Late Embryonic Loss Research Articles

Effect of post-mating GnRH or TAK-683 (Kisspeptin analog) treatment on the reproductive performance and serum progesterone concentration in ewes during the non-breeding season

This study was designed to evaluate the effect of post-mating GnRH or TAK-683 (kisspeptin analog) treatment on serum progesterone (P4) concentrations and fertility parameters of ewes during the non-breeding season. One hundred and twenty multiparous, lactating Awassi ewes were used. For estrus synchronization, vaginal sponges containing 60 mg of medroxyprogesterone acetate (MAP) were inserted into the vagina and kept there for nine days. On the day of sponge removal (day 0), 500 IU of eCG and 75 µg of d-cloprostenol were given intramuscularly. Rams were introduced in the flock 24 h after sponge removal and kept with the ewes for 26 days, allowing a second mating period after synchronized estrus. On the fourth day after mating (day 6) the ewes mated by the rams between the 24th and 72nd hours (n = 105) were randomly divided into three groups. Control group (n = 36) received 1 ml of saline solution subcutaneously; GnRH group (n = 34) received 4 μg of buserelin acetate intramuscularly; TAK-683 group (n = 35) received 5 μg of TAK-683 acetate subcutaneously. Blood samples were taken to measure serum P4 concentrations (ng/ml) at sponge insertion and on the 6th, 9th, 12th, 15th, 19th, 35th, and 50th days after sponge removal. Pregnancy diagnosis was conducted via serum P4 concentration measurement on the 19th day and transrectal ultrasonography on days 35 and 50. The results showed that GnRH treatment (4.823 ± 0.238; 2.151 ± 0.272) increased (P<0.05) the mean P4 concentration (ng/ml) in pregnant and non-pregnant ewes during the first mating period compared to Control (3.708 ± 0.207; 1.515 ± 0.164), while TAK-683 treatment (4.457 ± 0.181; 1.967 ± 0.213) was not different between groups. GnRH (58.82 %) and TAK-683 (42.10 %) treatments increased the pregnancy rate in the second mating period in comparison to the Control group (17.39 %) (P<0.05). Cumulative pregnancy and fecundity rates were higher in GnRH (79.41 %; 120.58 %) and TAK-683 (68.57 %; 100.0 %) groups than in the Control group (17.39 %; 58.33 %) (P<0.05). There was no difference in late embryonic loss rate among the groups (P>0.05), whereas early fetal loss rate tended to be lower in the TAK-683 (0 %) and GnRH (0 %) groups than in the Control group (15.38 %) (P=0.07). The total pregnancy loss rate (from day 19 to day 50 post-mating) was lower in GnRH (0 %) and TAK-683 (0 %) groups relative to the Control group (21.42 %) (P<0.05). There were no statistical differences among the groups in terms of the first mating period pregnancy rate, twinning rate, and litter size (P>0.05). As a result, treatment with GnRH and TAK-683 on the fourth day after mating increased fecundity in lactating ewes outside the breeding season by preventing total pregnancy losses (from day 19 to day 50) and increasing second mating pregnancy rates.

Profile and clinical relevance of non-criteria antiphospholipid antibodies in patients diagnosed with or highly suspected of APS.

This study investigates the positivity and relevance of non-criteria aPLs with clinical phenotypes in patients highly suspected of or diagnosed with APS. Outpatient cases were included from a prospectively maintained database, and patients were grouped into APS (n = 168), seronegative APS (SNAPS, n = 9), those meeting the diagnostic criteria for clinical events without laboratory results (only-event, n = 15), those that had aPL positivity without clinical manifestations (asymptomatic APA, n = 39), and healthy controls (n = 88). Criteria aPL results and APS-related clinical features were extracted. Sixteen non-criteria aPLs were tested and analysed. LA, aCL and anti-β2 glycoprotein-I were positive in 84.5%, 61.3% and 74.4% of APS patients, and 61.5%, 59.0% and 74.4% of asymptomatic APA patients, respectively. In patients negative for criteria serological tests, 23 out of 24 were positive for at least one non-criteria aPL. Triple-positive patients also had significantly higher tests of some aPLs in comparison with other groups. Stroke was associated with anti-phosphatidyl-inositol (aPI) IgG and anti-phosphatidyl-glycerol (aPG) IgG. Late embryonic loss correlated with aPI IgM, and premature birth/eclampsia was associated with aPI IgG and aPG IgG. There were also positive associations between heart valve lesions and anti-phosphatidylserine-prothrombin (aPS/PT) IgM, APS nephropathy and anti-phosphatidyl-choline IgG or aPS/PT IgG, and livedo reticularis and anti-phosphatidyl-ethanolamine IgM. The prevalence of non-criteria aPLs differed from diagnostic biomarkers in patients diagnosed with or suspected of APS. Detection of aPLs provided additive value in the evaluation of APS-related clinical manifestations.

Association of bovine viral diarrhea virus, bovine herpesvirus 1, and Neospora caninum with late embryonic losses in highly supplemented grazing dairy cows

The objectives of this study were: 1- to evaluate the association of Bovine Viral Diarrhea Virus (BVDV), Bovine Herpes Virus 1 (BoHV-1), and Neospora caninum (N. caninum) with the risk for Late Embryonic Loss (LEL) in grazing dairy cows, 2- to evaluate blood progesterone concentration at the time of LEL occurrence, and 3- to describe a novel ultrasound-guided technique for conceptus sampling. We run a prospective cohort study involving 92 cows (46 LEL and 46 NLEL). An LEL cow was that having an embryo with no heartbeat, detached membranes, or floating structures, including embryo remnants detected at pregnancy check by ultrasonography (US) 28–42 days post-AI, whereas an NLEL cow was that with embryo heartbeats detectable by US at pregnancy check 28–42 d post-IA. We took two blood samples from every cow at pregnancy check by US (the day of LEL detection) and 28 d later to perform serological diagnosis of BVDV, BoHV-1, and N. caninum; and to measure blood progesterone concentration at pregnancy check (28–42 d post-AI). We also sampled the conceptus from all the LEL cows. We performed PCR to detect BVDV, BoHV-1, and N. caninum in sampled conceptuses from LEL cows. Finally, we evaluated the associations of risk factors (serological titers, seroconversion, and progesterone) with LEL odds with logistic models. The risk for LEL was associated with serological titers to BVDV (P = 0.03) and tended to be associated with seroconversion to BVDV, given that 19.6% (9/46) in LEL and 6.5% (3/46) in NLEL cows seroconverted to BVDV (P = 0.09). In addition, BVDV was detected in conceptuses from LEL cows that seroconverted to BVDV but not in LEL cows that did not seroconvert. Conversely, the risk for LEL was not associated with the titers or seroconversion to BoHV-1 and N. caninum. BoHV-1 and N. caninum were not identified in any of the conceptuses. Finally, blood progesterone concentration was similar in LEL and NLEL cows, and it was not associated with the risk for LEL (P = 0.54). In conclusion, BVDV infection is a risk factor for LEL in dairy cows.

PSV-B-18 Effect of Puberty Induction on Embryonic Loss in Precocious Nellore Heifers

Abstract This study aimed to determine if heifers induced to puberty had damage in reproductive performance compared with heifers that reach puberty naturally. Nellore heifers (n = 210) were weaned at 8 ± 0.7 mo of age were assigned to 42 feedlot pens according to BW (184 ± 1 kg). The diet was compounded by Tifton-85 haylage (18% CP; 55% TDN) ad libitum and supplement (4g/kg of BW; 25% CP; 60% TDN). Puberty and growth were assessed weekly. At 14 mo of age, 46 heifers reached puberty naturally (precocious heifers; PH) and 164 non-pubertal heifers were submitted to puberty induction with progesterone (P4) insert for 10 days and estradiol cypionate (0.5 mg) at P4 removal (puberty induction; PI). After fourteen days, all heifers were submitted to TAI. Heifers were considered pregnant at 20 days (P20) after AI when CL had blood flow &amp;lt; 25% of area (Power-Doppler). Pregnancy rate was also determined at 30 (P30) and 60 (P60) days after AI by embryo detection. Early (P20 – P30) and late (P30 – P60) embryonic loss were determined. Reproductive data were analyzed by GLIMMIX, and BW was analyzed using repeated measures over time (MIXED; SAS 9.3). The PH was heavier than PI from 8 to 16 mo of age, which BW was 296 and 285 ± 3 kg at 14 mo of age, respectively. At beginning of TAI, 88% of PI heifers had a CL. Pregnancy rate was similar (P &amp;gt; 0.05) between treatments, in which pregnancy rate at 20, 30 or 60 days after AI was 65, 47 and 43% for PH and 61, 53 and 48% for PI, respectively. Early (26 vs 14%) and late (9 vs 9%) embryonic loss were similar (P &amp;gt; 0.05) in PH and PI, respectively. In summary, natural or induced pubertal heifers had similar reproductive performance.

Genetic parameters for reproductive losses estimated from in-line milk progesterone profiles in Swedish dairy cattle

This study assessed the extent of reproductive losses and associated genetic parameters in dairy cattle, using in-line milk progesterone records for 14 Swedish herds collected by DeLaval's Herd Navigator. A total of 330,071 progesterone samples were linked to 10,219 inseminations (AI) from 5,238 lactations in 1,457 Swedish Red and 1,847 Swedish Holstein cows. Pregnancy loss traits were defined as early embryonic loss (1-24 d after AI), late embryonic loss (25-41 d after AI), fetal loss (42 d after AI until calving), and total pregnancy loss (from d 1 after AI until calving). The following classical fertility traits were also analyzed: interval from calving to first service, interval from calving to last service, interval between first and last service, calving interval, and number of inseminations per service period. Least squares means with standard error (LSM ± SE), heritabilities, and genetic correlations were estimated in a mixed linear model. Fixed effects included breed, parity (1, 2, ≥3), estrus cycle number when the AI took place, and a linear regression on 305-d milk yield. Herd by year and season of AI, cow, and permanent environmental effect were considered random effects. Extensive (approximately 45%) early embryonic loss was found, but with no difference between the breeds. Swedish Red was superior to Swedish Holstein in the remaining pregnancy loss traits with, respectively: late embryonic loss of 6.1 ± 1.2% compared with 13.3 ± 1.1%, fetal loss of 7.0 ± 1.2% compared with 12.3 ± 1.2%, and total pregnancy loss of 54.4 ± 1.4% compared with 60.6 ± 1.4%. Swedish Red also had shorter calving to first service and calving to last service than Swedish Holstein. Estimated heritability was 0.03, 0.06, and 0.02 for early embryonic, late embryonic, and total pregnancy loss, respectively. Milk yield was moderately genetically correlated with both early and late embryonic loss (0.52 and 0.39, respectively). The pregnancy loss traits were also correlated with several classical fertility traits (-0.46 to 0.92). In conclusion, Swedish Red cows had lower reproductive loss during late embryonic stage, fetal stage, and in total, and better fertility than Swedish Holstein cows. The heritability estimates for pregnancy loss traits were of the same order of magnitude as previously reported for classical fertility traits. These findings could be valuable in work to determine genetic variation in reproductive loss and its potential usefulness as an alternative fertility trait to be considered in genetic or genomic evaluations.

Size and position of the reproductive tract impacts fertility outcomes and pregnancy losses in lactating dairy cows

There are multiple factors that contribute to reduced fertility in lactating dairy cows. Recently, a reproductive tract size and position score (SPS) system was developed as a management tool to identify dairy cows with decreased fertility. The aim of this study was to evaluate the association between the SPS on fertility outcomes such as ovulation failure, pregnancy per artificial insemination (P/AI), concentration of pregnancy-associated glycoproteins (PAGs), and pregnancy loss in lactating dairy cows. Primiparous and multiparous lactating Holstein cows (n = 869) were enrolled at two locations. Location 1 (Loc. 1) in Minas Gerais, Brazil (n = 613) and location 2 (Loc. 2) in Agassiz, British Columbia, Canada (n = 256). At the time of AI (d 0), cows were classified as SPS (small [SPS1], medium [SPS2], or large [SPS3] sized reproductive tract) and ovulation failure was determined at 48 h and 7 d post-AI via ultrasonography (Loc. 2 only). Blood samples were collected on d 24 and 31 of gestation for quantification of PAGs and pregnancy diagnosis was performed via ultrasonography at d 31 and 60 post-AI (Loc. 1) and at d 31 ± 3 and 60 ± 3 post-AI (Loc. 2). Cows diagnosed pregnant at d 31 post-AI but not pregnant at d 60 were defined to have undergone late embryonic pregnancy loss. Parity was found to impact SPS (P < 0.01), as primiparous cows had a higher frequency of SPS1 and lower frequency of SPS3 when compared with multiparous cows (SPS1: 42.6 vs. 15.0%; SPS3: 7.0 vs. 22.0%, respectively). Cows classified as SPS3 had greater ovulation failure at 48 h (P = 0.04) and 7 d post-AI (P = 0.05). Cows classified as SPS1 had greater P/AI when compared to SPS2 and SPS3 (45.9 ± 3.3 vs. 37.4 ± 2.6 and 29.1 ± 3.5%, respectively; P = 0.004). There was no interaction between parity and SPS on P/AI. Pregnancy loss between 31 and 60 d post-AI was increased in cows classified as SPS3 compared to SPS2 and SPS1 (24.3 ± 0.05 vs. 11.6 ± 0.02 and 9.4 ± 0.02%, respectively; P = 0.04). Cows classified as SPS1 and SPS2 had greater concentrations of PAGs at 31 d post-AI when compared to SPS3 at both Loc.1 (P < 0.01) and Loc. 2 (P < 0.01). There was no interaction between SPS and pregnancy loss on PAGs at 24 and 31 d post- AI for either Loc. 1 (P = 0.75 and P = 0.76, respectively) or Loc. 2 (P = 0.61 and P = 0.81, respectively). In conclusion, cows that were classified as SPS3 had greater ovulation failure, reduced P/AI, similar concentrations of PAG on d 24, but decreased on d 31, and a greater incidence of pregnancy loss. Thus, size and position of the reproductive tract is associated with fertility and this scoring system could be used to make reproductive management decisions on dairy operations.

Early and Late Embryonic Loss of Smallholder Synchronized Dairy Cows Within Ethiopia

This study was carried out on 53 cows selected from smallholder dairy farmers in the Ejerie, Adea Berga and Metarobi western Shoa of Oromia in Ethiopia. All of the cows were investigated in October and November, 2015 for their cyclicity, pregnancy and mainly for early embryonic mortality determination. Milk samples were collected from the 53 of synchronized lactating cows involved in the estrus synchronization programme at the time of AI (day 0). Out of lactating cows, 33 exhibited true heat but due heat detection error, only 26 lactating cows were inseminated in day AI (Artificial Insemination). After it was confirmed that 20 lactating cows were pregnant, then they were continued for further progesterone profiling starting from day 18 to 45 day of post AI at interval of 3 days for determination of early embryonic loss based on progesterone concentration. The milk sample was analyzed by Hormonost Farmer Test. Results of the study indicated that about 60% of lactating cows maintain pregnancy until 45-day post AI whereas 15%, 15% and 10% of early pregnant lactating cow’s loss their embryo at 21^st to 24^th days, 27^th to 30^th days and 33^rd day of post AI, respectively. The average progesterone concentration for pregnant cows was 24.46 ng/ml at day 21 to day 45 post AI. Based on finding of this result monitoring and evaluating reproductive traits with progesterone profiling is recommended to improve the fertility of dairy cattle. Finally, embryonic loss detection may serve as a basis for improvement of fertility of dairy cows mean while it will help for designing appropriate breeding management of dairy cattle.

Late embryonic losses in supplemented grazing lactating dairy cows: Risk factors and reproductive performance

The main objective of this study was to evaluate the risk factors for late embryonic loss (LEL) in supplemented grazing dairy cows. Additional objectives were to assess the incidence of LEL and its association with the reproductive performance of cows. A data set containing productive, reproductive, and health records of 13,551 lactations was used. A retrospective case-control study involving 631 cows with LEL (cases) and 2,524 controls (4 controls per case within each study year) was run. A case of LEL was defined when the embryo had no heartbeat or there was evidence of detached membranes or floating structures including embryo remnants by ultrasonography (US) at 28 to 42 d post-artificial insemination (AI), whereas a non-case was defined as a cow diagnosed with positive pregnancy by US 28 to 42 d post-AI and reconfirmed as pregnant 90 ± 7 d post-AI. Four controls per case were randomly selected from the non-cases with a temporal matching criterion (±3 d around the date of the fecundating AI of the case). Multivariable logistic models were offered with the following predictors: year of LEL (2011 through 2015), season of LEL (summer vs. fall vs. winter vs. spring), parity (1 vs. 2 vs. ≥3), uterine disease (UD), non-uterine disease (NUD), body condition score at parturition, body condition score at 28 to 42 d post-AI (BCS-LEL), days in milk (DIM), and daily milk yield (MY). Statistical significance was set at P < 0.05 and a tendency was set at P ≤ 0.10. We found that 4.7, 22, and 23% of cows had LEL, UD, and NUD, respectively. Cases tended to have higher daily MY than controls (32.5 vs. 31.8 kg); also, cases had much longer calving to pregnancy interval (226 vs. 118 d), lower hazard of pregnancy [hazard ratio = 0.39, 95% confidence interval (CI) = 0.35-0.43], and higher odds for non-pregnancy [odds ratio (OR) = 2.89, 95% CI = 2.37-3.54] than controls. We found that the odds for LEL increased with parity number (OR = 2.48, 95% CI = 1.99-3.08 for parity ≥3) and with BCS-LEL <2.50 (OR = 1.81, 95% CI = 1.33-2.47). Conversely, the odds for LEL decreased with BCS-LEL >3.00 (OR = 0.70, 95% CI = 0.53-0.91). The odds for LEL increased with UD (OR = 1.23, 95% CI = 1.01-1.49), NUD (OR = 1.24, 95% CI = 1.01-1.54), DIM (OR = 1.03, 95% CI = 1.00-1.05), and daily MY (OR = 1.14, 95% CI = 1.04-1.25) in univariable models only. Finally, the odds for LEL were not associated with year, season, DIM, and body condition score at parturition. In conclusion, LEL is associated with extended calving to pregnancy interval, and among its risk factors are parity number and BCS-LEL.

Extent and pattern of pregnancy losses and progesterone levels during gestation in Swedish Red and Swedish Holstein dairy cows

BackgroundPregnancy loss is a major source of infertility in dairy cows. Despite a fertilization rate after insemination (AI) of approximately 90%, calving rates are 30%–50%, indicating the occurrence of extensive embryonic and foetal losses. The aim of this study was to establish the extent and pattern of embryonic and foetal loss in Swedish Red (SR) and Swedish Holstein (SH) dairy cows, as well as, the relationship to oestrus intensity (OI) and progesterone (P4) concentration. In total, 2130 AIs and 16,176 milk P4 samples from 359 SR and 212 SH dairy cows were included in the study. Pregnancy losses were estimated using data from P4 values combined with AI information and calving data.ResultsTotal pregnancy loss from AI to the day of calving was 65%. Early embryonic loss, late embryonic loss and foetal loss were estimated to be 29, 14 and 13%, respectively. There is strong evidence in the literature that P4 concentrations at different time points are associated with pregnancy loss. In the present study, cows with pregnancy losses had significantly higher P4 levels at the day of AI and significantly lower P4 concentration at days 10, 21 and 30 after AI compared to pregnant cows. Swedish Red cows had significantly lower total pregnancy losses compared to SH cows (62% and 68% respectively, P = 0.017). Early embryonic loss was 6.7% points lower for cows inseminated at a stronger OI (OI = 3) compared to at a weaker OI (OI = 2, P = 0.006). Cows inseminated at ovulation number ≥ 5 had significantly lower early pregnancy losses compared to cows inseminated at first or second ovulation (11.5 and 8% points, respectively, P < 0.05). With an increase of one SD of milk (448 kg ECM) during the first 60 days in milk, early embryonic loss increased by 4.7% points (P = 0.006).ConclusionsIt is important to increase the number of cows calving per insemination by reducing embryo/foetal loss. This outcome can be achieved by management and breeding for optimal P4 levels at critical time points, and by considering oestrus expression in the breeding programmes to facilitate the correct timing of insemination.

Equine alpha-fetoprotein levels in Lipizzaner mares with normal pregnancies and with pregnancy loss

Alpha-fetoprotein has proved to be a good indicator of fetal well-being in human medicine for decades. Although this molecule is present in most of the mammalian species including horses, reference values in healthy and high-risk pregnant mares have not yet been published. The aim of the present study was to determine whether equine alpha-fetoprotein (eqAFP) is a good indicator of complicated pregnancies in Lipizzaner mares. A total of 111 serum samples from 30 mares have been analyzed for eqAFP levels throughout gestation (Days 60–325). After the pregnancy was confirmed, 23 mares had normal pregnancies with viable foals, six had late embryonic loss, and one of the mares aborted in the ninth gestational month. Equine alpha-fetoprotein concentrations significantly differed in the normal group (72.93 ± 49.25 pg/mL; mean ± standard deviation) and in the complicated pregnancy loss group (152 ± 36.48 pg/mL; mean ± standard deviation). The mares' age, gestational age, and the conception rate significantly affected the alpha-fetoprotein concentrations in the normal group. Furthermore, notable individual differences occurred in eqAFP concentrations between mares. Equine alpha-fetoprotein seems to be an important indicator of fetal well-being in horses, but there are still some unanswered questions (levels in foals of different age, ponies, and draft horses) regarding this serum protein. Large-scale studies are needed to assess the specificity, sensitivity, and reliability of this test as a possible future diagnostic tool for fetal well-being in horses.

Effects of early pregnancy diagnosis by per rectal palpation of the amniotic sac on pregnancy loss in dairy cattle

To determine effects of per rectal amniotic sac palpation (ASP) for pregnancy diagnosis during early gestation on pregnancy loss in lactating cows. Controlled, randomized block design. 368 pregnant dairy cows. Pregnancy was detected via transrectal ultrasonography (TRUS) at day 29 (day of estrus = day 0), and cows were allocated into a control group (n = 167 cows) and ASP group (180). Control cows were not subjected to pregnancy diagnosis via palpation per rectum. Per rectal ASP was performed between days 34 and 43 by only 1 experienced veterinarian. All cows were reevaluated with TRUS on days 45, 60, and 90. 21 cows were removed because of illness. Pregnancy loss between days 29 and 90 occurred in 44 of 347 (12.7%) cows. Pregnancy loss for the control and ASP groups from days 29 to 90 occurred in 22 of 167 (13.2%) and 22 of 180 (12.2%) cows, respectively. Late embryonic pregnancy loss (days 29 to 45) for the control and ASP groups occurred in 18 (10.8%) and 15 (8.3%) cows, respectively. Early fetal pregnancy loss (days 46 to 60) for the control and ASP groups occurred in 2 of 149 (1.3%) and 6 of 165 (3.6%) cows, respectively, and late fetal pregnancy loss (days 61 to 90) for the same groups occurred in 2 of 147 (1.4%) and 1 of 159 (0.6%) cows, respectively. Pregnancy diagnosis via per rectal ASP during early gestation did not increase pregnancy loss in dairy cattle.

An individual reproduction model sensitive to milk yield and body condition in Holstein dairy cows

To simulate the consequences of management in dairy herds, the use of individual-based herd models is very useful and has become common. Reproduction is a key driver of milk production and herd dynamics, whose influence has been magnified by the decrease in reproductive performance over the last decades. Moreover, feeding management influences milk yield (MY) and body reserves, which in turn influence reproductive performance. Therefore, our objective was to build an up-to-date animal reproduction model sensitive to both MY and body condition score (BCS). A dynamic and stochastic individual reproduction model was built mainly from data of a single recent long-term experiment. This model covers the whole reproductive process and is composed of a succession of discrete stochastic events, mainly calving, ovulations, conception and embryonic loss. Each reproductive step is sensitive to MY or BCS levels or changes. The model takes into account recent evolutions of reproductive performance, particularly concerning calving-to-first ovulation interval, cyclicity (normal cycle length, prevalence of prolonged luteal phase), oestrus expression and pregnancy (conception, early and late embryonic loss). A sensitivity analysis of the model to MY and BCS at calving was performed. The simulated performance was compared with observed data from the database used to build the model and from the bibliography to validate the model. Despite comprising a whole series of reproductive steps, the model made it possible to simulate realistic global reproduction outputs. It was able to well simulate the overall reproductive performance observed in farms in terms of both success rate (recalving rate) and reproduction delays (calving interval). This model has the purpose to be integrated in herd simulation models to usefully test the impact of management strategies on herd reproductive performance, and thus on calving patterns and culling rates.

Late embryonic and foetal losses in eight dairy herds in north-east Poland

The information about the occurrence of embryonic and fetal losses in dairy herds in Poland is limited. Thus, the objective of this study was to assess the pregnancy loss between days 30 and 45 (late embryonic mortality) and between days 45 and 260 after artificial insemination (AI) (foetal loss). The study was carried out in 8 dairy herds in north-east Poland. In total 954 cows were examined for pregnancy on day 30 after AI using an ultrasound scanner. Cows diagnosed pregnant were re-examined on day 45 and 260 after AI using transrectal palpation. The pregnancy rate on day 30 after AI was 62.0%, after re-examination on day 45 after AI the pregnancy rate was 56.4%. The late embryonic loss rate was on an average 9.1%. The occurrence of late embryonic mortality differed not significantly (p > 0.05) among herds and ranged from 13.1% to 19.3%. The pregnancy rate on day 260 after AI was 53.5%. The average foetal loss after day 45 of pregnancy was 5.0%, ranged between herds from 0 to 9.2% (p > 0.05) and was significantly lower than embryonic loss rate (p < 0.05). The study revealed that in 8 dairy herds in north-east Poland the overall pregnancy loss between days 30 and 260 averaged 13.7% and therefore it is an important factor affecting economic efficiency of dairy production. The foetal loss was less prevalent than the late embryonic loss. Future strategies to minimizing late embryonic loss are needed.

Seasonal Changes and the Efficiency of Hormonal Treatments for Pregnancy Rate and Late Embryonic Loss in Dairy Cattle

Seasonal Changes and the Efficiency of Hormonal Treatments for Pregnancy Rate and Late Embryonic Loss in Dairy Cattle

Early Detection of Pregnancy and Embryonic Loss in Dairy Cattle by ELISA Tests

Over a 25-month period 8118 blood samples were assayed for the presence of the serum pregnancy specific-protein B (PSPB) and progesterone (P4) concentrations on three Hungarian large-scale dairy farms. Pregnancy (n = 4085) was checked by BioPRYN assay at 30-36 days post-insemination (PI). Samples from all cows that tested not pregnant and from cows with an optical density (OD) reading in the BioPRYN test that was between 0% and 30% above the cutoff OD value were tested for serum P4 concentration. According to serum P4 concentration, cows were assigned to three categories: high (>4 ng/ml), medium (2-4 ng/ml) and low (<2 ng/ml) serum progesterone. The authors predicted a presumed (low) or possible (medium) late embryonic loss (LEL) or maintenance of the pregnancy (high). A total of 710 LELs were detected (17.4%) and 31.8% of them were predicted because of a low OD value at 30-36 days after insemination. Lower PSPB serum level significantly refers for LEL (p < 0.0001). The prediction rate for the true embryonic loss was 31.8% when OD cutoff from 0% to + 30% of cutoff was examined while it was 62.5% when the threshold was OD cutoff of 0% to 10% of cutoff. The authors conclude that BioPRYN was useful for prediction of a part of LEL in dairy cows and serum P4 concentration in these cows related to the rate of LEL.

Factors Influencing Pregnancy Rate and Late Embryonic Loss in Dairy Cattle

This trial was conducted on three Hungarian dairy farms between March 2003 and April 2004. The aims of this study were to examine the effect of milk production and milk contents, the day after calving (DAC) and the sire for the pregnancy rate (PR) and late embryonic loss (LEL) in dairies. Five thousand three hundred and eighty insemination was carried out in this period. Pregnancies (n = 1969) were detected by BioPryn test from 3919 blood samples between 30-36 days post insemination (PI). Retention of pregnancy was determined by rectal palpation on Day 60. LEL has been determined by the optical density (OD) of blood samples/cutoff ratio and the serum progesterone (P4) concentration 30-36 days PI. According to serum progesterone concentration the authors predicted a presumed or possible embryonic loss or maintenance of the pregnancy. The efficiency of the artificial inseminations (AI) was significantly lower 60 days within post-partum. Significant positive correlation was found between the result of early and late PR and DAC and the milk protein/fat ratio. Significant negative correlation was detected between the early and late PR the milk protein and fat content. A later stage (60 days PI) of pregnancy the milk production has a negative effect for retaining of pregnancy. More data would be necessary to state that sires can influence the reproduction ability of their progenies. This is a really important issue, because the AI bulls have a great impact on the herds and the one-way selection may cause decreased fertility on breed level as well.

Patterns of late embryonic and fetal mortality and association with several factors in sheep1

Embryonic and fetal mortality reduce lambing rates and litter sizes, thus contributing to economic losses in the sheep industry. In the current study, the timing of late embryonic and fetal loss in ewes and the factors with which these losses were associated were examined. Ewes lambing and lambs born were compared with pregnancy diagnosis and counts of embryos by ultrasonography near d 25, 45, 65, or 85 of gestation. Approximately 19.9% of the ewes experienced late embryonic loss, fetal loss, or both; and 21.2% of the embryos or fetuses were lost from d 25 to term. Potential offspring were lost throughout gestation; 3.7% of embryos from d 25 to 45, 4.3% of fetuses from d 45 to 65, 3.3% from d 65 to 85, and 11.5% from d 85 to parturition; thus, approximately 3 to 4% of the potential offspring were lost for each 20-d period of pregnancy beyond d 25. A greater proportion of ewes lost one (36.7%) rather than all (20.5% single; 3.8% multiple) embryos or fetuses. The patterns of loss were similar in ewes mated during the anestrous season and the transitional period and did not vary with service period within breeding season or method of synchronization of estrus. Late embryonic or fetal losses were not related to the temperature-humidity index. Maternal serum collected near d 25, 45, 65, or 85 of gestation was assayed for concentrations of progesterone, estradiol-17beta , and vascular endothelial growth factor (VEGF). The proportions of embryos or fetuses lost were associated with breed type (P < 0.05), as were concentrations of progesterone (P < 0.01), estradiol (P < 0.05), and VEGF (P < 0.01). The relationships of loss or retention of pregnancy to hormonal variables at the 4 stages studied were limited. Complete and partial losses increased rapidly as maternal progesterone at d 25 decreased below 2 ng/mL (P < 0.05). Survival of fetuses within a litter from d 25 to 65 was greater for ewes with medium concentrations of VEGF near d 25 and from d 65 to parturition was greater for ewes with high concentrations of VEGF near d 45 (P < 0.05). In summary, late embryonic or fetal losses occurred from d 25 throughout gestation and varied with breed type and with concentrations of progesterone in maternal serum on d 25.

Effect of addition of a progesterone intravaginal insert to a timed insemination protocol using estradiol cypionate on ovulation rate, pregnancy rate, and late embryonic loss in lactating dairy cows1

The objectives of this study were to determine the effects of incorporating a progesterone intravaginal insert (CIDR) between the day of GnRH and PGF2alpha treatments of a timed AI protocol using estradiol cypionate (ECP) to synchronize ovulation on display of estrus, ovulation rate, pregnancy rate, and late embryonic loss in lactating cows. Holstein cows, 227 from Site 1 and 458 from Site 2, were presynchronized with two injections of PGF2alpha on study d 0 and 14, and subjected to a timed AI protocol (100 mixrog of GnRH on study d 28, 25 mg of PGF2alpha on study d 35, 1 mg of ECP on study d 36, and timed AI on study d 38) with or without a CIDR insert. Blood was collected on study d 14 and 28 for progesterone measurements to determine cyclicity. Ovaries were scanned on d 35, 37, and 42, and pregnancy diagnosed on d 65 and 79, which corresponded to 27 and 41 d after AI. Cows receiving a CIDR had similar rates of detected estrus (77.2 vs. 73.8%), ovulation (85.6 vs. 86.6%), and pregnancy at 27 (35.8 vs. 38.8%) and 41 d (29.3 vs. 32.3%) after AI, and late embryonic loss between 27 and 41 d after AI (18.3 vs. 16.8%) compared with control cows. The CIDR eliminated cows in estrus before the last PGF2alpha injection and decreased (P < 0.001) the proportion of cows bearing a corpus luteum (CL) at the last PGF2alpha injection because of less ovulation in response to the GnRH and greater spontaneous CL regression. Cyclic cows had greater (P = 0.03) pregnancy rates than anovulatory cows at 41 d after AI (33.8 vs. 20.4%) because of decreased (P = 0.06) late embryonic loss (16.0 vs. 30.3%). The ovulatory follicle was larger (P < 0.001) in cows in estrus, and a greater proportion of cows with follicles > or = 15 mm displayed estrus (P < 0.001) and ovulated (P = 0.05) compared with cows with follicles <15 mm. Pregnancy rates were greater (P < 0.001) for cows displaying estrus, which were related to the greater (P < 0.001) ovulation rate and decreased (P = 0.08) late embryonic loss for cows in estrus at AI. Cows that were cyclic and responded to the presynchronization protocol (high progesterone at GnRH and CL at PGF2alpha) had the highest pregnancy rates. Incorporation of a CIDR insert into a presynchronized timed AI protocol using ECP to induce estrus and ovulation did not improve pregnancy rates in lactating dairy cows. Improvements in pregnancy rates in cows treated with ECP to induce ovulation in a timed AI protocol are expected when more cows display estrus, thereby increasing ovulation rate.

Extent, pattern and factors associated with late embryonic loss in dairy cows

Intensive genetic selection for increased milk production, coupled with increased dry matter intakes has led to significant improvements in cow milk yield, however, this increase in milk output has been accompanied by a decline in cow fertility. It has been suggested that there is a higher increment of late embryonic loss in high-yielding than in moderate yielding cows or in heifers. The objectives of this study were to establish the extent and pattern of embryonic loss, from days 28 to 84 of gestation, and to examine possible relationships between cow milk yield, cow genetic merit, parity, calving to insemination interval and embryonic loss in dairy cows managed mainly under pasture-based milk production systems. Multiparous dairy cows ( n=1046) located on 8 farms and nulliparous dairy heifers ( n=162) located on five of these farms were used in this study. The extent and timing of embryonic loss was measured by ultrasound scanning of the cows and heifers at 14-day intervals between days 28 and 84 of gestation. Positive diagnosis of pregnancy was based on the presence of an embryo or foetus with a visible heartbeat and, at the later scans, visible movement, whose size was compatible with stage of gestation and also on the presence of clear amniotic fluid of the cows and heifers presented as presumed pregnant on day 28 after insemination, 67 and 81%, respectively had a viable embryo. The subsequent embryonic loss rate between days 28 and 84 of gestation was similar ( P>0.05) for cows (7.2%) and heifers (6.1%) and the pattern of loss over this period was also similar ( P>0.05) for cows and heifers. There was no significant association ( P>0.05) between level of milk production or milk energy output measured to day 120 of lactation and embryonic loss rate. Similarly, there was no significant relationship ( P>0.05) between % milk fat, % milk protein and % milk lactose and embryonic loss rate. The extent and pattern of embryonic loss were not related ( P>0.05) to either cow or to cow sire genetic merit. There was no significant ( P>0.05) relationship between the calving to first service interval and embryonic loss. The extent of embryonic loss was greater ( P<0.05) in cows that lost body condition between days 28 and 56 of gestation compared with cows than either maintained or improved in body condition.

Effects of methyl benzimidazolecarbamate during early pregnancy in the rat

Methyl 2-benzimidizolecarbamate (MBC), an agricultural fungicide, and its parent compound benomyl have adverse reproductive effects on male rats and exhibit embryotoxicity, including teratogenicity, when administered to rats during mid to late pregnancy. This study was designed to assess potential maternal effects of MBC during early pregnancy, to distinguish maternal from embryotoxic effects of the chemical, and to differentiate between early pregnancy failure and late embryonic loss. MBC was administered to rats by gavage at 0, 25, 50, 100, 200, 400, and 1000 mg/kg/day during Days 1 through 8 of pregnancy (Day 0 = sperm positive). A range of maternal and embryonic parameters was assessed following euthanasia on Day 9, including the number of implantation sites, body weight gain, uterine weight, implantation site size, and serum ovarian and pituitary hormones. In a separate experiment, pseudopregnant rats were administered 0 or 400 mg/kg/day MBC during Days 1–8, received bilateral uterine decidual induction on Day 4, and were killed on Day 9 at which time the decidual cell response was evaluated as a measure of uterine competency. When dosages of up to 400 mg/kg/day of MBC were administered during early pregnancy, the chemical had no significant effect on any measured parameter but a trend toward increased resorptions was evident. The 1000 mg/kg/day dosage of MBC produced reductions in body weight gain, implantation site weight, and serum LH and an increase in serum estradiol. When administered during pseudopregnancy, 400 mg/kg/day MBC partially reduced uterine decidual growth but affected no other parameter. The data show that dosages of MBC (up to and including 400 mg/kg/day) which are embryotoxic and teratogenic when administered to rats during late pregnancy do not produce pregnancy failure, adverse maternal effects other than a partial decidual growth inhibition, or evidence of embryotoxicity other than a trend toward increased resorptions when administered during very early pregnancy.