Banca de DEFESA: PRICILA BALDESSAR

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : PRICILA BALDESSAR
DATE: 04/08/2022
TIME: 08:30
LOCAL: IFC - Campus Araquari.
TITLE:

The use of long-acting progesterone to induce puberty in gilts.

KEY WORDS:

progesterone metabolization, iP4, cyclicity, anestrus, reproductive performance, pigs.

PAGES: 45
BIG AREA: Ciências Agrárias
AREA: Medicina Veterinária
SUMMARY:

The management of the replacement herd of a swine production system is a limiting factor to reach the breeding targets and piglet production. Annual rates varying between 40 and 50% of sow culling are commonly practiced. In ruminants, the supplementation of exogenous progesterone (P4) is used for puberty induction as well as for the cyclicity return after calving or during the beginning of the breeding season. However, this approach has not yet been tested in pigs. The objective of this study was to evaluate both the effect of the long-acting injectable progesterone (iP4) to induce puberty in gilts and the reproductive performance. The study was carried out in a gilt development unit with a housing capacity for 2300 sows, located in the High Itajaí Valley region, Santa Catarina state, Brazil. Firstly, the iP4 metabolism was characterized in contemporary prepubertal gilts (153 d). Four groups were formed, in which 150mg, 300mg, and 600mg of P4i (Sincrogest Injectable, Ourofino, Brazil) was injected i.m. in the treated groups and 1ml of saline solution in the control group. Serum P4 was measured on days D0, D2, D4, D8, D12, and D16. Secondly, the use of P4i was evaluated for inducing the estrus in gilts. Two replicates were used. In the first, 179±5 days-old gilts were divided into two groups: Control group (n=108), that received 2.0 ml of saline solution IM; iP4 group (n=106), that received 300 mg of iP4 IM. In the second replicate, 148±5 days-old prepubertal gilts were divided into two groups: Control group (n=110), that received 2.0 ml of saline solution IM; iP4 group (n=108), that received 300 mg of iP4. Estrus stimulation with a mature boar occurred once daily, in which the starting date consisted on the day of treatment, for the first replicate, and at 184 days-of-age, for the second replicate. Gilts that reached a minimum of 230 days of age and 130 kg of body weight were submitted to an intracervical artificial insemination with heterospermic semen doses, at a concentration of 2.5 x 109 of viable spermatozoa. Gilts in anestrus were slaughtered and their reproductive tracts were observed for the evaluation of ovarian structures. Reproductive data on estrus return, pregnancy and farrowing rates, and litter size were registered. With respect to the metabolism curve of P4 in gilts, the effect of the treatment and the day after the injection of iP4 occured as well as an interaction in treatment*day (P<0.05). Treatment groups iP4 300 and iP4 600 mg maintained P4 plasma levels above 5 ng/ml for at least 8 days. In the second stage in the first replicate, the supplementation of progesterone at 179 d interfered with the iP4 induction interval and the onset of the first estrus (17.12±1.27 vs. 23.08±1.38; P=0.0018). However, in the second replicate, when iP4 was supplemented at 148 d, no difference was observed between treatments (P>0.05). Reproductive parameters (TB, TBA, NATI, MUM) were not influenced by control and iP4 treatments (300 mg) in the two replicates. Likewise, the frequencies (estrus expression, pregnancy, and adjusted parturition) were not influenced by the treatments of the two replicates of the study (P>0.05). The percentage of cycling gilts during slaughter inspection was 39.32%, with no difference between groups (P>0.05). The use of long-acting iP4 does not have a cyclicity-inducing effect in gilts, but it hinders the early manifestation of estrus in gilts that are possibly pubertal, supplemented at 179d of age.

BANKING MEMBERS:
Externo à Instituição - ANDRÉ FURUGEN CESAR DE ANDRADE - USP
Presidente - 2648941 - IVAN BIANCHI
Externo à Instituição - THOMAZ LUCIA JÚNIOR - UFPel