Reduction in size of the ovulatory follicle reduces subsequent luteal size and pregnancy rate

摘要: We hypothesized that reducing the size of ovulatory follicle using aspiration and GnRH would reduce resulting CL, circulating progesterone concentrations, alter conception rates. Lactating dairy cows (n=52) had synchronized ovulation AI by treating with PGF2alpha as follows: Day -9, (100 microg); -2, (25 mg); 0, 1, AI. Treated (aspirated group; n=29) all follicles > 4 mm in diameter aspirated on Days -5 or -6 order to start a new follicular wave. Control (nonaspirated group: n=23) no aspiration. The CL were monitored ultrasonography. rate (ovulation second injection: 42/52=80.8%) double (6/42=14.3%) did not differ (P 0.05) between groups. Aspiration reduced < 0.0001; 11.5 +/- 0.2 vs 14.5 0.4 mm), serum estradiol concentrations at treatment 0.0002; 2.5 5.7 0.6 pg/mL). volume was less for than nonaspirated 7 (2,862 228 5,363 342 mm3) 14 (4,652 283 6,526 373 mm3). Similarly, 0.10) cows. Pregnancy per lower (3/21=14.3%) (10/21=47.6%) In conclusion, smaller produced lowered fertility possibly because development decreased concentrations.