Aim: This study aimed to evaluate the pregnancy rates in hair ewes using an Ovsynch synchronization protocol under a breeding system that combines fixed-time insemination plus a 10-day mating period as an alternative. Materials and Methods: Through an experimental study (n=27), ewes were randomly located into one of three treatments: (1) Pre-synch (n=9): Prostaglandin F2α (PGF2α)+Gonadotropin-releasing hormone (GnRH)+PGF2α+GnRH; (2) Ovsynch (n=9): GnRH+PGF2α+GnRH; and (3) control: Ewes bred by natural mating (NM) (n=9). Ewes were fixed-time inseminated (fixed-time artificial insemination [FTAI]) with fresh semen, collected just before the insemination time through vaginoscopy at 16 h after the second GnRH (gonadorelin) injection. Each experimental group was placed separately during 15 days and, after this time, fertile rams were allowed back with ewes for a 10-day mating period. Control group ewes remained with the rest of the herd suitable for breeding and were bred under NM. Pregnancy diagnosis was performed by ultrasound at 28-, 56-, and 84-day post-breeding to differentiate between FTAI and NM pregnancies. Total (FTAI±NM) pregnancy rates at 56-day post-breeding were used to compared Pre-synch, Ovsynch, and control. For this purpose, two-tailed proportions comparison z-test was used with a 95% confidence level, for testing as the null hypothesis whether two proportions were equal. Results: Pregnancy rates were higher in control ewes (66.4%) than FTAI (46.6%). When pregnancy rates after a 10-day mating period (40%) were added, the final rate (86.6%) was significantly (p<0.05) higher in Ovsynch-based protocols. The pregnancy rate was significantly lower in FTAI ewes compared to FTAI +10-day mating group (p<0.05). The overall pregnancy rate was 88.0, 85.7, and 67.0 (p>0.05) for Pre-synch, Ovsynch, and control ewes, respectively. Conclusion: These results provide evidence on the benefits of combined FTAI protocols for improving the reproductive efficiency of sheep.
Background: Subclinical endometritis (SE) have a negative impact on fertility due to an absence of clinical signs which difficult its diagnosis and treatment. The prevalence and impact of the disease on the reproductive status of dairy herds is not known in the region, the objective of the present study was to determine the prevalence of the disease and its effect on the reproductive efficiency in cows of the dairy area from Putumayo State, Colombia.Materials, Methods & Results: Cross-sectional study was made of 166 dairy cows from 30 days postpartum in the municipalities: Santiago, Sibundoy, Colon, and San Francisco. Reproductive evaluation and endometrial cytology were made to establish the SE prevalence determining subsequently the number of open days. Cow whit more than 120 days in milk (DIM) and without confirmed pregnancy was defined as “not reproductive efficiency”. Association between SE and reproductive efficiency was established through Odds Ratio from contingency tables. Bias and confusion control was made through stratified analysis. Results showed 32 cows without changes in reproductive clinical evaluation and inflammatory changes in cytological evaluation (PMNn >5%) for a SE prevalence of 19.27%. Disease occurs most frequently in Colón (23.10%) but the frequency of the disease was not different among the regions (P > 0.05). The group of animals with the greatest days open (DO) mean (161 DIM) had a normal ovarian function and subclinical endometritis. The 6.6% of cows had a poor reproductive prognosis (subclinical endometritis, anestrous and 144 DIM). For the stratified analysis (controlling by anestrus) was estimated the crude OR (OR 5.93; P < 0.05; CI 95% 2.56-14.6) and adjusted ORMH (OR 5.78; P < 0.05; CI 95% 2.39-13.9). Difference between adjusted ORMH and crude OR (3%) and Wald X2 test (P > 0.05) suggesting that there is no confusion and allowed to establish that “the odds of low reproductive efficiency (Days open >120) increases 5.9 times when cows suffer subclinical endometritis, than when do not have the disease”.Discussion: Study prevalence was lower than the reported by other authors. Variability of the results by the different authors ratifies the multifactorial characteristic of the disease and thr differences in the immune response of the animals. Cows diagnosed with SE, normal ovarian function and 161 DIM shown that the disease increases significantly the open days of the herd reducing reproductive efficiency. These findings are consistent with other authors who report that subclinical endometritis: increased open days and reduced conception rates and increased the risk of no pregnancy at 150 days postpartum. In the study, cows with subclinical endometritis and normal ovarian function had open days mean lower to 120 and more probability to have a good reproductive performance if pregnancy is achieved, but the dairy herds of the region lack of adequate systems of detection of estro and services and have no systems that allow the diagnosis of SE and anoestrus. The 69% of the evaluated animals present some clinical characteristics (SE, anoestrous) that predispose them to low reproductive behaviour. It is recommended to routinely use endometrial cytology to diagnose SE and improving the reproductive efficiency of animals.
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