Comparison between transrectal ultrasonography and pregnancy-associated glycoprotein determination for early pregnancy diagnosis in the goat

The aim of the present workwas to compare the efficiency of transrectal ultrasonography technique and the determination of the pregnancy-associated glycoproteins (PAG) concentrations in plasma samples for pregnancy diagnosis in goats. Thirty nine Canary goats were synchronized and naturally mated every 12 hours throughout oestrous. Blood samples were collected on days 17, 18, 19, 20, 22, 24, 26 and 28 and transrectal ultrasonography was carried out on days 20, 22, 24, 26 and 28 (Day 0¼day of the last mating). PAG concentrations were analysed by a RIA method previously validated. There were 23 pregnant goats (10 single and 13 multiple pregnancies) and 16 nonpregnant goats. The pregnancy diagnosis was a little
earlier by PAG determination than transrectal ultrasonography (sensitivity: 95 and 91% on Day 24 and 100 and 96% on Day 26, respectively). The ultrasonography allowed to discriminate between single and multiple pregnancies in 70% of goats (16/23) on Day 28 of pregnancy. The PAG concentrations were significantly higher in multiple than single pregnancies from Day 19 onwards, suggesting that it could also be used as a tool to discriminate between single and multiple gestations. (Supported by D.G. de Universidades del Gobierno de Canarias).