Milk yields from feeding maize silage and meat-and-bone meal to Friesian cows grazing a tropical grass and legume pasture

Abstract

Twenty Friesian cows in mid-lactation were used in a 2x2 factorial experiment to determine the responses in milk yield, milk composition and liveweight to maize silage supplement (3 kg dry matter/cow.d, or free access during the day) with or without a meat-and-bone meal supplement (5 silage: 1 meat-and-bone meal, on a dry matter basis). Cows grazed green panic (Panicum maximum var. trichoglume) and glycine (Neonotonia wightii cv. Tinaroo) mixed pastures at 2.5 cowslha. Experimental treatments were maintained for eight weeks after which cows grazed as one group on unsupplemented pasture for a further eight weeks. Milk yields averaged 14.7 and 16.0 kg/cow.d for the low and high silage levels (P < 0.01), and 15.8 and 14.8 kg/cow.d with and without meat-and-bone meal (P < 0.05). There was a residual effect of 1.2 kg milk/cow.d (P < 0.05) for eight weeks after the experimental period from feeding silage at the high level. Feeding meat-and-bone meal reduced milk fat percentage from 3.61 to 3.30% (P< 0.05). Protein yield and the short-chain fatty acid (C4-C16) content of milk fat were increased by increasing the level of intake of silage (P < 0.01), while feeding meat-and-bone meal increased protein yield (P < 0.05), but decreased the short-chain fatty acid content of milk fat (P < 0.05). Cows lost an average of 15.2 kg liveweight at the low silage level and gained 6.7 kg at the high silage level (P< 0.01) over the eight weeks of experimental feeding.