Milk production and fatty acid profile of milkfat by dairy cows fed a winter oats (Avena sativa L.) pasture only or a total mixed ration

Abstract

Milk production and milk fatty acid (FA) composition were determined in 12 Holstein dairy cows in mid‐lactation fed winter oats pasture only (WOP) or total mixed ration (TMR) in a single crossover design. The WOP treatment cows received a high quality winter oats (Avena sativa L.) pasture rotationally grazed, while the TMR treatment cows were fed a corn silage‐based TMR feed ad libitum once daily. Milk production tended to be lower (14.9 versus 16.3 kg day^‐1; P = 0.15), and milkfat (32.2 versus 35.5 gkg^‐1; P < 0.01), and total protein (35.8 versus 37.8 g kg^‐1; P < 0.01) concentration were significantly lower for the WOP fed cows than for the TMR fed cows. The cows fed WOP lost live‐weight and body condition score, but the cows fed TMR gained liveweight. Cows fed WOP had a lower saturated:unsaturated FA ratio (1.85 versus 2.22; P < 0.02). The cis‐9 trans‐11 CLA content was 2.6‐fold higher (1.41 versus 0.55% of total FA; P < 0.01) for the WOP cows. These results indicated that the nutritive value of the milk could be improved by feeding cows on high quality pasture; however, milk production was lower for grazing dairy cows.

Keywords:

• winter oat
• total mixed ration
• conjugated linoleic acid