Influence of pasture and concentrates in the diet of grazing dairy cows on the fatty acid composition of milk

• Published in: Journal of dairy research 2003-08, Vol.70 (3), p.267-276
• Main Authors: Stockdale, C Richard, Walker, Glen P, Wales, William J, Dalley, Dawn E, Birkett, Anne, Shen, Zhiping, Doyle, Peter T
• Format: Article
• Language: English
• Subjects: Animal Feed; Animal productions; Animals; Biological and medical sciences; butyric acid; Cattle - metabolism; Cattle - physiology; cereal concentrates; Conjugated linoleic acid; Dairy cattle; dairy cows; Dairying - methods; Diet - veterinary; fatty acid composition; Fatty acids; Fatty Acids - analysis; Female; Food industries; Fundamental and applied biological sciences. Psychology; Grain; Grazing; Human nutrition; Lactation - metabolism; Linoleic Acid - analysis; Milk; Milk - chemistry; Milk and cheese industries. Ice creams; milk fat; Pasture; pastures; Poaceae; saturated fatty acids; Terrestrial animal productions; Vertebrates
• ISSN: 0022-0299; 1469-7629
• DOI: 10.1017/S0022029903006009

In five short-term experiments conducted in Victoria in 1997 and 1998, grazing dairy cows were given either pasture alone or pasture supplemented with high-energy concentrates, and the fatty acid profiles of milk fat were measured. We established the effects of these feeds on some aspects of milk fat of importance for human nutrition, but we specifically focused on the hypothesis that conjugated linoleic acid (CLA) concentrations in milk fat increase as pasture intake increases, and decrease as more concentrates are fed. In agreement with previous research, feeding fresh pasture alone resulted in high concentrations (1·0–1·8 g/100 g milk fat) of CLA. When the effect of level of pasture consumption on CLA content was examined, a significant positive relationship (r2=0·35; P