9 COMPARATIVE EFFICACY OF AN 8-DAY Cue-Mate®/ESTRADIOL BENZOATE PROGRAM WITH OR WITHOUT INCLUSION OF EQUINE CHORIONIC GONADOTROPIN IN ANESTROUS DAIRY COWS
M. A. Bryan, R. Emslie and C. Heuer
Reproduction, Fertility and Development
20(1) 85 - 85
Published: 12 December 2007
The objective was to quantify and compare the reproductive response of lactating, seasonally calving dairy cows diagnosed with anovulatory anestrus (AA) to treatment with two separate progesterone (Cue-Mate®, Bioniche Animal Health, Australasia, Armidale, NSW, Australia) and oestradiol benzoate (ODB) treatment regimes, either including or excluding eCG. Cows on six commercial seasonal-calving dairy farms in New Zealand (n = 2355) were presented following 3 weeks of tailpainting and a subsequent non-observed estrus. Cows which were confirmed in anestrus with no detectable corpus luteum (CL) by rectal palpation were selected for trial inclusion (n = 1382). All cows received the standard anestrous protocol, consisting of an 8-day insertion of the progesterone device containing 1.56 g of progesterone (Cue-Mate; injection of 2 mg of ODB at the time of insertion and further injection of 1 mg of ODB 24 h after Cue-Mate removal (Day 9)). Approximately half of the cows were randomly allocated (using the RAND function within Excel, Microsoft) to a further intervention consisting of an injection of 400 IU of eCG (Pregnecol®, Bioniche) on the day of Cue-Mate removal (Day 8). This became the Treatment group with the standard treatment the Control group. Cows were then mated to detected heats; all cows not detected in estrus and inseminated were blanket-mated 36 h after the second ODB treatment. Cows were scanned ultrasonically 10 weeks post-treatment and all pregnancies were aged to the nearest half-week. Where two matings were recorded within 7 days of each other, the later mating was used. Data were analyzed using both a matched logistic regression analysis and survival analysis, using SPSS (SPSS.com) and SAS (SAS.com). Pregnecol-treated cows were more likely to conceive in the first 48 h following treatment (48.84% v. 43.10%; P = 0.06), and were more likely to be in calf within 7 days following treatment (P = 0.07). The effect of Pregnecol was greater in cows over 5 years of age, such that this stratum of cows was significantly more likely to conceive within 48 h [58.33% v. 38.10%; P = 0.00; adjusted relative risk (RR) 1.51; 95% lower confidence interval (LCI) 1.15; 95% upper confidence interval (UCI) 2.00], and was significantly more likely to be in calf within 7 days (55.20% v. 37.86%; P = 0.00; RR 1.44; LCI 1.41; UCI 1.82). Pregnecol-treated cows over 5 years of age were significantly more likely to be in calf at 4 weeks (72.22% v. 59.57%; P = 0.02; RR 1.21; LCI 1.03; UCI 1.42). Cows that had calved less than 50 days were significantly less likely to be in calf by 4 weeks (62.26% v. 69.35%; P = 0.04). In summary, the addition of a 400 IU treatment of eCG (Pregnecol) at the time of Cue-Mate removal in a standard 8-day progesterone device/ODB anestrous treatment program increased the risk of pregnancy. The effects of eCG on cows over 5 years of age were very strong and highly significant.
Full text doi:10.1071/RDv20n1Ab9
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