Castration method and progesterone-estradiol implant effects on growth rate of suckling calves.

Eighty male calves nursing their dams and averaging 15 d of age were used to evaluate a method of nonsurgical castration and a growth implant in a 196-d experiment. On the 1st d of the experiment, 40 calves were castrated chemically using Chem-Cast (active ingredient: lactic acid 88% wt/wt), and 40 were castrated surgically. Twenty calves on each castration treatment were implanted with STEER-oid on d 1 and reimplanted on d 121 while 20 calves on each treatment were not implanted on either date. Chemical castration resulted in significantly lower scrotal edema and a trend toward increased rate of gain at d 28. Castration treatment did not affect 196-d rate of gain and weaning weights of calves. On d 121, bilateral castration was determined in 30 of 40 chemically castrated calves, a condition that persisted on d 196, resulting in a 75% castration rate. Implanted calves had rates of gain that were 14, 6, and 4% higher, respectively, on d 28, 121, and 196 compared with unimplanted calves.