MERINO STRAINS WITH HIGH WOOL PRODUCTION HAVE LOWER LIFETIME REPRODUCTION RATES

摘要

Previous studies have shown a negative genetic correlation between fleece weight and total weight of lamb weaned over three lambing opportunities. This study examined the reproductive performance of six different Merino strains in a Mediterranean environmental. Hogget clean fleece weight had a poor relationship with lamb output but when adjusted for body weight, it had a good relationship across strains except for the fine wool strain. The results indicate that strains that have higher wool production per unit body weight at hogget age will have a lower reproduction rate over their lifetime. This implies that strong selection for wool production will affect reproductive rate negatively. If strong emphasis is also placed on reducing fibre diameter, then this may exacerbate the negative effect. This may be related to a lower level of total fat reserves found in high wool producing sheep.