NEB). For nullifying this deleterious effect of negative energy balance on productive and reproductive performance a holistic approach is needed. Likewise it is comprehended that energy balance, metabolic hormone concentrations and genetic potential for milk production are interrelated and can be altered by providing suitable dietary modulation. Consequently, efforts to overcome early postpartum NEB via dietary modulations like bypass fat have logically potential to increase the energy density of the diet being fed without hampering fiber digestibility. Thus keeping these attributes on mind the objective of this article is to highlight the opportunities of improving milk productivity and counter the ill effects of negative energy balancethrough this energy dense nutritional interventions.

Transition period

The period between three weeks before calving to three weeks after calving is known as transition period. This period between late pregnancy (-3 weeks) and early lactation (+3weeks) exerts physical, biological and physiological stress on the animal to compensate for the hormonal and metabolic changes that arise due to surge in mammogenesisand onset of lactogenesis (Mondalet al., 2014).During this period, hormones and metabolites significantly alter and cause lipolysis and lipomobilization to meet energy requirement of fetus and initiation of lactation. Milk yield and the shape of the lactation curve are determined by the number of mammary secretory cells and the secretory activity per cell, thus making this phase very significant. Body condition score (BCS) is an important determinant of energy reserves and energy balance during entire lactation period enabling cell replacement or decreasing apoptosis during lactation and provide a means to increase persistency of lactation.The transition period is a critical determinant of both productivity and profitability of a dairy farm by lowering the BCS of animal.Energy requirement during transition period is approximately 3Mcal NEI/day while fat requirement during this period is about 6% (NRC, 2001).

Use of dietary fat spares energy by increasing metabolic efficiency for milk production by generating ATPs more efficiently than VFA or protein. It also lowers heat production, incorporate preformed FA into milk fat and optimize forage fiber intake and rumen function by substituting the rapidly fermentable carbohydrate (Palmquist, 1994). But the limitation of feeding high fat ration is that it depresses dry matter intake and fiber digestion. Thus there comes the requirement of energy dense ration which should be inert to ruminal fermentation.

Bypass fat

Dietary fat that resist lipolysis and biohydrogenation by rumen microbes, but gets digested in lower digestive tract is known as bypass fat. Prilled fat is a form of bypass fat. Adding protected fat to dairy rations can positively affect efficiency of dairy cows through combination of caloric and non-caloric effects and have been found effective to augment the overall productivity without affecting rumen microflora and blood metabolites.Caloric effects are attributed to higher energy content and increased energetic efficiency of lipids as compared to carbohydrates and proteins with the overall benefits of increased BCS, milk production and the persistency of lactation. The non-caloric effects include improved reproductive performance and altered fatty acid profile of milk (Tyagiet al., 2010). The other important form include calcium soaps of long chain fatty acid which are insoluble in rumen pH of 6.2-6.8 but soluble in the abomasum where the pH ranges between 2-3. Calcium salts of fatty acid are produced by double decomposition and fusion method and are commonly used because of its cheaper price.Supplementation of 6-8% of ration on DM basis with Ca-LCFA had no adverse effect on rumen fermentation of dairy animals (Naiket al., 2010) and have shown instantaneous effects on production performance.

Methods of protection

1. Natural dietary rumen protected fat
2. Hydrogenation of fat
3. Formaldehyde treatment of oil seeds
4. Calcium salt of long chain fatty acids
5. Fusion method

Energy Values of fat sources for dairy cows (NRC, 2001).

Prilled fat

Prilled fat is a sub-division of bypass fat, mostly a non-hydrogenated vegetable oil which contains more than 85% palmitic acid with higher melting point. Prill fat remains inert in the rumen and resist hydrolysis and association with the bacterial cells of feed particles. Liquefying a mixture of fatty acids having high saturated fatty acid content and spraying the mixture under pressure into a cooled atmosphere, results in a dried prilled fat that is inert in the rumen and is broken down in the intestine by lipase enzyme.This dried prilled fat is further processed in small spheres. It is also done by selective dry fractionation of palm oil. The product is hard fat with melting point>57ºC.

In Indian feeding condition 75gm prilled fat should be supplemented to lactating cows (Rajesh.,2013) orupto 9% of dry matter. Supplementation of prilled fat restores physiological adjustment earlier in lactating cows. Prilled Fat (PF) feeding enhances energy balance by improving TDNI, DE, ME and NE and enable more partitioning of nutrients towards mammary gland with 10-15% increase in milk yield (Singh et al., 2015).

Requirement of feeding

Feeding ordinary or unprotected fats has a depressing effect on rumen cellulolytic microbial activity while rumen inert fat escapes rumen bio-hydrogenation process and also reduces risk of metabolic acidosis. Inclusion of rumen inert fat in dairy cattle rations has four immediate benefits:

1) Increased caloric density without compromising fiber digestibility.

2) Increased energy intake to overcome higher nutritional demand during transition period when cows fail to consume sufficient feed.

3) Increased efficiency of energy utilization for production during early lactation.

4) Enhanced lipogenic:glucogenic ratio.

Fat inclusion in early lactation rations may mitigate negative energy balance and minimize weight loss. Milk production appears to be adversely affected when reduction in DM consumption is not compensated by the higher caloric density of fat in the ration. Thus this form of fat sources also has remarkable long term effects like-

• Easy way to fulfill nutritional demands tocounteract NEB and metabolic disorders of periparturient period.
• Enhance milk production without increasing dairy animal populations.
• Overall lactation yield is increased along with the improvement in post-partum recovery of the body weight and body condition score.
• Increase availability and utilization efficiency of energy, protein and other essential nutrients hastening reproductive potency of the dairy animals.
• Modulate milk composition with synchronized extraction of desired nutrients
• Have no adverse effect on the rumen fermentation, feed intake, digestibility of nutrients and different blood parameters of the dairy animals.
• Improve reproductive performance of the transition cows and there is less occurrence of periparturient disorders.
• Best possible mean to fulfill increased human population with minimum environment degradation by indirectly reducing greenhouse gasses emission

Impact of prilled fat on reproductive performance

NEB is marked by dysfunction of follicle growth, follicular maturation and ovulation. Due to the improved BCS post supplementation,prillfat have strong positive association with cow fertility. The improved reproductive performance could also be attributed to higher plasma cholesterol and higher IGF-I levels as both play important role in reproduction. Plasma insulin, leptin and insulin-like growth factor- I also changes post supplementation which was reported to control ovarian follicular development and serve as mediators of energy balance on cow’s fertility. Post supplementation following changes are observed-

• Duration for uterine involution was reduced
• The duration for commencement of postpartum cyclicity was reduced.
• No of AI done per conception was less.
• Increase in progesterone secretion improves fertility.
• Improved follicular recruitment.
• Feeding bypass fat @ 100/150g/day during transition period improves hormonal status and reproduction efficiency.

Effect of prilled fat on blood metabolites and hormones

Prilled fat escape rumen as they are relatively insoluble at rumen P^h and temperature.They undergo both digestion and absorbtion in lower tract. Digestion process involves breaking down into free fatty acid and glycerol and further formation of micelles.To regulate this metabolic condition, key hormones of somatotropic axis such as GH, IGF-I and insulin coordinate to acquire metabolic homeostasis (Kim, 2014).

• Glucose- Non significant change in the glucose level.It may be due to high metabolic rate of utilization of glucose and homeostatic mechanism of animal body.
• Non Esterified Fatty Acid (NEFA)- Reflects the degree of adipose tissue triacylglycerol mobilization.Stessors and poor nutritional management during peripartum influence its label.Lower NEFA level indicates effective checking of mobilization from adipose tissue.
• Beta Hydroxy Butyrate (BHBA)-BHBA is the key indicator of hepatic ketogenesis as a result of influx of NEFA into liver i.e due to excessive mobilization of body fat.Increasing ketone body production reduces DMI and consequently milk production as it indicate energetic stress.Periparturient cows fed prilled fat showed a decrease in BHBA concentration.
• Cholesterol-Higher plasma cholesterol and HDL label is noticed due to positive energy balance associated with prilled fat feeding.
• Triglycerides- Plasma triglycerides level found high in cows fed prilled fat which was expected because of enhanced uptake of dietary fatty acids.
• Growth hormone- Dairy cows during the parturition suffer a reduction of plasma IGF-I despite elevated plasma GH a condition known as GH resistance. Increased GH stimulates the lipolytic effects (elevated plasma NEFA and glycerol) and associates with adipose tissue mobilization. GH also stimulates hepatic gluconeogenesis to meet the energy requirement for mammary lactose synthesis. Therefore, after supplementatation elevated GH concentration drives nutrient partitioning to facilitate milk production.
• Thyroid hormones- High energy content of diet increases plasma concentration of galactopoietic hormones i.e. T3 & T4
• Progesterone-Prill fat feeding also results in higher progesterone level due to more energy content of diet and increase cholesterol level serves as precursor.

Conclusion

Present scenario of animal production system is imposing immense pressures on dairy animal production to deal with the demand of increasing world population, either with available dairy animal numbers, or even on reduced population aiming for a minimal greenhouse gases emission. The changes of dietary constituents of animals are therefore directed in order to fulfill such demands during this critical period and afterwards so that nutrient use efficiency and productivity will not compromise. However, identification of active compoundsto offsetthis NEB in ruminant production remain a big challenge for researchersbut the supplementation of prilled fat comes as a best possible mean to cope up this challenge of energy demand.

References

Kim, J. W. (2014). Modulation of the somatotropic axis in periparturient dairy cows. Asian-Australasian journal of animal sciences, 27(1), 147.

Mondal, S., Minj, A., Pathak, M. C., Singh, D. N., &Varshney, V. P. (2014).Importance of hormonal changes during the periparturition period in black Bengal goats. International Journal of Clinical and Experimental Physiology, 1(1), 20-25.

Naik, P. K., Saijpaul, S., &Kaur, K. (2010). Effect of supplementation of indigenously prepared rumen protected fat on rumen fermentation in buffaloes. Indian Journal of Animal Sciences, 80(9), 902.

Palmquist, D. L. (1994).The role of dietary fats in efficiency of ruminants. The Journal of nutrition, 124(suppl_8), 1377S-1382S.

Rajesh, G. (2013). Post Partum Physiological Adaptation in Hormones, Metabolites and Milk Production in Crossbred Cows Fed with Prilled Fat (Doctoral dissertation, NDRI).

Singh, M., Roy, A. K., & Sharma, S. (2015). Augmentation of milk production by supplementing bypass fat in dairy animals. Asian J. Anim. Vet.Adv, 10(9), 476-488.

Tyagi, N., Thakur, S. S., &Shelke, S. K. (2010).Effect of bypass fat supplementation on productive and reproductive performance in crossbred cows. Tropical animal health and production, 42(8), 1749-1755.

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