The effect of time of artificial insemination on fertilization status and embryo quality in superovulated cows

Citation
Jc. Dalton et al., The effect of time of artificial insemination on fertilization status and embryo quality in superovulated cows, J ANIM SCI, 78(8), 2000, pp. 2081-2085
Citations number
20
Categorie Soggetti
Animal Sciences
Journal title
JOURNAL OF ANIMAL SCIENCE
ISSN journal
00218812 → ACNP
Volume
78
Issue
8
Year of publication
2000
Pages
2081 - 2085
Database
ISI
SICI code
0021-8812(200008)78:8<2081:TEOTOA>2.0.ZU;2-E
Abstract
Thirty nonlactating Holstein cows were superovulated to determine the effec t of artificial insemination time on fertilization status and embryo qualit y. During the luteal phase of the estrous cycle, cows were administered 38 mg FSH-P in a 4-d descending dose regimen. Luteolysis was induced with two injections of prostaglandin on the last day of FSH-P treatment. All cows we re continuously monitored for behavioral estrus using the HeatWatch estrus detection system. All cows were inseminated once with one .5 mL straw (50 x 10(6) sperm) at either 0 (n = 10), 12 (n = 10), or 24 h (n = 10) after the first standing event. The elapsed time (mean +/- SD) from the first prosta glandin dose to the first standing event was 39.4 h +/- 7.7 h. The (mean +/ - SD) duration of behavioral estrus was 13.2 h +/- 4.1 h. The (mean +/- SD) number of standing events war; 27 +/- 17. Five hundred twenty-nine embryos and ova were recovered nonsurgically 6 d after insemination. Fertilization rates were 29 (0 h), 60 (12 h), and 81% (24 h) (P < .01). Percentages of e xcellent and good, fair and poor, and degenerate embryos were not different (P > .05). Percentages of embryos with accessory sperm were 5 (0 h), 8 (12 h), and 41 (24 h) and differed between the 0 and 24 h and the 12 and 24 h inseminations (P < .01). Artificial insemination of superovulated, nonlacta ting Holstein cattle 24 h after onset of estrus increased fertilization rat e and percentage of embryos with accessory sperm compared with insemination at 0 or 12 h after onset of estrus. Embryo quality was not affected by tim e of insemination.