Effect of limited or interrupted nursing on reproductive performance of beef cows

The objective of this experiment was to study, the effects of limited or interrupted nursing on reproductive performance of crossbred beef cows (5/8, 3/4 and 1/2 Charoles-Zebu). One hundred and 120 pregnant cons were nisrribrlied in two consecutive years, ill a completely randomized design with four treatments. T1 - cow and calf together all day long (control), T2 - once-a-day nursing, T3 - same as T1 with temporary calf removal for five consecutive days, every 30-day intervals, and T4 - same as T2 with temporary calf removal for five consecutive days, every 30-day intervals. The treatments did not differ regarding to cow weight ((X) over bar = 351kg) at the end of the breeding season. The reproductive efficiency of the cows was affected by rite suckling treatment during the 90-day breeding season, The cumulative percentages of cows showing estrus for T1, T2, T3 and T4 at the end of the breeding season were 47.3, 72.7, 76.4 and 90.9%, respectively. The pregnancy rate was also improved by controlled nursing. Conception and birth rates were lower for the control group (41.8 and 36.4%) compared to 69.0 and 63.6% for T2, 70.9 and 65.4% for T3 and 78.2 and 72.7% for T4, respectively. Higher weaning rare and total calf weaning weighs (kg of calf weaned for all cow) in the following year, were observed for the cows submitted to the controlled nursing treatments, with values of 61.8% and 5043kg, 61.8% and 4741kg and 69.1% and 5293kg for T2, T3 and T4, respectively, compared to 36,4% and 3180kg for the control group.