a1 Agricultural Institute, Grange, Dunsany, Co. Meath, Ireland
Two experiments were conducted to compare the effects of single and double suckling on the performance of Hereford × Friesian and Friesian cows at pasture. Double-suckled cows each fostered a Friesian male calf in addition to their own calf. Cows were housed from calving to turnout for 57 and 35 days in experiments 1 and 2 respectively, with corresponding grazing seasons lasting 152 and 146 days. During the grazing season the two suckling treatments were stocked on a series of adjacent plots of equal area, with the occupancy of each plot pair being reversed daily. Live weights, milk yields, herbage intakes, and daylight grazing times and nursing activities were recorded on three occasions 28 days apart.
Double-suckled cows lost significantly more weight than single-suckled cows from calving to turnout in both experiments (39·5 v. 3·3 kg and 45·7 v. 20·6 kg), gained more weight from turnout to weaning in experiment 1 (58·4 v. 23·3 kg) but gained less in experiment 2 (17·5 v. 32·3 kg). Double-suckled cows produced significantly more milk than single-suckled cows: 10·1 v. 8·3 and 13·5 v. 9 1 kg/day in experiments 1 and 2 respectively. Differences in daily milk yield in experiment 2 were apparent 28 days after calving.
Suckling treatments did not influence herbage intakes or daylight grazing times and nursing frequencies. Mean nursing intensities were 1·0 calves per single-suckled cow, compared with 1·8 calves (experiment 1) and 2·2 calves (experiment 2) per double-suckled cow. Double-suckled cows nursed significantly more ‘foreign’ calves than single-suckled cows. Total calf weight at weaning from double-suckled cows in experiments 1 and 2 was respectively 364·6 and 344·4 kg, which was 1·64 of the corresponding weights weaned by single-suckled cows (221·1 and 209·4 kg).
(Received February 01 1982)
(Accepted April 21 1982)
p1 Present address: Whatawhata Hill Country Research Station, Private Bag, Hamilton, New Zealand.