Lactation Response of Dairy Cows Receiving Bovine Somatotropin via Daily Injections or in a Sustained-Release Vehicle

Abstract

Three experiments were conducted to characterize metabolic and milk production responses of dairy cows receiving recombinantly derived bovine somatotropin administered either by daily injection or in a sustained-release vehicle. In Experiment 1, somatotropin (25 mg/d) purified by two methods was given by daily injection for 14 d and resulted in 3.5 and 3.8 kg/d more milk than controls. Percentages of fat and total solids in milk were also increased by somatotropin. Eleven hematology indices and 12 metabolites, minerals, and enzyme activities in serum were unaffected by somatotropin. In Experiments 2 and 3, somatotropin was administered in a sustained-release vehicle during an 84-d treatment period. In Experiment 2, administration of 960 mg of somatotropin at 28-d intervals increased milk and SCM yields by 4.1 and 3.3 kg/d compared with yields of controls. There were no significant differences in other production parameters. In Experiment 3, 320, 640, and 960 mg somatotropin were each administered in the sustained-release vehicle at intervals of 14, 21, and 28 d. An uninjected group served as control. Cows receiving somatotropin averaged 3.5 to 5.9 kg/d more milk than controls across all injection intervals. Among doses, milk yield was greater at 960 mg than at 320 or 640 mg. There were no significant differences in milk or SCM among injection groups. These experiments demonstrate the comparable efficacy of somatotropin when given by daily injections or in a sustained-release vehicle.

Production response of multiparous Holstein cows treated with bovine somatotropin and fed diets enriched with n-3 or n-6 fatty acids

“…The prolonged interval of negative EB delayed replenishment of body reserves, because BFT did not increase as quickly after the nadir in bST-treated cows. Although bST reduced BW and BCS, differences between overall treatment means were small and comparable with previous reports (McGuffey et al, 1990). Dohoo et al (2003) estimated that 200 d of bST administration reduced BCS by approximately 0.2 units, and we detected a comparable 0.25 ± 0.09-unit reduction.…”

The effect of bovine somatotropin in a sustained release preparation (Somidobove) on milk production of cows at pasture in New Zealand

“…This was a similar level of response to that obtained with a similar bST preparation in concentrate-fed cows (Oldenbroek et al 1989;McGuffey et al 1991). The study reported below was carried out with a sustained release preparation of bST (Somidobove, at two doses) as used in other trials (Oldenbroek et al 1989;McGuffey et al 1990McGuffey et al , 1991Valentine et al 1990). As well as determining responses in yield and composition, parameters of animal health, including maintenance and success of pregnancy and subsequent animal performance, were also examined.…”

Effect of rbST on Serum Biochemical Values During Various Physiological and Weather Conditions in Kundhi Buffaloes

“…In another study by McShane et al, [39] a slight lowering of urea concentration at 2, 3 and 4th week of bST treatment was observed. In contrast, Annexstad et al, [44] and McGuffey et al, [45] determined slight higher serum urea in dairy cow after administration of rbST. Limited information is available about the effects of rbST on proteins metabolism of domestic animals than for either lipid or carbohydrate metabolism.…”