Banca de DEFESA: YURI BARBOSA GUERSON

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : YURI BARBOSA GUERSON
DATE: 14/09/2020
TIME: 13:00
LOCAL: INSTITUTO DE ZOOTECNIA
TITLE:

Effect of reactivity on the vascular perfusion of the follicle and corpus luteum and on the fertility of Nellores cows submitted to TAI

KEY WORDS:

Stress, preovulatory follicle, color Doppler, progesterone, fertility.

PAGES: 93
BIG AREA: Ciências Agrárias
AREA: Zootecnia
SUBÁREA: Produção Animal
SUMMARY:

GUERSON, Yuri Barbosa. Effect of reactivity on the vascular perfusion of the follicle and corpus luteum and on the fertility of Nellores cows submitted to TAI. 2020. 80p. Thesis (Doctorate in Animal Science). Instituto de Zootecnia, Departamento de Reprodução e Avaliação Animal, Universidade Federal Rural do Rio de Janeiro, RJ, 2020. The present study was divided into two chapters, the first aimed to evaluate the effect of temperament on the vascular perfusion of the preovulatory follicle (POF) and the corpus luteum (CL) as well as on progesterone (P4) production and conception rate of Nellores cows submitted to TAI. In the second chapter, the objective was to study the relationship between the diameter of the POF and CL with the quantity and intensity of blood flow, P4 production and the fertility of Nellores cows submitted to TAI. In the first experiment, 201 females were subjected to synchronization of ovulation and, at the time of AI, reactivity assessments were performed using the chute score and exit speed. According to the individual scores, the animals were divided into two groups: adequate temperament (ADQ) and excitable (EXC). Blood samples were also collected to measure serum cortisol and P4. Color Doppler ultrasound evaluations were performed to determine the diameter, volume and vascularization of POF and CL at the time of AI (D0) and seven days (D7) later, respectively. The synchronization, ovulation and conception rates were compared between the ADQ and EXC groups. The variables number of POF pixels at the time of AI (p = 0.01), pixel intensity on the follicle wall (p = 0.01), diameter (p = 0.02) and volume (p = 0.01) of the POF at the time of AI were all lower for the group of females in the EXC group. The number and intensity of the pixels of the CL showed no difference between the groups, while the diameter and volume were also lower (p = 0.01) for the EXC group. There was no difference between groups for synchronization, ovulation and conception rates as well as for P4 concentration at D7. It can be concluded that Nellores females of excitable temperament have less follicular blood flow and reduction in the size of the follicle and corpus luteum without, however, compromising fertility. In the second chapter, the diameter and volume of the POF (D0) and CL (D7) of 201 cows subjected to TAI were determined, as well as the amount and intensity of colored pixels present in them. In addition, blood samples were also collected at D7 for P4 measurement. For data analysis, the females were divided into nonpregnant and pregnant and also according to the diameter of the POF: females of small follicle, with diameter <11mm (SF; n = 35); females of medium follicle, with diameter between 11 and 14mm (MF; n = 84) and females of large follicle, with diameter ≥ 14mm (LF; n = 70). The ultrasound variables of POF and CL, as well as the P4 concentration were compared between the groups SF, MF and LF and between nonpregnant and pregnant cows. Differences were found between the SF, MF and LF groups for the diameter and volume of the POF and CL, demonstrating that larger follicles also originate larger luteal bodies. The LF group showed a higher amount and intensity of pixels in the POF compared to the SF. The flow intensity in the CL and the P4 concentration were also higher in the LF. The SF group had lower flow intensity and ovulation rate compared to the others, although the conception rate was similar for all. Weak correlations were found between the size of the POF and the CL as well as between the diameter and volume of the CL with its pixel count and P4 concentration. In addition to a moderate correlation between the diameter and its pixel intensity. There was no difference between nonpregnant and pregnant cows for all variables analyzed. The results confirm the presence of relationships between the size of the ovarian structures and the quantity and intensity of their flow, as well as their ability to produce progesterone. The intensity of the POF pixels was shown to be relevant, showing correlations with the size and flow of the CL, which were not found by evaluating only the pixel quantity, revealing the importance of evaluating complementary flow characteristics.

BANKING MEMBERS:
Externo à Instituição - LUCIANO ANDRADE SILVA - USP
Externo à Instituição - JOAQUIM ESQUERDO FERREIRA - OUTRO
Externo ao Programa - 2202309 - JULIO CESAR FERRAZ JACOB
Interno - 1548043 - MARCO ROBERTO BOURG DE MELLO
Externa ao Programa - 1201559 - VERA LUCIA TEIXEIRA DE JESUS