Allometric growth of non-carcass components and hind limb tissue composition in saanen goat kids reared under natural and artificial systems

Abstract

The aim was to investigate the growth of certain non-carcass components and hind limb tissues using allometric coefficients in Saanen goat kids reared under natural and artificial systems and slaughtered at 80 days or 120 days of age. 42 Saanen kids were used in the study [(24 artificial reared kids (SA-80: 12 kids, SA-120: 12 kids), 18 natural reared kids (SA-80: 9 kids, SA-120: 9 kids)] for determination of indicated parameters. The effects of rearing system were not significant in weights of non-carcass components and hind limb tissue compositions, which indicate that, even though they were fed with milk replacers, artificial reared kids can have similar growth performance when they are slaughtered at similar age with natural raised kids. However, slaughter age had significant effect on many non-carcass components, since the weight of the organs increases in parallel with animal’s live weight. It is seen that allometric growth of non-carcass parameters, except skin and testis in both rearing groups and stomach and intestines in natural rearing, was slower (b<1) than EBW of kids slaughtered at 120th days of age. This result shows that when the Saanen kids will be slaughtered at later ages, the increase of live weight will be mainly due to the increased saleable carcass components. Additionally, tissue compositions showed that muscle growth continued rapidly (b=1.494 for natural and b= 1.251 for artificial reared) in both groups on the 120th day of age. This situation reveals that prolonging the fattening period with Saanen kids can increase meat production for both rearing systems. On the other hand, it is observed that the amount of both subcutaneous and intermuscular fat increased more rapidly at the 120th day of age in both groups. Therefore, the optimal slaughter age at 120th days should be determined by taking into account the possible increasing amount of fat.