Cannulation of the equine oviduct and chemical analysis of oviduct fluid.

The research involves cannulating an oviduct in mares to study fluid secretions during estrous cycles. It particularly focuses on changes in secretion rates and the chemical composition of these fluids, contributing to an understanding of equine reproductive biology.

Research Methodology

• The researchers used siliconized rubber tubes to cannulate one oviduct in seven mares. This involves the insertion of a tube into the oviduct for examination or treatment.
• The secretions from the oviduct were collected in an externally-located polycarbonate container positioned near the left paralumbar fossa, an area on the side of the horse just behind the ribcage.
• The rates of fluid secretion were recorded daily throughout each mare’s estrous cycle, which is the reproductive cycle in mares typically lasting around 21 days.

Chemical Analysis of the Oviduct Fluid

• Chemical analysis of the fluid extracted from the oviducts was conducted to determine the concentrations of various substances within, including calcium, magnesium, sodium, potassium, inorganic phosphorus, and glucose.
• This analysis was done for secretions across all stages of the estrous cycle, providing a comprehensive understanding of changes in the fluid’s composition throughout this biological cycle.

Findings

• Observations showed that secretion rates were at their peak during estrus, which usually spans between days 1-9 of the cycle. There was a significant decrease (P<.01) in these rates during the nonestrus period, which is the latter part of the cycle (days 10-21).
• Furthermore, the concentrations of all the substances measured in the oviduct fluids were found to be lower during estrus and significantly higher during the nonestrus period.

Post-Cannulation Examination

• After the long-term cannulation, a histologic examination of the oviducts was conducted. This revealed the presence of infiltrating lymphocytes (a type of white blood cell), plasma cells, and small areas of degenerated epithelium, which may indicate some damage or inflammatory response triggered by the cannulation procedure.