Insulin resistance and oocyte quality in high producing dairy cows at different stages of lactation

• Grant number: 12/50752-6
• Support Opportunities: Regular Research Grants
• Start date: June 01, 2013
• End date: November 30, 2014
• Field of knowledge: Agronomical Sciences - Veterinary Medicine - Animal Reproduction
• Agreement: CNPq - First Projects Program
• Principal Investigator: Roberto Sartori Filho
• Grantee: Roberto Sartori Filho
• Host Institution: Escola Superior de Agricultura Luiz de Queiroz (ESALQ). Universidade de São Paulo (USP). Piracicaba , SP, Brazil

Abstract

In recent years, several changes have been observed in the reproductive physiology of dairy cows, thus compromising fertility. These changes are apparently related to high milk production per cow, increased dry matter intake, genetic selection and management techniques aimed to increased milk production. Given the direct relationship between the increase in milk production and fertility reduction, more studies are necessary to better understand the reproductive physiology of this animal category, and to seek alternatives to improve fertility rates. It is possible that high-producing dairy cows experience decline in oocyte quality during the postpartum period because, among other reasons, they become resistant to insulin. The objective of this study is to test the hypothesis that high-producing cows become increasingly resistant to insulin during lactation and that oocyte quality is compromised in cows with insulin resistance. For the study, a glucose tolerance test (GTT) will be performed, as well as follicular aspiration for oocyte collection and in vitro embryo production. Medium to high milk production dairy cows around 50 (n = 30 cows), 100 (n = 30 cows) and 150 (n = 30 cows) days of lactation will used. To optimize the results of in vitro production of embryos, an initial trial will performed with 20 cows testing a protocol for wave synchronization and superstimulation of follicles prior to OPU. (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)

OLIVEIRA, L. H.; NASCIMENTO, A. B.; MONTEIRO, JR., P. L. J.; GUARDIEIRO, M. M.; WILTBANK, M. C.; SARTORI, R.. Development of insulin resistance in dairy cows by 150 days of lactation does not alter oocyte quality in smaller follicles. JOURNAL OF DAIRY SCIENCE, v. 99, n. 11, p. 9174-9183, NOV 2016. (12/50752-6, 11/07243-0)