Effects of Post Insemination Flunixin Meglumine Injection on Corpus Luteum Maintenance, Plasma Progesterone Concentrations and Pregnancy Rate in Heat Stressed Holstein Dairy Cows

摘要

Aim of the current study was to evaluate the effect of Flunixin Meglumine (FM) post insemination injection on Corpus Luteum (CL) function, its Progesterone (P4) secretion and pregnancy rate of dairy cows in heat stress condition. Estrus cycles of 120 Holstein cows were synchronized utilizing ovsynch protocol and cows were artificially inseminated. Environmental data indicated that the cows experienced medium heat stress during trials (mean daily temperature-humidity index = 79-84). They were randomly divided into three equal groups of 40. Two groups received FM injection between days 2-5 and 10-13 post inseminations once daily and the third group was selected as control. Blood samples were collected on days 7 and 14 post insemination for analysis of plasma P4 concentrations. Ultrasonography scanning was performed on these days for CL detection following which its volume was calculated. The pregnancy status of the cows was estimated at days 27-30 by ultrasonography and confirmed on day 42 by palpation per rectum. Plasma P4 concentrations showed no significant difference in groups receiving treatment compared by the control (p>0.05). However, CL volume was different between the treated groups on day 14 (p = 0.03). The pregnancy rate in group FM 10-13 (20%) was higher than that of group FM 2-5 (17.5%) and control (15%) but this improvement was not statistically significant (p>0.05). Treatment of heat stressed dairy cows with FM post insemination between days 2-5 or 10-13 led to CL maintenance but this treatment could neither increase the serum P4 concentrations nor improve the pregnancy rate.