A. Clinquart et al., PLASMA HORMONES AND METABOLITES IN CATTLE IN RELATION TO BREED (BELGIAN-BLUE VS HOLSTEIN) AND CONFORMATION (DOUBLE-MUSCLED VS DUAL-PURPOSE TYPE), Veterinary research communications, 19(3), 1995, pp. 185-194
Four Belgian Blue double-muscled type (BBDM) bulls, four Belgian Blue
dual-purpose type (BBDP) bulls and four Holstein bulls were used in a
fattening trial in order to relate differences in the extent of muscle
development and adiposity to differences in digestibility, endocrine
status, protein and lipid metabolism. The larger muscle development in
BBDM animals was associated with a trend to higher nitrogen retention
, higher food conversion efficiency (p<0.05) and lower apparent digest
ibility (p<0.05). No difference was found between the groups for plasm
a glucose concentration. Higher creatinine, lower alpha-amino nitrogen
, lower triglycerides and higher non-esterified fatty acid plasma leve
ls were observed in BBDM as compared to Holstein bulls (p<0.05), the B
BDP group being intermediate. A trend to a higher cholesterol plasma r
evel was found in BBDM animals. There was no difference between the th
ree groups in plasma fatty acid composition, except for the C-14:0 con
tent. Some of the differences in plasma metabolites were related to ca
rcass composition and endocrine regulation, a decrease in muscle devel
opment and an increase in adiposity being associated with lower growth
hormone production (p<0.05) and higher insulin (p<0.05) and IGF(1) se
cretions. The insulin/growth hormone ratio at the end of the fattening
period was 0.0011, 0.0018 and 0.0069 in BBDM, BBDP and Holstein bulls
, respectively, and was directly associated with fat deposition.