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Friedman E.,The Hebrew University | Voet H.,The Hebrew University | Reznikov D.,Hachakleit Veterinary Services | Wolfenson D.,The Hebrew University | Roth Z.,The Hebrew University
Journal of Dairy Science | Year: 2014

Reduced conception rate (CR) during the hot summer and subsequent autumn is a well-documented phenomenon. Intensive use of cooling systems can improve summer and autumn reproductive performance, but is unable to increase CR to winter and spring levels. We examined whether combined hormonal treatments-to increase follicular turnover before artificial insemination (AI) and progesterone supplementation post-AI-might improve fertility of cooled cows during the summer and autumn. The experiment was conducted from July to November in 3 commercial herds in Israel and included 707 Holstein cows at 50 to 60 d in milk (DIM). Cows were hormonally treated to induce 2 consecutive 9-d cycles, with GnRH administration followed by PGF2α injection 7 d later, followed by an intravaginal insert containing progesterone on d 5±1 post-AI for 14 d. Both untreated controls (n=376) and treated cows (n=331) were inseminated following estrus, and pregnancy was determined by palpation 42 to 50 d post-AI. First-AI CR data revealed a positive interaction between treatment and cows previously diagnosed with postpartum uterine disease [odds ratio (OR) 2.24]. Interaction between treatment and low body condition score tended to increase the probability of first-AI CR (OR 1.95) and increased pregnancy rate at 90 DIM (OR 2.50) and at 120 DIM (OR 1.77). Low milk production increased the probability of being detected in estrus at the end of synchronization within treated cows (OR 1.67), and interacted with treatment to increase probability of pregnancy at 90 DIM (OR 2.39) relative to control counterparts. It is suggested that when administered with efficient cooling, combined hormonal treatment in specific subgroups of cows, that is, those previously diagnosed with postpartum uterine disease or those with low body condition score or low milk yield might improve fertility during the summer and autumn. Integration of such an approach into reproductive management during the hot seasons might improve treatment efficiency and reduce expenses. © 2014 American Dairy Science Association. Source


Goshen T.,Hachakleit Veterinary Services | Goshen T.,Hebrew University of Jerusalem | Galon N.,Hachakleit Veterinary Services | Galon N.,Hebrew University of Jerusalem | And 2 more authors.
Israel Journal of Veterinary Medicine | Year: 2012

The objective of this study was to evaluate the effect of uterine biopsy on the reproductive performance of dairy cows in commercial herds. Fifty four Israeli Holstein cows in four dairy herds were randomly allocated for uterine biopsy before first service and 157 control cows were paired-matched to the biopsy cows. Reproductive performance of biopsy cows was not poorer than that of the control cows. Biopsy cows did not differ significantly from the control cows in the first artificial insemination conception rates, 44.4% and 38.9%, respectively, and for pregnancy rate at 150 Days in Milking (DIM), 55.6% and 45.2%, respectively. Using survival analysis to compare time to pregnancy, biopsy and control cows did not differ significantly in their pregnancy rates until 150 DIM (log-rank test, P =0.246). These results suggest that uterine biopsy done in post involution cows is not a detrimental procedure and does not affect reproductive performance. Source


Friedman E.,The Hebrew University | Voet H.,The Hebrew University | Reznikov D.,Hachakleit Veterinary Services | Dagoni I.,Hachakleit Veterinary Services | Roth Z.,The Hebrew University
Journal of Dairy Science | Year: 2011

Reduced conception rate during the hot summer and subsequent autumn is a well-documented phenomenon. Evaporative cooling systems greatly increase milk production but only slightly improve reproductive performance; hence, additional approaches to improving fertility during the hot season are required. The purpose of the present study was to examine whether the combination of an efficient cooling system and hormonal manipulation (GnRH+PGF2α) might improve fertility during the summer and autumn. The experiment was conducted from July to December in 2 commercial herds in Israel and included 382 healthy Holstein cows. Cows (50 to 60 d in milk) were hormonally treated to induce 3 consecutive 9-d follicular waves, with GnRH administration followed by PGF2α injection 7 d later. Both control (n=187) and treated (n=195) cows were inseminated following estrus, and pregnancy was determined by palpation 45 d post-insemination. Data revealed an interaction between treatment and primiparous cows, reflected by a 16% increase in conception rate [odds ratio (OR) 2.32, 95% confidence interval (CI): 0.96-5.61] and 14% increase in pregnancy rate at 120 d in milk (OR 3.16, 95% CI: 0.93-10.47). Interaction between treatment and high body condition score was reflected by a 14% increase in pregnancy rate at 90 d in milk (OR 3.02, 95% CI: 1.14-7.96). About 60% of the treated cows expressed estrus at the expected time (normal response within 5 d following the third PGF2α injection); the remaining 40% that manifested estrus later (late response) had higher milk yield and lower body condition score. Additional analyses indicated that treatment interacted with normal response to raise conception rates and pregnancy rates of primiparous cows and cows with high body condition score. On the other hand, treatment by late-response interaction lowered conception rate during the summer. Implementation of such hormonal treatment in combination with an efficient cooling system may improve reproductive performance of dairy cows during the summer and subsequent autumn. © 2011 American Dairy Science Association. Source

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