Growth, slaughter and intra-muscular collagen characteristics in Garganica kids

Growth performance, ossification of metacarpal growth plate, and intra-muscular collagen characteristics in three muscles of 10 intact male Garganica kids were studied. Each week, starting from the 47th day of age to slaughter (75th day of age), kids were weighed and blood samples taken for plasma non-protein hydroxyproline analysis. At slaughter, metacarpal, metatarsal bones and metacarpal growth plate thickness were measured. The semitendinosus (ST), semimembranosus (SM), and rectus medialis (RM) muscle samples were analysed for collagen concentration and hydroxylysyl pyridinoline (HP) cross-links. ST muscle had a collagen amount higher than SM and RM (P<0.01), and RM muscle had the highest (P<0.01) HP concentration. Tenderness index was the highest (P<0.01) in RM muscle. Animal growth rates slowed, starting from 61st day of age (P<0.01); this trend coincided with a marked reduction in concentration of plasma non-protein hydroxyproline (P<0.01). In addition, plasma non-protein hydroxyproline concentration was positively correlated (r=0.61, P=0.001) with growth rate of animals, suggesting that collagen turnover decreases during a slow growth phase. Based on the metacarpal growth plate width, the rate of bone ossification appears to be slower in goats than sheep.