Poster Presentation 24th Annual Lorne Proteomics Symposium 2019

A search for predictive biomarkers of ovine pre-partum vaginal prolapse (#64)

Stuart Brown 1 , Gillian Norris 1
  1. Massey University, Palmerston North, NZ, New Zealand

Ovine pre-partum vaginal prolapse (known as bearings in sheep) occurs within a few weeks prior to lambing and unless treated both ewes and unborn lambs will die. Rates of prolapse in New Zealand vary from 0.1 to 5% per annum, varying between season and farms. It is a worldwide problem which also affects the 70 million Australian sheep population. Much research has been undertaken over many years to determine the cause of this condition but no clear etiology has emerged [1]. In this study plasma samples were collected prior to prolapse occurring. An improved method for running sheep plasma on 2D gels was developed resulting in improved spot resolution along with a lower coefficient of variation for spot volume [2]. Using this improved method samples were subjected to 2D DIGE (differential in gel electrophoresis) to determine if there were differences between the protein profiles of ewes that were about to prolapse and control ewes. Results show only a few differences between controls and pre-prolapse samples. One of these was haptoglobin, a major acute phase protein in ruminants, in which some isoforms were upregulated prior to prolapse occurring. The haptoglobin isoform spot volumes were added together to calculate a global haptoglobin response and a haptoglobin assay was then used on the same samples which correlated well with the global haptoglobin gel data. Another finding was that alpha-1B-glycoprotein was down regulated close to prolapse. It also was found that ewes closest to prolapse had increased plasma cortisol concentrations compared to controls. Field observations indicate that ewes can prolapse whilst standing, which should not be possible if they are relaxed, due to negative intra-abdominal pressure [3]. Together these observations raise the question “could prolapse be caused by heightened anxiety?” This question and the biochemical analyses will be discussed.

  1. Jackson, R., et al., Epidemiology of vaginal prolapse in mixed-age ewes in New Zealand. New Zealand Veterinary Journal, 2014. 62(6): p. 328-337.
  2. Brown, S. and G. Norris, Improved consistency in 2D gel electrophoresis: Sheep plasma as a test case. Electrophoresis, 2017. 38(6): p. 906-913.
  3. McLean, J.W. and J.H. Claxton, Vaginal Prolapse in Ewes, Part VII: The measurement and effect of intra-abdominal pressure. The New Zealand Veterinary Journal, 1960. 8(3): p. 51-61.