Abstract

HERNANDEZ-CORONADO, Cyndi; ROSALES-TORRES, Ana; VAZQUEZ-LOPEZ, Salomón  and  GUZMAN-SANCHEZ, Adrián. Synchronization of estrus and ovulation in bovine females. Endocrine bases and treatments used. Abanico vet [online]. 2023, vol.13, e206.  Epub Oct 27, 2023. ISSN 2448-6132.  https://doi.org/10.21929/abavet2023.16.

In Mexico, reproductive efficiency of cows in calf production systems is low and the use of estrus and ovulation synchronization schemes can contribute to improve it. The objective of this review was to describe the endocrine regulation of the estrous cycle and follicular dynamics in cattle, highlighting how, using exogenous hormones, and these processes can be manipulated to implement different estrous and ovulation synchronization protocols. In addition, results of pregnancy rate at synchronized estrus (PRSE) with the different estrous and ovulation synchronization protocols reported in the literature are presented. Reviews and original articles on topics of estrous cycle and follicular development in cattle were collected and PRSE data were obtained from scientific articles published between 2000 and 2023. The reported PRSE ranges from 23 to 76 %, however, although the range is wide, in estradiol and GnRH based protocols about 50 % of the PRSE data collected are between 45 and 55 %. In progesterone-based protocols, 50 % of the data report PRSE between 55 and 65 %. Currently, there are three main estrous and ovulation synchronization protocols with which, according to the literature reviewed, PRSE between 45 and 65 % can be obtained in most occasions.

Keywords : oestrus cycle; waves of follicular growth; synchronization of estrus and ovulation; beef cows.

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