The effects of intrauterine infusion of peanut oil on endometrial health, salivary cortisol and interovulatory period in mares

A review of oestrus suppression techniques in mares

“…The ability of the treatment to block luteolysis was not significantly different when administered on Day 8 (9/12; 75%), 12 (10/12; 83%) or 14 (6/12; 50%) of dioestrus but declined significantly when given before Day 8. Despite this initial report other researchers have failed to repeat these results with 0% (n = 5; Diel de Amorim et al 2016b) to 33% (n = 6; Campbell et al 2017) of mares demonstrating prolonged luteal phases with coconut and peanut oils respectively. Campbell et al (2017) demonstrated superficial erosion of the endometrial surface epithelium in all mares and significantly increased eosinophil numbers in the endometrium of mares, postinfusion of peanut oil.…”

“…Despite this initial report other researchers have failed to repeat these results with 0% (n = 5; Diel de Amorim et al 2016b) to 33% (n = 6; Campbell et al 2017) of mares demonstrating prolonged luteal phases with coconut and peanut oils respectively. Campbell et al (2017) demonstrated superficial erosion of the endometrial surface epithelium in all mares and significantly increased eosinophil numbers in the endometrium of mares, postinfusion of peanut oil. They also demonstrated, in at least one mare, that the infusion resulted in a significant uterine reaction with the formation of fluid.…”

“…Campbell's and Diel de Amorim's groups either tested or filtered their oils for bacterial contamination however it raises the question if there could have been other contaminants such as endotoxins in the oils used? If Campbell et al (2017) findings are consistent then mares may have a hypersensitivity type reaction to the infusion of oil. The technique has been used clinically with success in low numbers (Crabtree 2019).…”

“…Client feedback was positive (Crabtree 2019); however, one cannot rule out the placebo by proxy effect. Campbell et al (2017) suggested that 'oils' may be considered 'medicines' by the regulatory authorities. To the author's knowledge, there is no current published regulatory opinion on the use of intrauterine oil(s) however, substances 'not-approved' by medicines agencies are considered 'prohibited' under many codes.…”