A comparison of grazing systems for dairy herd replacements

Abstract

SUMMARYAn experimental and a conventional grazing system for 7- and 19-month-old dairy replacements were compared during 136 days of the grazing season. In the experimental system A, 24 calves were rotationally grazed around paddocks followed by 24 pregnant heifers which ate the herbage residue left by the calves. The conventional system B consisted of 24 calves and 24 pregnant heifers maintained at the same overall stocking rate as in system A, but the calves and heifers grazed in completely separate rotations. Half the calves on each system were drenched with an anthelmintic at weekly intervals from mid-July onwards to estimate within systems the effect of gastrointestinal worms on live-weight gain.