Abstract

Marked increases in plasma C-type natriuretic peptide (CNP) during ovine pregnancy, and decline during periods of imposed caloric restriction, raise the possibility that CNP concentrations in ruminants are associated with changes in live weight (LWT) and metabolic demands. Accordingly we measured plasma concentrations of CNP and a related amino-terminal fragment of proCNP (NTproCNP) at weekly intervals in pregnant (n = 8) and non-pregnant red deer hinds (n = 4) and non-pregnant ewes (n = 8) run concurrently. Plasma CNP forms increased markedly during cervine pregnancy to achieve peak concentrations (NTproCNP 132 ± 9.5 pmol/L, CNP 2.14 ± 0.2 pmol/L) at 38 and 10 days pre-partum respectively, falling in the final week of gestation to reach pre-pregnancy levels immediately post-partum (P >0.05). There was no association between the concentration of CNP forms and change in LWT in either group of non-pregnant ruminants. We conclude that maternal concentrations of CNP forms are markedly raised in pregnant deer exhibiting similar changes to those found previously in pregnant ewes, and that the observed changes in plasma levels are likely to be independent of change in LWT. Maternal plasma concentration of CNP forms may be a useful marker of fetal well-being and maturation in ruminant livestock.

BA, McNeill, TCR Prickett, M Wellby, MJ Ridgway, EA Espiner, and GK Barrell

Proceedings of the New Zealand Society of Animal Production, Volume 70, Palmerston North, 13-18, 2010