title: Second oestrus synchronization and precocious embryo viability after puberty induction in gilts by the use of gonadotrophin treatment.
abstract: The use of exogenous gonadotrophins in puberty inducement and ovulation synchronization is a technique that has a positive influence on the management of swine. The purpose of this study was to verify the effects of a second gonadotrophin treatment [equine chorionic gonadotrophin (eCG) and luteinizing hormone (LH), intramuscularly (i.m.)] upon the second oestrus synchronization and fertility in gilts. Seventy-one NAIMA (Pen Ar Lan) gilts had their first oestrus (puberty inducement) induced by a hormonal treatment (eCG and LH). Then, they were randomly distributed into two treatments, with (T1) and without (C) gonadotrophin treatment at the second oestrus. The animals were fed with a single ration (16% of crude protein and 3286.73 kcal ME/kg), and timed artificial insemination performed at the second oestrus. Gilts were slaughtered for embryo recovery and ovary examination about 5 days after insemination. There was no evidence of a difference in the percentage of the second oestrus expression (T1 - 90.90% and C - 86.84%), the duration of the oestrus cycle (T1 - 19.62 +/- 0.82 days and C - 19.67 +/- 4.14 days), the percentage of follicular cysts (T1 - 15.15% and C - 18.42%) and number of ovulations (T1 - 14.60 +/- 5.7 and C - 13.23 +/- 4.8) between treatments (p > 0.05). However, the hormonal treatment (T1) showed minor oestrus dispersion and embryo viability (T1 - 8.4 +/- 5.6 and C - 11.2 +/- 4.6) (p < 0.05). These results indicate that the better synchronization and expression of the second oestrus when using gonadotrophins (eCG and LH) is followed by a lower embryo viability, which is probably the consequence of the heterogeneous follicle recruitment during the injection of eCG.
authors.affiliation: Laboratório de Pesquisa em Suínos, Faculdade de Medicina Veterinária e Zootecnia, Universidade de São Paulo, Pirassununga, Sao Paulo, Brazil.
authors.forename: V
authors.initials: V
authors.lastname: do Lago
authors.forename: Wl
authors.initials: W
authors.lastname: Vianna
authors.forename: Rd
authors.initials: R
authors.lastname: Gama
authors.forename: A
authors.initials: A
authors.lastname: Campos Rosseto
authors.forename: Me
authors.initials: M
authors.lastname: Pinese
authors.forename: A
authors.initials: A
authors.lastname: Sant'anna Moretti
mesh_terms: D000818:Animals; D006063:Chorionic Gonadotropin / Q000008:administration & dosage; D004971:Estrus / Q000502:physiology*; D004973:Estrus Synchronization / Q000187:drug effects*; D005260:Female; D005313:Fetal Death / Q000662:veterinary; D006062:Gonadotropins / Q000008:administration & dosage*; D006064:Gonadotropins, Equine / Q000008:administration & dosage; D007273:Injections, Intramuscular / Q000662:veterinary; D007986:Luteinizing Hormone / Q000008:administration & dosage*; D010060:Ovulation / Q000187:drug effects; D011897:Random Allocation; D012741:Sexual Maturation / Q000187:drug effects* / Q000502:physiology; D013552:Swine / Q000196:embryology / Q000502:physiology*; D013997:Time Factors
chemical_list: D006063:Chorionic Gonadotropin; D006062:Gonadotropins; D006064:Gonadotropins, Equine; D007986:Luteinizing Hormone