Abstract

This review covers results from numerous trials evaluating conjugated linoleic acid (CLA) effects on milk fat synthesis and its potential as an on-farm management tool to improve dairy cow performance. Supplemental CLA reduces milk fat synthesis in numerous animal models, and in grazing dairy cows can improve energy balance as well as increase milk and milk protein yield. Mammary lipid metabolism effects are thus far specific to trans-10, cis-12 CLA, and we demonstrated trans-10, cis-12 CLA reduces mRNA expression of enzymes required for de novo fatty acid synthesis, fatty acid uptake and intracellular transport, and triglyceride formation. The amount of CLA required to reduce milk fat synthesis in lactating cows has little or no effect on circulating basal bioenergetic metabolites and hormones or stimulated responses to homeostatic signals. We hypothesized CLA can be utilized to stimulate milk fat depression when milk synthesis and other physiological processes are limited by energy availability, as is the case in early lactation, during heat stress and occasionally in pasture based dairying. Our research focuses on identifying the mechanisms of action and potential use of CLA as an on-farm management tool to increase farm profit via increased milk production, improved reproduction and decreased metabolic disorders.

LH, Baumgard, JK Kay, CE Moore, JR Roche, MJ Vanbaale, and RP Rhoads

Proceedings of the New Zealand Society of Animal Production, Volume 65, Christchurch, 33-39, 2005