ovPAG measurements in early pregnancy detection by RiA in ewes

Sheep are seasonal polyestric animals due to the geographical location of our country. Ovulation occurs in every 17-20 days unless they become pregnant during the mating season in sheep. In an ideal herd management, it is important to identify pregnancies of sheep within 17 days after mating, and to make them ready to mate or inseminate before next oestrus cycle. Therefore, it is of great importance for production planning that pregnancy diagnosis is made within 17 days after mating. For this reason, it is aimed to make pregnancy diagnosis as soon as possible by measuring the Pregnancy-associated Glycoprotein (PAG) concentrations in sheep by radioimmunoassay (RIA) method. In this thesis, PAG concentrations were measured by RIA method from serum samples and real-time PCR method from tissue samples. As the materials, multiparous sheep who was 2-4 year old and had given birth 4 months ago were used. They were bought from a private farm located in Gorukle (40⁰ 23 'N, 28⁰ 85' E) in Bursa in Turkey. Sheep were selected based on the records of the Bursa Provincial Directorate of Agriculture and Forestry of the Ministry of Food related Agriculture and Forestry. Twenty sheep (pregnant: 10, non-pregnant: 10, n = 20) and 12 sheep (n = 12) were used for serum and tissue samples respectively. The oestrus synchronization of the ewes required for the collection of samples was begun in May 2017. Six different RIA methods were tested for early pregnancy diagnosis in sheep. Blood samples were taken on days 0, 10, 15, 16, 17, 18, 19 and 20 post-mating and ovPAG concentrations in blood serum were measured by using RIA-497, RIA-706, RIA-780, RIA- 860, RIA-srPool and RIA-wbPool methods for early pregnancy diagnosis. In this thesis, RIA-860 and RIA-wbPool methods were tested for pregnancy diagnosis in sheep, for the first time. In addition, real-time PCR was performed to determine ovPAG expression in uterine tissue samples. The tissue samples were collected from sheep on days 0, 14, 20 and 30 post-mating. The mean PAG concentrations were determined being increased from day 17, 18, 19 and 19 in RIA-780, RIA-706, RIA-srPool and RIA-wbPool, respectively (P <0.001). PAG1 gene expression was not upregulated or downregulated acording to real-time PCR results. The fact that ovPAG concentration can be measured in serum samples from day 17 post coitum has shown that the RIA method is both reliable and able to diagnoe early pregnancy.