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| Author(s): |
Cristian Hernando Martinez Garcia
Total Authors: 1
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| Document type: | Doctoral Thesis |
| Press: | Pirassununga. |
| Institution: | Universidade de São Paulo (USP). Faculdade de Medicina Veterinária e Zootecnia (FMVZ/SBD) |
| Defense date: | 2022-05-13 |
| Examining board members: |
André Furugen Cesar de Andrade;
Diego Vilela Alkmin;
Lúcio Francelino Araújo;
Luís Guilherme de Oliveira;
Rafael da Rosa Ulguim
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| Advisor: | André Furugen Cesar de Andrade |
| Abstract | |
During the summer and autumn periods, swine females have shown a decrease in reproductive performance when compared to winter and spring, as showed in countries such as the United States, Canada, France, Japan, Thailand, Finland, and Australia. The lower reproductive performance during these periods can be associated to several factors, but it is mainly associated to seasonal outdoors high temperatures and long photoperiod, which can lead to environmental stress conditions. Particularly, heat stress and long photoperiods can affect the release of gonadotropins by the hypothalamic-pituitary-ovarian axis, leading to related changes in follicular development or corpus luteum function. The main objectives were to identify the main negative effects of seasonal infertility on the reproductive performance of gilts and sows from commercial swine herds located in southeast of Brazil and to describe the main manifestations of seasonal infertility identified according to each farm. Data from four commercial swine farms located in the state of Minas Gerais, Brazil, were extracted from the recording system during the six-year period from January 2015 to December 2020. Seasons were included in the sow reproductive performance database. according to the date of each service. Weaning Estrus interval (IDE) was compared between seasons according to the weaning date. The genetic lines of the females were mainly Landrace (L), Large White (LW) and hybrid females (L×LW). The return to estrus rate, abortion rate, false pregnancy rate, culling rate, mortality rate and farrowing rate were 3.07%, 2.31%, 1.06%, 0.51% , 2.0% and 91.06%, respectively. For the climatic conditions of this study, a seasonal variation was observed for farrowing rate, return to estrus rate, false pregnancy rate, culling rate, number of piglets born alive and proportion of sows with a weaning-estrus interval between 0- 6 days. The results of this study showed seasonal infertility in sows located in commercial herds of swine located in Patos de Minas, MG, Brazil. The intensity of the negative effects depends on factors such as parity, climatic conditions of the year and individual characteristics of each farm. (AU) | |
| FAPESP's process: | 19/02113-3 - Seasonal infertility in swine: what is the impact on Brazilian swine production? |
| Grantee: | Cristian Hernando Martinez Garcia |
| Support Opportunities: | Scholarships in Brazil - Doctorate |