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

Abstract

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.

Obtaining and Use of the Recombinant Bovine Pregnancy-Associated Glycoprotein 1

“…This is because the intensification of animal husbandry and widening use of the artificial insemination technology. The PAGs proteins are widely considered to be the markers of choice (Green et al, 2005;Community et al, 2016;Oliveira Filho et al, 2020;Shephard and Morton, 2018;Szenci, 2021;Karen et al, 2015). In this article, we present a sequence of a gene encoding the boPAG1, recombinant expression of the boPAG1 protein, and obtaining of a mAb which reacts with the recombinant protein and with an antigen present in a cow's placenta.…”

Clinical Overview of Luteal Deficiency in Dairy Cattle

“…Beyond this time interval, the risk of losses is much lower. In a similar way to the luteal period post-AI, reduced plasma P4 concentrations at pregnancy diagnosis have often been associated with pregnancy loss [ 21 , 22 ]. Two facts reinforce this perception.…”

Señales embrionarias y hormonas placentarias: bases moleculares y potencial uso para el diagnóstico y el seguimiento de la gestación en animales de interés productivo

“…Si bien la técnica de RIA fue la técnica por la cual se comenzó a cuantificar la concentración de PAG en muestras de sangre materna, en la actualidad, se han desarrollado kits comerciales basados en la técnica de ELISA para su cuantificación ya sea en sangre como en leche (Szenci O., 2021) en bovinos, ovinos, caprinos, bisontes y fauna silvestre. En general, los métodos comerciales para la detección de PAG en sangre y leche materna de bovinos, son confiables y su precisión oscila entre el 93 % y el 96 % (Silva et al, 2007, Pohler et al, 2013, Szenci O., 2021.…”