Effect of freezing semen and dosage of sperm on number of accessory sperm, fertility, and embryo quality in artificially inseminated cattle.
This experiment was conducted to determine whether use of fresh or frozen semen at either 20 x 10(6) (low) or 100 x 10(6) (high) sperm per dose affects the number of accessory sperm and fertilization status/embryo quality as determined from ova/embryos recovered nonsurgically 6 d after insemination. Ejaculates of four bulls were split and prepared for use as fresh or frozen semen at either the high or low dose. From 129 inseminations to normally cycling cows, 98 ova/embryos were recovered. To reduce male effects, ova/embryos used were randomly balanced across treatments, by ejaculate within bull for evaluation of frozen vs fresh semen (n = 80) and by bull for evaluation of high vs low dosage treatments (n = 76). Distribution of accessory sperm was highly skewed downward; thus, median values were more meaningful than means. Freezing semen had no significant effect on fertility status/embryo quality or number of accessory sperm at either dosage. Increasing dosage improved the number of accessory sperm per ovum or embryo (median value) and fertility status/embryo quality (P < .05). Mean +/- SD and median values for accessory sperm were 37.8 +/- 38.3 and 27.5; 28.9 +/- 62.8 and 3.0 for the high and low dose, respectively. Percentage of unfertilized ova, degenerate embryos, and embryos classified poor to fair and good to excellent were 3, 5, 24, 68, and 21, 16, 18, 45, for the high and low dose, respectively. We conclude that number of accessory sperm and fertility status/embryo quality respond favorably to increased dosage of semen and that freezing semen in this study was not detrimental to these parameters.
Nadir
S
S
Department of Dairy Science, Virginia Polytechnic Institute and State University, Blacksburg 24061.
Saacke
R G
RG
Bame
J
J
Mullins
J
J
Degelos
S
S
D000818:Animals; D002417:Cattle / Q000196:embryology / Q000502:physiology*; D015925:Cryopreservation / Q000662:veterinary*; D004622:Embryo, Mammalian / Q000502:physiology; D005260:Female; D005298:Fertility; D005306:Fertilization; D007315:Insemination, Artificial / Q000592:standards / Q000662:veterinary*; D008297:Male; D011247:Pregnancy; D011897:Random Allocation; D012662:Semen Preservation / Q000662:veterinary*; D013076:Sperm Count; D013081:Sperm Motility; D013084:Sperm-Ovum Interactions; D013094:Spermatozoa / Q000502:physiology