Department of Animal Breeding, University of Helsinki
The phenotype testing of highly selected boars was studied. Two groups, each of 30 boars, were tested centrally at stations for growth rate and ultrasonically measured fat thickness. According to test points, made up of a combination of these two traits, the 5 best boars, 5 average boars and the 5 poorest boars where selected for progeny evaluation. In all 26 boars and 441 progeny were tested. The progeny evaluation showed that ultrasonic measurement of the fat thickness of the boars gave a very reliable estimate of the meatiness of their progeny. Those boars, as a group, giving the poorest carcass quality could be distinguished with statistical reliability from the other groups. The correlations between sires and progeny were significant for both daily gain (period 20—88 kg) and feed efficiency. The importance of rate of growth and feed efficiency has been neglected in selection for breeding as the test points used for the selection of boars depended almost entirely on fat thickness. More than 30 % of both boars and progeny boars suffered from some form of difficulty in walking. 13 % of the boars were eliminated because of leg faults. Leg faults in progeny were mainly inherited or caused through injury. A phenotype evaluation of progeny boars accounts much more effectively for the variation in their carcass value than does a full barrow sib evaluation alone. For best results, a progeny boar phenotype evaluation should be combined with a full barrow sib evaluation.
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