Ingestão de concentrado e concentração plasmática de progesterona em vacas da raça Holandesa
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Data
2006-12-01
Autores
Santos, R. M. [UNESP]
Vasconcelos, José Luiz Moraes [UNESP]
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Editor
Universidade Federal de Minas Gerais (UFMG), Escola de Veterinária
Resumo
Vacas da raça Holandesa não-lactantes (n=7), que receberam 4kg/dia de concentrado durante 28 dias e pasto ad libitum, foram sincronizadas com protocolo Ovsynch. No dia 0 (segunda aplicação de GnRH), as vacas foram distribuídas em dois grupos: as do grupo 2kg receberam 2kg/dia, e as do grupo 8kg receberam 8kg/dia de concentrado, oferecido duas vezes/dia. Os animais foram sincronizados novamente na fase 2. Aqueles que receberam 2kg de concentrado na primeira fase passaram a receber 8kg na segunda fase e vice-versa. As estruturas ovarianas foram avaliadas diariamente por ultra-sonografia. Amostras de sangue para dosagem de progesterona (P4), por radioimunoensaio, foram colhidas diariamente, antes do fornecimento do concentrado e quatro horas depois, até o dia 16 do ciclo estral. Não houve diferença entre os grupos quanto ao diâmetro do folículo ovulatório no dia 0 e ao diâmetro do maior folículo no dia 16. O diâmetro do corpo lúteo foi maior (P<0,05) no dia 16 nos animais do grupo 8kg. Observou-se interação (P<0,05) da quantidade de concentrado fornecida versus dia da colheita das amostras quanto à concentração plasmática de P4. A concentração plasmática de P4, imediatamente antes do fornecimento do concentrado e quatro horas depois, foi menor no grupo 8kg, após o dia 9 do ciclo estral.
Non-lactating Holstein cows (n=7) fed 4kg/day of concentrate for 28 days and kept on pasture were synchronized by Ovsynch protocol. on day 0 (day of 2nd GnRH injection), the cows were distributed in two groups: Group2 = 2kg/day and Group8 = 8kg/day of concentrate, fed twice a day. One replicate was performed (phase 1 and 2). Animals were synchronized again at the beginning of phase-2 and those that fed 2kg of concentrate on phase-1, fed 8kg on phase-2 and vice-versa. The ovarian structures were daily evaluated by ultrasound. Blood samples for progesterone (P4)dosage by RIA were collected daily, just before feeding the concentrate and 4 hours afterwards, until day 16 of the estrous cycle. No difference was detected between the groups in ovulatory follicle diameter on day 0 and in diameter of the largest follicle on day 16. The CL diameter was higher (P<0.05) in Group 8 on day 16 of the estrous cycle. There was an interaction (P<0.05) between the amount of concentrate intake and the day of blood sampling regarding P4 plasma concentration. Cows from Group 8 showed lower P4 plasma concentration, just before feed intake and four hours afterwards, after day 9 of the estrous cycle.
Non-lactating Holstein cows (n=7) fed 4kg/day of concentrate for 28 days and kept on pasture were synchronized by Ovsynch protocol. on day 0 (day of 2nd GnRH injection), the cows were distributed in two groups: Group2 = 2kg/day and Group8 = 8kg/day of concentrate, fed twice a day. One replicate was performed (phase 1 and 2). Animals were synchronized again at the beginning of phase-2 and those that fed 2kg of concentrate on phase-1, fed 8kg on phase-2 and vice-versa. The ovarian structures were daily evaluated by ultrasound. Blood samples for progesterone (P4)dosage by RIA were collected daily, just before feeding the concentrate and 4 hours afterwards, until day 16 of the estrous cycle. No difference was detected between the groups in ovulatory follicle diameter on day 0 and in diameter of the largest follicle on day 16. The CL diameter was higher (P<0.05) in Group 8 on day 16 of the estrous cycle. There was an interaction (P<0.05) between the amount of concentrate intake and the day of blood sampling regarding P4 plasma concentration. Cows from Group 8 showed lower P4 plasma concentration, just before feed intake and four hours afterwards, after day 9 of the estrous cycle.
Descrição
Palavras-chave
vaca de leite, progesterona, ingestão de concentrado, dairy cow, progesterone, concentrate intake
Como citar
Arquivo Brasileiro de Medicina Veterinária e Zootecnia. Universidade Federal de Minas Gerais, Escola de Veterinária, v. 58, n. 6, p. 1162-1167, 2006.