Milk yield, gross composition and fatty acid profile of dual-purpose Aosta Red Pied cows fed separate concentrate-forage versus total mixed ration

This study was designed to evaluate the effects of two feeding methods on milk yield, composition and fatty acid (FA) profile obtained from dual-purpose cattle. Twenty-four Aosta Red Pied cows beyond peak of lactation were assigned to two groups and fed hay and concentrates in the proportions 0.69 and 0.31 on a dry matter basis for 10 weeks. Concentrates were offered separately from forages 6 times a day (separate ration, SR) or as a total mixed ration (TMR). The feeding method did not significantly influence dry matter intake (16.8 vs. 16.9kg/head/day for SR- and TMR-fed cows, respectively), milk yield (17.4 vs. 17.5kg/head/day), milk fat, protein and lactose contents (36.4 vs. 35.2, 33.5 vs. 32.8, and 47.3 vs. 47.4g/kg) and yields (607.9 vs. 613.4, 567.4 vs. 572.7 and 805.5 vs. 829.7g/head/day). The overall milk FA profile was very similar between groups. Milk concentrations of FA used as indirect markers of rumen function (C18:2 t10c12, odd- and branched-chain FA) and the extent of ruminal biohydrogenation were comparable (P>0.05) between SR- and TMR-fed cows, suggesting that ruminal pH did not vary considerably as a consequence of the feeding strategy applied.