ANATOMICAL, PHYSIOLOGICAL AND BIOCHEMICAL DIFFERENCES BETWEEN CONVENTIONAL AND DOUBLE-MUSCLED CATTLE IN THE BELGIAN BLUE AND WHITE BREED

Some morphological and physiological characteristics of the culard phenotype have been studied on 'conventional' and 'double-muscled' animals slaughtered at a constant weight of 83 kg (experiment I) or at a constant age of 1 year (experiment II). Muscle hypertrophy of the culard occurs at the expense of other organs (thymus, spleen,*** ) or tissues (fat, bones) which are relatively hypotrophied. Haematocrit appears to be significantly lower in double-muscled animals. On the contrary, plasma creatinine concentration is much higher in the culard (+60% at 4.5 months, +35% at 12 months). Therefore, plasma creatinine concentration may be a useful laboratory test to distinguish between these two bovine phenotypes. However, this excess in creatinine concentration cannot be accounted for by the muscular hypertrophy alone which amounts to some 20% in the 'double-muscled' animals. © 1979.