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Simões LMS, Lima EA, Carvalho LR, Martínez MBP, Zanatta GM, Santos MFO, Machado AB, Dias MM, Guerreiro BM, Freitas BG, Bastos MR, Sales JNS. Exposure to progesterone before an ovulation synchronization protocol increases the follicular diameter and fertility of multiparous suckled Bos taurus cows. Theriogenology 2024; 218:239-243. [PMID: 38359562 DOI: 10.1016/j.theriogenology.2024.01.031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Revised: 01/22/2024] [Accepted: 01/24/2024] [Indexed: 02/17/2024]
Abstract
The objective of this study was to evaluate the effect of administering injectable progesterone (P4i) before a timed artificial insemination (TAI) protocol on the follicular growth, ovulation, and pregnancy rate of Bos taurus suckled cows. The effect of P4i administration before the TAI on the pregnancy rate (P/AI) was evaluated in 576 suckled Bos taurus cows at 30-90 days postpartum. In addition, the effect of P4i administration before TAI on follicular dynamics was evaluated in subgroup of 401 suckled Bos taurus cows. On Day -10 (D-10), cows were divided into two experimental groups (Control and P4i). In this moment, P4i cows received i.m. 150 mg of injectable long-action progesterone. After that, both experimental groups received a synchronization protocol (Day 0; D0) that consisted of administration i.m. of 2 mg of estradiol benzoate and a progesterone intravaginal insert on D0. On Day 8 (D8), the progesterone insert was removed, and the cows received 500 μg of cloprostenol, 400 IU of eCG, and 1 mg of estradiol cypionate. TAI was performed 48 h after the removal of the progesterone insert. The ultrasound exams were performed in a subgroup of cows on Days 0, 8, 10 and 12 to evaluate the diameter of the largest follicle, rate of follicular growth and risks of single and double ovulation. The pregnancy diagnosis was performed 30 days after TAI in all cows to determine the pregnancy rate. The diameter of the largest follicle, on D10 (P = 0.84), rate of follicular growth (P = 0.14), ovulation rate (P = 0.40) and double ovulation rates (P = 0.23) did not differ between experimental groups. The pregnancy rate was greater in the P4i group [Control 46.2 % (133/288) vs. P4i 55.6 % (160/288); P = 0.03]. The diameter of the largest follicles (LF) on D0 (Control 11.6 ± 0.2 vs. P4i 13.3 ± 0.3) was greater (P = 0.01) in the P4i group. In conclusion, injectable progesterone before the ovulation synchronization protocol increased the diameter of the largest follicle on the D0 and the pregnancy rate in multiparous Bos taurus suckled beef cows.
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Affiliation(s)
- L M S Simões
- Department of Veterinary Medicine, Federal University of Lavras (UFLA), Lavras, MG, 37200-900, Brazil.
| | - E A Lima
- Department of Veterinary Medicine, Federal University of Lavras (UFLA), Lavras, MG, 37200-900, Brazil
| | - L R Carvalho
- Department of Veterinary Medicine, Federal University of Lavras (UFLA), Lavras, MG, 37200-900, Brazil
| | - M B P Martínez
- National Autonomous University of Mexico (UNAM), Ciudad de México, 04510, Mexico
| | - G M Zanatta
- Department of Animal Reproduction, FMVZ-USP, São Paulo, SP, 05508-270, Brazil
| | - M F O Santos
- Ritter dos Reis University Center (UniRitter), Porto Alegre, RS, 91240-261, Brazil
| | | | - M M Dias
- Genex, São Carlos, SP, 13563-002, Brazil
| | - B M Guerreiro
- Ourofino Saúde Animal, Cravinhos, SP, 14140-000, Brazil
| | - B G Freitas
- Ourofino Saúde Animal, Cravinhos, SP, 14140-000, Brazil
| | - M R Bastos
- Ourofino Saúde Animal, Cravinhos, SP, 14140-000, Brazil
| | - J N S Sales
- Department of Veterinary Medicine, Federal University of Lavras (UFLA), Lavras, MG, 37200-900, Brazil; Department of Veterinary Medicine, Federal University of Juiz de Fora (UFJF), Juiz de Fora, MG, 36010-041, Brazil
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