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Welk, Allison

University of British Columbia

The objective of this study was to assess the effects of intake-based weaning methods and forage type on behaviour and growth of dairy calves. Holstein calves (n = 108) were randomly assigned to 1 of 3 weaning treatments: milk reduction by age (wean-by-age), individual dry matter intake (DMI) (wean-by-intake), or combination of individual DMI and age (wean-by-combination). Groups of calves were alternately assigned to 1 of 2 forage treatments: grass hay (Hay), or silage-based total mixed ration (TMR) (n = 6 groups per treatment). Until d 30, all calves received 12 L/d of milk. On d 31, milk was reduced by 25% of the individual’s average milk intake. For wean-by-age calves (n = 31), milk remained stable until d 62 when milk was reduced until weaning at d 70. For wean-by-intake calves (n = 35), milk was further reduced by 25% once calves consumed 200, 600, and 1150 g DM/d of solid feed. For wean-by-combination calves (n = 35), milk remained stable until calves consumed 200 g DM/d; milk was then reduced until weaning at d 70. If calves failed to reach DMI targets by d 62 (failed-to-wean, n = 10), milk was reduced until weaning at d 70. 27 wean-by-intake calves met all 3 DMI targets (successful-intake) and 33 wean-by-combination calves met the 1 DMI target (successful-combination). Successful-intake and successful-combination calves had greater body weight (BW) at 84 d than wean-by-age calves, followed by failed-to-wean calves (123.0 vs 121.6 vs 117.0 vs 100.1 ± 3.1 kg, respectively). During weaning, successful-intake calves ate more starter than successful-combination, wean-by-age, and failed-to-wean calves (1.18 vs 0.85 vs 0.49 vs 0.14 ± 0.08 kg DM/d, respectively). Hay calves had greater BW at 84 d than TMR calves (124.0 vs 119.0 ± 1.6 kg, respectively). During weaning, Hay calves consumed more starter than TMR calves (0.85 vs 0.65 ± 0.09 kg DM/d, respectively). Intake-based weaning can improve performance of calves that successfully wean, and grass hay can improve starter intake and growth around weaning. Some calves consume little solid feed before weaning; further research is needed to understand how these calves should be managed.

Text

2022-06-02

Attribution-NonCommercial-NoDerivatives 4.0 International

http://hdl.handle.net/2429/81686

Applied Animal Biology

University of British Columbia

UBCV

http://creativecommons.org/licenses/by-nc-nd/4.0/