Isolation and Characterization of Contemporary Bovine Coronavirus Strains.

Bovine coronavirus (BCoV) poses a threat to cattle health worldwide, contributing to both respiratory and enteric diseases. However, few contemporary strains have been isolated. In this study, 71 samples (10 nasal and 61 fecal) were collected from one farm in Ohio in 2021 and three farms in Georgia in 2023. They were screened by BCoV-specific real-time reverse transcription-PCR, and 15 BCoV-positive samples were identified. Among them, five BCoV strains from fecal samples were isolated using human rectal tumor-18 (HRT-18) cells. The genomic sequences of five strains were obtained. The phylogenetic analysis illustrated that these new strains clustered with US BCoVs that have been detected since the 1990s. Sequence analyses of the spike proteins of four pairs of BCoVs, with each pair originally collected from the respiratory and enteric sites of one animal, revealed the potential amino acid residue patterns, such as D1180 for all four enteric BCoVs and G1180 for three of four respiratory BCoVs. This project provides new BCoV isolates and sequences and underscores the genetic diversity of BcoVs, the unknown mechanisms of disease types, and the necessity of sustained surveillance and research for BCoVs.

Evaluation of the stress-reducing effect of trace mineral injection in beef calves.

BACKGROUND: Little is known about the effects of trace mineral supplementation on the stress response in beef calves. OBJECTIVES: To investigate the effect of injectable trace mineral supplementation (ITM) on the stress response in beef calves exposed to different types of stress. ANIMALS: Thirty weaned Angus and Angus crossbred calves. METHODS: The enrolled calves were randomly assigned to 2 groups: ITM, 15 calves received modified-live virus vaccine (MLV) and ITM SC and 15 calves received MLV and saline SC (CONT). The calves were exposed to 3 types of stress: the stress of MLV vaccination (d0), nasal aerosol with bovine viral diarrhea virus-2 (BVDV-2) challenge (d5), and liver biopsy (d26). The calves' body weights and health status were monitored. Leukocyte counts, serum cortisol concentration ([cort]), BVDV-2 serum neutralizing antibodies (SNA), and percentages of CD4+ , CD8+ , WC1+ , and CD25+ T-lymphocytes were measured. RESULTS: Serum cortisol concentration ([cort]) showed strong associations with the percentage of CD8+ (rs = .50), BVDV2-SNA (rs = -.43), and WC1CD25+ (rs = .41) cells, and rectal temperature (rs = .40). The highest [cort] was reported 3 days after aerosol BVDV-2 challenge. Serum [cort] was decreased in ITM-treated calves 3 days post-BVDV-2 challenge, compared with CONT calves, with an average decrease of 18.5 ng/µL (95% confidence interval [CI], -6.07 to -31.3). The ITM-treated calves were heavier and healthier (P < .01) than the CONT calves. CONCLUSIONS AND CLINICAL IMPORTANCE: Trace mineral supplementation appears to have stress mitigation effects in beef cattle that may reflect positively on growth and health performance. Viral exposure is associated with a high degree of stress, which is considered a major welfare concern.

Dynein localization and pronuclear movement in the C. elegans zygote.

Centrosomes serve as a site for microtubule nucleation and these microtubules will grow and interact with the motor protein dynein at the cortex. The position of the centrosomes determines where the mitotic spindle will develop across all cell types. Centrosome positioning is achieved through dynein and microtubule-mediated force generation. The mechanism and regulation of force generation during centrosome positioning are not fully understood. Centrosome and pronuclear movement in the first cell cycle of the Caenorhabditis elegans early embryo undergoes both centration and rotation prior to cell division. The proteins LET-99 and GPB-1 have been postulated to have a role in force generation associated with pronuclear centration and rotation dynamics. When the expression of these proteins is perturbed, pronuclear positioning exhibits a movement defect characterized by oscillatory ("wobble") behavior of the pronuclear complex (PNC). To determine if this movement defect is due to an effect on cortical dynein distribution, we utilize RNAi-mediated knockdown of LET-99 and GPB-1 to induce wobble and assay for any effects on GFP-tagged dynein localization in the early C. elegans embryo. To compare and quantify the movement defect produced by the knockdown of LET-99 and GPB-1, we devised a quantification method that measures the strength of wobble ("wobble metric") observed under these experimental conditions. Our quantification of pronuclear complex dynamics and dynein localization shows that loss of LET-99 and GPB-1 induces a similar movement defect which is independent of cortical dynein localization in the early C. elegans embryo.

Trace Minerals Supplementation with Great Impact on Beef Cattle Immunity and Health.

Trace minerals (TM) play an important role in cattle immunity, health and performance. Although TM are needed in small quantities, they are fundamental for enzymes involved in antioxidant protection against cellular damage and several pathways of the immune response. Cattle TM status results from the balance between TM dietary intake and their requirements. Free-choice oral TM supplementation is a common practice in beef cattle production systems. However, there is a high variation in TM intake and thus TM status and bioavailability in animals receiving free-choice oral TM supplements. Strategic pulse-dose supplementation during critical points of beef cattle management provides a controlled amount of TM intended to remove such a variation. Adequate TM supplementation should not only satisfy the basal requirements but also provide a source of TM when there is a higher demand of the antioxidant systems or during the development of the immune response. This paper reviews the research-based evidence of the effects of TM supplementation on immunity and its impact on beef cattle health. This review highlights the benefits of a novel approach of strategic administration of injectable trace minerals (Se, Zn, Cu and Mn) during critical episodes of cattle management (e.g., around weaning or at vaccination) in combination with free-choice oral supplementation to maintain adequate TM and oxidative status, enhanced immunity and overall cattle health. This strategy has proven to decrease morbidity, which would positively impact the productivity of the beef cattle systems.

Comparison of the immune response following subcutaneous versus intranasal modified-live virus booster vaccination against bovine respiratory disease in pre-weaning beef calves that had received primary vaccination by the intranasal route.

This study was performed to elucidate whether the route of booster vaccination affects the immune response against respiratory vaccine viruses in pre-weaning beef calves that receive primary intranasal (IN) vaccination during the first month of life. The objective was to compare the serum neutralizing antibody (SNA) titers to BHV1, BRSV, and BPI3V, cytokine mRNA expression and mucosal BHV1- and BRSV-specific IgA in nasal secretions following administration of IN or subcutaneous (SC) modified-live virus (MLV) booster vaccines 60 days after primary IN vaccination in young beef calves. Twenty-one beef calves were administered 2 mL of an IN MLV vaccine containing BHV1, BRSV, and BPI3V (Inforce3®) between one and five weeks of age. Sixty days after primary vaccination, calves were randomly assigned to one of two groups: IN-MLV (n = 11): Calves received 2 mL of the same IN MLV vaccine used for primary vaccination and 2 mL of a SC MLV vaccine containing BVDV1 & 2 (Bovi- Shield GOLD® BVD). SC-MLV (n = 10): Calves were administered 2 mL of a MLV vaccine containing, BHV1, BRSV, BPI3V, and BVDV1 & 2 (Bovi-Shield GOLD® 5). Blood and nasal secretion samples were collected on days -61 (primary vaccination), -28, -14, 0 (booster vaccination), 14, 21, 28, 42 and 60 for determination of SNA titers, cytokine gene expression analysis and nasal virus-specific IgA concentrations. Statistical analysis was performed using a repeated measures analysis through PROC GLIMMIX of SAS®. Booster vaccination by neither IN nor SC routes induced a significant increase in SNA titers against BHV1, BRSV, and BPI3V. Subcutaneous booster vaccination induced significantly greater BRSV-specific SNA titers (on day 42) and IgA concentration in nasal secretions (on days 21 and 42) compared to calves receiving IN booster vaccination. Both IN and SC booster vaccination were able to stimulate the production of BHV1-specific IgA in nasal secretions. In summary, booster vaccination of young beef calves using either SC or IN route two months after IN MLV primary vaccination resulted in comparable SNA titers, cytokine gene expression profile and virus-specific IgA concentration in nasal secretions. Only a few differences in the systemic and mucosal immune response against BHV1 and BRSV were observed. Subcutaneous booster vaccination induced significantly greater BRSV-specific SNA and secretory IgA titers compared to IN booster vaccination.

Characterizing Anti-Müllerian Hormone (AMH) concentration and change over time in Holstein dairy cattle.

The objective of this study was to characterize circulating Anti-Müllerian Hormone (AMH) concentrations in a population of Holstein heifers and examine the impact that life events and stage of life have on those concentrations. Virgin, Holstein heifers (n = 105) 13 ± 0.8 months old were heat detected using tail-chalk, bred via artificial insemination and pregnancy checked 32+ days later. Serum samples for AMH were collected upon enrollment (heifer), at 5-20 days in milk (fresh) and at 45-60 days in milk (pre-breeding). Transrectal ultrasonography was performed upon enrollment (heifer) and at 45-60 days in milk (pre-breeding) to determine antral follicle count (AFC), cyclicity status, and uterine health. Heifers were blocked into thirds by AMH concentration: HIGH (>354 pg/mL; n = 34), MID (183-354 pg/mL; n = 35) and LOW (<183 pg/mL; n = 36), with distribution re-evaluated at subsequent samplings (fresh, pre-breeding). As heifers, age and conception risk to first service were not impacted by AMH (P > 0.05). Reason for leaving the herd, health incidences and calving difficulty were not impacted by AMH (P > 0.05). AFC and cyclicity had a positive impact on heifer AMH (P < 0.01). AFC and AMH in heifers were highly correlated (0.56, P < 0.001). AFC for heifers differed by AMH group with the HIGH group having the greatest AFC (8.76), followed by the MID (5.87), then the LOW (3.53) group (P < 0.0001). However, this association was not evident in the pre-breeding group (P > 0.05). From the heifer to the fresh sample, average AMH dropped from 313.15 pg/mL to 160.01 pg/mL (P < 0.0001). Average AMH at the pre-breeding sample was 183.23 pg/mL, which was lower than the heifer sample (P < 0.0001), but not different from the fresh sample (P > 0.05). AFC and AMH at the heifer sample had a positive impact on AMH at the fresh sample (P < 0.01) and pre-breeding AMH was positively impacted by both the fresh and heifer AMH concentration (P < 0.001). Most animals kept their AMH categorization through all three time points with more of the LOW AMH animals maintaining their categorization than the other groups. However, 32.1% of animals changed their AMH categorization from the heifer sample to the fresh sample, with 53.8% moving to a lower AMH categorization (corresponding to lower AMH) and 46.2% moving to a higher AMH categorization (corresponding to higher AMH). No differences were seen in circulating AMH based on health events however, differences in AMH concentration over time indicate a drop in circulating AMH post-calving. Circulating AMH concentration as a pre-breeding heifer is highly indicative of circulating AMH concentration as a first lactation animal and may be used to predict an adult animal's AMH concentration. However, it is necessary to compare AMH concentrations to herdmates as published AMH values vary widely from herd to herd. In addition, sampling time should be considered when determining AMH categorization of animals as circulating AMH concentration immediately post-calving may not be indicative of an animal's true AMH categorization.

Lunar Cycle Influences Reproductive Performance of Crossbred Brahman Cows Under Tropical Conditions.

Evidence has accumulated over the years indicating that the moon influences some aspects of the reproductive activity in animals and humans. However, little is known about the influence of the lunar cycle on the reproductive performance of cows under tropical conditions, where the environment strongly affects reproduction. This retrospective study was conducted with the aim of assessing the influence of the lunar cycle on some reproductive traits of tropical crossbred cows managed in a pasture-based system. Data from 5869 reproductive records from two commercial farms localized in the Maracaibo Lake Basin of Zulia State, Venezuela, were analyzed. Variables studied were first service conception rate, calving frequency, first postpartum estrous frequency, and pregnancy frequency. In addition to the lunar cycle, the effects of farm, season, and predominant breed were also considered. Data were analyzed using logistic regression and general linear model from SAS. First service conception was affected by lunar phases and predominant breed, but not by farm or season. For frequencies of calving, first postpartum estrus, and pregnancy, there was no main effect of farm, season, and predominant breed, whereas the effect of lunar phases was highly significant. First service conception was significantly greater in waning than in crescent phase of the lunar cycle. Frequencies of calving, first estrus, and pregnancy were highly correlated and showed greater figures around full moon and new moon. In conclusion, lunar cycle influenced first service conception, attaining greater values in the waning phase of the moon cycle. Frequencies of calving, first postpartum estrus, and pregnancy in crossbred cows showed a clear bimodal rhythm, whose greatest values coincided with new moon and full moon.

Antisperm antibodies and sperm function in bulls undergoing scrotal insulation.

Bovine antisperm antibodies (ASAs) have been associated with teratospermia and asthenospermia. It was hypothesized here that scrotal insulation induces the formation of ASAs and deterioration of sperm function. Scrotal insulation bags were placed in 10 bulls for 8 days. Semen was collected on days -29, -22 and -2, twice weekly from days 5 to 54, and thereafter weekly until day 96 (day 0 = first day of scrotal insulation). On each collection day, scrotal circumference, sperm motility, morphology, membrane integrity, acrosome integrity, apoptosis, lipid peroxidation, mitochondrial membrane potential, ASA binding and DNA integrity were evaluated. The percentage of IgG- and IgA-bound sperm increased between days 12 and 96 (P < 0.0001), in association with poor motility (days 19-30, P < 0.005) and morphology (days 8-40, P < 0.0001). Mean scrotal circumference decreased between days 15 and 75 (P < 0.0001). There was also a deterioration in sperm membrane integrity (days 19-40, P < 0.0001), acrosome integrity (days 26-89, P < 0.0001), lipid peroxidation (days 5-12, P < 0.0001), and mitochondrial membrane potential (days 12-96, P = 0.001). In contrast, a decrease in apoptotic cells (days 37-83, P = 0.0002) and lipid peroxidation (days 19-96, P < 0.0001) was noticed. Most bulls recovered normospermia by day 96. However, the persistence of ASAs, acrosomal damage and dysfunctional mitochondria suggest a long term effect of scrotal insulation on sperm function and the homeostasis of the reproductive immune system.

Immune response and onset of protection from Bovine viral diarrhea virus 2 infection induced by modified-live virus vaccination concurrent with injectable trace minerals administration in newly received beef calves.

Strategies to improve the onset of protective immunity induced by vaccination against respiratory pathogens may have a significant impact on health of newly received beef calves. The objective was to determine if the use of injectable trace minerals (ITM; Se, Zn, Cu, and Mn) concurrent with a modified-live virus (MLV) vaccine enhances the immune response and onset of protection in beef calves challenged with BVDV2 five days after vaccination. Forty-five calves were randomly assigned to one of three groups (15/group): VAC + ITM, received MLV-vaccine and ITM (Multimin®90) subcutaneously (SC); VAC + SAL, received the same vaccine and saline SC; or UNVAC, unvaccinated. Five days after vaccination (d.0), calves were challenged with BVDV2 strain 890. Health status was evaluated and blood samples were collected for leukocyte counts, BVDV1 and 2 serum neutralizing antibodies (SNA), BVDV-PCR, and percentage of CD4+, CD8+, WC1+ and CD25+ T-cells. VAC + ITM had lower health scores than UNVAC (d.8 and 9). VAC + ITM had higher BVDV1 & 2 SNA titers than VAC + SAL and UNVAC on d.21 and 28. Lymphocyte counts decreased in UNVAC but not in VAC + ITM or VAC + SAL (d.3 to 11). CD4+ T-cells significantly decreased in UNVAC and VAC + SAL (d.3). VAC + ITM had higher percentage of CD4+ T-cells than UNVAC (d.3 and 7). VAC + ITM had lower percentage of activated CD4+ and CD8+ T-cells than UNVAC (d.7). In summary, vaccination induced a rapid protection against BVDV2 infection. Administration of ITM was associated with increased SNA response to BVDV1 & 2, enhanced health status, mitigation of CD4+ T-cells decrease, and reduction of T-cell activation in calves challenged with BVDV2 five days after immunization. These results support the strategic use of ITM concurrent with vaccination, especially when a rapid protection is needed in newly received beef calves.

Bovine Respiratory Disease Vaccination Against Viral Pathogens: Modified-Live Versus Inactivated Antigen Vaccines, Intranasal Versus Parenteral, What Is the Evidence?

Vaccination of cattle against viral respiratory pathogens to minimize losses associated with bovine respiratory disease (BRD) is a common practice among producers and veterinarians. Three different calf populations in which BRD is most prevalent (recently weaned beef calves, preweaning beef calves, and young dairy calves) are the principal focus of morbidity and mortality prevention through vaccination; however, the evidence of vaccination efficacy is inconsistent in the literature. This review addresses the evidence of efficacy of vaccination in the prevention or reduction of naturally occurring and experimentally induced BRD in each calf group.

Comparison of follicular development, timing of ovulation and serum progesterone, estradiol and luteinizing hormone concentrations in dairy heifers treated with 4- or 5-day CoSynch + CIDR protocols.

The use of 4-day CoSynch + Controlled internal drug release (CIDR) + timed artificial insemination (TAI) in dairy heifers has resulted in adequate pregnancy rates compared with the 5-day CoSynch + CIDR + TAI protocol. The objective of this study was to compare follicular growth, timing of ovulation and serum progesterone (P4 ), estradiol (E2 ) and luteinizing hormone (LH) concentrations in dairy heifers treated with modified 4- or 5-day CoSynch + CIDR protocols (CIDR for 4 or 5 days, PGF2 α at CIDR removal and GnRH + TAI 72 h later). Twelve cycling Holstein heifers were randomly assigned to either the 4- or 5-day Co-Synch+CIDR (n = 6/treatment) to receive an intravaginal insert CIDR® containing 1.38 g of P4 for 4 or 5 days, respectively. At CIDR removal, 25 mg of PGF2 α was injected IM; 72 h after CIDR removal, heifers received 100 µg of GnRH IM and timed artificial insemination (TAI). Follicular growth and timing of ovulation were assessed using transrectal ultrasonography. Blood samples were collected at the time of CIDR insertion and at frequent time points after CIDR removal for determination of P4 (at TAI), E2 (every 12 h) and LH (every 6 h during the first and second day and every 2 h on the third day). Heifers in the 4-day group had smaller follicles from CIDR insert removal to ovulation compared with heifers in the 5-day treatment. Five of six heifers (83.3%) in the 4-day treatment ovulated at 90-96 h post CIDR insert removal, whereas most heifers in the 5-day treatment (4/6; 66.6%) ovulated at 84-90 h post CIDR insert withdrawal. Heifers in the 5-day treatment reached greater peak LH concentration between 48 and 72 h after CIDR insert removal and lesser E2 concentration at TAI than heifers in the 4-day treatment. In conclusion, heifers in the 4-day treatment had smaller follicular diameter at 0, 30, 36, 42 and 48 h after CIDR insert removal, longer interval from CIDR insert removal to ovulation, greater E2 concentrations at TAI, and lesser peak LH concentration than heifers in the 5-day treatment. These results represent a baseline for further studies to determine if prolonging the interval to TAI by 6 h in the 4-day CoSynch+CIDR would improve pregnancy risk.

Chronic inflammatory and degenerative endometrial lesions in subfertile Criollo Limonero cattle; a B. taurus Latin-American breed threatened with extinction; A case-control study.

Criollo Limonero is a tropical Bos taurus breed for sustainable dual purpose (milk and beef) production in the South-American tropics, which is currently threatened with extinction. The objective was to perform a clinical evaluation and histopathological assessment of uterine biopsy samples of repeat breeder (RB) Criollo Limonero cattle to determine the occurrence of pathological conditions as potential causes of subfertility. Twenty-four Criollo Limonero cattle [18 cows (5-13 years old) and 6 heifers (6-7.5 years old)] that had failed to conceive after four or more services were considered for this study. Additionally, five cows with history of adequate reproductive performance were used as a control group. Animals were submitted to physical exam, vaginoscopy, and ultrasonographical evaluation of the reproductive tract. Uterine biopsy samples were collected for histopathological evaluation. Vaginoscopy revealed that 41.7% of the RB cattle had abnormal vaginal secretions, while abnormal secretions were not observed in any control cow. Ultrasonographical examination of the uterus revealed the presence of free uterine fluid in 20.8% of the RB animals, while none of the control cows had fluid in the uterine lumen. In addition, ovarian cysts were observed in 25.0% of the RB animals. Histopathological evaluation of the endometrial biopsies revealed that mononuclear leukocyte infiltration, dilated uterine glands, and periglandular fibrosis were the most prevalent lesions in the sub-fertile animals. Chronic endometritis characterized by inflammatory (mononuclear leukocyte infiltration) and degenerative (dilated glands and periglandular fibrosis) endometrial lesions, and ovarian cysts were the most frequent reproductive pathologies observed in the studied subfertile Criollo Limonero cattle, suggesting a strong association with their reduced fertility.

Efficacy of four commercially available multivalent modified-live virus vaccines against clinical disease, viremia, and viral shedding in early-weaned beef calves exposed simultaneously to cattle persistently infected with bovine viral diarrhea virus and cattle acutely infected with bovine herpesvirus 1.

OBJECTIVE: To evaluate the efficacy of 4 commercially available multivalent modified-live virus vaccines against clinical disease, viremia, and viral shedding caused by bovine viral diarrhea virus (BVDV) and bovine herpesvirus 1 (BHV1) in early-weaned beef calves. ANIMALS: 54 early-weaned beef steers (median age, 95 days). PROCEDURES: Calves were randomly assigned to 1 of 5 groups and administered PBSS (group A [control]; n = 11) or 1 of 4 commercially available modified-live virus vaccines that contained antigens against BHV1, BVDV types 1 (BVDV1) and 2 (BVDV2), parainfluenza type 3 virus, and bovine respiratory syncytial virus (groups B [11], C [10], D [11], and E [11]). Forty-five days after vaccination, calves were exposed simultaneously to 6 cattle persistently infected with BVDV and 8 calves acutely infected with BHV1 for 28 days (challenge exposure). For each calf, serum antibody titers against BVDV and BHV1 were determined before vaccination and before and after challenge exposure. Virus isolation was performed on nasal secretions, serum, and WBCs at predetermined times during the 28-day challenge exposure. RESULTS: None of the calves developed severe clinical disease or died. Mean serum anti-BHV1 antibody titers did not differ significantly among the treatment groups at any time and gradually declined during the study. Mean serum anti-BVDV antibody titers appeared to be negatively associated with the incidence of viremia and BVDV shedding. The unvaccinated group (A) had the lowest mean serum anti-BVDV antibody titers. The mean serum anti-BVDV antibody titers for group D were generally lower than those for groups B, C, and E. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated differences in vaccine efficacy for the prevention of BVDV viremia and shedding in early-weaned beef calves.

Acute infection with bovine viral diarrhea virus of low or high virulence leads to depletion and redistribution of WC1(+) γδ T cells in lymphoid tissues of beef calves.

The objective of this study was to determine the abundance and distribution of γδ T lymphocytes in lymphoid tissue during acute infection with high (HV) or low virulence (LV) non-cytopathic bovine viral diarrhea virus (BVDV) in beef calves. This study was performed using tissue samples from a previous experiment in which thirty beef calves were randomly assigned to 1 of 3 groups: LV [n=10; animals inoculated intranasally (IN) with LV BVDV-1a (strain SD-1)], HV [n=10; animals inoculated IN with HV BVDV-2 (strain 1373)], and control (n=10; animals inoculated with cell culture medium). On day 5 post inoculation, animals were euthanized, and samples from spleen and mesenteric lymph nodes (MLN) were collected to assess the abundance of WC1(+) γδ T cells. A higher proportion of calves challenged with BVDV showed signs of apoptosis and cytophagy in MLN and spleen samples compared to the control group. A significantly lower number of γδ T cells was observed in spleen and MLN from calves in HV and LV groups than in the control calves (P<0.05). In conclusion, acute infection with HV or LV BVDV resulted in depletion of WC1(+) γδ T cells in mucosal and systemic lymphoid tissues at five days after challenge in beef calves. This reduction in γδ T cells in the studied lymphoid tissues could be also due to lymphocyte trafficking to other tissues.

Comparison of 4- versus 5-day Co-Synch + controlled internal drug release (CIDR) + timed artificial insemination protocols in dairy heifers.

The objective of this study was to compare the pregnancy rate after timed artificial insemination (P/TAI) in dairy heifers treated with 4- versus 5-day Co-Synch + controlled internal drug release (CIDR) protocols. A total of 120 Holstein heifers were randomly assigned to one of two groups. The heifers received an intravaginal CIDR insert containing 1.38 g of progesterone for 4 days (Monday-Friday 4-day Co-Synch + CIDR; n = 60) or 5 days (5-day Co-Synch + CIDR; n = 60). At the time of CIDR removal, 25 mg of PGF2α was injected intramuscularly, and 72 hours after CIDR removal, the heifers received 100 µg of GnRH intramuscularly and were artificially inseminated. Artificial insemination was performed by an experienced technician, using commercial frozen-thawed semen from a single sire. Pregnancy diagnosis was performed by ultrasonography per rectum 32 days after TAI. Categorical data were analyzed using proc logistic and the chi-square test, whereas continuous variables were analyzed using the t-test of Statistical Analysis Systems. Heifers in the 4-day Co-Synch + CIDR group had an acceptable P/TAI32 (55.0%, 33 of 60), which was not different (P = 0.35) from that observed in the 5-day Co-Synch + CIDR group (63.3%, 38 of 60). Progesterone concentration at CIDR insertion or estradiol concentration at TAI did not influence the pregnancy outcomes. Interestingly, estradiol concentration at TAI was greater in the 4-day Co-Synch + CIDR group compared to the 5-day Co-Synch + CIDR group (P < 0.01). In conclusion, the Monday to Friday 4-day Co-Synch + CIDR protocol resulted in adequate P/TAI in dairy heifers, which was similar to that of the 5-day Co-Synch + CIDR protocol. This novel protocol might represent a promising hormonal treatment for TAI in dairy heifers, facilitating their reproductive management routine, while maintaining an adequate fertility.

Analysis of mRNA expression for genes associated with regulatory T lymphocytes (CD25, FoxP3, CTLA4, and IDO) after experimental infection with bovine viral diarrhea virus of low or high virulence in beef calves.

Immunosuppression caused by bovine viral diarrhea virus (BVDV) has been associated with lymphocyte depletion, leukopenia and impairment of leukocyte function; however, no work has been done on the relationship between BVDV and regulatory T lymphocytes (Tregs). The objective of this study was to compare the mRNA expression of genes associated with Tregs (CD25, FoxP3, CTLA4, and IDO), after experimental infection of beef calves with low (LV) or high (HV) virulence BVDV. Thirty BVDV-naïve calves were randomly assigned to three groups. Calves were intra-nasally inoculated with LV (n=10, strain SD-1) or HV (n=10, strain 1373) BVDV or BVDV-free cell culture medium (control, n=10). Quantitative RT-PCR was used to determine the expression of target genes in tracheo-bronchial lymph nodes and spleen on day 5 post-infection. The mRNA expression of CD25 was up-regulated in tracheo-bronchial lymph nodes of LV (P<0.05), but not in HV compared to the control group. The expression of FoxP3 and CTLA4 was not increased in tracheo-bronchial lymph nodes of either of the BVDV-inoculated groups. A dramatic up-regulation of IDO mRNA was observed in tracheo-bronchial lymph nodes of LV (P<0.05), but not HV compared to the control calves. In conclusion, experimental infection with BVDV did not provide evidence of Treg activation based on expression of FoxP3 and CTL4. Differential expression of CD25 and IDO mRNA on day 5 post-infection with HV or LV BVDV might reflect temporal differences in transcription occurring during the immune response elicited by these viral strains, or differences in viral infectivity of the host cells.

Expression of toll-like receptors and co-stimulatory molecules in lymphoid tissue during experimental infection of beef calves with bovine viral diarrhea virus of low and high virulence.

The objective of this study was to compare the mRNA expression of Toll-like receptors (TLR3 and TLR7), and costimulatory molecules involved in activation of lymphocytes and antigen presenting cells (CD80, CD86, CD28, and CD40L) after experimental infection of beef calves with low or high virulence noncytopathic (ncp) bovine viral diarrhea virus (BVDV) strains. Thirty BVDV-naïve, beef calves were intranasally inoculated with low (LV; n=10, SD-1) or high (HV; n=10, 1373) virulence ncp BVDV or with BVDV-free cell culture medium (Control, n=10). Calves were euthanized on day 5 post-inoculation and tracheo-bronchial lymph node (TBLN) and spleen samples were collected for mRNA expression through quantitative-RT-PCR. Levels of mRNA for TLR3 and TLR7 were increased in spleen of HV group (P<0.05), but not in LV group, compared to the control group. Expression of CD86 mRNA was up-regulated in TBLN of both LV and HV groups (P<0.05). A significant up-regulation of CD80 mRNA was observed in TBLN for LV calves (P<0.05), but not for HV calves. In conclusion, experimental inoculation with high virulence BVDV-2 1373 stimulated the expression of TLR3, TLR7 and CD86 in spleen and TBLN on day 5 post infection. In contrast, experimental challenge with the low virulence BVDV-1 SD-1 uniquely resulted in up-regulation of both CD80 and CD86 in TBLN samples on day 5 post infection. The observed differential expression during acute infection with high or low virulence BVDV might reflect differences in immune activation by these strains, which could be associated with differences in genotype and/or virulence.

Comparison of levels and duration of detection of antibodies to bovine viral diarrhea virus 1, bovine viral diarrhea virus 2, bovine respiratory syncytial virus, bovine herpesvirus 1, and bovine parainfluenza virus 3 in calves fed maternal colostrum or a colostrum-replacement product.

Colostrum-replacement products are an alternative to provide passive immunity to neonatal calves; however, their ability to provide adequate levels of antibodies recognizing respiratory viruses has not been described. The objective of this study was to compare the serum levels of IgG at 2 d of age and the duration of detection of antibodies to bovine viral diarrhea virus 1 (BVDV-1), bovine viral diarrhea virus 2 (BVDV-2), bovine respiratory syncytial virus (BRSV), bovine herpesvirus 1 (BHV-1), and bovine parainfluenza virus 3 (BPIV-3) in calves fed maternal colostrum (MC) or a colostrum replacement (CR) at birth. Forty newborn male Holstein calves were assigned to the CR or the MC group. Group CR (n = 20) received 2 packets of colostrum replacement (100 g of IgG per 470-g packet), while group MC (n = 20) received 3.8 L of maternal colostrum. Blood samples for detection of IgG and virus antibodies were collected from each calf at birth, at 2 and 7 d, and monthly until the calves became seronegative. Calves in the MC group had greater IgG concentrations at 2 d of age. The apparent efficiency of absorption of IgG was greater in the MC group than in the CR group, although the difference was not significant. Calves in the CR group had greater concentrations of BVDV neutralizing antibodies during the first 4 mo of life. The levels of antibodies to BRSV, BHV-1, and BPIV-3 were similar in the 2 groups. The mean time to seronegativity was similar for each virus in the 2 groups; however, greater variation was observed in the antibody levels and in the duration of detection of immunity in the MC group than in the CR group. Thus, the CR product provided calves with more uniform levels and duration of antibodies to common bovine respiratory viruses.

Les produits de remplacement du colostrum sont une alternative pour fournir une immunité passive aux veaux nouveau-nés; toutefois, leur capacité à fournir des niveaux adéquats d'anticorps reconnaissant les virus respiratoires n'a pas été décrite. L'objectif de la présente étude était de comparer les niveaux d'IgG sériques à 2 jours d'âge et la durée de détection des anticorps contre le virus de la diarrhée virale bovine de type 1 (BVDV-1), le virus de la diarrhée virale bovine de type 2 (BVDV-2), le virus respiratoire syncitial bovin (BRSV), l'herpesvirus bovin de type 1 (BHV-1), et le virus parainfluenza bovin de type 3 (BPIV-3) chez des veaux nourris avec du colostrum maternel (MC) ou du colostrum de remplacement (CR) à la naissance. Quarante veaux nouveau-nés mâles de race Holstein ont été assignés soit au groupe CR ou MC. Les animaux du groupe CR (n = 20) ont reçu deux paquets de substitut de colostrum (100 g d'IgG par paquet de 470 g), alors que les animaux du groupe MC (n = 20) ont reçu 3,8 L de colostrum maternel. Des échantillons sanguins pour la détection d'IgG et d'anticorps contre les virus ont été prélevés de chaque veau à la naissance, à 2 et 7 j d'âge, et à chaque mois jusqu'à ce que les veaux deviennent séronégatifs. Les veaux dans le groupe MC avaient des concentrations d'IgG plus élevées à 2 j d'âge. L'efficacité d'absorption apparente d'IgG était plus grande dans le groupe MC que dans le groupe CR, bien que la différence ne fût pas significative. Les veaux dans le groupe CR avaient des concentrations plus élevées d'anticorps neutralisants envers BVDV durant les 4 premiers mois de vie. Les niveaux d'anticorps contre BRSV, BHV-1, et BPIV-3 étaient similaires dans les deux groupes. Le temps moyen pour atteindre la séronégativité était similaire pour chaque virus dans les deux groupes; toutefois, de plus grandes variations étaient observées dans les niveaux d'anticorps et la durée de détection de l'immunité dans le groupe MC comparativement au groupe CR. Ainsi, le produit CR a fourni des veaux avec des niveaux d'anticorps contre les virus respiratoires bovins communs plus uniformes et de plus longue durée.(Traduit par Docteur Serge Messier).

Differential expression of pro-inflammatory and anti-inflammatory cytokines during experimental infection with low or high virulence bovine viral diarrhea virus in beef calves.

The objective was to compare the mRNA expression of pro-inflammatory (TNF-α, IL-1ß, IFN-γ, IL-2, IL-12, IL-15) and anti-inflammatory (IL-4, IL-10, TGF-ß) cytokines, after experimental infection with low or high virulence noncytopathic (ncp) bovine viral diarrhea virus (BVDV). Thirty BVDV-naïve, beef calves were intranasally inoculated with low (LV; n=10, SD-1) or high (HV; n=10, 1373) virulence ncp BVDV or with BVDV-free cell culture medium (Control, n=10). Calves were euthanized on day 5 post-inoculation, and tracheo-bronchial lymph node and spleen samples were collected for mRNA expression through quantitative-RT-PCR. mRNA levels of pro-inflammatory (TNF-α, IL-1ß, IL-2, IFN-γ) and anti-inflammatory (IL-4 and IL-10) cytokines were up-regulated in tracheo-bronchial lymph nodes of HV, but not in LV, compared to the control group (P<0.05). IL-12 mRNA level was up-regulated in tracheo-bronchial lymph nodes of both LV and HV groups (P ≤ 0.05). A significant up-regulation of IL-15 mRNA was observed in tracheo-bronchial lymph nodes for LV calves (P<0.002), but not for HV calves. Experimental inoculation with BVDV-2 1373 stimulated significant mRNA expression of pro-inflammatory and anti-inflammatory cytokines. In contrast, inoculation with BVDV-1a SD-1 only resulted in up-regulation of IL-12 and IL-15 mRNA, which is associated with activation of macrophages and NK cells during innate immune response.

Bovine viral diarrhea virus fetal persistent infection after immunization with a contaminated modified-live virus vaccine.

The objective was to determine whether a multivalent modified-live virus vaccine containing noncytopathic bovine viral diarrhea virus (BVDV) administered off-label to pregnant cattle can result in persistently infected fetuses and to assess whether vaccinal strains can be shed to unvaccinated pregnant cattle commingling with vaccinates. Nineteen BVDV-naïve pregnant heifers were randomly assigned to two groups: cattle vaccinated near Day 77 of gestation with modified-live virus vaccine containing BVDV-1a (WRL strain), bovine herpes virus-1, parainfluenza 3, and bovine respiratory syncytial virus (Vx group; N = 10) or control unvaccinated cattle (N = 9). During the course of the study a voluntary stop-sale/recall was conducted by the manufacturer because of the presence of a BVDV contaminant in the vaccine. At Day 175 of gestation, fetuses were removed by Cesarean section and fetal tissues were submitted for virus isolation, and quantitative reverse transcription polymerase chain reaction using BVDV-1- and BVDV-2-specific probes. Nucleotide sequencing of viral RNA was performed for quantitative reverse transcription polymerase chain reaction-positive samples. Two vaccinated and two control heifers aborted their pregnancies, but their fetuses were unavailable for BVDV testing. Virus was isolated from all eight fetuses in the Vx group heifers and from 2 of 7 fetuses in the control unvaccinated heifers. Only BVDV-2 was detected in fetuses from the Vx group, and only BVDV-1 was detected in the two fetuses from the control group. Both BVDV-1 and BVDV-2 were detected in the vaccine. In conclusion, vaccination of pregnant heifers with a contaminated modified-live BVDV vaccine resulted in development of BVDV-2 persistently infected fetuses in all tested vaccinated animals. Furthermore, BVDV was apparently shed to unvaccinated heifers causing fetal infections from which only BVDV-1 was detected.