Location: Food and Feed Safety ResearchTitle: Ovarian activity and uterus organometry in delayed puberty gilts Author
Submitted to: Theriogenology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/10/2011
Publication Date: 10/1/2011
Publication URL: http://handle.nal.usda.gov/10113/57347
Citation: Stancic, I., Stancic, B., Bozic, A., Harvey, R.B., Anderson, R.C., Gvozdic, D. 2011. Ovarian activity and uterus organometry in delayed puberty gilts. Theriogenology. 76:1022-1026. Interpretive Summary: Estrus is a stage of the reproductive cycle in swine when the female is ovulating and ready to breed, either by artificial insemination (AI) or with a male. In order to maximize conception rates with AI, it is highly important to be able to detect estrus. The clinical signs of estrus are often missed in young female pigs, so they do not get bred, and therefore we have a missed pregnancy. In this study, it was determined that even when young female pigs did not show signs of estrus, their reproductive tracts were still functional, thus ruling out things such as disease, nutritional deficiency, and genetics as potential causes for infertility. This is important because it means that human error, not pathology, is the cause of missed estrus, and therefore young female swine can be retained (not culled) for breeding in the swine herd.
Technical Abstract: About 30% of the total number of gilts selected for reproduction at the large breeding farm units in Vojvodina (Republic of Serbia) are culled due to the prolonged pre-insemination anoestrus (estrus not detected until 8 months of age). The aim of this study was to provide the answer to the following question: do the culling gilts at all reach cyclic ovarian activity? Total number of 175 culled gilts in which external estrus manifestations were not detected by the 8 months of age were sacrificed, and their reproductive organs were examined for determination of sexual maturity (ovaries exhibiting pre-ovulatory follicles 8 to 11 mm in diameter, corpora hemorrhagica, corpora lutea, and corpora albicantia). Uterine weights and horn length were also determined. Functional ovaries were observed in 107 (61.1%) examined gilts, with 62 animals having one and 45 having two puberty ovarian cycles (57.9% and 42.1%, respectively). Pathomorphological changes which could result in the prolonged pre-insemination anoestrus were not observed on the reproductive organs of sexually mature gilts. Our results indicate that most of the culling gilts have reached cyclic ovarian activity. The main reason for culling due to the absence of external estrus manifestations in sexually mature gilts could be inadequate estrus detection technology.