Abstract

Conjugated linoleic acid (CLA) is a collective term for the range of conjugated isomers of linoleic acid (C182). These fatty acids occur naturally in milkfat and have proven anticarcinogenic properties in laboratory rodents (Ip et al., 1999). Additionally, the various isomers have other reputed benefits for human health such as enhanced bone mineralisation, antidiabetic effects, reduced atherosclerosis and immune system modulation (Whigham et al., 2000). Such potential benefits for human health have focussed international research on enhancing concentrations of CLA in milk and dairy products. Overseas data show that one way to increase the concentrations of CLA in milk is to change the diet of cows from a typical total mixed ration (TMR) to pasture (Kelly et al., 1998; White et al., 2001). This points to a potential competitive advantage for the New Zealand dairy industry, in which pasture is already almost the sole source of feed. Despite this there are no data confirming the beneficial effects of pasture for enhancing CLA under New Zealand grazing conditions. The experiment described here used an existing experiment to compare the concentrations of CLA in milk from cows fed TMR or grazing pasture for an entire lactation under New Zealand conditions.

MJ, Audlist, JK Kay, NA Thomson, AR Napper, and ES Kolver

Proceedings of the New Zealand Society of Animal Production, Volume 62, Palmerston North, 240-241, 2002