Physiological attributes as possible selection criteria for milk production 3. Plasma hormone concentrations and metabolite and hormonal responses to changes in energy equilibrium

Abstract

1983). Physiological attributes as possible selection criteria for milk production 3. Plasma hormone concentrations and metabolite and hormonal responses to changes in energy equilibrium. Request Permissions : Click here Downloaded from http://journals.cambridge.org/ASC, IP address: 205.175.97.198 on 05 Apr 2015 Arum. Prod. litf. J7: 165-178 (*K)3-.V6l/83/23010165$()2'H0 ABSTRACT Plasma hormone concentrations and metabolite responses to changes in energy equilibrium were measured in experiments designed to compare a) Hereford x Friesian with Friesian calves and b)Friesian calves sired by bulls with a high level of Improved Contemporary Comparison with those sired by bulls of a low level. The concentration of thyroxine and triiodothyronine tended to be greater in calves of higher dairy merit. The concentration of growth hormone was largely unrelated to dairy merit in the circumstances studied. The concentration of insulin was greater in Hereford x Friesian than in Friesian calves following feeding and following the injection of propionate. Responses to the injection of insulin and of growth hormone (as measured by changes in the plasma concentration of urea nitrogen, free fatty acids, glucose or the other hormone) were little affected by the level of Improved Contemporary Comparison of a calfs sire.It was concluded that the thyroid system and the response of insulin to perturbation of energy balance may provide criteria of genetic merit for milk production which are neither age-nor sex-limited.

Plasma metabolite and hormone concentrations in Friesian calves of low or high genetic merit: effects of sex and age

“…This elevated blood glucose of HBI animals is consistent with previous studies of the Massey University selection lines (Flux et al, 1984;Xing et al, 1988;Xing, 1989). It is, however, important to note that while differences with respect to circulating insulin have been obtained consistently with the Massey University selection lines, they have not been observed with other dairy cattle selection lines (Land, Carr, Hart, Osmond, Thompson and Tilakaratne, 1983;Serjsen et al, 1984;Barnes, Kazmer, Akers and Pearson, 1985;Sinnett-Smith et al, 1987). Alternatively, the greater basal glucose levels in the HBI calves may have arisen from a decreased glucose utilization by peripheral tissues.…”

Rôles et mécanismes d'action de la somatotropine (hormone de croissance) chez le ruminant en lactation

“…Il est cependant possible que les races ou les individus à fort potentiel laitier présentent, à bilans nutritionnels comparables, des taux de somatotropine endogène plus élevés, bien que les données existantes soient peu nombreuses et contradictoires (Hart, 1983 ;Land et al, 1983 ;Truscott et al, 1983 ;Flux et al, 1984 ;Barnes et al, 1985 ;Lukes et al, 1987 ; Oyler, 1987 , et plus récemment avec des formes « retard » de la somatotropine recombinée.…”

Blood Composition of Different Beef Breed Types

“…Blood components are related to fertility, growth and body composition in cattle (Blum et al 1983; Land et al 1983;Rowlands et al 1983). Selection experiments designed to change some blood components in poultry (McClung et al 1972) and mice (Tilakaratne et al 198 I ; Yamaki and Mizuma 1982) have been successful.…”

“…Comparison of blood composition in different biological types of dairy cattle (Tilakaratne et al 1980;Land et al 1983; Roy et al 1983;Flux et al I 984), and dairy and beef crossbreds (Blum et al 1983) have been reported. Correlated changes of blood composition in pigs selected for growth rate and reduced backfat have also been examined (Bakke and Tveit 1977; Mersmann et al 1982).…”

“…Cattle in the second study consisted of 48 purebred Shorthorn cows ranging in age from 2 to l0 yr and their calves. Twenty-three of these cows belonged to a line that had been selected for yearling weight for a total of 14 yr and the other 25 were from a nonselected control line (Newman et al 1973 (Tilakaratne et al 1980), higher concentration of T3 and T4 (Land et al 1983), and higher level of glucose (Flux et al 1984) For personal use only. (Smith and Goodman 1970) in chickens and to growth rate and milk production in mice (Yamaki and Mizuma 1982).…”