Evaluation of the early conception factor (ECF) test for the detection of nonpregnancy in dairy cattle

Changes in plasma PLAC-1 concentration and its expression during early-mid pregnancy in bovine placental tissues - a pilot study

BACKGROUND

Placenta-specific protein 1 (PLAC1) is a small secreted protein considered to be a molecule with a significant role in the development of the placenta and the establishment of the mother-foetus interface. This study aimed to confirm the presence of bovine PLAC1 and to examine its profile in the placenta and plasma in the first six months of pregnancy. The expression pattern of PLAC1 was analysed by RT-qPCR and Western Blotting. Quantitative evaluation was carried out using ELISA.

RESULTS

PLAC1 concentrations in the plasma of pregnant cows were significantly higher (p < 0.05) than those obtained from non-pregnant animals. PLAC1 protein concentrations in the placental tissues of the foetal part were significantly (p < 0.05) higher than in the tissues of the maternal part of the placenta. PLAC1 transcripts were detected in both placental tissue samples and epithelial cell cultures.

CONCLUSIONS

In conclusion, the results of the present preliminary study suggest that PLAC1 is involved in the development of bovine placenta. The presence of this protein in the plasma of pregnant animals as early as the first month may make it a potential candidate as a pregnancy marker in cows. Further studies on exact mechanisms of action of PLAC1 in bovine placenta are necessary.

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

Simple Summary

Pregnancy diagnosis plays an essential role in decreasing days open in dairy farms; therefore, it is very important to select an accurate method for diagnosing early pregnancy. Besides traditional pregnancy diagnoses made by rectal palpation of the uterus from 40 to 60 days after AI and measuring the serum or milk progesterone concentration between 18 to 24 days after AI, there are several new possibilities to diagnose early pregnancy in dairy farms. However, it is very important to emphasize that before introducing any new diagnostic test, we need to make sure the accuracy of that particular test to be able to decrease the rate of iatrogenic pregnancy losses caused by prostaglandin or resynchronization treatments. This review focuses on the diagnostic possibilities and limitations of early pregnancy diagnosis in the field.

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.

Relaxin as a hormonal aid to evaluate pregnancy and pregnancy loss in bottlenose dolphins (Tursiops truncatus)

This study was conducted to critically evaluate weekly and monthly circulating concentrations of immunoreactive relaxin throughout pregnancies that resulted in live births, stillbirths, and abortions in aquarium-based bottlenose dolphins. A relaxin RIA was used to analyze serum collected during 74 pregnancies involving 41 dolphins and 8 estrous cycles as well as 8 non-pregnant dolphins. Pregnancies resulted in live births (n=60), stillbirths (n=7), or abortions (n=7). Relative to parturition (Month 0), monthly changes (P<0.0001) in relaxin was indicated by relatively low concentrations during early pregnancy (Months -12 to -9) which subsequently increased (P<0.05) during mid- (Months -8 to -5) to late (Months -4 to -1) pregnancy; relaxin was highest (P<0.05) at the time of parturition. Post-parturition (Month 1), concentrations decreased (P<0.05). During the first 4weeks post-ovulation, relaxin concentrations were not different between pregnant and non-pregnant dolphins (status-by-week interaction, P=0.59). Status-by-month interaction (P<0.0002) involving different pregnancy outcomes was due, impart, to an increase in relaxin during early pregnancy (P<0.05) that was comparable among dolphins with live births, stillbirths, and abortions except concentrations were lower (P<0.05; 52%) at mid-pregnancy in association with pregnancy loss. Thereafter, concentrations increased (P<0.05) during late pregnancy in dolphins with stillbirths but not in dolphins with abortions. In conclusion, this study provided new information on the pregnancy-specific nature of relaxin, critical evaluation of the fundamental characteristics of relaxin during pregnancy and pregnancy loss, and clarification on the strengths and limitations of relaxin as a diagnostic aid to determine pregnancy status and assess maternal-fetal health in bottlenose dolphins.

Identification of serum protein markers for early diagnosis of pregnancy in buffalo

Improper or delayed pregnancy diagnosis has significant impact over animal production, particularly in buffaloes which inherently suffer from several reproductive inefficiencies. Thus the present study has undertaken to identify serum protein markers pertaining to early pregnancy diagnosis in buffaloes. Serum samples were collected from 10 pregnant Murrah Buffalo heifers at weekly intervals from days 0-35 post-artificial insemination and from 12 inseminated non-pregnant cyclic buffalo heifers on days 0, 7, 14 and 21. Two-dimensional gel electrophoresis and densitometric analysis revealed the presence of five protein spots showing average density fold change of ≥4 during early pregnancy. Mass spectrometry analysis identified these up-regulated proteins as anti-testosterone antibody light chain, apolipoprotein A-II precursor, serum amyloid A, cytokeratin type II, component IV isoform 1, which are have established roles in embryogenesis, but over-expression of the fifth identified protein immunoglobulin lambda light chain in pregnancy has been elucidated as a novel finding in the current study. Further, with bioinformatics analysis, potential antigenic B-cell epitopes were predicted for all these five proteins. An antibody cocktail-based approach involving antibodies against all these five up-regulated entire proteins or their epitopes could be developed for early detection of pregnancy in buffaloes. © 2016 Japanese Society of Animal Science.

Comparison between allantochorion membrane and amniotic sac detection by per rectal palpation for pregnancy diagnosis on pregnancy loss, calving rates, and abnormalities in newborn calves

The objectives of the present investigation were to evaluate the pregnancy diagnosis by detection of either the allantochorion membrane (FMS) or amniotic sac (ASP) by per rectum palpation (PRP) during late embryonic or early fetal period on pregnancy loss (PRL) at reexamination, calving rates, and abnormalities in newborn calves. A controlled randomized blind design with 800 lactating dairy pregnant cows diagnosed by transrectal ultrasonography (TRUS) between Days 35 and 57 of gestation from one dairy farm were included. The cows were randomly divided according to detection of allantochorion membrane (FMS group; n = 264), detection of amniotic sac (ASP group; n = 266), and TRUS (control [CON] group; n = 270). TRUS was considered as the criterion standard method of comparison. The entire PRP was performed by one experienced veterinarian. Then, all the cows were reexamined only by TRUS between 2 and 4 weeks later by two independent veterinarians to assess PRL. The calving rate one (number of cows calved divided by the number of cows initially pregnant) and calving rate two (number of cows calved divided by the number of cows pregnant at reexamination) for each group was calculated. All abortions and stillborns were necropsied, and calves alive were followed for 5 days. The overall initial PRL (between initial pregnant cows and reexamination) for FMS, ASP, and CON groups was 7.4% (19/258), 8.8% (23/262), and 9.2% (24/260), respectively (P = 0.75). The overall late PRL (between reexamination and calving) for FMS, ASP, and CON groups was 4.2% (9/213), 5.7% (12/209), and 4.2% (9/216), respectively (P = 0.71). The calving rate one for FMS, ASP, and TRUS groups was 79.1% (204/258), 75.2% (197/262), and 79.6% (207/260), respectively (P = 0.63). The calving rate two for the same groups was 85.4% (204/239), 82.4% (197/239), and 87.7% (207/236), respectively (P = 0.27). The number of fetuses aborted late, premature, and mature dead from FMS, ASP, and CON groups was 6, 4, and 5, respectively (P = 0.85), and no abnormalities at necropsy were detected. One stillborn male calf with atresia coli after 281 days of gestation from a cow examined by ASP at Day 51 was diagnosed. It was concluded that the use of either FMS or ASP for pregnancy diagnosis during late embryonic or early fetal period did not increase the PRL, affect calving rates, or produce calves with congenital abnormalities.

Effect of early pregnancy diagnosis by per rectum amniotic sac palpation on pregnancy loss, calving rates, and abnormalities in newborn dairy calves

The objectives of the present study were to evaluate the effect of per rectal amniotic sac palpation (ASP) for pregnancy diagnosis during the late embryonic period on pregnancy loss, calving rates, and abnormalities in newborn calves. A controlled, randomized, blocked, blind experiment containing 680 lactating pregnant dairy cows with a viable embryo diagnosed by transrectal ultrasonography was performed. Two dairy operation sites (farm A and farm B) were selected. At each farm, the cows were randomly divided into control (CON) and ASP groups. The CON group was not subjected to pregnancy diagnosis via per rectum palpation. The ASP examinations were performed by one experienced veterinarian between Days 34 and 45 after breeding. All cows were reevaluated by transrectal ultrasonography only between 2 and 4 weeks later. Two calving rates were calculated: calving rate 1 (cows that calved from the initial number of pregnant cows) and calving rate 2 (cows that calved from cows pregnant at reexamination). In farm A, the percentages of early pregnancy loss were 11.5% (19 of 165) and 13.2% (24 of 182) for the CON and the ASP groups, respectively (P = 0.64). In farm B, the percentage of early pregnancy loss was 11.2% (19 of 170) for the CON group and 8.8% (14 of 159; P = 0.48) for the ASP group. In farm A, the percentage of late pregnancy loss was 7.6% (11 of 145) for the CON group and 5.5% (8 of 155; P = 0.39) for the ASP group. In farm B, the percentage of late pregnancy loss was 3.7% (5 of 137) for the CON group and 6.3% (8 of 127; P = 0.32) for the ASP group. In farm A, early pregnancy loss was higher than late pregnancy loss (12.4% vs. 6.3%; P = 0.01), and in farm B, the same tendency was detected (10.0% vs. 4.9%, for early and late pregnancy loss, respectively; P = 0.02). In farm A, calving rate 1 was 81.2% (134 of 165) for the CON group and 80.8% (147 of 182; P = 0.92) for the ASP group. Calving rate 2 for the same groups was 92.4% (134 of 145) and 94.8% (147 of 155), respectively (P = 0.68). In farm B, calving rate 1 was 77.7% (132 of 170) for the CON group and 74.8% (119 of 159; P = 0.55) for the ASP group. Calving rates 2 for the same groups were 87.4% (132 of 151) and 82.1% (119 of 145), respectively (P = 0.20). Two female calves with atresia coli were diagnosed only in the CON group. It was concluded that ASP during the late embryonic period for pregnancy diagnosis did not increase the pregnancy loss, affect calving rates, or produce abnormalities in calves.

Relaxin: a hormonal aid to diagnose pregnancy status in wild mammalian species

In the beginning of 1960s, seminal studies characterizing circulating concentrations of immunoreactive relaxin in companion dogs and evaluating the differences in concentrations among pregnant, nonpregnant, and pseudopregnant bitches indicated the potential for relaxin to be applied clinically as a diagnostic aid to detect pregnancy status in wild animal species. A brief historical overview of the nature of relaxin and early work to develop and validate immunologic methods to analyze relaxin in the blood of rodents and pigs is initially discussed, which is followed by a summary of the development and validation of relaxin immunoassays to diagnose pregnancy in companion dogs and cats. Thereafter, observation of the pregnancy-specific increase in circulating concentrations of relaxin in laboratory, companion, and farm animal species leads to discussion on the application of radioimmunoassays, enzyme immunoassays, and a rapid immunomigration assay to diagnose pregnancy in wild terrestrial (e.g., wolves, lions, elephants, rhinoceros, panda) and marine (e.g., seals, dolphins) mammal species. A reference table is included with a comprehensive list of numerous species and essential reagents that have been used in various in-house and commercial immunoassays to successfully analyze relaxin quantitatively and qualitatively in blood (serum or plasma) and to some extent in urine. Although the detection of relaxin concentrations has the potential to aid in the diagnosis of pregnancy in many wild animal species, there are challenges in other species. Future efforts should focus on validation of nonradiolabeled relaxin immunoassays for broader application among species and improving techniques (e.g., extraction, purification) to analyze relaxin in samples other than blood (e.g., urine, feces, saliva, blow, skin, blubber) that can be collected in a less-invasive or -stressful manner and processed accordingly for basic and applied purposes, especially with application toward conservation of threatened or endangered species.

Early pregnancy diagnosis in bovines: current status and future directions

An early and accurate diagnosis of reproductive dysfunctions or aberrations is crucial to better reproductive management in livestock. High reproductive efficiency is a prerequisite for high life-time production in dairy animals. Early pregnancy diagnosis is key to shorten the calving interval through early identification of open animals and their timely treatment and rebreeding so as to maintain a postpartum barren interval close to 60 days. A buffalo, the most important dairy animal in the Indian subcontinent, is known for problems related to high calving interval, late puberty, and high incidence of anestrus. Lack of reliable cow-side early pregnancy diagnosis methods further aggravates the situation. Several methods of pregnancy diagnosis are being practiced in bovine species, yet none qualifies as the ideal pregnancy diagnosis method due to the inherent limitations of sensitivity, accuracy, specificity, speed, and ease of performing the test. The advancement of molecular techniques like proteomics and their applications in animal research has given a new hope to look for pregnancy biomarker molecules in these animals. This review attempts to examine common pregnancy diagnosis methods available for dairy animals, while assessing the usefulness of the modern technologies in detecting novel pregnancy markers and designing future strategies for research in this area.

Gestational, periparturient and preweaning growth traits of Holstein versus Gir x Holstein F1 crossbred dairy calves born to Holstein dams

The objectives of this study were to assess the gestational, periparturient and preweaning growth traits of Holstein vs Gir x Holstein (G x H F1) cross-bred dairy calves. Holstein cows (n=64) pregnant with Holstein (H x H) calves (bulls, n=16; heifers, n=18) or G x H (bulls, n=8; heifers, n=22) calves were sampled from 60 days of gestation through calving for serum progesterone (P4) and in utero placentome sizes, and at parturition for calving ease scores (CES), calf vigour scores (CVS), and placental characteristics. Post-calving calf measures included birth weight (day 0) and body weight (kg), hip width (HW), body length (BL), wither height (WH), hip height (HH) and heart girth (HG) through 42 days of age. Serum IgG and calf vital function tests (respiration rate (RR), heart rate (HR), rectal temperature (RT) and fecal scores) were recorded on days 1, 3, 7 and 14 of age (a.m. and p.m.). Serum gestational P4 was higher (p < 0.05) for cows with H x H than G x H calves. Placentome measurements in utero were greater (p < 0.01) for H x H calves than for G x H calves, while at parturition placental characteristics did not differ (p > 0.10). Gestation length, CES and CVS also did not differ (p > 0.10) between H x H and G x H calves. Calf RR and HR were higher (p < 0.05) for H x H than G x H calves at both a.m. and p.m., while RT, fecal scores and serum IgG did not differ (p > 0.10) between H x H and G x H calves. Birth weight did not differ (p > 0.10) between H x H and G x H calves within sex. Moreover, bulls did not differ (p > 0.10) in any of the growth measures between H x H and G x H calves, whereas H x H heifers at days 28 and 42 of age were greater (p < 0.05) in all growth traits than G x H heifers. Nevertheless, the relative change in growth measures over time (days 0 to 42) did not differ (p > 0.10) between H x H and G x H calves. While subtle differences in gestational, early growth and vital function characteristics were observed, these data suggest very similar developmental profiles between H x H and G x H calves.

Administration of 6-methoxybenzoxazolinone (MBOA) does not augment ovulatory responses in St. Croix White ewes superovulated with PMSG

The objective of this investigation was to examine the effects of 6-methoxy-benzoxazolinone (MBOA), a plant compound that resembles melatonin and alters ovarian function in rodents, in combination with PMSG on superovulatory responses in the cycling ewe. In Experiment I, St. Croix White ewes (n = 44) were synchronized (intra-vaginal progestin sponge) for 14days followed by hCG (750 IU) at 1 day after sponge removal (day 0). Ewes were assigned to one of six treatments administered on day -1: Control (no PMSG or MBOA; n = 7); PMSG (1000 IU i.m.; n = 7); Low MBOA (0.43 mg/kg i.m.; n = 7); High MBOA (1.15 mg/kg i.m.; n = 7); Low MBOA + PMSG (n = 8); High MBOA + PMSG (n = 8). In Experiment II, St. Croix White ewes (n = 24) were synchronized (progestin CIDR) for 14 days followed by hCG on day 1 after CIDR removal (day 0). Ewes were assigned to one of three treatments administered on day -1: Control (n = 8); PMSG (n = 8); Low MBOA+PMSG (n = 8). Laparoscopy was performed on day 9 to assess numbers of corpora lutea (CL) and visible follicles on each ovary. Blood samples were collected on day -13, -1, 0, 1, and days 6 or 7-12 for analysis of serum progesterone (P4) by RIA. Treatment groups receiving PMSG (alone or with MBOA) exhibited greater (P < 0.05) serum concentrations of P4 post-synchrony than Control and MBOA-only groups. Ovulation rate was lower (P < 0.05) for Control and MBOA-only treated ewes than ewes receiving PMSG. Ovulation rate in ewes treated with MBOA alone was similar (P > 0.10) to Controls, and PMSG treatment alone did not differ (P > 0.10) from MBOA + PMSG treatment. Ewes treated with PMSG alone did not differ (P > 0.10) in follicle number from High MBOA + PMSG treated ewes, however, Low MBOA + PMSG treated ewes had greater numbers of follicles at day 9 (P < 0.05) than the PMSG or High MBOA + PMSG groups in Experiment I; although, this was not replicated in Experiment II with numbers of follicles in the Low MBOA + PMSG group being similar (P > 0.10) to PMSG alone. In summary, the addition of MBOA in combination with PMSG as part of a synchronization-superovuation protocol in the ewe did not increase ovulation rate.

THE RELATIONSHIP BETWEEN VAGINAL ELECTRICAL IMPEDENCE AND HORMONE PROFILES DURING PREGNANCY AND PARTURITION OF A WHITE RHINOCEROS (CERATOTHERIUM SIMUM SIMUM)

In this study, an attempt was made to use vaginal electrical impedance to predict calving in a female white rhinoceros (Ceratotherium simum simum) and to determine the relationship between vaginal electrical impedance and hormonal profiles during pregnancy. The principle behind vaginal electrical impedance is that a change in the ionic balance of vaginal and cervical mucus occurs in response to changes in reproductive hormones. Three times weekly vaginal electrical impedance readings and fecal samples were collected from midgestation to calving (a 6-mo period). The extracted fecal samples were analyzed for immunoreactive estrogens, progestagens, and corticoids by RIA. Vaginal electrical impedance readings did not decrease before calving but remained consistent throughout the last 140 days of pregnancy. Fecal progestagens in the white rhinoceros decreased between day 17 and day 1 before calving, whereas estrogens increased between 4 and 2 mo before calving, with an additional increase occurring 1 mo before calving. Fecal corticoids increased 5 mo before calving, slowly declined, and increased again within 3 wk before calving. A decline in vaginal electrical impedance was noted 168 days before calving and remained at low levels for 4 wk. At the time of this decrease, the female became aggressive toward the male and began lactating. Fecal progestagens and estrogens did not change during this time; however, fecal corticoids increased as vaginal electrical impedance readings returned to normal along with her behavior and cessation of lactation. In summary, the use of vaginal electrical impedance could not predict parturition in the white rhinoceros. However, an anomaly occurred during pregnancy that was supported by vaginal electrical impedance readings, a change in female behavior, premature lactation, and a subsequent increase in fecal corticoids. The etiology of this physiological anomaly is unknown, yet it did not compromise pregnancy.

The effects of GnRH administration postinsemination on serum concentrations of progesterone and pregnancy rates in dairy cattle exposed to mild summer heat stress

The objective of this study was to evaluate whether administration of GnRH postinsemination would improve reproductive performance in heat-stressed dairy cattle. Estrous cycles of Holstein cows were synchronized using the OvSynch protocol and cows were artificially inseminated. Cows were then administered the following treatments: control (no GnRH; n=37), GnRH (100 microg) on Day 5 (GnRH-D5; n=34), or GnRH (100 microg) on Day 11 (GnRH-D11; n=34) postinsemination. Cows were provided access to both fans and sprinklers, and environmental data was collected hourly. Rectal temperatures and blood samples were obtained from cows on Days -9, -2, 0 (AI) and on alternate days from Day 5 to Day 19 postinsemination. Blood serum was collected for the analysis of progesterone (P(4)) by RIA. In a subset of cows (n=6/treatment) ultrasonography was performed on alternate days from Day 5 to Day 19 postinsemination to assess numbers of corpora lutea (CL) and CL cross-sectional areas. Pregnancy status of cows was confirmed at Day 30 postinsemination. Environmental data indicated that cows experienced mild heat stress during the trials (mean daily THI=73-77). Serum P(4) was greater (P<0.05) after Day 9 for GnRH-D5 cows and after Day 15 for GnRH-D11 cows through Day 19 postinsemination. The number of CLs present for GnRH-D5 cows was greater (P<0.05) on Day 17 than in either the control or GnRH-D11 treatment groups. On Day 17 postinsemination, both the GnRH-D5 and GnRH-D11 cows were observed to have greater (P<0.05) total CL tissue area than control cows. The interval from insemination to when serum P(4) returned to <1 ng/ml (i.e. luteolysis and return to estrus) did not differ (P>0.10) among treatment groups. Control cows (19%) tended to exhibit lower pregnancy rates (P<0.08) compared to the GnRH-D5 and GnRH-D11 treatment groups combined (35%). In summary, the treatment of heat-stressed dairy cows with GnRH postinsemination (Day 5 or 11) results in the appearance of more CL tissue, increased serum concentrations of P(4) and a tendency toward greater pregnancy rates.