Effects of nutrition and paring on linear hoof growth in sheep

Abstract

Paring increased the linear hoof growth on the forefeet of Merino wethers by an average of 4.1% (P < 0.05) with a tendency for paring to promote faster growth on the medial digits. Effects of feeding these sheep with 400, 600, or 1000 g pelleted ration day-1 were assessed in a 4 X 4 Latin square design with 28-day periods using four measures of response. An extra (fifth) period was used to determine residual effects. The proportion of residual (carryover) to direct effect was much smaller for hoof growth than for wool. Hoof growth was not related to wool production. In another experiment, hoof growth rate of sheep increased from 103 to 136 8m day-1 when the intake of digestible dry matter was increased from 400 to 600 g day-1 (P< 0.001), and from 115 to 125 8m day -1 (P> 0.05) when the intake of digestible nitrogen was increased from 12 to 25 g day-1. Hoof growth rates of Merino wethers grazing native or sown pasture were not significantly affected by injecting DL-methionine daily into the abomasum. Hoof growth is not an appropriate index of wool growth. It may provide an easily measured, rapidly responsive and cumulative measure of nutritional changes, but its use cannot be recommended until more information is available on the factors that affect it and their interaction with ambient temperature.