Prevalence, Influential Factors and Oestrus Behaviour of Mares with Pneumovagina in a Tropical Region

This study determined the prevalence, the contributing factors, and the oestrus behaviour commonly observed in mares with pneumovagina in the tropical region. Pneumovagina is an anatomical conformational deformity due to inclined vulva that resulted in the vulva opening stretching beyond the limit set by the ischium of the pelvis. This condition compromised the vulva’s functional barrier in protecting the reproductive tract from contaminants. The current study involved 116 mares enrolled during clinical reproduction ambulatory work using purposive case-control cohort sampling method. Physical examinations were conducted to determine the Caslick’s index (CI) and body condition score (BCS). The oestrus behaviour was observed partly by the researcher. The recorded information was comprised of age, breed and reproductive history using a structured questionnaire responded by the owners. This study revealed that large breed mares with low BCS were those afflicted with the most severe pneumovagina. Brooding mares that had multiple pregnancies and first pregnancy before two years of age were more susceptible to severe pneumovagina at later stages of life. The mares with severe pneumovagina exhibited inconsistent oestrus intervals, yet strong stallion receptiveness. This behaviour mimicked the situation of irregular oestrogen secondary wave during the follicular phase with delayed LH surge at primary waves peak to facilitate ovulation. This situation implicates the erratic oestrus behaviour and poses challenges on reproduction management.