Metabolic Effects of Ovine Growth Hormone in Sheep

Abstract

SUMMARY The administration of 5 mg. ovine growth hormone (GH) per day for 4 weeks to adult sheep resulted in the retention of 0·5 g. nitrogen/24 hr. This is less than that reported to occur in man and dog with a similar dose of GH. Both plasma volume and red blood cell volume increased by 20 % during treatment. A small decrease occurred in the amount of sodium excreted, but no change in potassium excretion could be demonstrated. The water intake of the treated group declined during GH injections. Plasma glucose concentrations increased slightly during treatment but there was no alteration in the concentration of plasma free fatty acids or ketone bodies. Body weight did not change measurably with GH treatment. Wool growth decreased during treatment but then increased and remained above control values for at least 20 weeks.

Effects of Growth Hormone Administration on Wool Growth in Merino Sheep

“…The net retention of N during the period of GH administration is in accord with previous studies in the sheep (Manns and Boda 1965;Wheatley et at. 1966;Davis et at.…”

“…The depression in wool growth during treatment with GH and the subsequent protracted increase following the cessation of GH treatment is consistent with the findings of Ferguson et al (1965), Wheatley et al (1966) and Wallace (1979). However, while the observation that the decrease in wool growth resulted mainly from a decrease in fibre diameter agrees with the finding of Wallace (1979), the observation that the post-treatment surge in wool growth resulted from a proportional increase in both fibre length and diameter does not.…”

“…Similar results were obtained by Ferguson et al (1965) using crude extracts of sheep and ox pituitaries. Wheatley et al (1966) confirmed that the causative agent was GH by using a highly purified ovine GH preparation to obtain the same response. The cause of this response in wool growth is not yet known.…”

Identification of Polymorphism in the Keratin Genes (KAP3.2, KAP6.1, KAP7, KAP8) and Microsatellite BfMS in Merino Sheep Using Polymerase Chain Reaction-Single Strand Conformational Polymorphism (PCR-SSCP) Analysi

“…In contrast, no effect of recombinant growth hormone on CFW was found in a study by Zainur et al (1989). Wheatley et al (1966) found that growth hormone suppressed wool growth and that there was accelerated wool growth after withdrawal of growth hormone. Polymorphism at the genes encoding growth hormone have been reported (Valinsky et al, 1990;Wallis et al, 1998;Sami et al, 1999), and different alleles of growth hormone may affect wool growth in different ways.…”

Influence de l'hormone de croissance sur la production de viande chez les génisses

“…Cependant, les premières expérimentations consacrées à l'étude des effets de la GH exogène sur la croissance se sont souvent soldées par des échecs chez le porc, le mouton et le bovin (Turman et Andrews, 1955 ;Henricson et Ullberg, 1960 ;Wheatley, 1966 ;Vézinhet, 1973 ;Reklewska, 1974 ;Muir et al, 1983 ;Brumby, 1959 ;Znidar, 1976 (Adam et al, 1985). Un bref résumé est repris ci-dessous.…”