Abstract #T140

# T140
Weaning based on starter intake: Effects on weight gain and behavior.
Juliana Benetton1, Heather W. Neave1, Joao H. C. Costa1, Marina A. G. von Keyserlingk1, Daniel M. Weary*1, 1University of British Columbia, Vancouver, BC, Canada.

Automated feeders can be used to wean calves according to individual solid feed intakes. The aim of this study was to compare feeding behavior and performance of calves that were weaned based on individual starter intakes versus a step-down procedure based upon calf age. Dairy calves (n = 32) were randomly assigned to either step-down (Step) or individual starter intake weaning (ISW). All calves were offered 12 L/d milk until d 30 of age. At d 31, Step calves were reduced to 6 L/d of milk over 5 d and received 6 L/d milk from d 35 until d 63 when milk was reduced over 7 d until complete weaning at d 70. At d 31, ISW calves were reduced to 75% of that individual’s previous 3-d milk intake average. Milk was further reduced (by 25%) when calves consumed a 3-d rolling average of 225 g/d of starter. Milk was again reduced by 25% when calves reached 675 g/d, and then completely weaned at 1300 g/d. Milk and starter intake, number of unrewarded visits to the milk feeder and ADG were calculated for 3 periods: weaning (d31–70 for Step; d31 until 1300 g/d of starter was consumed for ISW), post-wean (d70–98 for Step; d of completed weaning until d 98 for ISW), and experimental period (d0–98). Over the experimental period, no difference in performance was found between treatments, but calves in the ISW treatment consumed less milk (123 ± 15.2 L) and more starter (47 ± 8.9 kg) compared with Step calves. ISW calves tended to gain more weight during the weaning period compared with Step calves (1.1 ± 0.1 vs 0.7 ± 0.1 kg/d) but there were no treatment differences during post-wean. ISW calves consumed less milk and ate more starter during the weaning period compared with Step calves (milk: 5.0 ± 0.2 vs 2.0 ± 0.2 L/d; starter: 1.5 ± 0.1 vs 0.6 ± 0.1 kg/d, respectively). However, ISW calves had more unrewarded visits to the milk feeder during weaning compared with Step calves (12.4 ± 1.6 vs 6.4 ± 1.2 visits/d, respectively). These results suggest that calves weaned based on individual starter intake consume less milk and eat more starter but show greater signs of hunger during the weaning period compared with calves weaned on a step-down method. Further research is needed to develop appropriate weaning methods.

Key Words: precision dairy, automated milk feeder, weaning