Effect of forty-eight-hour calf removal, once- or twice-daily suckling and Norgestomet on beef cow and calf performance

Trials were conducted in 1980 and 1981 to evaluate the effects of once-daily suckling, twice-daily suckling, 48-h calf removal, and Norgestomet on performance of spring-calving cows and their calves. Eighty-three and 73 Polled Hereford and 29 and 42 Simmental-cross cows were utilized in 1980 and 1981, respectively. Cows were allotted by age, breed, calving date and winter nutrition treatment to one of four groups: 1) once-daily suckle for 24 d starting 11 d before the beginning of the breeding season, 2) twice-daily suckle (same time frame as 1), 3) 48-h calf removal ending immediately before the breeding season, 4) calves remained with cows (controls). One-half.of each group was implanted with Norgestomet from 11 until 2 d before the start of the breeding season. Once- and twice-daily suckling increased (P<0.05) the percentage of noncycling cows showing estrus the first 3 wk after the start of treatment. Pregnancy rates for the breeding season were higher (P<0.1) in the once-daily suckle and 48-h calf removal groups for cows that had not exhibited estrus before the beginning of treatment. Norgestomet increased (P<0.05) the percentage of cows showing estrus within 3 wk after the start of treatment within the 48-h calf-removal and control groups. Milk production was not affected (P>0.1) by suckling treatment. Calf weight gains during suckling treatment were greater (P<0.05) in control and twice-daily suckled calves than in 48-h calf removal or once-daily suckled calves. Suckling treatment did not affect (P>0.1) adjusted weaning weights of calves or frequency and duration of suckling recorded 2 wk after the end of suckling treatment.