Strategies to improve pregnancy rates in prepubertal Nellore heifers

• Grant number: 11/15079-6
• Support Opportunities: Scholarships in Brazil - Master
• Start date: March 01, 2012
• End date: December 31, 2012
• Field of knowledge: Agronomical Sciences - Animal Husbandry - Animal Production
• Principal Investigator: José Luiz Moraes Vasconcelos
• Grantee: Adnan Darin Pereira Rodrigues
• Host Institution: Faculdade de Medicina Veterinária e Zootecnia (FMVZ). Universidade Estadual Paulista (UNESP). Campus de Botucatu. Botucatu , SP, Brazil

Abstract

The present study was design to evaluate strategies to increase pregnancy rates in prepubertal Nellore heifers treated with the induction protocol with an intravaginal progesterone device previously used for 27 days (4th use). Will be used 1000 prepubertal Nellore heifers, identified by two ultrasonography evaluation with a 7 days interval. Heifers with absence of a corpus luteum in both evaluations will be considered prepubertal. Between days -12 and 0, heifers will be treated with a 4th use intravaginal progesterone device. On day 0 after device remove, heifers will be randomly assigned to receive: 1) No additional treatment (Control Group); 2) 200 IU of equine chorionic gonadotropin (eCG Group); 3) 0.5 mg of estradiol cypionate (ECP Group); 4) 200 IU of eCG plus 0.5mg of ECP (eCG+ECP Group). The estrus detection will be performed two times per day for one hour for 7 days. Heifers will be inseminated 10 to 12 hours after estrus detection. To improve estrus detection, heifers will be painted with tail paint. On day 8, heifers that did not were detected in estrus will be evaluated by ultrasonography to determine the corpus luteum presence. On day 38 heifers will be evaluated by ultrasonography to pregnancy check. Binomial dependent variables will be analyzed by PROC LOGISTIC of SAS software and continuous variables will be analyzed by PROC MIXED of SAS software. (AU)

Scientific publications

(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)

RODRIGUES, A. D. P.; PERES, R. F. G.; LEMES, A. P.; MARTINS, T.; PEREIRA, M. H. C.; CARVALHO, E. R.; DAY, M. L.; VASCONCELOS, J. L. M.. Effect of interval from induction of puberty to initiation of a timed AI protocol on pregnancy rate in Nellore heifers. Theriogenology, v. 82, n. 5, p. 760-766, SEP 15 2014. (11/15079-6)

Academic Publications

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

RODRIGUES, Adnan Darin Pereira. Estratégias hormonais para aumentar a taxa de prenhez em novilhas nelore pré-púberes. 2012. Master's Dissertation - Universidade Estadual Paulista (Unesp). Faculdade de Medicina Veterinária e Zootecnia. Botucatu Botucatu.