The effect of prostaglandin F2α administration at the time of insemination on the pregnancy rate of dairy cows

• DOI: 10.1016/j.anireprosci.2010.11.010
• Publication Date: 2010-11-27T09:40:23Z
• Authors: H.G. Gabriel; S. Wallenhorst; E. Dietrich; W. Holtz
• Keywords: 2. Zero hunger; Time Factors; Pregnancy Rate; 0402 animal and dairy science; 04 agricultural and veterinary sciences; Dinoprost; Injections, Intramuscular; Drug Administration Schedule; 3. Good health; Dairying; Pregnancy; Animals; Pregnancy, Animal; Cattle; Female; Seasons; Estrus Synchronization; Insemination, Artificial

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.