Banca de DEFESA: LARISSA DE PAIVA NUNES GONÇALVES

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : LARISSA DE PAIVA NUNES GONÇALVES
DATE: 04/10/2023
TIME: 08:00
LOCAL: Sala 212 C
TITLE:

REPRODUCTIVE EFFICIENCY OF NELORE COWS IN FIXED-TIME ARTIFICIAL INSEMINATION (FTAI) PROGRAMS WITH RESYNCHRONIZATION AT 22 DAYS

 

KEY WORDS:

biotechnology; follicular dynamics; reproductive

PAGES: 47
BIG AREA: Ciências Agrárias
AREA: Zootecnia
SUBÁREA: Produção Animal
SPECIALTY: Manejo de Animais
SUMMARY:

The objective of this study is to evaluate the parameters related to reproductive efficiency of female Nelore cattle subjected to fixed-time artificial insemination protocol (FTAI) with resynchronization at 22 days and 54 days. For this, 318 animals will be used, divided into two experimental groups: G1 - control group: Traditional resynchronization or resynchronization at 30 days (n = 77); G2 - test group: Early resynchronization or resynchronization at 22 days (n = 241). The two groups will be submitted to 3 FTAIs and later on they will be bred with bulls. All animals will undergo the following protocol: On D0 an intravaginal device impregnated with 0.5mg of progesterone (DIB®, Zoetis, São Paulo, Brazil) and 2mg of estradiol benzoate (EB) (Bioestrogen®, Biogénesis Bagó, Curitiba, Brazil) via intramuscular (IM) will be applied. On D8 the implant will be removed and 0.4mg of estradiol cypionate (E.C.P.®, Zoetis, São Paulo, Brazil), 2.5mg of Dinosprost tromethamine (Lutalyse®, Zoetis, São Paulo, Brazil), 300 IU of eCG (Novormon®, Zoetis, São Paulo, Brazil) via IM will be applied. In D10 the cows will be inseminated 48 to 54 hours after the removal of the intravaginal device (D10) and the animals that do not show estrus will be applied 2.5ml of GnRH (Gonaxal®, Biogénesis Bagó, Curitiba, Brazil). In G1 cows will be performed the pregnancy diagnosis (DG) by transrectal ultrasonography 30 days after the first FTAI. At this moment, the females diagnosed as empty will be resynchronized. A second resynchronization will be performed, making that in an interval of 80 days, three IATFs will be performed. In G2 cows the resynchronization will occur 22 days after the first IATF, without prior diagnosis of pregnancy, performing the insertion of P4 intravaginal device associated with the administration of BE (1mg). The DG will be performed normally around day 30, accompanied by the removal of the P4 device. Females diagnosed as empty will follow the hormonal treatment, and the second AI will be performed after two days. In a subgroup (n=49) ultrasonographic exams will be performed to verify the ovulation rate and the moment of ovulation. The ultrasonographic exams will begin on Day 8 of each protocol, that is, at the moment of P4 intravaginal device removal, and will be repeated on Day 10. From Day 10 on, US will be performed every 12 hours until ovulation is verified. Statistical analysis will be performed using the Statistical Analysis System for Windows® (SAS, 2000) software. Binary logistic regression will be used to measure the association between pregnancy (dependent variable), ECC, groups, reproductive category.

 

COMMITTEE MEMBERS:
Presidente - 1835418 - KEDSON ALESSANDRI LOBO NEVES
Interno - 1843993 - ANTONIO HUMBERTO HAMAD MINERVINO
Externa ao Programa - 2140955 - ALINE PACHECO - UFOPA