Evaluation of Ovarian Potential for In vitro Embryo Production in Indian Buffalo at Haryana State, India

Abstract

The present study was conducted at the Central Institute for Research on Buffaloes, Haryana, India to evaluate the ovarian potential for in vitro embryo production in Indian buffaloes. This study comprised two parts. In the first part, 296 samples of buffalo ovaries were used to determine the ovaries weights (using electronic scale balance), lengths, widths, thicknesses, follicular population ( using electronic Vernier calipers), oocytes grades, oocytes recovery rate, oocytes index, cleavage rate and blastocyst rate. The samples were collected from Delhi slaughterhouse and classified into two groups; group with a corpus luteum (CL) and a group without CL. The group of ovaries having CL was classified into three groups: ovaries having CL in early stage, middle stage and late stage. There was significant difference (P < 0.05) in CL stages groups with ovary weight and size. The ovaries having CL in late stage showed the highest mean of ovary weight (5.03±0.17 g), length (2.35±0.05 cm), width (1.74±0.05 cm) and thickness (1.48±0.03 cm) as compared to that having CL in early (3.38±0.24 g, 2.09±0.09 cm, 1.41±0.06 cm and 1.20±0.02 cm) and middle stage (4.03±0.24 g, 2.14±0.09 cm, 1.54±0.06 cm and 1.47±0.04 cm). No significant difference was observed on follicular population between ovaries bearing CL and without CL. The number of small, large follicles and average number of follicles per ovary were found significantly higherin

ovaries weighting more than 5g (1.76 ± 0.37 , 0.41±0.51 and 2.59±0.48) as compared to less than 3g (1.01±0.11 , 0.22±0.04and 1.80±0.10 ) and 3 to 5g (1.32±0.12 , 0.36±0.05 and 2.22±0.14). The number of small follicles in the large size ovaries was significantly higher (1.43±0.12) as compared to small size ovaries (0.90±0.10). No significant difference was observed between number of medium, large follicles and ovary size. There were no significant differences in oocytes recovery per ovary, oocytes index, cleavage, blastocyst rates between the ovaries with and without CL. Also, presence or absence of CL and its stages were not affected significantly on oocytes grades. In the second part, 160 female Murrah buffaloes were used and divided into two groups (pregnant80 and non pregnant 80) to monitor the effect of body condition score (BCS), age, pregnancy, present or absent of CL and ovary localization on follicular population using ultrasonography technique. Animals with BCS 4 having a higher total number of follicles per ovary (9.85±0.74) than those with BCS 3 (6.78±0.69). There was no significant difference in a number of small and large follicles between animals with BCS 3 and BCS 4. The pregnant buffaloes have more medium size follicles (1.96 ± 0.17) than the non pregnant ones (1.48± 0.19). There was no significant difference between the number of small follicles, large follicles and total number of follicles in pregnant and non pregnant animals. The right ovaries have lower number of large follicles (0.81±0.08) as compared to left ovaries (0.91±0.09). Also,the

ovaries contained CL have significantly higher number of medium follicles (1.95±0.17) than the without CL (1.39±0.18).No significant difference on follicular population between different ages of buffaloes. In conclusion, this study showed that the ovarian and non ovarian factors influenced on follicular population in Murrah buffaloes. The ovaries of buffaloes have a good potential for In vitro embryo production.