Orientador: José Eduardo Portela Santos / Resumo: The objectives of these experiments were to determine the effects of a second prostaglandin F2α (PGF2α) dose in an estradiol (E2) and progesterone (P4) based timed AI (TAI) protocol on LH pulsatility, pre-ovulatory follicle characteristics, and pregnancy per AI (P/AI) in anestrous lactating Holstein cows. In experiment 1, 2,011 Holstein cows had their estrous cycles synchronized and ovaries scanned by ultrasound to determine if a corpus luteum (CL) was present at the time of protocol initiation (d-12) and on the day of PGF2α (d-4). Cows without CL on d-12 and d-4 were classified as anestrous (n = 454) and submitted to the following TAI protocol: d -12 or -11: two intravaginal P4 devices and estradiol benzoate (EB); d -4 PGF2α and withdrawal of one P4 device; d -2 estradiol cypionate (ECP) and withdrawal of the second P4 device; on d 0, TAI was performed. On d -4, cows were randomly assigned to one of four treatments: one dose of PGF2α on d -4 and 9 days with a P4 device (1PGF9d, n = 116); two doses of PGF2α, the first on d -4 and the second on d -2 and 9 days with a P4 device (2PGF9d, n = 115); one dose of PGF2α on d -4 and 10 days with a P4 device (1PGF10d, n = 111) or two doses of PGF2α, the first on d -4 and the second on d -2 and 10 days with a P4 device (2PGF10d, n = 112). Rectal temperature (RT) was measured on d 0 and 7 and cows were classified as RT below (normothermic) or above 39.0oC (hyperthermic). Pregnancy was diagnosed on d 30 and 58 after AI. In experiment 2,... (Resumo completo, clicar acesso eletrônico abaixo) / Mestre
| Identifer | oai:union.ndltd.org:UNESP/oai:www.athena.biblioteca.unesp.br:UEP01-000891511 |
| Date | January 2017 |
| Creators | Lopes Junior, Francisco Rebôlo |
| Contributors | Universidade Estadual Paulista "Júlio de Mesquita Filho" Faculdade de Medicina Veterinária e Zootecnia. |
| Publisher | Botucatu, |
| Source Sets | Universidade Estadual Paulista |
| Language | Portuguese |
| Detected Language | English |
| Type | computer file |
| Relation | Sistema requerido: Adobe Acrobat Reader |
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