Comparative studies on pasture and animal performance and parasite infestation in sheep grazing Yorkshire fog, perennial ryegrass and tall fescue pastures

Abstract

The results are briefly reported of seven comparative studies on aspects of pasture and animal performance from pastures based on Yorkshire fog (Holcus Zanatus), perennial ryegrass (Lofiurn perenne) or tall fescue (Festuca arundinacea) grown under adequate soil nutrient conditions (e.g., Olsen P 20-30 pg/g) and under continuous or rotational stocking by sheep. Pasture production, as measured by the stocking rate required to maintain specified sward conditions, was 2.5% greater on perennial ryegrass than on Yorkshire fog pastures, and 25% greater on Yorkshire fog than on tall fescue. Differences in liveweight gain and wool production in weaned lambs between pastures were relatively small and inconsistent, but levels of worm egg output were lower for lambs on Yorkshire fog than on tall fescue. The use of polyethylene glycol to bind condensed tannins reduced performance slightly in lambs on Yorkshire fog and tall fescue, but not those on perennial ryegrass. Keywords: condensed tannins, Festuca arundinacea, Holcus lanatus, lamb growth, Lolium perenne, wool production