|Ansotegui, R - MSU BOZEMAN|
|Thompson, B - USDA-APHIS-VS BILLINGS MT|
|Lipsey, R - AM. SIMMENTAL ASSOCIATION|
Submitted to: Western Section of Animal Science Proceedings
Publication Type: Proceedings
Publication Acceptance Date: June 1, 2005
Publication Date: June 15, 2005
Citation: Geary, T.W., Ansotegui, R.P., Roberts, A.J., Waterman, R.C., Macneil, M.D., Grings, E.E., Thompson, B.D., Lipsey, R.J. 2005. Effects of flunixin meglumine on pregnancy establishment in beef cattle. Western Section of Animal Science Proceedings. 56:309-311 Interpretive Summary: During maternal recognition of pregnancy, the embryo must prevent PGF release by the uterus in order to survive. Subjecting cattle to stressors, such as handling stress, may be sufficient in some females to interfere with embryonic inhibition of PGF release that signals maternal recognition of pregnancy. Experiments reported here provide evidence that handling stress may interfere with this process more in heifers than cows. A single injection of Flunixin Meglumine (1.1 mg/kg BW, i.m.) was inadequate to overcome the impacts of stress.
Technical Abstract: Our objective was to determine effects of a single injection of the prostaglandin inhibitor Flunixin Meglumine (FM; 1.1 mg/kg BW, i.m.) approximately 13 d after AI on pregnancy establishment. Three experiments were conducted using estrus-synchronized heifers and cows. Technicians and AI sires were equally represented across treatments within locations and experiments. Bulls were introduced following FM treatment (approximately 13 d after AI). Pregnancy to AI was diagnosed 28 to 50 d after AI using ultrasonography. In Exp 1, beef heifers (n = 1,221) were divided within five locations to receive FM or no further treatment (Control). At insemination, heifers were divided into two similar pastures or pens and approximately 13 d later, one group of heifers within each location was worked through an animal handling facility to administer FM treatment. Location had no effect (P > 0.10) on AI pregnancy rates, so data were pooled. Pregnancy rates to AI were reduced (P < 0.025) among heifers receiving FM (65%) compared to control heifers (71%). In Exp 2, cows (n = 719) were assigned within two locations to receive FM or no further treatment (Control) 13 d after AI. At insemination, Control and FM cows were divided into separate pastures and only FM cows were handled after AI. Pregnancy rates differed by location (P < 0.01), but there was no location by treatment interaction (P > 0.10) so data were pooled. Pregnancy rates to AI did not differ (P > 0.10) between FM (57%) and Control cows (59%). In Exp 3, heifers (n = 247) and cows (n = 335) from one location were assigned at AI to receive FM or Control treatment approximately 13 d later. In Exp. 3, all cows and heifers were handled through a working facility but only half of each age group received FM treatment. Pregnancy rates to AI between FM (45%) and Control cows (42%) or FM (56%) and Control (55%) heifers were not different (P > 0.10). We conclude FM administration at the current dosage of 1.1 mg/kg BW approximately 13 d after AI did not improve pregnancy establishment in beef cows and heifers and that the additional stress of handling heifers at this time may decrease pregnancy establishment.