Castration experiments with Yugoslav Simmental cattle. I. The effect of castration on growth and live-weight gains

Abstract

1. Bulls and steers of the Yugoslav Simmental breed (38 in total) were reared and fattened to 470 kg live weight. Half received a moderate level of feeding to 8 months of age and half a high level of feeding over this period; all were fed on a high level from 8 months to slaughter, their diet involving a concentrate mixture, lucerne hay and maize silage.2. At slaughter weight, steers were 2·5% higher at withers than bulls, but other body measurements showed no significant difference.3. Castrates needed a 3 to 8% longer fattening period depending on the feeding treatment.4. Castration reduced the rate of live-weight gain by 4·9% over the whole rearing and fattening period, and by 8·0% over the fattening period only.5. Bulls had better feed conversion ratios overall. Steers consumed more starch units per kg of live-weight gain—8·1% more over the whole rearing and fattening period and 9·8% over the fattening period. Consumption of digestible crude protein was also higher in steers.6. The detrimental effect of castration was more strongly expressed on the HH feeding treatment. An increase in the concentration of the rations did not improve food conversion ratios.