The aims of this study was to see the effect of breed, parity and scheme of collection on the quality and quantity of OPU derived oocytes and effect of transvaginal ultrasound guided follicular aspiration on subsequent fertility of donor cows. A total of 28 animals (11 Boran and 11 Boran Holstein-Friesian cross for once per week collection, and 7 Boran and 7 Boran Holstein-Friesian cross for twice per week collection) were used in this experiment. A total of 22 animals were evaluated for the effect of the OPU procedure on subsequent reproductive function. In 150 Ovum Pick up sessions, irrespective of collection scheme, breed and parity, 1124 follicle (554 in Boran and 570 in HF crosses) were punctured with a recovery rate of 51.1% in Boran and 48.6% in the crosses. Relatively more follicles were aspirated in crosses compared to Borans although the difference in oocyte recovery rate and quality were not statistically significant. Overall recovery rate was 57.7% in heifers and 42% in cows. Frequency of aspiration significantly influenced (P<0.05) oocyte recovery rate with more follicles aspirated in Once per week per session compared to twice per week per session but there was no difference in the mean number of recovered oocytes. A significantly higher number of follicles were aspirated (P<0.05) and good quality oocytes were greater in heifers than cows. Different COCs quality grades were recovered from breed, parity and frequency of collection category. Overall from a total of 574 collected COCs, about 326 (57%) of the recovered COCs were of the quality grades I and II, whereas 248 (43%) were with quality grades III and IV. All 22 animals showed estrus on average after 19 days of the last OPU procedure though a relatively weaker intensity of estrus signs, irregularity of the cycle and minor ovarian morphological change were noted. Response rate to a single PGF2α treatment on 18 animals was 72% (13/18). Subsequent insemination of those in estrus resulted in 53.8% (7/13) first service conception rate. In conclusion, parity, and to some extent frequency of collection had a significant effect on the quality and quantity of oocyte but not breed. Animals at post OPU were able to continue cycling and become pregnant.
Understanding the reproductive physiology of female animals is used to optimize reproductive management of dairy cattle. This study was conducted at Adea Berga Dairy Research sub Center of the Ethiopian Institute of Agricultural Research. A total of 15 experimental animals were used to characterize the follicular dynamics of Fogera (n=9) and Jersey (n=6) dairy cattle breeds. Characterization of ovarian follicular dynamics was done using a trans-rectal real-time B-mode ultrasound system for three consecutive estrus cycles; and behavioral estrus signs were visually observed and recorded. Fogera cows manifested two (n=2, 29.62%), three (n=5, 55.55%), and four (n=1, 14%) follicular waves whereas Jersey cows showed two (n=2, 38.9%) and three (n=4, 61.11%) follicular waves. Cycle length or inter ovulatory interval was 20.35 ± 2.8 and 20.67 ± 2.6 days for Fogera and Jersey cows, respectively. The mean number of follicular population per animal was 13.9 ± 5.9 for Fogera and 17.9 ± 7.0 for Jersey cows. There was a significant (p<0.001) difference in follicular number observed between the two breeds. The mean maximum diameter of the ovulatory follicle for Jersey cows was 17.2 ± 0.86 mm and for Fogera 15.22 ± 1.3 mm. There was no statistical difference between the breed in terms of inter-ovulatory interval (IOI), however, there was significant difference (p<0.001) between the breeds in number of follicular population and ovulatory follicle size. In conclusion, behavioral signs of estrus were weaker in fogera breeds as compared to their Jersey counterpart, and relatively higher number of ovarian follicles recorded in Jersey than Fogera cattle breed.
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