Milk yield, gross composition and fatty acid profile ofdual-purpose Aosta Red Pied cows fed separateconcentrate-forage versus total mixed ration

摘要

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 totwo 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). Thefeeding method did not significantly influence dry matter intake (16.8 vs. 16.9 kg/head/day for SR- and TMR-fed cows,respectively), milk yield (17.4 vs. 17.5 kg/head/day), milk fat, protein and lactose contents (36.4 vs. 35.2, 33.5 vs. 32.8, and47.3 vs. 47.4 g/kg) and yields (607.9 vs. 613.4, 567.4 vs. 572.7 and 805.5 vs. 829.7 g/head/day). The overall milk FA profilewas 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- andTMR-fed cows, suggesting that ruminal pH did not vary considerably as a consequence of the feeding strategy applied.