Banca de QUALIFICAÇÃO: MARIANA DOS SANTOS DUTRA OKADA

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
STUDENT : MARIANA DOS SANTOS DUTRA OKADA
DATE: 31/08/2022
TIME: 15:00
LOCAL: Encontro remoto via plataforma Google Meet
TITLE:

Short-term protocols for timed artificial insemination in dairy cattle.

KEY WORDS:

Bovine, ovulation rate, conception rate.

PAGES: 13
BIG AREA: Ciências Agrárias
AREA: Medicina Veterinária
SUBÁREA: Reprodução Animal
SPECIALTY: Inseminação Artificial Animal
SUMMARY:

Reproductive efficiency is an important factor to ensure the profitability of dairy cattle
production. The Timed Artificial Insemination (TAI) aims to optimize this efficiency,
facilitating the application of Artificial Insemination and consequently improving the
reproductive rates of the herd. Traditional protocols for performing TAI are usually of long
duration (10 to 12 days) and more expensive, involving the administration of a series of
hormones. The simplification of these protocols, associated with lower costs and reduction in
the number of management, become interesting as they facilitate the diffusion of this
technique. Therefore, the objective of the present study is to compare two short term protocols
for synchronization of ovulation using estradiol benzoate or estradiol cypionate as ovulation
inducers in dairy cattle. To this end, 200 Girolando females (primiparous and multiparous),
cyclic, with dominant follicle and corpus luteum presenting diameters between 8-20 mm and
≥ 16 mm, respectively, will be selected. These animals will be randomly divided into two
treatments: Estradiol benzoate group (BE; n=100) and Estradiol cyprionate group (CE;
n=100). In the females of Group BE, 24 hours after the application of PGF2alpha, 2mg of BE
(im) will be applied, being the TAI performed 24 to 28 hours after this administration. The
animals belonging to Group CE will receive 2mg of CE (im) simultaneously to the application
of PGF2alpha, and the TAI will be performed 48 to 52 hours after this application. The
pregnancy diagnosis will be performed 30 days after artificial insemination using transrectal
ultrasonography. Two experiments will be carried out. In experiment I, the follicular
dynamics of twenty females submitted to two short term protocols for synchronization of
ovulation will be followed (Group BE = 10 animals and Group CE = 10 animals). The
following parameters will be evaluated: follicular growth rate (mm/day); pre-ovulatory
follicle diameter (mm); ovulation moment in relation to PGF2alpha application and TAI
(hours) and ovulation rate (%). In Experiment II, 180 females will be submitted to the same
two synchronization protocols (Group BE = 90 animals and Group CE = 90 animals) with the
objective of calculating the conception rate, that is, the number of pregnancies divided by the
number of cows submitted to the protocol (P/TAI). Statistical analyses were performed using
JMP software (JMP Statistics and Graphics Guide, ver. 11.0; SAS Inst., Inc., Cary, NC).
Multivariable logistic regression analysis will be used to determine factors related to
conception rate (P/IA). For all analyses, it will be considered statistically significant when P <
0.05.

BANKING MEMBERS:
Presidente - 1548043 - MARCO ROBERTO BOURG DE MELLO
Externo ao Programa - 2142739 - RODRIGO VASCONCELOS DE OLIVEIRA - UFRRJExterna ao Programa - 1201559 - VERA LUCIA TEIXEIRA DE JESUS - UFRRJ