title: The effect of prostaglandin F(2α) administration at the time of insemination on the pregnancy rate of dairy cows.
abstract: This paper addresses the question whether the pregnancy rate of dairy cows and heifers may be affected by administering prostaglandin F(2α) at the time of artificial insemination. A field trial involving 1031 dairy cows and heifers distributed to a large number of small dairy farms in an area of extensive farming in central Germany provided evidence that intramuscular administration of 25mg Dinoprost (Dinolytic(®)) at the time of insemination has no effect on pregnancy rate (61% of the cows and heifers were pregnant in both prostaglandin F(2α)-treated and saline control groups). On the other hand, deposition of 0.5mL of a 0.5mg/mL Dinoprost solution in the uterine lumen immediately after artificial insemination gave rise to a pregnancy rate of 66% as compared with 59% in saline controls. The increase in pregnancy rate of 229 prostaglandin F(2α)-treated animals (66% pregnant) over that of 226 saline controls (59% pregnant) amounted to 12%. This improvement was not statistically significant (P=0.12). Factors exerting a significant effect on pregnancy rate were parity (74% pregnancies in heifers versus 57% in cows, P<0.01 and 65% pregnancies in first parity-cows versus 55% in older cows, P<0.01) and season (57% during the barn season versus 64% during the pasture season, P<0.05), whereas length of service period, level of milk production and serum or milk progesterone level at the time of insemination did not. A follow-up trial involving more animals will have to be conducted aimed at confirming the promising results obtained by intrauterine PGF(2α) administration.
authors.affiliation: Department of Animal Science, Albrecht-Thaer-Weg 3, Goettingen, Germany.
authors.forename: H G
authors.initials: HG
authors.lastname: Gabriel
authors.forename: S
authors.initials: S
authors.lastname: Wallenhorst
authors.forename: E
authors.initials: E
authors.lastname: Dietrich
authors.forename: W
authors.initials: W
authors.lastname: Holtz
mesh_terms: D000818:Animals; D002417:Cattle / Q000502:physiology; D003612:Dairying; D015237:Dinoprost / Q000008:administration & dosage / Q000494:pharmacology*; D004334:Drug Administration Schedule; D004973:Estrus Synchronization / Q000379:methods; D005260:Female; D007273:Injections, Intramuscular; D007315:Insemination, Artificial / Q000379:methods / Q000662:veterinary; D011247:Pregnancy; D018873:Pregnancy Rate; D011270:Pregnancy, Animal / Q000187:drug effects; D012621:Seasons; D013997:Time Factors
chemical_list: D015237:Dinoprost