Banca de DEFESA: VANESSA LEMOS DE SOUZA

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
DISCENTE : VANESSA LEMOS DE SOUZA
DATA : 26/07/2019
HORA: 14:00
LOCAL: Embrapa Rondonia, Porto Velho, BR364 Km 5.5
TÍTULO:

Effect of ECP and GnRH on estrus and fertility of beef cows submitted to TAI protocols

PALAVRAS-CHAVES:

cows, estrus, ovulation

PÁGINAS: 35
GRANDE ÁREA: Outra
ÁREA: Multidisciplinar
RESUMO:

Estradiol esters can induce females to display estrus without necessarily having preovulatory follicles. The objectives of this study were to evaluate the effect of estrus, the application of  Estradiol Cypionate (ECP) and gonadotrophin releasing hormone (GnRH) on the fertility of cows submitted to FTAI. Eighty-four hundred and eighty-four Nelore cows in the postpartum period were enrolled to the FTAI protocol: (2 mg EB + CIDR in D0 / 12,5 mg Dinoprost Trometamina (PGF analogue) in D7 / 300 IU eCG + 1 mg ECP -CIDR® in D9 + cows were scored in the sacro-caudal region with a marker stick for identification of estrus / FTAI after 48h). Also in D9 females were randomly assigned into three groups: 1) ECP group (n = 269), cows received 1 mg Estradiol Cypionate (ECP®, Pfizer, São Paulo, Brazil, i.m) on D9; 2) ECP + GnRH group (n = 269), cows received ECP on D9 and animals that did not display estrus received GnRH on D11; and, 3) GnRH group (n = 266), cows did not receive ECP on D9 and only animals that did not display estrus received GnRH on D11. The dose of GnRH used in the ECP + GnRH and GnRH groups was 10.5 μg of buserelin acetate (Gonaxal®, Biogenesis Bagó, Buenos Aires, Argentina) i.m.. The animals were submitted to FTAI on D11. Thirty days after TAI, the pregnancy diagnosis was performed by transrectal ultrasonography (SIUI® CTS-900, China). Statistical analyzes were performed using the statistical program SAS (1998). Pregnancy per AI (P/AI) and the proportion of cows in heat were analyzed by the chi-square test. The proportion of animals in standing estrus was higher in the ECP (68.7%, 185/269) and ECP + GnRH groups (57.2%, 154/269) when compared to the GnRH group (35.7%, 95/266 ; P <0.0001). There was no difference in P/AI between the ECP groups (58.7%, 158/269), ECP + GnRH (59.8%, 161/269) and GnRH (57.51%, 152/266, P = 0.8). Considering only cows that display estrus, there was no difference in P/AI between the ECP (61.6%, 114/185), ECP + GnRH (68.1%, 105/154) and GnRH groups (63.1% 60/95, P> 0.05). Among the animals that did not display estrus, there was also no difference (P> 0.05) in the P/AI between the ECP (52.3%, 44/84), ECP + GnRH (48.6%, 56/115) and GnRH groups (53.8%, 92/171 P> 0.05). Regardless of the experimental group, the animals that display estrus obtained higher P/AI (64.3%, 279/43) than animals that did not display estrus at the time of TAI (51.9%, 192/370, P = 0.0004). The results demonstrate that cows receiving ECP have higher expression of estrus. In addition, cows that display estrus at the time of TAI are more likely to be pregnant. Finally, administration of GnRH in cows that did not display estrus at the time of TAI did not increase P/AI. Regardless of the experimental groups, the animals that display estrus obtained higher P/AI (64.3%, 279/43) than animals that did not display estrus at the time of TAI (51.9%, 192/370, P = 0.0004). Cows that received estradiol cypionate had a greater estrus expression. In addtion cows that display estrus in FTAI protocols had more likely to get pregnant. Finally, the administration of GnRH in cows that not display estrus at FTAI protocol did not increase the pregnancy per AI.

MEMBROS DA BANCA:
Presidente - 958.305.370-87 - LUIZ FRANCISCO MACHADO PFEIFER - EMBRAPA
Interno - 162.237.228-00 - ANA KARINA DIAS SALMAN - EMBRAPA
Externo ao Programa - 1810533 - JUCILENE CAVALI
Externo à Instituição - ELIZANGELA MIRIAM MOREIRA - USP
Externo à Instituição - PEDRO GOMES DA CRUZ - EMBRAPA