The effect of cultivated mixed-species green fodder on intake, milk production and milk composition of housed dairy goats

Most New Zealand dairy goat farmers utilise pastures dominated by perennial ryegrass (Lolium perenne L.) and white clover (Trifolium repens L.), but anecdotal evidence suggests milk production may be improved when using more diverse pastures. The aim of this experiment was to determine the effects on feed intake and milk production and composition of lactating goats fed a mixed pasture (MP, consisting of perennial ryegrass, timothy (Phleum pratense L.), prairie grass (Bromus willdenowii Kunth), white clover, red clover (Trifolium pratense L.), lucerne (Medicago sativa L.), chicory (Cichorium intybus L.) and plantain (Plantago lanceolate L.) compared to a standard ryegrass and white clover pasture (SP). Thirty six mid-lactation goats were housed indoors in pairs and split into 2 groups (A and B). The trial was split into 3 periods, firstly a uniformity period of 6 days, in which all goats were fed a combination of both pasture types, followed by 2 treatment periods (P1 and P2) of 12 days. For P1, group A was fed MP and group B was fed SP and then groups switched diets for P2. Goats fed MP had 13% higher dry matter intakes and 7% higher milk yields than goats fed SP. In addition, the percentage of protein within milk of goats fed MP was 4% higher whereas there was no detectable effect on fat or lactose percentage. The milk fatty acid profile was affected by the pasture type, with concentrations of pentadecylic acid (C15:0), palmitic acid (C16:0), gondoic acid (C18:1 c11), linoleic acid (C18:2 n6) and α-linolenic acid (C18:3 n3) being increased in response to MP consumption. In contrast, caproic acid (C6:0), myristic acid (C14:0), stearic acid (C18:0), arachidic acid (C20:0), iso-C15, iso-C17, cis-10-heptadecenoic acid (C17:1) and oleic acid (C18:1 c9) concentrations were lower. In summary, this study demonstrated that goats fed MP increased feed intakes and milk production compared to SP. The pasture type had an effect on the fatty acid profile of the goat’s milk, with MP increasing the levels of beneficial polyunsaturated omega fatty acids (linoleic and α-linolenic acids).