Recent Possibilities for the Diagnosis of Early Pregnancy and Embryonic Mortality in Dairy Cows

One of the most recent techniques for the on-farm diagnosis of early pregnancy (EP) in cattle is B-mode ultrasonography. Under field conditions, acceptable results may be achieved with ultrasonography from Days 25 to 30 post-AI. The reliability of the test greatly depends on the frequency of the transducer used, the skill of the examiner, the criterion used for a positive pregnancy diagnosis (PD), and the position of the uterus in the pelvic inlet. Non-pregnant animals can be selected accurately by evaluating blood flow in the corpus luteum around Day 20 after AI, meaning we can substantially improve the reproductive efficiency of our herd. Pregnancy protein assays (PSPB, PAG-1, and PSP60 RIA, commercial ELISA or rapid visual ELISA tests) may provide an alternative method to ultrasonography for determining early pregnancy or late embryonic/early fetal mortality (LEM/EFM) in dairy cows. Although the early pregnancy factor is the earliest specific indicator of fertilization, at present, its detection is entirely dependent on the use of the rosette inhibition test; therefore, its use in the field needs further developments. Recently found biomarkers like interferon-tau stimulated genes or microRNAs may help us diagnose early pregnancy in dairy cows; however, these tests need further developments before their general use in the farms becomes possible.

Subsidiary methods of pregnancy diagnosis in diary cattle – alternative for the future

Early pregnancy diagnosis in cows is one of the key elements of effective reproduction management of this species. Still imperfect effectiveness of procedures performed motivates veterinarians for further exploration of new techniques for the diagnosis of pregnancy and their new application. The following article aims to give existing laboratory methods and possibilities for their use in the diagnosis of pregnancy before the 3rd day of insemination. In particular, substances that can be identified as soon as possible after insemination are presented: early pregnancy factor (EPF), progesterone (P4), estrogen sulfate and pregnancy-associated glycoproteins (PAG). A detailed description of these substances and their role in the formation and maintenance of celibacy in cows are given. The possibility of using laboratory methods in modern milk reproduction protocols is shown. From the perspective of modern literature sources, the most effective laboratory methods for diagnosing pregnancy in dairy farming today are the definition of an early pregnancy factor (EPF) and pregnancy-associated glycoproteins (PAG). Description of the methods available on the market and a new compilation (protocols) above techniques may be of interest for veterinarian involved in cattle reproduction. Despite the rapid development and the presence of more and more effective ultrasound devices, a practical veterinarian should not forget about the existence of indirect methods of diagnosis of pregnancy, which in large herds can significantly improve the economic conditions for the management of reproduction of cows in the future.