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Abstract
Genetic parameters were estimated from test data on 8234 Landrace, 4448 Yorkshire and 1122 Hampshire pigs from the Swedish progeny/sib testing stations. Feed conversion ratios (kg feed/kg gain) were on average 2.81, 2.75, and 2.85 for Landrace, Yorkshire and Hampshire pigs respectively. Heritabilities for feed conversion ratio were 0.25, 0.36, and 0.14, for percentage refused feed 0.20,0.14, and 0.18, and for daily gain 0.26, 0.23, and 0.09 for Landrace, Yorkshire and Hampshire pigs respectively. Genetic correlations between feed conversion ratio and daily gain were -0.96 and -0.98, between feed conversion ratio and lean percentage -0.44 and -0.55 and between feed conversion ratio and meat colour -0.32 and -0.36 for Landrace and Yorkshire respectively. Hampshire pigs had lower genetic variation than the other breeds for all traits except percentage refused feed. Index selection, including lean percentage, daily gain, feed conversion ratio and meat colour as measurements, was predicted to increase the percentage refused feed. Possible ways of avoiding undesirable responses are discussed.