In vitro embryo production following Ovum Pick-up (OPU) in buffalo cows (Bubalus bubalis).

The aim of this study was to evaluate the in vitro embryo production efficiency following OPU and to investigate the correlation between follicles (FL), cumulus-enclosed oocytes (COCs) and blastocysts (Bl). Results here reported refer to the first 6 months of a trial which was carried out on eight dry buffalo cows. Follicles were classified, according to their size, as large (≥ 10 mm), medium (5 to 9 mm) and small (< 5 mm). COCs were morphologically categorized according to their quality (A to D). COCs were in vitro matured, fertilized and cultured with our standard procedures. ANOVA and correlation analysis were used for data evaluation. The animals were divided according to their different (P<0.001) Bl yield: 0.47 per buffalo/session (group I) and 0.18 per buffalo/session (Group II). Although number of follicles was similar among groups (4.96 vs 4.54) a higher number of total COCs (2.70 vs 1.98; P<0.001) and good quality (A+B) COCs (1.67 vs 1.04; P<0.001) was recorded in group I vs group II. Recovery rate (COCs/FL) was also higher in group I (52.11 vs. 42.21; P<0.05). The incidence of FL of different size and COCs of different grades were similar among groups. The high variability observed within subjects resulted in Bl production being correlated only to the total number of oocytes retrieved (r= 0.43; P< 0.01) and to the total number of punctured FL (r= 0.26; P< 0.01).