157 Impact of weaning strategy on heifer performance and reproductive development Academic Article uri icon

abstract

  • Abstract Weaning is recognized as one of the most stressful times of a beef calf’s post-natal life. The objective of this study was to determine if weaning strategy impacts heifer development and reproduction. At 7 months of age, 96 predominantly Angus heifers at 2 locations were assigned to 1 of 3 weaning treatments: abrupt relocation of the calf on d0 (Abrupt, n = 32), fenceline contact starting on d0 prior to relocation of the calf on d7 (Fence, n = 33), and abrupt relocation of the calf on d84 (Late, n = 31). Calf weights, hip heights, and body condition scores (BCS) were collected to evaluate post-weaning performance. Reproductive tract scores (RTS; 0–5 scale, 5=most mature) were assigned every 54 days from d56 to d218. Heifers were synchronized using a 7-day CO-Synch + CIDR® protocol and artificially inseminated (AI) on d246. Data were analyzed using PROC MIXED of SAS with repeated measures. Statistical significance was determined at P ≤ 0.05. Late heifers were heavier at d28 and d56 than Abrupt and Fence (P > 0.05), but BW was similar across treatments starting at d84. Average daily gain (ADG) was greater for Late than Abrupt (0.39 and -0.03 kg/day respectively; P > 0.01) and tended to be greater than Fence (0.16 kg/day; P = 0.07) to d28; however, Late had lower ADG than Abrupt and Fence from d28-84 (0.66, 0.83, and 0.81 kg/day respectively; P > 0.05). No treatment differences were observed in BCS or hip height. Late tended to have greater RTS than Abrupt and Fence (2.54, 2.20, and 2.16 respectively; P ≤ 0.10) on d56, but there was no difference on or after d164. Fence tended to have greater AI conception rates than Abrupt and Late (66%, 44%, and 42% respectively; P ≤ 0.08). This data indicates there were initial performance differences based on weaning strategy, but this had minimal impact on heifer development.

published proceedings

  • Journal of Animal Science

author list (cited authors)

  • Ott, G. C., Poole, R. K., Poore, M. H., & Pickworth, C. L.

citation count

  • 0

complete list of authors

  • Ott, Grace C||Poole, Rebecca K||Poore, Matt H||Pickworth, Carrie L

publication date

  • December 2019