Effects of mating, artificial insemination and intravaginal deposition of raw semen or seminal plasma on vaginal and uterine blood flow in German Holstein cows

Aim: The present study was performed in order to characterize and compare the perfusion of vaginal and uterine arteries after challenging the reproductive tract of dairy cows via natural mating, artificial insemination (AI), or intravaginal deposition (vaginal fundus) of different biological fluids or a placebo. Material: and methods: In a double-blind study, six German Holstein cows were administered PGF2α during diestrus and 48 h later treated with GnRH. Intravaginal or intrauterine treatments were carried out 12 h after GnRH was administered. Animals served as their own controls, using a cross-over design with an interval of 14 days between experiments. Corresponding time intervals were chosen for the untreated control estrus. Blood flow volume (BFV) in the uterine (u) and vaginal (v) arteries ipsilateral to the ovary bearing the preovulatory follicle was determined using transrectal Doppler sonography. Results: : All animals exhibited estrus and ovulated between 30 h and 36 h after GnRH. Transient increases (P < 0.05) in vaginal blood flow occurred between 3 and 12 h following mating as well as 3 to 9 h after deposition of raw semen and seminal plasma, respectively. The most distinct increases (199%) in vBFV occurred 6 h after mating compared to values immediately before mating (= time 0 h). Neither AI nor deposition of a placebo into the vagina affected vBFV (P>0.05). Only mating and deposition of either raw semen, seminal plasma or AI increased (P<0.0.003) UBFV. The greatest rise in uBFV occurred after natural mating. Maximum uBFV values were detected 9 h after mating when values were 79 % greater (P < 0.05) than at 0h. Conclusions: : The natural mating, deposition of raw semen or seminal plasma and conventional AI affects vaginal and/ or uterine blood flow to different degrees. The factors responsible for these alterations in blood flow and their effects on fertility remain to be clarified in future studies.