Effects of forage species and stage of maturity on bovine milk fatty acid composition

Abstract

AbstractFive cows were used in a 5×5 Latin square to evaluate the effects of forage type and stage of herbage maturity on milk fatty acid (FA) composition. Four silages were prepared from primary growths of timothy‐meadow fescue and red clover swards at an early and late stage of growth. Treatments consisted of these silages and an additional treatment comprised of an equal mixture of late‐cut grass silage and early‐cut red clover silage. Forages were fedad libitumand supplemented with 9 kg/day of a standard concentrate. Compared with grass silage, red clover silage diets enhanced milk fat monounsaturated FA (MUFA) and polyunsaturated FA (PUFA) content, 18:3 n‐3 in particular, responses that were associated with concomitant reductions in 10:0 to 16:0 concentrations. Decreases in 16:0 and increases in PUFA concentrations were more pronounced for early than late growths of red clover. Even though red clover resulted in marginal increases in total milk fattrans18:1 content, milktrans‐11 18:1 concentrations were lower for red clover than for grass silage diets. It is concluded that replacing grass with red clover silage prepared at an early stage of maturity represents a sustainable nutritional strategy for enhancing the MUFA and PUFA content of milk.