The dairy farmers are well aware of the importance of rumen protected protein and protected fat in milk production and reproduction. However, these two plays important role in post-partum only but the protected choline is very much important during peri-partum period. As choline do so many metabolic activities like lipid transport and utilization within the cells. High-producing dairy cows experience negative nutrient balance during late gestation and early lactation that induces excessive tissue mobilization, primarily of fat but also of protein, leading to subclinical and clinical ketosis and fatty liver (Drackley, 1999). About 50 to 60% of transition cows experience moderate to severe fatty liver (Bobe et al., 2004). This fatty liver condition is a classical deficiency symptom for choline in dairy animals and also in chicken. Hence, there will be choline deficiency in transition cows a period which extends between three weeks pre and post-calving (Grummer, 2012). Choline is a vitamin-like compound whose metabolism interacts very closely with methionine and vitamin B12 metabolism (Mohensen et al., 2011). Choline (trimethyl, 2-hydroxy ethyl ammonium hydroxide) was first identified in 1862 by Andreas Strecker from hog bile.
Role of Choline
In the body choline plays numerous functions, however, the six main functions of choline are: 1. Cellular integrity – as a component of cell plasma membrane it is essential for the maintenance of cellular integrity.
2. Cell signalling – the metabolic products of phosphatidyl choline like phosphatic acid, platelet activating factor, etc. responsible for wound healing and reproduction.
3. Osmoregulation – plays an important role in cell water metabolism through betaine, as it reduces the muscle drip loss.
4. Lipid transport and metabolism – Lecithin a component of bile, reduces the surface tension and improves fat assimilation.
5. Methyl donor – the oxidation product of choline – betaine is a potent methyl donor for synthesis of biomolecules like plasma membrane, RNA, DNA, carnitine, creatinine, etc.
6. Neurotransmitter – as a component of acetyl choline, it involved in nerve impulse transmission (Hartwell et al., 2000).
Even though choline is considered as a B vitamin is endogenously synthesized by sequential methylation process. The dietary choline, betaine, methionine, folic acid, Vitamin B12 all contribute to the body choline content. In adult dairy animals, choline is extensively degraded in the rumen; dietary choline therefore contributes insignificantly to the choline body storage. The various protein (protected or unprotected) sources are rich sources of choline but due to rumen degradability (85-95%) the animal will depend on its endogenous choline synthesis for their metabolic needs. Hence, there is need for use of protected choline in the diet of dairy animals for better health and productivity.
Courtesy the data obtained from Pandurang (2012)
Microencapsulation is used to protect a substance from degradation in the rumen. Commercially available microencapsulated products contains about 28–50% choline chloride, out of which about 85% its choline rumen undegradable. These products can be added directly to the compound feed or administered as a top dress.
Protected choline supplementation will reduces the fatty liver condition in transition cows because, higher fat content in the liver is associated with poor reproductive performance (Bobe et al., 2004). The first service conception rate was higher in protected choline supplemented animals than the control Oelrichs et al. (2004). Feeding of protected choline will improve the milk production in newly calved animals (Hartwell et al., 2000; Scheer et al., 2002). Feeding protected choline increased the milk yield, milk fat percentage, milk protein content in animals fed with protected fat than feeding protected fat alone. Feeding choline in this form not only meeting the requirement of choline it also reduces the requirement of methionine and lysine as these two amino acids involved in the endogenous synthesis of choline. Hence, obtaining choline from individual supplement is more economically beneficial than through feed ingredients or endogenous synthesis.
Choline increase productive performance and prevents the metabolic disorders with better nutrient digestibility, increases milk yield and milk fat percentage. It also increases reproductive efficiency in dairy cows. Choline especially during transition cows @ 10 to 20 g per animal per day as protected form will be helpful for better health and performance.
ICAR-Central Avian Research Institute, Izatnagar - 243122
2Veterinary College and Research Institute, Thirunelveli.
Drackley, J.K., Overton, T.R. and Douglas, G.N. 2001. Adaptations of glucose and long- chain fatty acid metabolism in the liver of dairy cows during the periparturient period. J. Dairy Sci., 84: 100-112.
Bobe, G., Young, J.W. and Beitz, D.C. 2004. Invited review: Pathology, etiology, prevention, and treatment of fatty liver in dairy cows. J. Dairy Sci., 87: 3105-3124.
Grummer, R. R. 1993. Etiology of lipid related metabolic disorders in periparturient dairy cattle. J. Dairy Sci., 76: 3882-3896.
Mohensen, M.K., Gaafar, H.M.A., Khalafalla, M.M., Shitta, A.A. and Yousif, A.M. 2011. Effect of rumen protected choline supplementation on digestibility, rumen activity and milk yield in lactating Friesian cows. Slovak J. Anim. Sci., 44(1): 13-20.
Hartwell, J.R., Cecava, M.J. and Donkin, S.S. 2000. Impact of dietary rumen undegradable protein and rumen-protected choline on intake, peri-partum liver triacylglyceride, plasma metabolites and milk production in transition dairy cows. J. Dairy Sci., 83: 2907-2917.
Oelrichs, W.A., Lucy, M.C., Kerley, M.S. and Spain, J.N. 2004. Feeding soybeans and rumen-protected choline to dairy cows during the periparturient period and early lactation. 2. Effects on reproduction. J. Dairy Sci. 87(Suppl. 1): 344.