Bone growth in the indigenous Nigerian pigs as a function of age, sex and body weight

Abstract

SummaryThe left half carcasses of 64 female, 64 castrated male and 64 intact male indigenous Nigerian pigs were dissected in order to study the bone growth between birth and 672 days of age. Total bone weight as well as the weights and lengths of femur, tibia–fibula, humerus and radius–ulna were studied at 16 ages. While bone weights increased between 34 and 45 times from birth to the terminal age range, bone lengths on the average only quadrupled within the same period. Maximum growth in bone weight occurred at 112 days of age whereas bone length attained maximum growth rate at 56 days of age when the body weights had averaged 15·8 and 6·2 kg respectively.Beyond these body weights, the growth rates declined. Although sex differences for total bone weight were not significant, the individual long bones studied exhibited significant sex differences. Highly significant age and sex influences were obtained for the relative bone weights.The growth coefficientsbdetermined for the individual bones and total bone using the logarithmically transformed allometric equationY=oXb, ranged from an average of 0·76 for radius–ulna to O·80 for femur. Pooled values for total carcass bone was 0·84. The values agreed with those reported in literature with side weight as independent variable, and confirm bone to be early developing. Bone lengths were related more to body weight than to chronological age as judged by theR2values. In all the bone traits studied, intact male pigs showed larger values than the castrated male and female pigs.