Relation between Growth Rate, Serum Somatomedin and Plasma Testosterone in Young Bulls

Abstract

Twenty "Red Danish" bulls were tested for rate of gain, linear growth, longissimus muscle area and efficiency of feed utilization from the age of l'h to 12 months. These variables were correlated to blood concentrations of testosterone and somatomedin, which were measured at 4 to 5 months, 6 to 7 months and/or 8 to 10 months of age.Average testosterone concentrations of bulls above 6 months of age were found to be correlated negatively (P<.05) with feed utilization (feed units/kg gain). Average somatomedin activities throughout the test period were positively correlated with rate of gain (P<.05) and linear growth (P<.05), and negatively to feed utilization (P<.05). Also, the somatomedin activity was found to increase significantly from 6 to 7 months up to 10 months of age (P<.05). No significant correlation between testosterone and rate of gain, linear growth or longissimus muscle area was found, and, likewise, there was no significant correlation between somatomedin activity and longissimus muscle area.It is concluded that the blood level of somatomedin at an early age may represent a possible indicator of future growth capacity in young bulls. (

Plasma metabolite and hormone concentrations as predictors of genetic merit for lean meat production in sheep: Effects of metabolic challenges and fasting

“…Similar observations have been made in sheep (Olsen et aI. 1981) and in cattle (Ringberg Lund-Larsen 1977).…”

Profiles of serum IGF-I concentrations in calves from birth to eighteen months of age and in cows throughout the lactation Cycle

“…The reasons for the species differences in this sexuaf dimorphism are unknown. In the present study, a portion -0.22 -0.54 DISCUSSION The age-dependent increases in serum IGF-I levels found in the calftrial are in accordance with previous findings in mice (Blair et al 1987), rats (Handelsman et al 1987), pigs (Scanes et al 1987), calves (Lund-Larsen et al 1977;Holland et al 1988;Abribat et al 1990), chickens (Goddard et al 1988) and humans (Furlanetto et al 1977;Silbergeld et al 1986). With the exception of the report by Lund-Larsen etal.…”

Steroid Hormone May Modulate Hepatic Somatomedin C Production in Newborn Calves

“…levels in intact female baboons after administration of large doses of estro gens. In red Danish bulls rate of gain, linear growth and efficiency of fed utilization were correlated to blood concentration of testos terone and sulfation activity [15].…”

“…Effective ly, although IGF] elicits rapid metabolic changes in classical insulin target tissues, its primary function is believed to be a critical involvement in the multifactorial stimula tion of longitudinal body growth [ 15]. The liver has received greatest attention as a source of IGF and potential locus of IGF reg ulation.…”