Summer Grazing and Winter Feeding Studies with Suckler Cows

Abstract

Stocking rates of 2.47 (low), 3.71 (medium) and 4.94 (high) spring calving cows plus calves per ha were compared during three grazing seasons. Cows at the high stocking rate had lowest daily gains in all three years. Prior to early August, stocking rate had no effect on calf performance except in year 2 when those at the high stocking rate had lower daily gains. From early August until the end of the grazing season stocking rate significantly affected calf gains in all three years. Stocking rate had no effect on milk yield in year 1 but cows at the high stocking rate had reduced yields for most of year 2 and at the end of year 3. Regressions of calf daily gain from birth to the end of the season on milk yield of the cow were significant in all three years.

In two further experiments, beef cows were individually fed grass silage either to appetite (control) or 27 kg per head daily (restricted) during late pregnancy. All cows received silage to appetite during the first 42 (Experiment 1) or 49 days (experiment 2) of lactation and were subsequently grazed together at pasture. Plane of nutrition during late pregnancy affected cow liveweight changes. All cows lost weight during the first 6 to 7 weeks of lactation but recovered at pasture. Liveweight gains from 4 to 240 days post-calving in Experiment 1 for control and restricted cows were 33 and 84 kg respectively. The corresponding figures for the period 7 to 240 days post-calving in Experiment 2 were 70 and 95 kg. Plane of nutrition during late pregnancy did not influence the incidence of calving difficulties, feed intake during early lactation, milk production or cow fertility. Likewise, there was no effect of cow feeding level pre-calving on birth-weight or liveweight gain of calves in either experiment. Calf liveweight gains were significantly affected by milk yield of the dam.