REGULAR ARTICLES Biomarkers coding for ovPAG-1 mRNA expression and pregnancy status in Dohne Merino ewes at an abattoir Peter Olutope Fayemi & Voster Muchenje Accepted: 12 March 2013 # Springer Science+Business Media Dordrecht 2013 Abstract The objective of the present study was to deter- mine the pregnancy status of Dohne Merino ewes at slaugh- ter. This was done by collecting blood samples from the ewes (n =60) during exsanguination to assay for pregnancy biomarkers using radio-immunological and TaqMan reverse transcription polymerase chain reaction techniques. The ex- pressions of ovine pregnancy-associated glycoprotein with- in a range of 1.068 -09 to 8.977 -07 indicated 43.33 % ewes with pregnancy (ΔmRNA) signals at the point of slaughter. The assay validation showed that half of these ewes were truly pregnant, and most of the ewes that exhibited ‘true positives’ were within 56–60 kg live weight and were about 30 months old. The biomarkers used in this study, therefore, showed that approximately 22 % Dohne Merino ewes were truly pregnant at the point of slaughter. Keywords Dohne Merino ewes . Pregnancy . RNA extraction . Reverse transcription PCR Introduction Typically, the slaughter of animals of both sexes occurs ev- erywhere, and conventionally, ovine species are converted to meat. In South Africa, Dohne Merino is one of the commonest composite sheep breeds that are mostly presented for slaughter at the registered abattoirs. This breed was developed in the 1930s as a cross-breed between the local Merino and the German Mutton Merino at the Dohne Research Farm in the Eastern Cape Province (McMaster and Kotze vader van die 1991; VanWky et al. 2008). The Merinos have received a topmost rating among the registered breeds by the South African Studbook Association due to their immense contribu- tions to the subsistence economy and to the meat–wool indus- tries (Cloete and Olivier 2010). A decline in the number of sheep in South Africa (from approximately 30 to 22 million) was reported between the early 1980s and 2007 by Cloete and Olivier (2010) due to the outbreak of rift fever valley disease, predation, theft, slaughter and other factors. The conversion of these animals to meat has been found to be one of the key reasons for the decline in sheep population nationwide and in the sub-Saharan of Africa, too (Ngbede et al. 2012). This is because not only the conventional non-breeding, old or accidentally injured ewes are slaughtered for meat but also the productive pregnant ones (Addass et al. 2010; Muhammad et al. 2009). The aftermath, therefore, is the wastage of pregnancies with singleton, twins or multiple foetuses at different gestational stages (Bokko 2011; Mailafia and Ramalan 2010). The dangers of slaughtering pregnant ewes lie in the possibility of converting the most productive animals to meat and of eroding useful genetic resources from the herd. The need for accurate diagnosis that could provide useful information whether in culling of non-pregnant ewes or ascertaining the pregnancy status becomes critical for the sustainability of this meat species. In an effort to identify the cause of pregnancy wastages, primary attention is mostly directed to infections, while the non-infectious causes amounting to almost 70 % are perhaps ignored (Christianson 1992; Grazul-Bilska et al. 2010). Conventionally, the simplest method of observing return to oestrus may often prove unreliable since records on dates of natural service are sometimes unobserved or unrecorded by the farmers. Although an ultrasound examination can be quite useful (De Barbier et al. 2012; Fthenakis et al. 2012) to view developing embryo within few weeks of gestation or P. O. Fayemi : V. Muchenje (*) Department of Livestock and Pasture Science, Faculty of Science and Agriculture, University of Fort Hare, P. Mail Bag X1314, Eastern Cape, South Africa e-mail: vmuchenje@ufh.ac.za Trop Anim Health Prod DOI 10.1007/s11250-013-0404-5