The effect of varying ratios of roughage to concentrates on composition and yield of cow's milk

Abstract

SummaryTWO levels of roughage, 3 FU (feed units) and 5 FU daily, were fed to Israeli?–Friesian cows and heifers receiving either a normal (Normal) or a high-energy (High) diet.Milk yield and composition were examined for 12 weeks following parturition. The animals receiving 5 FU of roughage daily showed a higher milk yield during the first 8 weeks. With the Normal diet the amount of roughage had no effect on milk composition. With the High diet, milk yield was higher than with the Normal, and a depression in fat percentage was observed in the milk of cows and heifers receiving 3 FU daily. No corresponding fall in milk protein percentage was observed – the cows of this group (High-3 FU roughage) showing, in fact, a rise in protein percentage. No differences in milk total solids were found. With these high-energy low-roughage diets no correlation was apparent between milk fat and protein percentages.