Efeito de protocolos de sincronização de ovulação na taxa de prenhez em vacas leiteiras mestiças mantidas a pasto no verão
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Data
2003
Autores
Garcia, Wagner Rodrigues [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
O objetivo deste trabalho foi o testar a combinação de tratamentos hormonais com progesterona (CIDR), gonadorelina (análogo de GnRH), prostaglandina F2a (PGF2a) e cipionato de estradiol (ECP), com a finalidade de avaliar tratamentos hormonais de sincronização da ovulação e viabilizar a inseminação artificial em tempo fixo (IATF), em vacas mestiças lactantes Holandês-Zebu mantidas a pasto no verão. O trabalho foi dividido em 2 experimentos. Experimento I foi realizado entre Dezembro (2001) a Fevereiro (2002), em Fernandópolis, SP, Brasil. Os animais foram divididos aleatoriamente em 4 tratamentos: Controle (n=51): inseminação artificial (IA) 12 horas após detecção do estro; GP + CIDR (n=50): GnRH - 6dias - PGF2a e IA 12 horas após detecção do estro; ECPsynch + CIDR (n=52): GnRH - 6dias - PGF2a - 24hs – ECP - 48hs - IATF e Ovsynch + CIDR (n=53): GnRH - 6dias - PGF2a - 36hs – GnRH - 12hs - IATF. A análise estatística foi procedida por CATMOD (com nível de significância de P<0,05). A eficiência na detecção de estro foi de 50,9%. A taxa de ciclicidade foi influenciada por ordem de lactação (P<0,001; sendo de 41,4% nas vacas primíparas e de 72,6% nas multíparas) e por escore de condição corporal (ECC; P<0,001). A resposta ovulatória ao 1° GnRH foi influenciada por ECC (P< 0,01). A taxa de sincronização de ovulação não foi influenciada por tratamentos (P=0,45, sendo de 75,4% no protocolo Ovsynch + CIDR e de 73,0% no protocolo ECPsynch + CIDR), porém condição corporal (P<0,05) proporcionou efeito sobre a taxa de sincronização. Na taxa de prenhez a IATF, foi verificada interação entre os tratamentos e ordem de lactação (P<0,01), sendo o protocolo ECPsynch + CIDR mais eficiente nas multíparas (50,0%) em relação ao Ovsynch + CIDR (16,7%), e nas primíparas o protocolo Ovsynch + CIDR (37,9%) foi superior...
The objective of this experiment was to evaluate the combination of hormonal treatments with progesterone (CIDR), gonadorelin (GnRH analogue), prostaglandin F2a (PGF2a) and estradiol cypionate (ECP), in protocols that allow fixed time artificial insemination (TAI) in crossbred cows managed in a grazing based dairy system during the summer. The experiment was divided in two trials. Trial I was conducted from December (2001) to February (2002), in Fernandópolis, SP, Brazil. The animals were randomly assigned to one of 4 treatment groups: Control (n=51) AI 12 hours after estrus detection; GP + CIDR (n=50): GnRH - 6day - PGF2a - AI 12 hours after estrus detection; ECPsynch + CIDR (n=52): GnRH - 6day - PGF2a - 24h – ECP - 48h - AI and Ovsynch + CIDR (n=53): GnRH - 6day - PGF2a - 36h – GnRH - 12h - AI. Data were analyzed by CATMOD procedure of SAS. Efficiency in the heat detection was 50,9%. The cyclicity was influenced by parity (P<0,001; 41,4% in primiparous cows and of 72,6% in multiparous cows) and by body condition score (BCS, P<0,001). The ovulatory response to the first GnRH injection was influenced by BCS (P<0,01). Synchronization rate was not influenced by treatments (P=0,45, 75,4% in the Ovsynch+CIDR and of 73,0% in the ECPsynch+CIDR), but it was influenced by BCS (P<0,05). Interactions were observed between treatments and parity (P <0,01) in the pregnancy rate at TAI. Treatment ECPsynch+CIDR was more efficient in multiparous cows (50,0%) when compared with Ovsynch+CIDR (16,7%). In primiparous cows the Ovsynch+CIDR (37,9%) was more efficient then ECPsynch+CIDR (25,0%). Pregnancy rate in groups with TAI was influenced by BCS (P<0,01). The service rate in GP+CIDR, evaluated for 5 day after the application of PGF2a, was influenced by cyclic status (P<0,05). Conception rate of the animals that were inseminated after the heat detection (GP+CIDR and Control) was influenced by BCS (P<0,05)...(Complete abstract click electronic access below)
The objective of this experiment was to evaluate the combination of hormonal treatments with progesterone (CIDR), gonadorelin (GnRH analogue), prostaglandin F2a (PGF2a) and estradiol cypionate (ECP), in protocols that allow fixed time artificial insemination (TAI) in crossbred cows managed in a grazing based dairy system during the summer. The experiment was divided in two trials. Trial I was conducted from December (2001) to February (2002), in Fernandópolis, SP, Brazil. The animals were randomly assigned to one of 4 treatment groups: Control (n=51) AI 12 hours after estrus detection; GP + CIDR (n=50): GnRH - 6day - PGF2a - AI 12 hours after estrus detection; ECPsynch + CIDR (n=52): GnRH - 6day - PGF2a - 24h – ECP - 48h - AI and Ovsynch + CIDR (n=53): GnRH - 6day - PGF2a - 36h – GnRH - 12h - AI. Data were analyzed by CATMOD procedure of SAS. Efficiency in the heat detection was 50,9%. The cyclicity was influenced by parity (P<0,001; 41,4% in primiparous cows and of 72,6% in multiparous cows) and by body condition score (BCS, P<0,001). The ovulatory response to the first GnRH injection was influenced by BCS (P<0,01). Synchronization rate was not influenced by treatments (P=0,45, 75,4% in the Ovsynch+CIDR and of 73,0% in the ECPsynch+CIDR), but it was influenced by BCS (P<0,05). Interactions were observed between treatments and parity (P <0,01) in the pregnancy rate at TAI. Treatment ECPsynch+CIDR was more efficient in multiparous cows (50,0%) when compared with Ovsynch+CIDR (16,7%). In primiparous cows the Ovsynch+CIDR (37,9%) was more efficient then ECPsynch+CIDR (25,0%). Pregnancy rate in groups with TAI was influenced by BCS (P<0,01). The service rate in GP+CIDR, evaluated for 5 day after the application of PGF2a, was influenced by cyclic status (P<0,05). Conception rate of the animals that were inseminated after the heat detection (GP+CIDR and Control) was influenced by BCS (P<0,05)...(Complete abstract click electronic access below)
Descrição
Palavras-chave
Bovino de leite, Bovino - Inseminação artificial, Estradiol, Bovino - Reprodução, Vacas mestiças, Crossbred dairy cows
Como citar
GARCIA, Wagner Rodrigues. Efeito de protocolos de sincronização de ovulação na taxa de prenhez em vacas leiteiras mestiças mantidas a pasto no verão. 2003. xvi, 69 f. Dissertação (mestrado) - Universidade Estadual Paulista, Faculdade de Medicina Veterinária e Zootecnia, 2003.