Susceptibility to tooth wear inherited

Waimarino Bulletin, Volume 1, Issue 9, 2 August 1983, Page 10

Susceptibility to tooth wear inherited

Susceptibility to tooth wear in sheep is inherited and selection could effectively reduce the rate of wear. Scientists at Ruakura Animal Research Station measured tooth wear in nine Romney and Crossbred groups. They found that genetic variation among genotypes accounted for most of the variation in the wear rate. Border Leicester derived animals showed most tooth

wear and Merino derived animals the best. Romneys and Perendales were intermediate. There was also considerable variation among sires within breeds. The scientists said the trial did not help explain what causes tooth wear, or wear differences between regions or diets. Meanwhile a study carried out by a scientist at Wallaceville Research Station has shown that rotational grazing hoggets over winter reduces toothwear substantially. Grazing systems Derek Kane compared sheep toothwear under

winter set stocking and rotational grazing systems in the Wairarapa. "By the end of the 104-day trial, tooth length had decreased by 1.5mm in the rotational grazing study and 2.7mm in the set stocking group," Mr Kane said. "Wear was greater in the set stocking hoggets regardless of their weight gains relative to the rotational grazing hoggets." Mr Kane said relationships between toothwear and liveweight or liveweight change were small or nonexistent. The low correlations between wear and liveweight suggested that heavier sheep might, as a consequence of having to eat more and therefore use their teeth more, experience slightly greater tooth wear to develop a weight advantage.