Pregnant Cattle Research Articles

428 Influence of melatonin supplementation in pregnant multiparous crossbred beef cows grazing endophyte-infected tall fescue on dam weight, milk yield, and pre-weaning growth of steer calves

Abstract The objective was to evaluate the influence of melatonin supplementation in pregnant beef cattle grazing toxic, endophyte-infected tall fescue (E+) on post-calving dam body weight (BW), milk production, and preweaning growth of steer calves. Multiparous cows were artificially inseminated with sex-sorted semen (Y chromosome-bearing sperm) from a single Red Angus sire and maintained on pastures free from E+ fescue prior to the start of the treatment period. Pregnant cows were assigned to one of three treatment groups with two replications per treatment: non-toxic, novel endophyte-infected (NE+) tall fescue without melatonin supplementation (NE+/NM; n = 15), E+ fescue with melatonin supplementation (E+/M; n = 16), and E+ fescue without melatonin supplementation (E+/NM; n = 18). The treatment period was over 70 d between May and July (d 147 ± 1 to 217 ± 1 of gestation). A commercially available feed was mixed with melatonin (100 µg/kg BW) or without melatonin and hand-fed to each cow daily. At the conclusion of the treatment period (56 ± 18 d before parturition), cattle were moved to a single group and maintained on pastures free from E+ fescue for the remainder of the study. Dams and steer calves were weighed at d 0, 28, 56, 84, 112, 140, and 168 relative to calving (d 0 = calving). Four-hour milk yields on d 28 ± 3 and d 56 ± 3 were used to estimate daily milk volume and weight. Dam and calf BW were analyzed using the MIXED procedure of SAS specific for repeated measures with treatment, time, and the interaction as fixed effects and replicate as random. Calf birth weight, dam milk volume, and dam milk weight were analyzed using the MIXED procedure of SAS with treatment as a fixed effect and replicate as random. On d 28, estimated daily milk volume and weight were decreased (P < 0.05) in E+/NM dams relative to NE+/NM dams. On d 56, estimated daily milk volume and weight were decreased (P < 0.03) in E+/NM and E+/M dams relative to NE+/NM dams. There was an effect of time for dam and calf weights (P < 0.01). There was a treatment by time interaction for calf body weight, with calves born to E+/NM dams having decreased body weight relative to calves born to NE+/NM and E+/M dams from d 112 to d 168 (P = 0.02). There were no other effects of treatment, time, or the interaction (P > 0.05). These data suggest melatonin supplemented to pregnant crossbred multiparous beef cows grazing endophyte-infected tall fescue during mid-late gestation may increase preweaning growth of steer calves.

The history of interferon-stimulated genes in pregnant cattle, sheep, and pigs.

The trophectoderm of the elongating conceptuses of cattle, sheep, and pigs secrete high amounts of interferons that increase or induce the expression of interferon-stimulated genes (ISGs) in the endometrium. Research concerning ISGs, performed from 1995 through 2023, is reviewed in this manuscript. Expression of the classical interferon (IFN) stimulated genes (ISGs) increases in the endometrial stroma and glandular epithelium (GE) through activation of signal transducer and activator of transcription (STAT) signaling in response to the secretion of IFN tau (IFNT) and IFN gamma (IFNG) by the conceptuses of ruminants, including cattle and sheep, and pigs, respectively. The first of the classical ISGs to be characterized was ISG15 in cattle. Classical ISGs are not expressed by the endometrial luminal epithelium (LE) due to the expression of interferon regulatory factor 2 (IRF2) in the LE that prevents the expression of ISGs in the LE. Classical ISG expression in the endometrium serves as a reliable indicator of conceptus health and elongation in cattle. There are also nonclassical ISGs that are upregulated in endometrial LE in response to progesterone (P4) that are further stimulated by IFNT in sheep, the intracellular signaling pathway responsible for IFN effects on expression is unknown. ISGs are also upregulated in extrauterine tissues including CL and peripheral blood mononuclear cells (PBMCs). The expression of ISGs by the PBMCs of cattle serves as an early prognosticator of pregnancy. The physiological roles of ISGs remain obscure, but evidence suggests that they are at least in part involved in modifying the immune system to support endometrial remodeling necessary for the successful implantation of the conceptus. Our understanding of these ISGs is primarily the result of work from the laboratories of Drs Fuller Bazer, Thomas (Tod) Hansen, Gregory Johnson, Hakhyun Ka, Patrick Lonergan, Troy Ott, and Thomas Spencer.

Immunogenicity, safety and dual DIVA-like character of a recombinant candidate vaccine against neosporosis in cattle

Neosporosis is the major infectious cause of abortion and reproductive losses in cattle worldwide; however, there are no available vaccines or drugs to control this disease. Recently, a dual (positive and negative) DIVA-like (Differentiation of Infected from Vaccinated Animals) vaccine was evaluated in a pregnant mouse model of neosporosis, showing promising immunogenic and protective results. The current report aimed to study the safety, the dose-dependent immunogenicity and the dual DIVA-like character of a recombinant subunit vaccine composed of the major surface antigen from Neospora caninum (rNcSAG1) and the carrier/adjuvant Heat shock protein 81.2 from Arabidopsis thaliana (rAtHsp81.2) in cattle. Healthy heifers were separated and assigned to experimental groups A-F and subcutaneously immunized with 2 doses of vaccine formulations 30 days apart as follows: A (n = 4): 50 μg rNcSAG1 + 150 μg rAtHsp81.2; B (n = 4): 200 μg rNcSAG1 + 600 μg rAtHsp81.2; C (n = 4): 500 μg rNcSAG1 + 1,500 μg rAtHsp81.2; D (n = 3): 150 μg rAtHsp81.2; E (n = 3):1,500 μg rAtHsp81.2, and F (n = 3) 2 ml of sterile PBS. The immunization of heifers with the different vaccine or adjuvant doses (groups A-E) was demonstrated to be safe and did not modify the mean value of the evaluated serum biomarkers of metabolic function (GOT/ASP, GPT/ALT, UREA, Glucose and total proteins). The kinetics and magnitude of the immune responses were dose-dependent. The higher dose of the vaccine formulation (group C) stimulated a broad and potent humoral and cellular immune response, characterized by an IgG1/IgG2 isotype profile and IFN-γ secretion. In addition, this was the first time that dual DIVA-like character of a vaccine against neosporosis was demonstrated, allowing us to differentiate vaccinated from infected heifers by two different DIVA compliant test approaches. These results encourage us to evaluate its protective efficacy in infected pregnant cattle in the future.

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.

HSP90 is part of a protein complex with the L polymerase of Rift Valley fever phlebovirus and prevents its degradation by the proteasome during the viral genome replication/transcription stage.

The mosquito-borne Rift Valley fever virus (RVFV) from the Phenuiviridae family is a single-stranded RNA virus that causes the re-emerging zoonotic disease Rift Valley fever (RVF). Classified as a Category A agent by the NIH, RVFV infection can cause debilitating disease or death in humans and lead to devastating economic impacts by causing abortion storms in pregnant cattle. In a previous study, we showed that the host chaperone protein HSP90 is an RVFV-associated host factor that plays a critical role post viral entry, during the active phase of viral genome replication/transcription. In this study, we have elucidated the molecular mechanisms behind the regulatory effect of HSP90 during infection with RVFV. Our results demonstrate that during the early infection phase, host HSP90 associates with the viral RNA-dependent RNA polymerase (L protein) and prevents its degradation through the proteasome, resulting in increased viral replication.

Effects of 2 wintering practices on behavioral and physiological indicators of welfare of nonlactating, pregnant dairy cattle in a pasture-based system

In countries with pasture-based dairy systems and relatively cold winters, such as New Zealand, it is common to manage pregnant, nonlactating cows on forage crop paddocks rather than pasture, due to slow pasture growth rates. Wintering dairy cattle on grazed crops can compromise welfare if wet and muddy underfoot conditions occur, which can reduce lying. This study investigated behavioral and physiological indicators of welfare of cows under 2 wintering practices: cows managed on and grazed kale crop (Brassica oleracea), and cows managed on pasture with baled hay. Following dry-off (d 0), 80 cows were randomly assigned to 1 of the 2 wintering practices (40 cows/practice) and monitored between d 4 and 32 (phase 1). During this period, lying and stepping behavior was continuously recorded using leg-based accelerometers. Blood samples were obtained at d 0 and 32 for measurements of thyroxine (T4), nonesterified fatty acids (NEFA), white blood cells (WBC), and red blood cells. All data for phase 1 were presented descriptively due to the lack of treatment replication. Daily mean air temperature during this period was 5.2°C (range: 0.0-10.7°C), and rainfall was 1.1 mm/d (range: 0-5.6mm/d). Between d 4 and 32, cows in both groups spent similar amounts of time lying (pasture with hay cows: 8.9 h/24 h ± 2.57, kale crop cows: 8.7 h/24 h ± 3.06, mean ± SEM). Both groups reduced their lying on wet and cold days, and there was evidence of rebound lying once unfavorable weather conditions stopped. Cows on kale crop had numerically higher NEFA and lower WBC compared with cows managed on pasture, although most physiological values were within normal ranges. In a second phase of the study (d 34 and 35), cows were managed under controlled, replicated conditions in the 2 wintering practices using typical on-farm stocking rates (2 or 4 cows per group in the pasture with hay and kale crop treatments, respectively; n = 10 groups/treatment). During this period, cow behavior, skin and surface temperatures, hygiene scores, feed intakes, and ground conditions were measured. Weather conditions during the 48-h exposure were mostly cold and dry (mean air temperature: 7.8°C, range: -2.2 to 20.5°C). Cows managed on pasture with hay spent more time lying down on the first day of exposure; however, this was likely due to less space being available to kale cows on this day. Cows managed on pasture with hay ruminated more than cows on kale crop on both days of observations (d 1: 37.9% vs. 30.9% of observations, d 2: 36.8% vs. 28.7% of observations for pasture with hay and kale crop groups, respectively) and were lying more often in postures indicative of greater thermal comfort. Cows managed on pasture with hay had higher skin and surface temperatures compared with cows on kale crop, whereas cows on kale crop had dirtier coats. Results suggest that opportunities for thermal comfort were greater for cows managed on pasture with hay bales, which may be due to increased rumination activities and more insulated lying areas.

Lactation performances in primiparous Holstein cows following short and normal gestation lengths.

Despite decades of research, little is known regarding physiologic temporal limits for initiation of lactation in pregnant non-lactating cattle the aim of this study was to compare the lactation performances in primiparous Holstein cows after a short gestation length (GL) or abortion to those after a normal GL. The data were collected using an automated data collection system. The 94 herds evaluated were located in Belgium, France, Italy, the Netherlands and Germany. Data from a wide range of physiological cow-life events including birth and calving events, reproduction events (insemination, pregnancy checks, and abortions), and milking events were collected. The GL was defined as the interval between the last insemination and the subsequent calving (or abortion) within a range of 150-297 days. Animals were categorized into one of five categories based on GL quantiles (C-I to C-V). Lactation curve parameters including the scale, ramp, and decay were estimated using the Milkbot model. Then, the derived 305-day milk yield (M305-d), peak yield, and time to peak were compared between different GL categories. Of 13,732 lactations, 15 (0.11%) were found with a GL shorter than 210 days (ranging from 158 to 208 days). The 305-day milk yield was significantly lower in the C-I (7,566 ± 186) and C-II groups (7,802 ± 136 kg), compared to the C-III (8,254 ± 116 kg), C-IV (8,148 ± 119 kg), and C-V (8,255 ± 117 kg) groups. The same trends were found for the scale and peak yield of the lactation; the lowest scale were found for the C-I (31.5 ± 0.73) and C-II (32.8 ± 0.53) groups, and the highest were found for the C-III (34.5 ± 0.46), C-IV (34.9 ± 0.45), and C-V (35.0 ± 0.45) groups. Peak yield increased significantly from C-I (27.8 ± 0.66 kg) and C-II group (28.8 ± 0.48 kg) to the C-III (30.2 ± 0.42 kg) and further to the C-IV (30.6 ± 0.40 kg) and C-V (30.6 ± 0.41 kg) groups. Moreover, primiparous cows in the C-II GL category showed a higher milk yield persistency (decay of 1.30E-4 ± 3.55E-5) compared to those belonging to the C-IV (decay of 1.38E-4 ± 2.51E-5) and C-V (decay of 1.38E-4 ± 2.58E-5) group. In conclusion, results showed that primiparous cows with a shorter GL produced significantly less 305-day milk and peak yields, had a higher lactation persistency, and showed a lower upward slope of the lactation curve compared to those with a normal GL.

Epidemiological Characteristics of the Lumpy Skin Disease Outbreak in Nawalpur, Nepal, 2022

Lumpy skin disease (LSD) is an economically important and notifiable transboundary viral disease of cattle and water buffalo, predominantly transmitted by arthropod vectors. In recent times, LSD has emerged as a notable concern in Nepal, with the first outbreak reported in June 2020, in Morang district. In 2022, outbreaks of LSD were observed in several districts with Nawalpur district being the hard‐hit district. The objective of this study is to provide insights into the epidemiological characteristics of LSD, to identify potential sources and associated risk factors for LSD outbreak in Nawalpur, and its financial impact. The overall morbidity rate was observed to be 28.02% (n = 431/1,538) and the mortality rate was 3.06% (n = 47/1,538), resulting in a case fatality rate of 10.90% (n = 47/431). The predominant clinical symptoms were skin nodules, lameness, and decreased milk production in milking animals. Dry cattle, including pregnant cows and cattle heifers were the most affected. Univariable logistic regression analysis identified factors linked to disease outbreaks, such as importing animals from disease prevalent regions, sharing feed and water, herd size, and the presence of clinical signs in neighboring farms. Multivariable analysis highlighted the significance of neighboring farms having sick animals in resulting disease outbreaks. Because of the substantial economic impact due to LSD, it is imperative to implement effective control and preventive measures. These include animal movement control and quarantine, following biosecurity protocols during nearby outbreaks, and targeted vaccination of susceptible populations to prevent further disease spread.

Lupine-induced crooked calf syndrome: mitigation through intermittent grazing management of cattle.

Lupines are responsible for a condition in cattle referred to as "crooked calf syndrome" (CCS) that occurs when pregnant cattle graze teratogenic lupines. A proposed management strategy to limit these types of birth defects includes utilizing an intermittent grazing schedule to allow short durations of grazing lupine-infested areas interrupted by movement to a lupine-free pasture. The objective of this study was to determine if an intermittent schedule of ten continuous days of lupine treatment followed by 5 d off treatment would be sufficient to decrease, or prevent, the incidence of lupine-induced malformations. Continuous dosing of the teratogenic lupine (Lupinus leucophyllus) to pregnant cows for 30 d during the most susceptible stage of pregnancy (gestation days 40 to 70) resulted in severe skeletal birth defects in their calves. However, intermittent dosing of the teratogenic lupine demonstrated that interrupted intake of lupine reduced the severity, or eliminated, permanent skeletal malformations in calves born to cows dosed lupine. Toxicokinetic and ultrasound data demonstrated a clear inverse correlation between serum anagyrine (the primary teratogenic alkaloid in some lupines) concentrations in the dam and fetal movement. In the intermittent group, fetal movement quickly returned to normal after lupine feeding stopped and remained normal until lupine treatment resumed. Therefore, interrupting lupine intake for at least 5 d through an intermittent grazing program could reduce the severity of the CCS. Furthermore, this method would allow ranchers to move cattle back into lupine pastures after a brief interruption, which would allow for more efficient utilization of forage resources.

Comparability of Pregnancy Specific Protein-B (PSPB) Concentration in Serum and Urine of Kedah-Kelantan (KK) Cattle

This study aimed to investigate the effect of serum and urine PSPB levels based on different biomarkers, such as serum and urine. Serum PSPB levels significantly increased from day 0 to day 164 (P<0.05). However, the PSPB urine concentration through the ELISA test showed higher concentration and reached the sensitivity of the ELISA test from Day 0 until Day 164 after AI. The results of urine biomarkers at Day 0, Day 42, and Day 164 were not significant (P>0.05). Serum PSPB production begins to be established after day 24 of parturition due to embryonic development. Furthermore, the urine PSPB concentration is considered an abundant protein circulating in the animal body and ready to be excreted in the urine. In this study, the ELISA test was unsuitable for detecting pregnancy. However, urine biomarkers can potentially become biomarkers by studying the range of concentrations of PSPB that can be considered pregnancy. In addition, the PSPB protein allows for more prolonged survival in the bovine body and decreases gradually from the 22nd to the 54th day after calving. The results demonstrate that PSPB can detect pregnancy early in pregnancy using biomarkers and evolution. Therefore, this study could be improved by examining PSPB levels of pregnant and non-pregnant cattle.

205 Level of Supplemental Fat in the Diet of Gestating Beef Cows: Effects on Cow and Calf Performance

Abstract This study evaluated the effects of feeding a canola seed-based (7.2% ether extract) pellet to gestating cows on cow performance, reproductive efficiency, milk yield and composition, and calf birth weight. Seventy-two pregnant, multiparous cows were allocated to 12 pens in a completely randomized block design. Body weight (BW; 605 ± 35 kg) was utilized as the blocking criteria. Diets were formulated to be isonitrogenous (CP: 8.20 ± 0.24% and 9.07 ± 0.05% second and third trimesters, respectively) and isocaloric (TDN: 58.29 ± 0.24% and 60.50 ± 0.04% second and third trimesters, respectively), and to meet NASEM (2016) nutrient requirements for pregnant beef cattle. Pens were randomly assigned to three replicated (n = 4) dietary treatments: 0 (CON), 150 (LOW), and 300 (HIGH) g of fat/d (DM basis). Dietary treatments were fed from 148 ± 8 d prepartum until at least 50% of all cows had calved, then switched to a common lactation diet. Body condition score (BCS), BW and subcutaneous fat thickness were measured at the start (SOT) and end of trial (EOT), and at 21 and 42 d postpartum. Orthogonal contrasts were used to assess linear and quadratic relationships between fat inclusion and dependent variables. At SOT, there were no differences (P ≥ 0.73) in conceptus corrected BW (597 ± 34 kg) or (P ≥ 0.13) BCS (2.85 ± 0.12, Canadian System: 1 to 5). After 84 d on trial (64 ± 8 d prepartum), conceptus corrected average daily gain (ADG) increased linearly (P = 0.04) as fat inclusion increased. After 151 d of supplementation (EOT), conceptus corrected ADG and subcutaneous fat thickness did not differ (P ≥ 0.71 and 0.63, respectively). BCS change from SOT to EOT increased, while EOT to 21 d postpartum decreased quadratically as fat inclusion increased (P = 0.02 and 0.01, respectively). Female calf birth weight decreased quadratically (P = 0.01) as fat inclusion increased, but there was no effect (P ≥ 0.75) on male calf birth weight. As fat inclusion increased, lactose concentration in milk decreased linearly (P = 0.04). As days in milk (DIM) increased, milk protein, total solids, and milk energy yield decreased (P ≤ 0.05). Milk urea-N tended to increase (P = 0.07), while 12 h milk yield (P = 0.05) tended to decrease as DIM increased. Milk fat and energy were not affected by fat inclusion, day, or the interaction between fat inclusion and day (P ≥ 0.16). There was a quadratic tendency for fat inclusion to affect pregnancy rate (P = 0.09), being maximized on LOW treatment. These results suggest that increasing fat inclusion during mid-to-late gestation tended to improve cow reproductive efficiency. Further investigation is required to determine the optimal level of fat inclusion from canola seed.

188 Characterization of the Vagino-Uterine Microbiota in Pregnant and Non-Pregnant Beef Cattle Using 16S Rrna Gene Sequencing and Culturing

Abstract Emerging evidence suggests that urogenital microbiome-targeted approaches may provide a novel opportunity to reduce the incidence of reproductive failures in cattle. The objectives of this study were to: 1) characterize the vaginal and uterine microbiota between beef cattle that became pregnant via artificial insemination (AI) and those that did not; 2) identify differentially abundant taxa between pregnant and non-pregnant cattle; and 3) characterize the culturable fraction of the vaginal and uterine microbiota using extensive culturing. Vaginal and uterine swab samples were collected from two cohorts of Angus-crossbred cattle: mature cows (n =100) and heifers (n = 72, vaginal swab only) at the time of AI. At 35 days post-AI, pregnancy diagnoses were made via ultrasound. A subset of vaginal and uterine swabs from cows (27 non-pregnant and 31 pregnant) and heifers (26 non-pregnant and 33 pregnant) were selected and processed for microbiota assessment using 16S rRNA gene (V3-V4) sequencing. For culturing, a subset of cryopreserved vaginal and uterine swabs (128) were plated onto three different agar types and cultured, and isolates were identified by near-full length 16S rRNA gene sequencing. Sequencing results revealed 11 taxa that were more abundant in the vaginas of heifers that failed to become pregnant via AI than heifers that did become pregnant. While there was no significant difference in vaginal microbiota community structure (P = 0.21) between pregnant and non-pregnant cows, non-pregnant cows tended to have greater microbial richness and Shannon diversity (P ≤ 0.08) compared with pregnant cows. No differentially abundant taxa were detected in the vaginas of pregnant versus non-pregnant cows. Pregnant cows had a distinct uterine microbiota community structure (R2 = 0.032, P = 0.008) but similar alpha diversity (P &amp;gt; 0.1) compared with non-pregnant cows. Twenty-eight differentially abundant taxa were observed in the uterine microbiota between pregnant and non-pregnant groups, with 11 of them more abundant in pregnant cows. Methanobrevibacter ruminantium (archaea) and Fusobacterium necrophorum were among these 11 positive pregnancy-associated taxa. Although community structure was significantly different between the vagina and uterus, 277 “core taxa” (present in ≥ 80% of all samples) were shared between the two communities. A total of 733 bacterial isolates were recovered from vaginal (512) and uterine (221) swabs under aerobic (n = 363, 83 different species) and anaerobic (n = 370, 69 species) culturing. Potential pathogenic isolates within the Trueperella, Mannheimia and Histophilus genera were most exclusively identified from vaginal swabs. Only two Lactobacillus isolates were recovered. Overall, our results indicate that pregnancy-associated taxonomic signatures are present in the bovine uterine and vaginal microbiota. Among 39 pregnancy status-associated taxa, 41% were unclassified at the genus level, suggesting that shotgun metagenomics and culturomics are needed to identify and characterize the pregnancy-associated taxa in cattle.

BoHV-1 affects abortion and progesterone in dairy cows Bovine alphaherpesvirus 1 (BoHV-1) seropositivity, progesterone levels and embryo loss of 30-day-old pregnant dairy cows in Zagros Industrial Dairy Farm in Shahrekord: Examination and analysis.

Bovine alphaherpesvirus 1 (BoHV-1) is a serious disease with severe negative economic effects on the global cattle sector, especially in Iran. This cross-sectional study was carried out to examine the seroprevalence and associated risk factors of BoHV-1 infection with progesterone levels and embryo death in 30-day pregnant dairy cattle at Zagros Industrial Dairy Farm in Shahrekord, Iran. Between December 2017 to February 2018, blood samples were obtained from 60 dairy cow herds. To determine whether BoHV-1 was present, serum samples were examined using the ELISA for serum antibodies. To find progesterone (P4) in blood, the progesterone ELISA test was used. 96.7 % of sera tested positive for BoHV-1 antibodies, according to the findings. Additionally, 60.34 % of blood samples that tested positive had an experience of abortion and significantly more inseminations that resulted in pregnancy, consistent with findings from other studies conducted in Iran and other nations. Since this study is the first to document the risk factor for BoHV-1 infection in Shahrekord, Iran, we could infer that the virus is extensively dispersed in this area.

Forensic age assessment of late-term bovine fetuses

BackgroundTransporting pregnant cattle that have passed 90% or more of the expected gestation period (G90 threshold) is prohibited within the European Union. Therefore, there is a need to determine whether this threshold has been exceeded in late-gestation cows sent to slaughter. The aim of this study was to evaluate fetal parameters’ reliability for use in forensic age assessment of late-term Holstein fetuses.ResultsAnalysis of the gestation length of 2734 Holsteins that calved with a single liveborn fetus revealed a median gestation length of 278 days with 99% of parturitions occurring between day 261 and 290, corresponding to G90 thresholds of 235 and 261 days, respectively. The association between gestation length and neonatal body weight had an R2 of 0.27. The influence of fetal sex and cow parity on gestation length was ± 2 days. The eruption of incisor and canine teeth was assessed in preterm calves delivered by caesarean section (n = 52) and full-term neonatal calves (n = 54). Statistical analysis of tooth eruption data showed a statistically significant variation in fetal age at tooth eruption.ConclusionsDefining the G90 threshold for a cow not having reached parturition is challenging. Body weight was not found to be a reliable parameter for identifying fetuses beyond the G90 threshold. Statistical analysis of the association between fetal age and eruption through the gingival mucosa of incisor and canine teeth revealed significant variation, making tooth eruption a challenging parameter to use in forensic cases. Assessment of the evaluated parameters, therefore, cannot be considered a scientifically validated method to conclude definitively and beyond reasonable doubt whether or not a given fetus has passed the G90 threshold.

Interferon-Stimulated Gene Expression in Peripheral Blood Leucocytes as a Convenient Prediction Marker for Embryo Status in Embryo-Transferred Japanese Black Cows during the Peri-Implantation Period.

Pregnancy diagnosis during early gestation is important for cattle reproduction. The expression of interferon-stimulated genes (ISGs) in peripheral blood leukocytes (PBLs) was studied in embryo-transferred (ET) Japanese Black cattle. ISGs in PBLs-ISG15, MX1, MX2, and OAS1-were detected in multiple ovulation ET cattle using a real-time quantitative polymerase chain reaction, and receiver operating characteristic (ROC) curve analysis was performed. Gestational status was predicted using the average ISG levels during the normal estrous cycle (AVE) and the Youden index from the ROC curve analysis as cutoff values. The ISG15, MX1, and MX2 levels were significantly higher in pregnant cattle (n = 10) than in non-pregnant cattle (n = 23) on gestation day 21, whereas the levels of all ISGs were similar between non-pregnant and non-pregnant cattle with late embryonic death (n = 7). ISG15, MX1, and MX2 appropriately predicted the gestational status of ET cows. The statistical evaluation of the diagnostic accuracy in ET cows on day 21 of gestation presented higher values of sensitivity, specificity, accuracy, and positive predictive values of ISG15, MX1, and MX2 using the Youden index than using the AVE. Therefore, ISG15, MX1, and MX2 are excellent biomarkers of gestational status during the peri-implantation period in ET cattle.

FOETAL WASTAGE IN KANO CENTRAL ABATTOIR AND ITS IMPACT ON THE NIGERIAN ECONOMY

The study was designed to determine the incidence of feotal wastage and its economic impacts in Kano central abattoir. Total cattle presented for slaughter, number of bulls and cows slaughtered and number of condemned foetuses were recorded on daily basis for one month. The results revealed that 64.28% and 35.72% of the cattle slaughtered during the study period were cows and bulls respectively. Out of the percentage of cows slaughtered, 7.5% were pregnant and their foetuses were wasted. Furthermore, the study revealed that there was one case of foetal wastage for every thirty three (1:33) cows slaughtered. This wastage may lead huge depletion of future reproductive stock which is disastrous to the future of livestock industry in meeting beef and milk demand of the teaming population. The estimated financial losses accrued were ₦3,944,000.00 monthly translating to annual economic loss of ₦47,280,000.00 which is enormous for the State bear. The finding urges for urgent action to be put in place to checkmate the marketing and slaughter of pregnant cattle in the State. Cattle marketers, rearers, butchers and consumers should be sensitized on the financial and health implications of pregnant cows slaughter and foetus handling in transmitting zoonotic diseases.

18 Influence of Pregnant Cattle Grazing Endophyte-Infected Tall Fescue on Innate Immune Response of Male Offspring

Abstract The objective was to evaluate the influence of dams grazing endophyte-infected tall, toxic, fescue (E+) during gestation on innate immune response of male offspring to an endotoxin challenge. Crossbred pregnant multiparous cows (n = 36) bred to Red Angus sires were housed in replicated E+ or novel endophyte-infected, non-toxic, fescue (NE+) pastures before breeding and through the length of gestation. After parturition, cows and calves were moved to a common bermudagrass pasture until calves were weaned. From this calf-crop, a subset of post-weaned steers (E+ n = 8; NE+ n = 8) were selected for a lipopolysaccharide (LPS) challenge. Steers (302 ± 36 d of age; 261 ± 62 kg body weight) were fitted with jugular vein catheters &amp;gt;7 h before sampling. Blood was collected every 30 min starting 2 h before (Pre-LPS) and 9 h following (Post-LPS) LPS administration (0.5 µg/kg body weight). Sickness behavior score (SBS), cortisol, and glucose were analyzed every 30 min. Complete blood count (CBC) and rectal temperature (RT) were analyzed hourly. Peak concentration, time at peak concentration, baseline, return to baseline, and area under the curve (AUC) were evaluated for cortisol and glucose. Cortisol and glucose were determined by radioimmunoassay and hexokinase colorimetric assay, respectively. The CBC data were analyzed using a Hemavet hemocytology analyzer. Pre-LPS and Post-LPS cortisol, glucose, SBS, RT, and CBC were analyzed using the MIXED procedure of SAS specific for repeated measures with treatment, time, and the interaction as fixed effects and dam sire breed as a random effect. Peak concentration, time at peak concentration, baseline, return to baseline, and AUC for cortisol and glucose were analyzed using the MIXED procedure of SAS with treatment as a fixed effect and dam sire breed as a random effect. There was a Pre-LPS treatment by time interaction for RT (P &amp;lt; 0.05). Pre-LPS monocyte count was lower in offspring of dams grazing E+ relative to NE+ during gestation (P &amp;lt; 0.05). Pre-LPS hematocrit was increased in offspring of dams grazing E+ relative to NE+ during gestation (P &amp;lt; 0.05). There was a Pre-LPS effect of time on SBS (P &amp;lt; 0.05). As expected, Post-LPS cortisol, glucose, RT, WBC, neutrophil count, lymphocyte count, lymphocyte percentage, eosinophils count, eosinophils percentage, hematocrit percentage, RBC, and platelets changed over time in response to LPS (P &amp;lt; 0.05). Post-LPS lymphocyte count and monocyte percentage were decreased in offspring of dams grazing E+ relative to NE+ during gestation (P &amp;lt; 0.05). Post-LPS eosinophils count, eosinophil percentage, and hematocrit were increased in offspring of dams grazing E+ relative to NE+ during gestation (P &amp;lt; 0.05). There was a Post-LPS treatment by time interaction for monocyte count and neutrophil percentage (P &amp;lt; 0.05). Preliminary results suggest an altered innate immune response of male offspring of dams grazing toxic relative to novel fescue during gestation.

89 Influence of Melatonin Supplementation in Pregnant Cattle Consuming Endophyte-Infected Tall Fescue Seed on Offspring Performance

Abstract The objective was to evaluate growth performance and estimates of body composition in offspring of dams that consumed diets containing tall fescue seed with (E+) or without (E-) the toxic endophyte and with or without melatonin during mid-late gestation. Pregnant heifers (n = 57) artificially inseminated with sex-sorted semen (X chromosome-bearing sperm) from a single Angus sire were administered dietary treatments in a 2 x 2 factorial treatment arrangement (E- without melatonin, E-/NM; E- with melatonin, E-/M; E+ without melatonin, E+/NM; or E+ with melatonin, E+/M; melatonin dose: 100 µg/kg of BW) for a 70-day period between May and July starting at 160±13 d of gestation to mimic ergot alkaloid concentrations in a grazing scenario. All diets contained corn gluten and molasses and were fed using SmartFeed Pro (C-Lock Inc.) controlled feeding units between 0900 and2 1200 h daily. Cattle were removed from dietary treatments 39 ± 19 d before calving. Two replicates were housed separately in an open-air barn, each with a 1.2-ha paddock. Prior to and following the 70-d treatment period, all cattle were maintained as a single group free from toxic fescue. Calves were weaned at 226 ± 19 d of age. Gestation length, calf birth weight, 205-day adjusted weaning weight (205-d WW), carcass ultrasonography measures (ribeye area, REA; REA/CWT; percent intramuscular fat, IMF; rib fat thickness, UFAT; rump fat thickness, URUMP), post-weaning weights (recorded every 28 d between weaning and 84 d post-weaning), and post-weaning ADG (between weaning and 84 d post-weaning) were evaluated in offspring (n = 44). Post-weaning calf weights were analyzed using the MIXED procedure of SAS specific for repeated measures with treatment and time as fixed effects and replicate as random. All other variables were analyzed using the MIXED procedure of SAS with treatment as a fixed effect and replicate as random with gestation length as a covariate for birth weight. Gestation length, birth weight, 205-d WW, and post-weaning calf weight were decreased (P &amp;lt; 0.04) in offspring of dams that consumed E+ relative to E- during gestation. Birth weight was increased (P = 0.02) in offspring of dams receiving melatonin relative to those without melatonin during gestation. The 205-d WW and REA were decreased in calves born to E+/NM dams relative to E-/NM, E-/M, and E+/M (P &amp;lt; 0.03). Post-weaning weight tended to be decreased in calves born to E+/NM dams relative to E-/NM, E-/M, and E+/M (P = 0.06). The UFAT tended to be decreased (P = 0.06) in offspring of dams that consumed E+ relative to E- during gestation. There were no other effects of treatment, time or the interaction (P &amp;gt; 0.10). To our knowledge, these preliminary results are the first to evaluate the potential of melatonin as a therapeutic to recover performance losses in offspring born to pregnant cattle consuming toxic fescue.

47 Influence of Melatonin Supplementation in Pregnant Cattle Consuming Endophyte-Infected Tall Fescue Seed on Offspring Performance

Abstract The objective was to evaluate growth performance and estimates of body composition in offspring of dams that consumed diets containing tall fescue seed with (E+) or without (E-) the toxic endophyte and with or without melatonin during mid-late gestation. Pregnant heifers (n = 57) artificially inseminated with sex-sorted semen (X chromosome-bearing sperm) from a single Angus sire were administered dietary treatments in a 2 x 2 factorial treatment arrangement (E- without melatonin, E-/NM; E- with melatonin, E-/M; E+ without melatonin, E+/NM; or E+ with melatonin, E+/M; melatonin dose: 100 µg/kg of BW) for a 70-d period between May and July starting at 160 ± 13 days of gestation to mimic ergot alkaloid concentrations in a grazing scenario. All diets contained corn gluten and molasses and were fed using SmartFeed Pro (C-Lock Inc.) controlled feeding units between 0900 and 1400 h daily. Cattle were removed from dietary treatments 39 ± 19 days before calving. Two replicates were housed separately in an open-air barn, each with a 1.2-ha paddock. before and following the 70-d treatment period, all cattle were maintained as a single group free from toxic fescue. Calves were weaned at 226 ± 19 d of age. Gestation length, calf birth weight, 205-day adjusted weaning weight (205-d WW), carcass ultrasonography measures (ribeye area, REA; REA/CWT; percent intramuscular fat, IMF; rib fat thickness, UFAT; rump fat thickness, URUMP), post-weaning weights (recorded every 28 days between weaning and 84 days post-weaning), and post-weaning ADG (between weaning and 84 days post-weaning) were evaluated in offspring (n = 44). Post-weaning calf weights were analyzed using the MIXED procedure of SAS specific for repeated measures with treatment and time as fixed effects and replicate as random. All other variables were analyzed using the MIXED procedure of SAS with treatment as a fixed effect and replicate as random with gestation length as a covariate for birth weight. Gestation length, birth weight, 205-d WW, and post-weaning calf weight were decreased (P &amp;lt; 0.04) in offspring of dams that consumed E+ relative to E- during gestation. Birth weight was increased (P = 0.02) in offspring of dams receiving melatonin relative to those without melatonin during gestation. The 205-d WW and REA were decreased in calves born to E+/NM dams relative to E-/NM, E-/M, and E+/M (P &amp;lt; 0.03). Post-weaning weight tended to be decreased in calves born to E+/NM dams relative to E-/NM, E-/M, and E+/M (P = 0.06). UFAT tended to be decreased (P = 0.06) in offspring of dams that consumed E+ relative to E- during gestation. There were no other effects of treatment, time or the interaction (P &amp;gt; 0.10). To our knowledge, these preliminary results are the first to evaluate the potential of melatonin as a therapeutic to recover performance losses in offspring born to pregnant cattle consuming toxic fescue.

Slaughter of pregnant Tanzania shorthorn Zebu cattle at Morogoro abattoir: Prevalence, fetal wastage, and placentome morphology

Slaughtering pregnant cattle for meat is unethical, impends food security, and brings animal cruelty. A six-month study spinning from June and December 2020 was carried out to determine the number of Tanzania shorthorn zebu (TSHZ) slaughtered cattle, level of fetal wastage, number, size, and morphology of placentomes and their relationship with fetal age, sex, weight, and location in uteri. Results showed that 15,239 cattle were slaughtered, of which 99% (n=15,087) were TSHZ aged above three years. 61.38% (n= 9,353) of slaughtered cattle were female cattle, of which 2,599 (27.79%) were pregnant at varied gestation periods, and only 5,886 (38.63%) were males. Recovered fetuses were 1,450 (55.79%) males and 1,149 (44.21%) females, with a total of 1,081 (41.59%), 919 (35.36%), and 599 (23.05%) recovered in the first, second and third trimester, respectively. Fetal ages varied from 2.2 to 8.9 months, with body length (crown-crump) ranging from 13.7 to 83.1 cm. Fetus weight ranged from 1.1 kg to 23.2 kg. A total of 1545 (59.45%) pregnancies were localized in the right uterine horn, whereas 1054 (40.55%) were in the left uterine horn. The number of placentomes was significantly larger (P &lt; 0.05) in gravid horns ranging from 71 to 115, than in non-gravid horns (5-28). Placentomes in gravid horn were greatly vascularized, large in size, convex in shape, and measured 7 cm in length and 2 cm in width. In non-gravid horns, placentomes were pale, small, and flat and measured 4 cm in length and 1 cm in width. At the microscopic level, the fetal cotyledons comprised a chorionic plate with a smooth external surface of cuboidal epithelium. From the chorionic plate's internal surface, numerous primary villi sprout inside in a pinnate fashion, producing secondary and tertiary villi. A significant fetal loss was resulting from the slaughter of pregnant animals warrants stepping up routine veterinary ante-mortem inspection of traded animals to salvage the high level of fetal wastage.