Silage and milk production: a comparison between concentrates containing different amounts of protected protein as supplements for silage of high digestibility

Abstract

AbstractGrass silage made in late May from S24 perennial ryegrass was offered ad libitum to eight Ayshire cows in a 16‐week feeding experiment. The silage had a DM concentration of 244 g kg−1, contained 163 g crude protein (kg DM)−1 with a ruminal degradability of 0.77 and had an in vitro DOMD concentration of 678 g kg−1. In addition, four concentrates each containing 167 g soya‐bean meal kg−1 were consumed at a mean daily rate of 6.43 kg DM per cow. The soya‐bean meal was either untreated, or ‘protected’ by formalin and mixed in the following proportions, 100:0; 66:34; 34:66; and 0:100 respectively, in the four concentrates. The daily intakes of silage DM were not significantly different on the four treatments and averaged 90 kg DM per cow, giving a mean total daily DM intake of 32.4 g kg−1 live weight. The milk yields were not significantly different on the four treatments and averaged 23.9 kg −1 The treatments had small and non‐significant effects on milk composition and live weight. It is concluded that with a high‐digestibility, well‐preserved grass silage of satisfactory protein content the inclusion of ‘protected’ protein in the supplementary concentrate had no beneficial effects on milk production.