Title:Tejhasznú tehenészetekben alkalmazott korai vemhességvizsgálati módszerek és gazdasági jelentőségük Irodalmi összefoglaló
Summary Suboptimal reproductive performance is a common problem in dairy herds worldwide. Open cows after insemination can be found by efficient heat detection, or by early pregnancy diagnosis. The authors reviewed the factors relateing to the accuracy of the early pregnancy diagnosis methods used on dairy farms, and summarized the results of the studies on the production and economic consequences of the early pregnancy diagnosis. Transrectal ultrasonography and pregnancy-associated glycoprotein (PAG) tests allow for accurate diagnosis about one week before rectal palpation (26-28 vs. 35 days after insemination). Therefore, the interbreeding interval (IBI) can be shortened, cows get in calf earlier, pregnancy rate (PR) increases, and days open is reduced. However, a drawback of the early diagnosis is, that a larger proportion of naturally occurring pregnancy losses is observed. Since iatrogenic pregnancy loss is more costly than the increase in the number of open days, it is important to use a diagnostic method with high sensitivity and negative predictive value. Confirmation of pregnancy status 60-70 days after insemination is suggested. The results of field trials conducted in Hungarian dairy herds and simulation studies from the literature consistently show that the use of early pregnancy diagnosis methods is beneficial from an economic point of view. The economic benefit of early pregnancy diagnosis is higher in herds with poor reproductive performance, because a higher proportion of cows is found open at the pregnancy examination, thus these cows take advantage of the earlier diagnosis compared to rectal palpation. Higher cost per day open and larger herd size result in shorter payback time of the investments in early pregnancy diagnosis methods.