Levels of first winter feeding in relation to performance of Cheviot hill ewes V. Dental development and persistence

Abstract

1. The effects of different levels of first-winter nutrition over 3 years were studied on the subsequent dental development of groups of North and South Country Cheviot ewe hoggs (sheep between months and 1½ years) by recording the time eruption of each of the four pairs of permanent incisors. High-plane first-winter feeding resulted earlier eruption of the first pair of permanent incisors. Later pairs were affected to a lesser extent, with low-plane/hill-wintered groups consistently the latest to erupt. Breed and year deviations from the general pattern were small and were largely due variations in growth rate both prior to and during treatment.2. The effects of first-winter treatment were also studied on the heavy and light hoggs (i.e. those above and below average weight) prior to treatment. Although there was only a very limited difference the time of eruption of the heavy and light within each treatment group, the effects of treatment were greater in the heavy-weight class than they were the light.3. The effects of first-winter treatment on dental efficiency and long-term persistence were also studied. There was little difference amongst treatments at 5½ years of age in the bite position, or looseness, wear, or condition of the teeth. Brokenmouth, i.e. the loss of one or more permanent incisors, did not appear in significant proportions until 7½ years of age, when considerable treatment, breed, and year differences were present. The incidence of broken-mouth was lowest in the high-plane and hill-wintered groups and highest in the lowplane and mid-plane/away-wintered.