Effect of the stage of the oestrous cycle and the frequency of sample collection on the composition of ovine uterine fluids

Abstract

Surgical procedures were employed to collect ovine uterine fluids on days 0, 3, 6, 9, 12 and 15 of the oestrous cycle, and at the subsequent return to oestrus. Samples from both uterine horns were collected from each ewe on two separate occasions, 3 days apart. Each group of ewes received its first uterine flush at one of the 6 days of the cycle indicated above. Uterine flushes were analysed for total protein, alkaline phosphatase, β-glucuronidase, leucine aminopeptidase and albumin. There were significant differences in the levels of leucine aminopeptidase, alkaline phosphatase, total protein and albumin between ewes experiencing their first collection of uterine fluid, and ewes at the same stage of the cycle which had been sampled 3 days previously. Investigation of the first sample collected from each ewe revealed cyclic changes in the levels of each of the five proteins. This experiment supports the view that ovarian steroids influence uterine fluid composition and indicates that serial samples of uterine flushings within a ewe may not give a valid representation of uterine function during the oestrous cycle.