Research articleAccuracy of diagnosing double corpora lutea and twin pregnancy by measuring serum progesterone and bovine pregnancy-associated glycoprotein 1 in the first trimester of gestation in dairy cows
Introduction
Several pregnancy diagnosing methods are intensively used worldwide to diagnose whether a pregnant cattle is carrying multiple fetuses or not. The different rectal palpation techniques (palpation of the uterine fluctuation, amniotic vesicle, or fetal membrane slip) [1] are useful and widespread; however, they are really dependent on the skill of the examiner. An experienced veterinarian or technician even from Day 35 with the fetal membrane slip technique is able to set up pregnancy diagnoses [2]. However, the manual techniques are limited in diagnosing twins: Usually only the bilateral twins can be diagnosed accurately. The prediction accuracy of unilateral twinning is low [3].
Ultrasonography in the early period (around Day 30) of gestation is also widely used with high accuracy to diagnose early pregnancy. At this time, usually, twin pregnancies are also visible. When dealing with twin pregnancies at a herd level, we always have to take into consideration the phenomenon of late embryonic or early fetal mortality [4]. This can influence the accuracy of our diagnostic tests.
Another possibility for diagnosing early pregnancy in the field is the measurement of pregnancy specific proteins such as bovine pregnancy-associated glycoprotein 1 (bPAG-1), bovine pregnancy-specific protein B, or pregnancy serum protein, which are secreted by the binucleate cells originating from the bovine trophoblast. In contrast to progesterone (P4) measurements, they are probably good indicators of the presence of an alive conceptus [5], [6], [7]. Several assays have been developed, and nowadays not only blood but milk tests can be used for an accurate pregnancy diagnosis [8]. Numerous factors are influencing the levels of these proteins throughout gestation; twin pregnancy is one of these factors [9], [10]. There are several studies [11], [12] focusing on the measurements of pregnancy proteins in case of bovine twin pregnancies. Regarding these studies, the question is still open: whether we can determine a cutoff value for the pregnancy proteins at different time periods of gestation by which twin pregnant animals can be distinguished from singleton carrying ones.
Progesterone assays are also widely used to measure the blood P4 concentration even at a herd level. The disadvantage of these tests is that the P4 itself is nonspecific for pregnancy; therefore, performing pregnancy diagnoses by means of P4 measurement is not resulting in an accurate sensitivity and specificity [4], [5], [6].
We have hypothesized that serum P4 concentrations will be different between the single and twin pregnancies, and this will be a sensitive and specific clinical indicator for the prediction of the number of CL. Furthermore, we have also hypothesized that serum bPAG-1 concentrations will be different between single and twin pregnant groups at each time points and thus will serve as a sensitive and specific clinical indicator for the prediction of the number of fetuses.
The objectives of this study were to compare serum P4 (1) and bPAG-1 (2) concentrations at different time points of gestation in cattle with the accurate determination of one or two CL; to assess whether or not serum P4 concentration is a useful clinical indicator for the determination of the number of CL at any of the previously mentioned time points (3); and to assess whether or not serum bPAG-1 concentration is a useful clinical indicator for the determination of the number of fetuses at any of the previously mentioned time points (4).
Section snippets
Animals
Altogether 84 Holstein-Friesian dairy cattle were included in our study with a confirmed pregnancy by means of ultrasonography at the late embryonic period between Days 29 and 42 of gestation (time point 1). Animals were divided into three groups: the first group (TWIN group, n = 29) had two viable embryos in the uterine horns and two mature CL on the ovaries at the time of pregnancy diagnosis. Animals with one viable embryo in the pregnant uterine horn and two CL on the ovaries formed the
Analysis of serum P4 and bPAG-1 concentrations
The descriptive data of serum P4 and the bPAG-1 concentrations of the groups at different time points are given in Table 1.
The general linear model analyzing bPAG-1 concentrations revealed significant differences (P < 0.001) within groups and at every sampling time points. Regarding serum P4 concentrations, the general linear model revealed statistically significant differences (P < 0.005) between the time points 1 versus 4 and 2 versus 4.
Association between serum P4 concentrations and the number of CL
Cows were regrouped on the basis of the number of the CL
Discussion
In this study, the concentrations of P4 and bPAG-1 were measured in cases of singleton and twin gestations with one or two CL. Due to the fact that almost 95% of twin pregnancies are dizygotic [19], it was worth testing that double CL might produce more P4 at different stages of gestation. Because generally from around Day 150 of gestation, the placenta provides a marked amount of P4, it was important to test the animals before this time point to achieve a clinically reliable diagnosis. Several
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Relationship of foetal number and parity in Barbari goats to plasma profile of caprine pregnancy-associated glycoprotein (caPAG) during gestation and the early postpartum period
2019, Animal Reproduction ScienceCitation Excerpt :This difference was first observed at d 45 of pregnancy (1.74 fold; S-N = 1.22 ± 0.21 compared with 0.70 ± 0.04) and the pattern of greater concentrations was sustained until the end of gestation. Results from the present study where there was a greater caPAG concentration in does with two foetuses than one foetus are consistent with results from earlier studies with other farm animals such as cattle (Szelényi et al., 2015) and sheep (Ledezma-Torres et al., 2006). Szelényi et al. (2015) reported that there was a 1.36 fold greater concentration of PAG in cows with two foetuses compared with a single foetus at 29 to 42 d of gestation.
Temporal changes in plasma profile of pregnancy-associated glycoprotein, progesterone and estrone sulfate associated with fetal number during early- and mid-pregnancy in goats
2019, Animal Reproduction ScienceCitation Excerpt :The difference in PAG concentrations was first detectable at d 28 of pregnancy and the pattern was similar until d 93 of gestation. In the present study, the results of greater plasma PAG concentrations in goats bearing twin fetuses compared with a singleton fetus during early- and mid-pregnancy is consistent with results from earlier reports on goats (Batalha et al., 2001), cattle (Szelényi et al., 2015) and sheep (Ledezma-Torres et al., 2006). In some studies, however, there was an effect of litter size on circulating PAG concentration only during mid- and late-pregnancy in farm animals (de Sousa et al., 1999; Szelényi et al., 2015).
Pregnancy and its diagnosis
2018, Veterinary Reproduction & ObstetricsThe dilemma of twin pregnancies in dairy cattle. A review of practical prospects
2017, Livestock ScienceCitation Excerpt :Approaches for induced embryo reduction are also discussed. Although plasma concentrations of pregnancy-associated glycoproteins have been recently used to discriminate between singleton and twin pregnancies (Szelényi et al., 2015; García-Ispierto et al., 2016), ultrasound imaging is routinely used for twin pregnancy diagnosis in dairy cattle (López-Gatius and García-Ispierto, 2010). The first problem in diagnosing twin pregnancies is that the two embryos must be clearly observed.
Identification of the pregnancy-associated glycoprotein family (PAGs) and some aspects of placenta development in the European moose (Alces alces L.)
2016, TheriogenologyCitation Excerpt :The proximity of the TRD cells expressing the PAGs allows for growing their concentrations in the maternal blood, and for pregnancy diagnoses in white-tailed deer [79], in semi-domesticated reindeer [48,49], and some other wild and domestic ruminants [see: 1,2]. In bovine females with single and twin gestations, the different sensitivities of the commercial ELISAs and radioimmunoassays for pregnancy tests depend on many heterologous tracers and mainly polyclonals recognizing various PAG epitopes [45,80]. Therefore, the AaPAGs, secreted into maternal blood vessels, will be a good prenatal marker for the future evaluation of pregnancy and embryonic mortality in wild ruminants maintained in conservation parks or zoos.