Association between the number and quality of bitch COCs and selected donor factors

The aim of the present study was to investigate whether selected factors attributed to oocyte donors can affect the number and quality of canine cumulus-oocyte-complexes (COC). The following parameters were considered: female age and body mass, ovarian weight, presence of functional ovarian structures (eg. corpus luteum, visible follicles), and ovarian and uterine pathology. Altogether 10 077 COCs were collected, on average 125.6 per bitch. The number and quality of collected COCs was significantly affected by female age and the presence of functional ovarian structures. We found an increased total number of COCs in up to 8-month-old bitches as compared to up-to-3-year-old and up-to-7-year-old females (P < 0.001). Moreover, senile females produced more high quality COCs than the younger ones. However, the differences between those groups were not statistically significant (P = 0.469, P = 0.346). A higher number of COCs was collected from ovaries with a smooth surface (202.8) or with visible follicles (121.1), in comparison to ovaries with corpus luteum (97.6), bitches with pyometra and pathologies of the ovaries or the uterus (82.8). No influence of the bitch’s body mass and ovarian weight on the number of COCs was observed, although a higher number of oocytes was usually collected from the right ovary. The quantity and morphological quality of bitch COCs varied significantly among individual females in an age-dependent manner. The greater number of COCs, isolated from younger bitches, may be associated with a higher reproductive potential and hormonal activity of these females. The study suggests that the age affects the total number of collected COCs but has no influence on the quality of bitch oocytes.