Maternal pre- and postpartum supplementation of a Bacillus-based DFM enhanced cow and calf performance.

This study evaluated the effects of maternal supplementation of a Bacillus-based direct-fed microbial (DFM) on the physiology and growth performance of Bos indicus-influenced cow-calf pairs. On day 0 (~139 d before expected calving date), 72 fall-calving, Brangus crossbred beef heifers (20 to 22 mo of age) pregnant with first offspring were stratified by their initial body weight (BW; 431 ±â€…31 kg) and body condition score (BCS; 6.0 ±â€…0.36; scale 1 to 9), and randomly allocated into 1 of 12 bahiagrass pastures (1 ha and six heifers per pasture). Treatments were randomly assigned to pastures (six pastures per treatment) and consisted of heifers supplemented with 1 kg/d of soybean hulls (dry matter, DM) that was added (BAC) or not (CON) with DFM containing Bacillus subtilis and B. licheniformis (Bovacillus; Chr. Hansen A/S, Hørsholm, Denmark). Treatments were provided from days 0 to 242 (139 ±â€…4 d prepartum to 104 ±â€…4 d postpartum). Calves were weaned on day 242 (96 ±â€…30 d of age) and then allocated into 1 of 16 drylot pens and fed the same concentrate at 3.25% of BW (DM) until day 319. Maternal treatment effects were not detected (P ≥ 0.29) for herbage allowance and forage chemical composition. Heifer BCS on days 39 and 63 tended (P ≤ 0.09) to be greater for BAC vs. CON heifers, whereas heifer BCS on day 91 was greater (P = 0.01) for BAC vs. CON heifers. Heifer BCS did not differ (P ≥ 0.20) between treatments on days 179 and 242. Plasma glucose concentration did not differ from days 0 to 63 (P ≥ 0.14) but were greater (P < 0.01) on day 179 and tended (P = 0.09) to be greater on day 242 for BAC vs. CON heifers. Calf BW at birth, ADG from birth to weaning, and BW at weaning did not differ (P ≥ 0.19) between treatments, but calf BW at drylot exit (day 319) was greater (P = 0.05) for BAC vs. CON calves. Maternal treatment effects were not detected (P ≥ 0.42) for calf serum concentration of IgG at birth and postvaccination plasma concentrations of glucose, cortisol, and haptoglobin. Serum titers against bovine respiratory syncytial virus (BRSV) were greater (P = 0.04) for BAC vs. CON calves on day 287, whereas seroconversion against parainfluenza-3 virus (PI-3) was greater (P < 0.01) for BAC vs. CON calves on day 271. Thus, maternal supplementation of a Bacillus-based DFM increased prepartum BCS gain and postpartum plasma glucose concentration of heifers and led to positive carryover effects on postweaning BW gain and humoral immune response in their offspring.

Direct-fed microbials (DFM), such as Bacillus spp., have been shown to produce a wide variety of enzymes related to nutrient digestion and to support gastrointestinal tract immune function and integrity, leading to increased nutrient digestibility and cattle performance. Nutritional management of beef cows during gestation and early lactation has been associated with enhanced future offspring growth performance and immune response following birth. The present study combined the use of Bacillus-based DFM for pregnant heifers during critical production stages (late gestation and early lactation) to promote the overall performance of heifers and their offspring. Heifers offered Bacillus-based DFM had greater body condition score at calving and postpartum plasma concentration of glucose, whereas their offspring had similar body weight at birth, but greater growth performance when fed relatively high amounts of protein and energy in drylot compared to cohorts born from heifers that did not receive Bacillus-based DFM supplementation.

Removing maternal heat stress abatement during gestation modulated postnatal physiology and improved performance of Bos indicus-influenced beef offspring.

This study evaluated the growth and immune response of beef calves born from Bos indicus-influenced beef heifers provided pre- and postpartum heat abatement on pasture. On 83 ±â€…4 d prepartum (day 0), 64 Brangus crossbred beef heifers (~» B. indicus) were stratified by body weight (BW; 454 ±â€…37 kg) and body condition score (BCS; 6.3 ±â€…0.28; scale 1 to 9), and then allocated into 1 of 16 bahiagrass pastures (1 ha and 4 heifers per pasture). Treatments were randomly assigned to pastures (8 pastures per treatment) and consisted of heifers provided (SH) or not (NSH) access to artificial shade (4.5 m2 of shade area per heifer) from 83 d prepartum to 50 d postpartum (days 0 to 133). Heifers and calves were managed similarly from day 133 until the start of the breeding season (day 203). Calves were weaned on day 203 (at 119 ±â€…19 d of age), limit-fed the same drylot diet at 3.5% of BW (DM basis) days 209 to 268 (3 to 4 calves per pen; 8 pens per treatment) and vaccinated against respiratory disease pathogens on days 222 and 236. Heifer intravaginal temperatures from days 35 to 42 were lower (P ≤ 0.03) for NSH vs. SH heifers from 0000 to 0800 hours but greater (P ≤ 0.05) for NSH vs. SH heifers from 1100 to 1800 hours. Heifer intravaginal temperature from days 126 to 132 did not differ (P = 0.99) between NSH and SH heifers. Heifers assigned to NSH had greater respiration rates from days 20 to 96 (P ≤ 0.0007), greater plasma concentration of cortisol on days 35 (P = 0.07) and 55 (P = 0.02), less plasma concentration of insulin-like growth factor 1 (IGF-1) on days 35 (P = 0.10), 55, and 133 (P ≤ 0.05), and less BCS from days 55 to 203 (P ≤ 0.01) compared to SH heifers. Calves born from NSH heifers had less birth BW (P = 0.05), greater overall plasma haptoglobin concentrations (P = 0.05), greater seroconversion against bovine respiratory syncytial virus on day 222 (P = 0.02), tended to have greater ADG from days 209 to 268 (P = 0.07), and had greater BW on day 268 (P = 0.05) compared to SH offspring. Plasma concentrations of cortisol and serum titers against other respiratory disease pathogens did not differ (P ≥ 0.15) between NSH and SH offspring. Hence, removing maternal access to artificial shade: (1) increased prepartum intravaginal temperature and plasma concentrations of cortisol but reduced prepartum BCS and plasma concentrations of IGF-1 in grazing B. indicus-influenced beef heifers; and (2) increased post-weaning BW gain and had positive effects on humoral immune response of their offspring.

In dairy cattle, heat stress during late gestation negatively impacted offspring postnatal growth and immune function. The use of artificial shade is a management strategy that alleviates heat stress in environments with high temperatures and humidity. The effects of maternal access to artificial shade and its impacts on offspring performance have not been reported for Bos indicus influenced-beef cattle and were the main objective of the present study. From 83 d prepartum until 50 d postpartum, heifers had access or not to an artificial shade structure located centrally on their pastures. Overall, removing maternal access to artificial shade increased maternal internal body temperature and respiration rates, and reduced maternal body condition score from calving until the start of the breeding season and calf body weight at birth. However, calves born from heifers with no access to shade were remarkably heavier at the end of the drylot period and had lower plasma indicators of inflammatory response and positive effects to humoral immune response to vaccination.

Bakery waste supplementation to late gestating Bos indicus-influenced beef cows successfully impacted offspring postnatal performance.

This study evaluated the growth and immune function of beef calves born to cows supplemented with bakery waste containing two concentrations of crude fat. On day 0 (~90 d before calving), 108 multiparous Brangus crossbred cows were stratified by body weight (BW; 551 ±â€…65 kg) and body condition score (BCS, 5.5 ±â€…0.9) and randomly allocated into 1 of 18 bahiagrass (Paspalum notatum) pastures (6 cows and 4.3 ha per pasture). Treatments were randomly assigned to pastures (6 pastures per treatment) and consisted of no prepartum supplementation (NOSUP) and isocaloric and isonitrogenous supplementation of low-fat (LFAT; 6.4% crude fat) or high-fat (HFAT; 10.7% crude fat) bakery waste from days 0 to 70 (1 kg DM per cow per day). Calves were weaned on day 292 (201 ±â€…17 d of age). Then, 15 heifers per treatment were randomly selected and assigned to drylot pens from days 300 to 345 and vaccinated against respiratory pathogens on days 300 and 315. Cow BCS near calving (day 70) was the least (P ≤ 0.05) for NOSUP cows and did not differ (P = 0.12) between LFAT and HFAT cows. Cow BCS at the start of the breeding season (day 140) was greater (P = 0.05) for HFAT vs. NOSUP cows and intermediate (P ≥ 0.35) for LFAT cows. Plasma concentrations of total polyunsaturated fatty acids in HFAT cows did not differ (P ≥ 0.76) compared with LFAT cows but were greater (P ≤ 0.05) compared to NOSUP cows on day 70. Final pregnancy percentage did not differ (P ≥ 0.26) among treatments, but a greater percentage of HFAT cows calved (P ≤ 0.05) their second offspring during the first 21 d of the calving season compared to NOSUP and LFAT cows (bred by natural service). Weaning BW was the greatest (P ≤ 0.05) for LFAT and least for NOSUP calves. Maternal treatments did not impact (P ≥ 0.11) postweaning growth and total DM intake of calves. Average plasma cortisol concentrations were greater (P = 0.03) for NOSUP vs. HFAT calves and intermediate for LFAT calves (P ≥ 0.26). Serum titers against infectious bovine rhinotracheitis and bovine respiratory syncytial virus were greater or tended to be greater (P ≤ 0.08) for HFAT vs. LFAT calves and intermediate (P ≥ 0.27) for NOSUP calves at the end of preconditioning. Thus, supplemental fat concentration fed to late-gestating beef cows had variable effects on calf performance. Low-fat bakery waste led to the greatest calf preweaning growth, whereas high-fat bakery waste enhanced maternal reproduction and had minor benefits to calf humoral immune function.

This study evaluated the effect of bakery waste supplementation during the last trimester of gestation in Bos indicus-influenced beef cows and the subsequent impact on their offspring. Brangus cows were allocated to one of three prepartum treatments consisting of no prepartum supplementation, 1 kg/d of bakery waste with low or high concentration of crude fat. Prepartum supplementation of bakery waste, regardless of crude fat concentration, increased maternal plasma concentrations of ω-6 fatty acids during gestation and body condition score at calving. Offspring birth weights were not affected but offspring born to cows that received prepartum supplementation of bakery waste, regardless of crude fat concentration, were heavier at weaning compared to no prepartum supplementation. However, the greatest improvements to weaning weights were observed for offspring born to cows fed low-fat vs. high-fat bakery waste. In contrast, high-fat bakery waste supplementation during late gestation alleviated physiological stress and improved humoral immune response to vaccination during preconditioning compared to low-fat bakery waste supplementation. Thus, altering the crude fat concentration of bakery waste provided to Bos indicus-influenced beef cows during the third trimester of gestation can be implemented to modulate offspring preweaning growth or postweaning immune function.

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.

Analytical Validation of the IMMULITE® 2000 XPi Progesterone Assay for Quantitative Analysis in Ovine Serum.

Monitoring circulating progesterone (P4) concentration is an important component of basic and applied reproduction research and clinical settings. IMMULITE® 2000 XPi (Siemens) is a newly upgraded fully automated immunoassay system marketed for human use to measure concentrations of different analytes including P4. Our objective was therefore to characterize the analytical performance of the IMMULITE® 2000 XPi P4 immunoassay across the reportable range in ovine serum. This validation of analytical performance included determining (1) linearity, (2) precision through within-run, and between-run coefficient of variation (CV) calculations, (3) accuracy through bias calculations for spiking-recovery bias and interlaboratory (range and average based) bias for two laboratories across the reportable range (0.2−40 ng/mL). The average within-run and between-run precision (CV%) across the reportable range of the IMMULITE® 2000 XPi P4 immunoassay for serum P4 concentration were both <5%, ranging between 2−8%. The average Observed Total Analytic Error (TEo) reported here for serum P4 concentration across the reportable range was ~30%, ranging from 14.8−59.4%, regardless of the considered bias. Based on these data we conclude that the automated IMMULITE® 2000 XPi P4 immunoassay provides a precise, accurate, reliable, and safe method for measuring P4 concentration ovine serum.

Ovulatory response to GnRH agonist during early and late fall in mares.

This study aimed to assess the ovulatory response of deslorelin acetate during the fall and the response to PGF2α 8 d post-ovulation. One hundred estrous cycles from 22 mares kept in 40° latitude were evaluated. Mares were checked by transrectal ultrasonography until a preovulatory follicle was detected and ovulation induced with deslorelin acetate. Ovulation was confirmed by ultrasonography performed at 24, 36 h post-induction and then repeated at 2-h intervals post-induction. Serum progesterone concentrations and luteal tissue area were determined daily to assess CL function. A dose of PGF2α was administered 8 d post-ovulation and interval to the subsequent ovulation was observed; each mare completed up to five cycles. The effects of local climate on endpoints were analyzed. Cycles were grouped as early (Sept 13, 2020-Oct 31, 2020; n = 55; 22 mares) and late fall (Nov 1, 2020-Dec 31, 2020; n = 45; 20 mares) based on the date of induction. The overall number of cycles with ovulations between 24 and 48 h was 90%. The number of multiple ovulations were similar between early (n = 5) and late (n = 4) fall (P = 0.87). There were no differences in deemed spontaneous ovulations occurring before 24 h between early (n = 6) and late (n = 2) fall (P = 0.29). Two failures to respond to deslorelin by 48 h were recorded in early fall and none in the late fall. The interval from induction to ovulation was similar in early (40.6 ± 0.4 h) and late (41.2 ± 0.5 h) fall (P = 0.55). The percentage of mares ovulating between 36 and 48 h post-deslorelin did not vary between early and late fall (91 vs. 95%, P = 0.21), as did not for ovulation occurring between 38 h and 44 h (62 vs. 60%, P = 0.69). Edema scores varied with time relative to ovulation (P < 0.001) and were lower in late fall (P = 0.01). Progesterone concentrations varied with time (P < 0.001) but did not differ between early and late fall (P = 0.73) and correlated weakly with the luteal area (r = 0.13; P = 0.031). Follicles <35 mm at the PGF2α had a shorter interval to the next ovulation than follicles ≥ 35 mm (9.2 ± 0.5 d vs. 10.6 ± 1.2 d) (P = 0.03). Lower temperature was associated with a smaller follicle size at induction (P = 0.0021) and ovulation (P = 0.009) and lower relative humidity was associated with a larger follicle size at ovulation (P = 0.032). In conclusion, cycling mares displayed a highly efficacious response to deslorelin acetate and apparently normal luteal function during the fall, despite lower edema scores in late fall.

Validation of a fully automated chemiluminescent immunoassay for cattle serum and plasma progesterone measurement.

Introduction: Monitoring circulating progesterone concentration ([P4]) is an important component of basic and applied reproduction research and clinical settings. IMMULITE® 2000 XPi (Siemens Healthineers, Cary, NC) is a newly upgraded fully automated immunoassay system marketed for human use to measure concentrations of different measurands including P4. Objectives: Our objective was therefore to characterize the analytical performance of the IMMULITE® 2000 XPi P4 immunoassay (IPI) across the reportable range in serum and plasma of cattle. Methods: The IPI validation protocols included characterization of the method linearity, within-run, and between-run precision through calculation of the coefficient of variation (CV). The method accuracy was assessed through the calculation of the spiking-recovery (SR) bias across the reportable range (0.2-40.0 ng/mL). Passing-Bablok regression and Bland-Altman plots were used to determine the interlaboratory bias for two laboratories. Three types of observed total error (TEo) were calculated based on the considered type of bias, TEoSR (spiking-recovery), TEoRB (range-based bias), and TEoAB (average-based bias). Results: The IPI was linearly related to the true value (R 2 = 0.997) across the reportable range. The within-run and between-run precision (CV%) of the IPI for both serum and plasma [P4] of clinical relevance (1, 2, 5, and 10 ng/mL) were <5 and <10%, respectively. The TEo reported here for serum and plasma at [P4] of 1 and 5 ng/mL was ~20 and 25%, respectively. Of interest, the three types of TEo were relatively similar regardless of the considered bias. Conclusions: We concluded that the automated IPI provides a precise, accurate, reliable, and safe method for measuring [P4] in both serum and plasma of cattle. Consistent with the manufacturer's recommendations, the serum matrix is more accurate than plasma.

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.

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.

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.