The conversion of pasture to milk: the effect of stocking rate and concentrate feeding

Abstract

1. An experiment is described in which the effect of the level of nutrition, as determined by stocking rate and the use of supplementary concentrates, on milk yield and efficiency of production was studied.2. Three levels of nutrition were used: Treatment (A)—one milking cow per acre plus 1 lb. of concentrate mixture for each 5 lb. of milk produced. Treatment (B)—one milking cow per acre—no concentrates. Treatment (C)—one milking cow per sixtenths of an acre—no concentrates.3. Fifteen sets of identical twins were used per year over an experimental period of 3 years. The groups were rotationally grazed with a daily shift to a fresh pasture on a 14-day rotation. Ninety complete lactations were available for analyses.4. The A cows produced 45% and the B cows 16% more f.c.m. than the C cows. Per unit area, however, the C treatment produced 30% more than the B.5. Significant differences in milk composition were established, but these were of much smaller magnitude than those in milk yield.