Abstract
Abstract Feed cost is the largest expense in developing dairy heifers with improved reproductive performance there is opportunity to reduce costs through decreasing days on feed to first calving. The objective of this study was to compare the economic impact of a 14-d CIDR pre-synchronization protocol to no pre-synchronization in Holstein heifers during an 84-d breeding period. Heifers were divided in two treatment groups 1) 14-d CIDR pre-synchronization (pre-synch; n = 20) and 2) control (n = 16). Heifers in the pre-synch treatment received a CIDR on d -30 which were removed on d -16. On d 0 (day of breeding eligibility) heifers in both groups were administered PGF2α and an Estrotect patch for estrus detection. On d 0, body weight of the heifers was estimated using a heart girth tape for large breeds. Estrotect patches were assessed once daily in the morning and heifers with ≥ 50% of the patch scratched received AI the same morning with Holstein sexed semen. After AI, heifers received a new Estrotect patch to facilitate return to estrus. Heifers that failed to express behavioral estrus within 14 d after PGF2α administration received another dose of PGF2α every 14 d until the first behavioral estrus was observed. Approximately thirty days after AI, heifers were subjected to ultrasonography of uterine contents for pregnancy diagnosis, and re-confirmed pregnant at ~60 d. Heifers diagnosed open received an injection of PGF2α and a new Estrotect patch. Partial budget analyses utilize these prices: feed cost ($1.75/heifer/day), PGF2α ($3.29/dose), needle and syringes ($0.12/per injection), Estrotect patch ($1.20/unit), AI procedure ($10.00/AI), semen ($35.00/straw), CIDR ($16.60/unit), pregnancy diagnosis ($5.00/heifer), overall labor ($0.41/heifer/day), and extra labor for CIDR group ($1.25/heifer). The partial budget was calculated per heifer and per pregnant heifer by charging pregnant heifers the cost of the remaining open heifers at the end of the 84-d period. There was no difference (P ≥ 0.26) in weight at d 0 (399.9 ± 15.2 vs 398.4 ± 15.8 kg), age at d 0 (371.6 ± 8.7 vs 371.5 ± 8.9 d), days to first AI (6.85 ± 2.28 vs 6.27 ± 2.50 d), days to pregnancy (20.55 ± 7.52 vs 14.09 ± 8.22 d), average number of services (2.10 ± 0.30 vs 2.06 ± 0.34 AI/heifer), average number of services to pregnancy (1.56 ± 0.24 vs 1.50 ± 0.27 AI/heifer), proportion of heifers receiving AI in the first 7 d (85.0 ± 8.0 vs 68.8 ± 11.6 %), proportion of heifers pregnant at first service (50.5 ± 12.5 vs 56.4 ± 13.5 %) and final pregnancy rates (80.0 ± 8.9 vs 75.0 ± 10.8 %) for pre-synch and control, respectively. Average cost per animal ($ 194.50 ± 30.27 vs 170.44 ± 33.85) and average cost per pregnancy ($ 243.12 ± 37.16 vs 206.95 ± 42.91) were not statistically different (P ≥ 0.53) between pre-synch and control, respectively. In summary, the use of a 14-d CIDR pre-synchronization did not have a significant economic impact on the performance of Holstein heifers during an 84-d breeding period.