Choline, a trimethylated quarternary amine involved in transport of fat from liver, provides labile methyl groups for transmethylation reactions and is required for the synthesis of phosphotidylcholine from cell membrane. Its ability to increase milk fat synthesis and treat cows suffering from fatty liver after parturition has stimulated research on dietary supplementation of choline to dairy cows. Although the choline requirement of dairy cows has not been established (NRC, 2001), it has been reported that the duodenal flow of choline represents less than 30 per cent of the dietary needs.
That just goes to suggest that dietary choline gets degraded in rumen to a greater extent and not available to the host ruminant.
Therefore, it becomes imperative that the choline is supplemented in the diet of cows in rumen protected form, so that its degradation in rumen is reduced and the undegraded part is absorbed post-ruminally to be available to the host ruminant. In NDRI Karnal, an experiment was conducted recently to test the efficacy of the rumen protected choline (RPC) of the commercially available preparation, so as to find to what extent it is degraded and the proportion which escapes ruminal degradation. The second part of the experiment was to see as to what extent does the dietary supplementation of choline influences, milk yield, milk composition and choline content in milk. The results showed that RPC was only 27.11 % degraded in rumen and 72.8 % remained undegraded in rumen. While choline supplementation had no influence on milk yield and milk composition of cows, even the lowest dose of 54g/day/ cow choline was good enough to increase the milk choline content.
Source: Indian Journal of Animal Nutrition