This study aimed at determining the association between reproductive indexes and total milk yield in non-planed lactations ≥600 days sub-fertile Holstein cows treated or not with recombinant bovine somatotropin (rbST) experienced prolonged hyperthermia. A of 1141 a single lactation were enrolled study: 622 rbST (control) 519 (500 mg every 14 throughout lactation). Across parities, control >4...

Negative energy balance associated with the onset of lactation results in hypoinsulinemia, uncoupling of the IGF-somatotropin axis, attenuation of gonadotropin release and delayed first ovulation. Our objectives were to examine the effects of elevated insulin during the immediate postpartum period on circulating IGF-I concentrations, ovarian follicular growth, estradiol secretion and LH pulse p...

The effects of somatotropin (STH) and energy intake on serum concentrations of glucose (GLU), insulin (INS), nonesterified fatty acids (NEFA), urea nitrogen (UN) and insulin-like growth factor-I (IGF-I) were determined in 40 Angus heifers. At 7 mo (208 +/- 8 d) of age heifers were assigned to four treatment groups: 1) vehicle (V) + high energy (HE; 2.68 Mcal ME/kg DM), 2) recombinant DNA-derive...

We describe a new "sandwich"-type non-isotopic immunoassay for human somatotropin (GH, growth hormone) in serum. In the assay, GH is captured by a monoclonal antibody immobilized in a white microtiter well and simultaneously reacted with a second biotinylated monoclonal antibody. The degree of binding of biotinylated antibody, which increases with increasing amount of GH in the sample, is quant...

Eight multiparus lactating goats, matched for parity and days in milk were used to evaluate the effects of recombinant bovine somatotropin (rbST) administration on milk yield and composition, as well as on certain metabolic parameters. The experiment was a switch-back design, with three periods lasting 28 days each. Animals were divided into two groups (n ˆ 4) and treatments consisted of subcut...