Effect of seminal plasma on uterine inflammation, contractility and pregnancy rates in mares.
BACKGROUND
There is conflicting evidence over the role seminal plasma plays in sperm transport and inflammation within the uterus of mares. In in vitro studies, seminal plasma has been shown to reduce polymorphonuclear neutrophil (PMN) function, but the opposite effect on uterine inflammation has been reported in vivo.


OBJECTIVE
To study the effect of seminal plasma on uterine contractility, inflammation and pregnancy rates by inseminating mares with low doses of sperm free from seminal plasma (Group 1) and containing seminal plasma (Group 2).


METHODS
Synchronised mares were inseminated with 50 x 10(6) sperm in either skim milk extender or seminal plasma. Uterine lavage was performed 6 h after insemination to assess the inflammatory response. The contraction frequency of the uterus was measured over a 4 min period 10 mins and 6 h after insemination, using B-mode ultrasonography. Pregnancy rates were assessed 16 days after insemination.


RESULTS
Uterine contractions were less frequent in Group 1 mares inseminated with seminal plasma and significantly more PMNs were found in the lavage fluid of those mares. Pregnancy rates were identical in both groups (62%).


CONCLUSIONS
This study provides evidence that seminal plasma decreases uterine contractility and increases the inflammatory response of the uterus to semen. No effect of seminal plasma on pregnancy rates was demonstrated.


CONCLUSIONS
Mares that develop persistent mating-induced endometritis may have inherently poor uterine contractility and impaired uterine clearance. The presence of seminal plasma during breeding may not be desirable in these mares. The role of seminal plasma in problem mares warrants additional study.
Portus
B J
BJ
MTT Agrifood Research Finland, Animal Production Research, Equines, 32100 Ypäjä, Finland.
Reilas
T
T
Katila
T
T
D000818:Animals; D001947:Breeding; D004716:Endometritis / Q000209:etiology / Q000276:immunology / Q000662:veterinary; D004717:Endometrium / Q000276:immunology*; D005260:Female; D006734:Horse Diseases / Q000209:etiology / Q000276:immunology; D006736:Horses; D007315:Insemination, Artificial / Q000379:methods / Q000662:veterinary; D008297:Male; D009504:Neutrophils; D011247:Pregnancy; D018873:Pregnancy Rate; D012661:Semen / Q000276:immunology* / Q000502:physiology; D029589:Seminal Plasma Proteins / Q000276:immunology* / Q000494:pharmacology; D013094:Spermatozoa / Q000502:physiology*; D014590:Uterine Contraction / Q000187:drug effects* / Q000502:physiology
D029589:Seminal Plasma Proteins