Strategies to improve the fertility of dairy cows inseminated with ovulation synchronization programs

• Grant number: 12/19059-2
• Support Opportunities: Scholarships in Brazil - Doctorate
• Start date: January 01, 2013
• End date: October 31, 2015
• Field of knowledge: Agronomical Sciences - Animal Husbandry - Animal Production
• Principal Investigator: José Luiz Moraes Vasconcelos
• Grantee: Marcos Henrique Colombo Pereira
• Host Institution: Faculdade de Medicina Veterinária e Zootecnia (FMVZ). Universidade Estadual Paulista (UNESP). Campus de Botucatu. Botucatu , SP, Brazil

Abstract

The objective of this study is to evaluate whether cycle phase at the beginning of ovulation synchronization protocol interferes on follicular wave emergence and luteolysis and strategies to increase fertility in lactating cows subjected to TAI protocols and FTET. In exp. 01 will be used 80 lactating Holstein cows, the animals will be pre-synchronized and the protocol will be initiated at different stages of the estrous cycle (days 2, 7, 12 and 17). The protocol being used is: day 0 - 2 mg EB + CIDR; day 7 - PGF2a; day 9 - CIDR + 1 mg ECP, where half the animals receive GnRH (GnRH group) at the beginning of the protocol (day 0) and the other half received saline (control group). On days 0, 3, 4, 5, 7, 9 and 18 will be performed ultrasound scan (to evalute follicular wave emergence, follicular growth, and time of luteolysis) and blood samples (P4 and FSH). In exp. 02 will be used 2400 lactating Holstein cows submitted to protocols of fixed-time artificial insemination (TAI - 1500) and embryo transfer in fixed time (FTET - 900). The animals will be randomly assigned to receive one of the following treatments: (BE 1) day 0-2 mg EB + CIDR; day 7 - PGF2a; day 9 - CIDR + 1 mg ECP; day 11 - TAI or day 18 FTET ; (BE 2), the same protocol BE 1, carrying two doses of PGF2a, the first at day 7 and the second at day 9; (GnRH) the same protocol BE 2, performing a GnRH injection on day 0. Pregnancy diagnosis will be performed by ultrasonography at 32 and 60 days of gestation. Blood samples will be collected to analyze the concentration of P4 on days 0, 7, 11 and 18 of protocol.

Scientific publications

(4)

(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)

PEREIRA, M. H. C.; WILTBANK, M. C.; BARBOSA, L. F. S. P.; COSTA, JR., W. M.; CARVALHO, M. A. P.; VASCONCELOS, J. L. M.. Effect of adding a gonadotropin-releasing-hormone treatment at the beginning and a second prostaglandin F-2 alpha treatment at the end of an estradiol-based protocol for timed artificial insemination in lactating dairy cows during cool or hot seasons of the year. JOURNAL OF DAIRY SCIENCE, v. 98, n. 2, p. 947-959, FEB 2015. (12/19059-2)

PEREIRA, M. H. C.; WILTBANK, M. C.; VASCONCELOS, J. L. M.. Expression of estrus improves fertility and decreases pregnancy losses in lactating dairy cows that receive artificial insemination or embryo transfer. JOURNAL OF DAIRY SCIENCE, v. 99, n. 3, p. 2237-2247, MAR 2016. (12/19059-2)

PEREIRA, M. H. C.; SANCHES, JR., C. P.; GUIDA, T. G.; WILTBANK, M. C.; VASCONCELOS, J. L. M.. Comparison of fertility following use of one versus two intravaginal progesterone inserts in dairy cows without a CL during a synchronization protocol before timed AI or timed embryo transfer. Theriogenology, v. 89, p. 72-78, FEB 2017. (11/16774-0, 12/19059-2)

PEREIRA, M. H. C.; WILTBANK, M. C.; GUIDA, T. G.; LOPES, JR., F. R.; VASCONCELOS, J. L. M.. Comparison of 2 protocols to increase circulating progesterone concentration before timed artificial insemination in lactating dairy cows with or without elevated body temperature. JOURNAL OF DAIRY SCIENCE, v. 100, n. 10, p. 8455-8470, OCT 2017. (12/19059-2)

Academic Publications

(References retrieved automatically from State of São Paulo Research Institutions)

PEREIRA, Marcos Henrique Colombo. The manipulation of progesterone profiles during progesterone + estradiol timed ai protocols in dairy cattle: effects on fertility. 2016. Doctoral Thesis - Universidade Estadual Paulista (Unesp). Faculdade de Medicina Veterinária e Zootecnia. Botucatu Botucatu.