Post-partum follicular dynamics in beef cows calving during spring and autumn in southern Brazil.

• Autor(a) principal: MORAES, J. C. F.
• Data de Publicação: 2002
• Outros Autores: JAUME, C. M., PALUDO, G. R., MÜLLER, L.
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Institucional da EMBRAPA (Repository Open Access to Scientific Information from EMBRAPA - Alice)
• Texto Completo: http://www.alice.cnptia.embrapa.br/alice/handle/doc/1094585
• topic: Pós-Parto; Vaca de Corte; Condição Corporal

Ovarian activity early post-partum in beef cows with intermediate body condition scores that calved during spring and autumn and treated with either 48 h of temporary weaning or exogenous hormones was investigated. Calving cows were given body condition scores and their ovaries were ultrasonographically scanned daily starting on day ten postpartum. The number and size of the follicles were recorded. Upon detection of a dominant follicle (>9 mm), the animals were distributed to different treatments. Over 80% of the animals (41/49) in both seasons presented a dominant follicle during the second or third week post-partum. The percentage of cows ovulating within seven days after treatment varied from 30% (3/10) for control cows to 60% (6/10) for MAP+GnRH treated cows for both spring and autumn calving cows. A reduction of 16% and 19% in body condition score was observed during the post-partum period studied for both spring and autumn calving cows, respectively. The decrease in body condition score was accompanied by a reduction in the follicular population of 43% during the fifth week post-partum only in those calving during autumn. In the spring calving cows, no change was detected in the follicular population despite the decrease in body condition score. Irrespective of the differences in environmental conditions between the two breeding seasons, cows present large follicles in their ovaries that are capable of responding to hormonal treatments, during the early post-partum period.