Forty Holsteincows, with previous reproductive problems, empty, at second or more lactations,with an average milk production of 9,200 kg in the previous lactation and adry period over than 50 days were distruibuted in two groups to evaluate twoprotocols of milking induction. It was given to group 1, on days one, eightand 21 recombinant bovine somatotropin-bSTr (500 mg); from day two to eight,estradiol cypionate (0.075 mg/kg BW) and medroxi progesterone acetate (0.25mg/kg BW); from days nine to 15, estradiol cypionate (0.037 mg/kg BW); on day19, prostaglandin F2α(0.530 mg) and from days 19 to 21, isoflupredone acetate (0.05 mg/kg BW). Grouptwo was given, on days one, eight and 21, bSTr (500 mg), from days 2 to 15,estradiol benzoate (0.071 mg/kg BW), from days two to eight, acetate of medroxiprogesterone (0.25 mg/kg BW), day 19, prostaglandin F2α(0.530mg) and from days 19 to 21 isoflupredone acetate, (0.05 mg/kg BW). Teats andudders of all cows were massaged for five minutes from day 17 to 21. Milkingwere carried out from the 22nd day of induction. After beginningof lactation, both groups were given bsTr (500 mg) every 14 days. It was useda complete random design with 20 replicates per treatment and a split-plot scheme.Evaluation of the protocols was carried out by using analyses of variance usingFisher´s test at 5% and production of milking per day using regressionanalyses. Milking was successfully induced in 85% of the animals. Animals fromgroup 2 showed production mean 21.9 ± 12.9 kg of milk/day which was higherthan group 1 mean 18.9 ± 11.5 kg of milk/day. There was no differencefor milk composition in either groups. Twenty-nine cows were inseminated and41.1% became pregnant.
