Low doses of bovine somatotropin during the transition period and early lactation improves milk yield, efficiency of production, and other physiological responses of Holstein cows.

The objectives of this experiment were to determine whether low doses of bovine somatotropin (bST) during the transition period and early lactation period improved dry matter intake (DMI), body weight (BW), or body condition score (BCS); provoked positive changes in concentrations of somatotropin, insulin, insulin-like growth factor-I (IGF-I), glucose, nonesterified fatty acids, and Ca; or improved milk yield (MY) response without obvious adverse effects on health status. Eighty-four multiparous Holstein cows completed treatments arranged in a 2 x 3 x 2 factorial design that included prepartum and postpartum bST, dry period (30 d dry, 30 d dry + estradiol cypionate, and 60 d dry), and prepartum anionic or cationic diets. Biweekly injections of bST began at 21 +/- 3 d before expected calving date through 42 +/- 2 d postpartum (control = 0 vs.

Milk production and feed intake of Holstein cows given short (30-d) or normal (60-d) dry periods.

Eighty-four Holstein cows were utilized to evaluate effects of dry period (60 d vs. 30 d), with or without estradiol cypionate (ECP) injections to accelerate mammary involution, on prepartum and postpartum dry matter intake (DMI), body weight (BW), body condition score (BCS), and subsequent milk yield (MY). Treatments were arranged in a 3 x 2 x 2 factorial design that included dry period (30 d dry, 30 d dry + ECP, and 60 d dry), prepartum and postpartum bovine somatotropin (bST; 10.