The Optimized Ultrasound Guided Ovum Pick-up System Base On The Characters Of Follicular Growth In Infertile Dairy Cows

The objective of this study was to develop a simple and effectiveultrasound guided ovum pick up (OPU) protocol for cows on the base ofcharacters of follicular growth, optimized for oocyte harvest and subsequentin in vitro production (IVP).The characters of the bovine ovaries were detected in the first part ofwork, ovaries from 2 cows and 2 heifers in each group were checked daily intwo estrous cycle. The result showed that the estrous cycle in cows wassignificant longer than that of in heifers (24.5d vs 21.0d, P<0.05) and nodifference among cows (25.0d vs 24.0d, P＞0.05) and heifers (21.0d vs 21.0d,P＞0.05); the number of medium size follicles (5～7mm) and the small sizefollicles (≤4mm) increased as wave formation and reached the largest sizeon day 20 and decreased quickly later in the cows on day 17 and thendecreased quickly later in the heifers. Quantity of medium size and smallsize follicles decreased with the large size follicle (≥8mm) appeared andincreased as it degenerated. The images of corpus luteum and follicles indifferent phases were also described in detail and showed in the latersections.In experiment 2, OPU was carried out on infertile cows (uterus handicap mainly) of 3～6 year old (n=6) for 72 sessions totally and anaverage of 5.6±2.4 oocytes were retrieved in each session. Meanwhile,factors affecting recovery rate and quality of oocytes for bovine embryoproduction in vitro were investigated and optimized: different concentrationof heparin in the flushing medium were tested, PBS contain 5IU/mL heparinshowed poor anticoagulant gained significant lower recovery rate than thatof 10 IU/mL and 15 IU/mL ( 41％vs 51％, 53％, P＞0.05) but gained betterblastocyst rate (32％vs 10％, 0％, P＜0.05); velocity of liquid flow in 60drop/rain showed significant weaker to improve recovery rate (35％vs 49％,53％P＞0.05) than 100drop/min and 150 drop/min but higher cleavage rate(84％vs 73％, 33％, P＜0.01) in later IVC; significant higher recovery ratewas achieved in collecting large and medium size follicles than small ones(77％, 64％vs 30％, P＜0.01), eggs from medium and small size folliclesweremore capable to cleavage (81％, 73％vs 39％, P＜0.01) than whichfrom large ones in IVF. A higher recovery rate was obtained when animalswere injected 1500IU PMSG and 150IU FSH prior to OPU than other dosesbut no difference in growth competence; higher frequency (2 session perweek) OPU gained less eggs than 1 session per week(8.0+2.0 vs 5.3±3.1,P＜0.05) in each session and also no difference in quality of retrieved oocytes(cleavage rate:84％vs 77％, P＞0.05); there were no differences in oocyterecovery rates (48％, 51％vs 45％P＞0.05) and quality (cleavage rate:78％,81％vs 80％, P＞0.05) among the Jiangs(?) 18# two way needle, COOK(?) twoway needle and 18# one way needle from FHK(?) in the research.