Abstract:
Three experiments were conducted to test the hypothesis that increased naturally occurring breech bareness would reduce the incidence of breech strike. Breech bareness was scored from 1 where wool was growing around the edges of the anus (and vulva in females) to five where there was an extensive area bare of wool (50 cm2 on a 23 kg lamb). There were very few lambs with a bareness score of 5, so for the purposes of these experiments score 4 and 5 were pooled for analysis. The first experiment showed no significant difference between breech bareness scores, although the trend was similar to subsequent experiments. The second (P<0.05) and third (P<0.10) showed that lambs with breech bareness scores of 4 or greater were much less likely to be flystruck. Females had slightly greater mean breech bareness score than males (2.3 vs 2) but were more susceptible to flystrike (P<0.05) in the first experiment. For management reasons, males and females were run in separate mobs in the second and third experiments. Overall, 22%, 16%, 11%, and 0% of lambs were flystruck when they had breech bareness scores of 1, 2, 3 and 4 or greater respectively. Considering the negligible loss of wool, the labour savings, the reduced suffering due to flystrike and the appeal to modern consumers, the trait seems a worthy selection goal.
