RESUMO
The aim of this study was to evaluate follicular dynamics and ovum pick-up (OPU) efficacy in untreated mares or mares treated with an intravaginal progesterone (P4) device during seasonal anestrus (acyclic) and during the breeding season (cyclic). Six mares (mean age = 5 years), were recruited into an ovum pick-up scheme that was performed every 14 days with and without the P4 device, during the acyclic and cyclic phases. Aspirations amounted to seven procedures with or without the P4 device during each phase. Five ultrasound assessments were performed at each interval between the OPUs. Data on follicular number and diameter as well as the numbers of recovered and the percentage of recovered oocytes were also collected. The number of follicles from mares in the acyclic phase was higher (P < .005) regardless of the treatment. However, the follicular diameter was smaller for the P4 group (P < .005) from the 2nd to the 5th evaluation post-OPU procedure. The percentage of oocytes recovered during the acyclic phase was higher for mares treated with the P4 device (P < .005). The P4 device resulted in follicles with smaller diameters and facilitated OPU efficacy.
Assuntos
Folículo Ovariano , Progesterona , Animais , Feminino , Cavalos , Folículo Ovariano/diagnóstico por imagem , Oócitos , AnestroRESUMO
Early weaning is a technique used to increase swine health status, and may cause consequences in reproductive performance of sows. An experiment was performed to evaluate these effects in a herd of sows, with weaning at 9 or 10 days post-farrowing, located in west of Minas Gerais, Brazil. Large-White sows (n=102), with three or four previous parturitions were randomly allocated to three treatment groups: T1: artificial insemination (AI) at first post-weaning estrus of the sows; T2: AI at second post-weaning estrus, T3: AI at first estrus, after an administration of a daily individual dose of 20 mg of altrenogest from 5 to 8 days post-weaning. The duration of the first post-weaning estrus did not differ among treatment groups; however, the second estrus of the T2 group was of shorter duration relative to the other treatment groups (P< or =0.035). Ovulation occurred earlier at the second estrus of the T2 group, compared with the T1 and T3 groups (P< or =0.027), being similar to that at the first estrus of T2 group (P=0.177). The relationship of the timing between ovulation and estrus was similar among treatment groups (P> or =0.221). There was no difference in farrowing rate among treatment groups (P> or =0.313). The T2 group produced a mean of 2.5 more piglets per litter (P=0.002). In conclusion, the use of altrenogest did not increase the reproductive performance of early-weaned sows.