Pregnancy-associated glycoprotein (PAG) profile of Holstein-Friesian cows as compared to dual-purpose and beef cows

Comparison of serum concentrations of pregnancy-associated glycoproteins and estrone sulphate during pregnancy in eutocia and dystocia beef cattle

Preventing dystocia can stabilise beef cattle management. This study aimed to investigate the relationship between serum pregnancy-associated glycoproteins (PAGs) S-N values and estrone sulphate (E1S) concentrations during pregnancy and the calf birth weight in beef cattle and to evaluate their usefulness as new predictive parameters for dystocia due to foetal overgrowth. Thirty-eight pregnant Japanese Black cattle were used. Blood samples were collected at 40, 70, 100, 150, 200, 250, 280, and 285 days after artificial insemination (AI), and birth weight of the offspring was measured. Serum PAGs S-N values and E1S concentrations were measured, and the area under the curve (AUC) and the ratio of change based on 70 days after AI were calculated, followed by calculation of the correlation coefficient with the birth weight of the offspring and comparison between the eutocia (n = 32) and dystocia (n = 6) groups. The birth weight of the offspring was moderately positively correlated with the AUC of serum PAGs S-N values and E1S concentrations in the second (r = 0.425, P < 0.01) and third (r = 0.595, P < 0.01) trimesters, respectively. The ratio of change in serum E1S concentrations between 70 and 280 days after AI was greater (P < 0.05) in the dystocia group (1276.6 ± 229.1 %) than in the eutocia group (852.6 ± 69.6 %). These results suggest that blood PAGs S-N values at mid-pregnancy (100-199 days after AI) and the ratio of changes in blood E1S concentrations between 70 and 280 days after AI may be new parameters for predicting dystocia.

Recent advances in early pregnancy loss diagnosis in dairy cows: New approaches

Early pregnancy loss is a primary cause of low reproductive rates in dairy cows, posing severe economic losses to dairy farming. The accurate diagnosis of dairy cows with early pregnancy loss allows for oestrus synchronization, shortening day open, and increasing the overall conception rate of the herd. Several techniques are available for detecting early pregnancy loss in dairy cows, including rectal ultrasound, circulating blood progesterone, and pregnancy-associated glycoproteins (PAGs). Yet, there is a need to improve on existing techniques and develop novel strategies to identify cows with early pregnancy loss accurately. This manuscript reviews the applications of rectal ultrasound, circulating blood progesterone concentration, and PAGs in the diagnosis of pregnancy loss in dairy cows. The manuscript also discusses the recent progress of new technologies, including colour Doppler ultrasound (CDUS), interferon tau-induced genes (ISGs), and exosomal miRNA in diagnosing pregnancy loss in dairy cows. This study will provide an option for producers to re-breed cows with pregnancy loss, thereby reducing the calving interval and economic costs. Meanwhile, this manuscript might also act as a reference for exploring more economical and precise diagnostic technologies for early pregnancy loss in dairy cows.

Economics of Rebreeding Nonpregnant Dairy Cows Diagnosed by Transrectal Ultrasonography on Day 25 after Artificial Insemination

Pregnancy rates of Holstein cows showed a substantial decline in the past years, which caused intensive TAI programs for nonpregnant cows to shorten the period between unsuccessful insemination and the next attempt on the same cow. Although many studies examined the improvement in pregnancy rates following TAI, only a few examined the economic impact of such programs. In this study, we look at the feasibility of reproductive programs that included early pregnancy diagnosis performed by transrectal ultrasonography 25 days after artificial insemination (AI) and TAI of nonpregnant cows. This resulted in the following two TAI programs: a modified OvSynch program with a second PGF2α treatment at 24 h interval (GPPG, n = 100) and a modified OvSynch program with an intravaginal progesterone-release device inserted between days 0−7 (PRID + GPPG, n = 100). Cows included in the TAI programs recorded an improvement in the cumulative pregnancy rate (67% vs. 53%; 69% vs. 53%) compared to those in which this strategy was not applied (p < 0.05). An economic analysis was performed using a decision-support tool to estimate the net present value (NPV; USD/cow/year). The analysis revealed a difference in NPV of 89.6 USD/cow/year between the programs (rebreeding the nonpregnant cows following the TAI program vs. AI at detected estrus). In summary, rebreeding the nonpregnant cows after early negative pregnancy diagnosis (25 days after AI) using this strategy can improve the cumulative pregnancy rate and profitability of dairy farms.

Pregnancy-Specific Protein B in Yankasa Ewes During Pregnancy and Postpartum Periods

Pregnancy-specific protein B (PSPB) is produced by mono and binucleate trophoblast cells in the placenta of ruminants during pregnancy. This study was designed to determine the pattern of serum PSPB in Yankasa ewes during pregnancy and postpartum periods. Mature cycling Yankasa ewes were synchronized and divided into two groups A (n=11) and B (n=13). Group A was bred, while group B was unbred. Blood samples for PSPB assessment were collected from the ewes starting from the day of breeding until 4 weeks post-lambing. All pregnant Yankasa ewes lambed with singleton lambs after an average of 151.18 days. There was a significant (p<0.05) increase in PSPB in pregnant compared with the non-pregnant ewes in the period between 3 weeks post-breeding and 3 weeks post-lambing. Peaks were detected in the first (100.60 ng/ml), second (133.90 ng/ml), and third (114.82 ng/ml) trimesters at 5, 10 and 21 weeks of gestation, respectively, but steadily decreased within 4 weeks (2.38 ng/ml) postpartum. In conclusion, PSPB detected pregnancy in Yankasa ewes from 3 weeks post-breeding with peak levels at 5, 10 and 21 weeks post-breeding in the first, second, and third trimesters, respectively. PSPB decreased gradually after lambing until 4 weeks postpartum.

Plasmatic Profile of Pregnancy-Associated Glycoprotein (PAG) during Gestation and Postpartum in Sarda and Lacaune Sheep Determined with Two Radioimmunoassay Systems

Simple Summary

Nowadays the need to optimize and maximize the productivity of dairy sheep leads farmers to plan lambing in specific periods in order to avoid economic loss due to nonproductive animals. The goal is to diagnose pregnancy at early gestation in order to minimize the costs of unproductive animals and to properly formulate rations for the energy requirements of gestating or lactating animals at the same time. Moreover, early pregnancy diagnosis, as well as the possibility of distinguishing between single and multiple gestations, enables farmers to plan the management of lambing well in advance thus minimizing manpower requirements. This study showed, for the first time, the plasmatic profile of PAG (pregnancy-associated glycoproteins) in Sarda and Lacaune ewes during gestation and the postpartum period using two different radioimmune assay (RIA) systems, thus enhancing our knowledge regarding PAG concentrations in domestic ruminants. Moreover, it showed that for both breeds these RIA systems are capable of distinguishing pregnant from nonpregnant ewes starting from day 18 of gestation. Furthermore, the rapid disappearance of PAG concentration following lambing did not require the use of a cut-off limit in postpartum animals as a means for detecting a new pregnancy.

Abstract

This study was carried out to determine ovine pregnancy-associated glycoprotein (oPAG) levels in the plasma of Sarda and Lacaune ewes throughout gestation and in the first month postpartum, using two heterologous radioimmunoassays (RIA-706 and RIA-srPool) and to study the correlations between PAG levels and fetal gender and number. On Day 18 of pregnancy, PAG concentrations were detected in 90.1% and 80.8% of Sarda pregnant ewes with RIA-706 and RIA-srPool, respectively; and in 90% and in 75% of Lacaune pregnant ewes with RIA-706 and RIA-srPool, respectively. From Day 30, PAG concentrations were detected in all pregnant ewes by using both RIA methods. In the postpartum period, the PAG concentrations in Sarda ewes decreased rapidly reaching minimal levels (<1 ng/mL) on day 28 using both RIA-706 and RIA-srPool. In Lacaune ewes, PAG-706 levels were higher than PAG-srPool from parturition until the last day of observation (Day 28 postpartum). It was also observed that mean concentrations were higher in multiple than in single pregnancies in Sarda and Lacaune ewes. Moreover, due to the rapid disappearance of PAG concentration following lambing, a cut-off limit in postpartum animals was not required as a means for detecting a new pregnancy.

Evaluation of a cattle rapid test for early pregnancy diagnosis in sheep

The early pregnancy diagnosis allows optimizing production and timely management correction, with a greater reproductive output of livestock. The Idexx Rapid Visual Pregnancy Test® consists of an ELISA for visual reading which does not require the use of readers in the laboratory, with satisfactory pregnancy diagnoses at 28 days of pregnancy in cattle. Therefore, the aim of this study was to evaluate this rapid test and to verify the most appropriate day for the diagnosis of pregnancy in the ovine species. For this purpose, 98 serum samples from pregnant sheep and 36 from non-pregnant were used, with duplicate samples, and diagnosis was confirmed by ultrasound examination, used as the gold standard. The numbers of positive samples obtained at 26, 28, and 30 days of pregnancy were 26, 27, and 45, respectively. The Rapid Visual Pregnancy Test correctly identified 100% of the samples as positive at pregnancy of days 26, 28, and 30. The sensitivity and specificity of the test were also 100%. The Idexx Rapid Visual Pregnancy Test, initially indicated for cattle, is effective for the detection of pregnancy in the ovine species, enabling diagnosis of pregnant sheep from the 26th day of pregnancy.