Effect of ovarian structure and bovine's age on amount and quality of oocytes and in vitro embryo production

• Autor(a) principal: Reis, A.
• Data de Publicação: 2006
• Outros Autores: Metelo, R., Santos, P., Silva, F. Moreira da
• Tipo de documento: Artigo
• Idioma: por
• Título da fonte: Brazilian Journal of Veterinary Research and Animal Science
• Texto Completo: https://www.revistas.usp.br/bjvras/article/view/26571
• topic: In vitro embryo production; In vitro fertilization; In vitro maturation; Follicle; Ovary

The aim of the present study was the evaluation of whether the age or the estrous cycle phase would influence the quantity and/or quality of oocytes and in vitro embryo production. Oocytes from ovaries of 63 Holstein- Friesian slaughtered cows, aging between 1 and 15 years old, were divided into 5 groups considering their age and then subdivided according to their phase of estrous cycle. The groups were: ;8 years old. The estrous cycle phase (lutheal or follicular) was evaluated by the presence or absence of a functional corpus luteum. The cumulus-oocyte-complex (COC's) was divided in classes A, B, C and D according to their morphological aspect. The COC's classed as C and D were excluded, being the COC's classed as A and B matured in vitro and fertilized. As result of the study, it was observed that the number of total produced COC's was directly proportional to the age of the cow (R=0,99 - P<0,001). It has also noticed that cows in the lutheal phase produced more COC's than cows in the follicular phase (P<0,001), respectively 7,05 ± 0,11 and 10,87 ± 1,01. The COC's quality augmented from the group of cows aging less than 2 years to cows aging between [7, 8] years old, with a positive correlation (R = 0.94 p<0.01) starting then to decrease. It was also realized that cows in the lutheal phase produced better COC's quality than cows in the follicular phase (6,77 ± 0,64 e 3,84± 0,64; respectively). In what cleavage rate is concerned, better results were achieve with cows in lutheal phase (59,03%) then in follicular phase (45,52%). It was also possible to notice a better embryo production in cows in the lutheal phase (44,23%) then cows in the follicular phase. The results of the present study allow to conclude that there is a relation between the age and the estrous cycle stage in the quality and quantity of COC's and in vitro produced bovine embryos.