Banca de DEFESA: MARIANA DOS SANTOS DUTRA OKADA

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : MARIANA DOS SANTOS DUTRA OKADA
DATE: 29/08/2023
TIME: 14:00
LOCAL: Remota - Plataforma GoogleMeet
TITLE:

Comparison of estradiol benzoate and cypionate in short-term timed artificial insemination protocol in dairy cattle. 

KEY WORDS:

bovine, ovulation rate, conception rate.

PAGES: 40
BIG AREA: Ciências Agrárias
AREA: Medicina Veterinária
SUBÁREA: Reprodução Animal
SPECIALTY: Inseminação Artificial Animal
SUMMARY:

The simplification of Timed Artificial Insemination (TAI) protocols, with a reduction in costs and a reduction in the number of procedures, becomes interesting since it facilitates the dissemination and application of this technique. Therefore, the aim of the present study was to compare two short-term protocols for synchronization of ovulation and TAI using estradiol benzoate or cypionate as ovulation inducers in dairy cattle. For that, 172 Girolando cows were submitted to ultrasonographic evaluation (Mode B) of the ovaries and selected after the identification of a corpus luteum and a dominant follicle with diameters ≥ 14 mm and between 8-20 mm, respectively. From the identification of these structures, all animals received 500 µg of sodium cloprostenol (D0) and were randomly divided into two treatments: estradiol benzoate (EB) group and estradiol cypionate (EC) group. In the females of the BE Group, 24 hours after the application of PGF2alpha, 2 mg of EB were applied (D1), and the TAI was performed 24 to 28 hours after this administration (D2). The animals in the EC Group received 2 mg of EC simultaneously with the application of PGF2alpha, with TAI being performed 48 to 52 hours after this application. Pregnancy diagnosis was performed 30 days after artificial insemination using transrectal ultrasonography. In the present study, two experiments were carried out. In the first (experiment I), the follicular dynamics of eighteen females submitted to the two treatments (EB Group; n = 9; EC Group; n = 9) was monitored, and the following parameters were evaluated: follicular growth rate (mm/day); preovulatory follicle (POF) diameter on D0 and D2 (mm); time of ovulation in relation to PGF2alpha application and TAI (hours) and ovulation rate (%). In the second part of this study (experiment II), 172 females were submitted to the two treatments (EB Group; n = 85 animals and EC Group; n = 87 animals) with the aim of comparing conception rates. Regarding experiment I, no statistical difference (p > 0.05) was observed for any of the evaluated parameters, and the ovulation rate was 77.8% for both treatments. The overall conception rate, regardless of the ovulation inducer, was 30.2% (52/172) and when the two treatments were compared (EB = 27.1%; EC = 33.3%), no difference was observed. It was observed that cows with a body score < 3.0 tended to have a higher conception rate when the ovulation inducer was EC (39.1% x 18.2%; p = 0.06). When conception rates were analyzed according to preovulatory follicle diameter on D0 (FPO ≥ or < 10 mm), cows in the EC group had significantly higher conception rates than females synchronized with EB (48.3 % x 29.0%; p = 0.03). It is concluded that estradiol benzoate and cypionate can be used with the same efficiency in short-term timed artificial insemination protocol n dairy cows, and treatment with cypionate is more efficient in cows presenting FPO > 10 mm at the beginning of the protocol.

COMMITTEE MEMBERS:
Interno - 2202309 - JULIO CESAR FERRAZ JACOB
Presidente - 1548043 - MARCO ROBERTO BOURG DE MELLO
Externa ao Programa - 1201559 - VERA LUCIA TEIXEIRA DE JESUS - nullExterno à Instituição - ÂNGELO JOSÉ BURLA DIAS - UENF