Clinical status and endoscopy of the upper respiratory tract of dairy calves infected with Bovine viral diarrhea virus 2 and Bovine herpes virus 1 after vaccination and trace minerals injection.

The objective was to compare clinical protection [evaluated through health scoring, endoscopy score of the upper respiratory tract (URT-ES), leukocyte count, viremia, and virus shedding in nasal secretions] following Bovine viral diarrhea virus 2 (BVDV2) and Bovine herpes virus 1 (BHV1) challenge among calves submitted to modified-live virus (MLV) booster vaccination (either intranasal or subcutaneous) concurrent with injectable trace minerals (ITM) or saline. Forty-eight dairy calves received an MLV intranasal (IN) vaccine containing BHV1, BRSV, and BPI3V and subcutaneous (SC) ITM (Se, Cu, Zn & Mn; ITM, n = 24) or saline (SAL, n = 24). Ten weeks later, calves received a second dose of ITM, or saline, according to previous groups and were randomly assigned to receive the same IN vaccine [ITM-IN (n = 12), SAL-IN (n = 12)] or a SC MLV vaccine containing BHV1, BRSV, BPI3V, BVDV1 & 2 [ITM-SC (n = 12), SAL-SC (n = 12)]. Additionally, 12 calves did not receive vaccine or treatment and served as a control group (UNVAC, n = 12). Forty-nine days after booster, calves were challenged with BVDV2; and seven days later with BHV1. Health scores indicated disease in UNVAC on days 6, 10 and 12 compared to the vaccinated groups. Unvaccinated calves had the highest URT-ES after BHV1 challenge. Calves that received SC booster had lower URT-ES after BHV1 challenge than UNVAC calves. Calves in ITM-IN had significantly lower URT-ES after BHV1 infection than SAL-IN and UNVAC calves. In conclusion, IN or SC MLV vaccination was similarly effective in protecting calves from BVDV2 + BHV1 challenges (reducing clinical and endoscopy scores, preventing leukopenia, and viremia), compared to unvaccinated calves. Endoscopic evaluation of the URT allowed visualization of the inflammation and damage at multiple depths in the URT caused by a serial BVDV2 + BHV1 challenge. Calves that received SC vaccination had significantly lower URT-ES after BHV1 challenge than the UNVAC calves. Administration of ITM concurrent with IN vaccination was associated with reduced URT inflammation after BVDV2 + BHV1 challenge.

Changes in serum testosterone and anti-Müllerian hormone concentration in bulls undergoing scrotal insulation.

While changes in semen quality after heat stress are well characterized in the bull, changes in endocrine function have not been critically evaluated. It was hypothesized here that scrotal insulation results in alterations in Sertoli cell and Leydig cell function, as measured by changes in serum testosterone and anti-Müllerian hormone (AMH) concentration. Scrotal insulation bags were placed in 10 bulls for 8 d. Blood was collected on days -22 and -2, and weekly from days 5 to 96 (day 0 = first day of scrotal insulation) for measurement of serum concentration of AMH and testosterone using ELISA. The concentration of AMH decreased on day 5, followed by an increase on day 54 (P = 0.014). When AMH concentration was normalized to pre-insulation values, the percent increase in serum concentration of AMH was significant between days 26 and 54, with another peak at 75 d (P = 0.031). The serum concentration of testosterone (P = 0.0001) and the percentage of change in testosterone concentration (P < 0.0001) increased on day 5, followed by a decrease from days 33 to 96. Scrotal insulation was associated with Sertoli and Leydig cell dysfunction, as measured by serum testosterone and AMH concentration. The persistently low concentration of testosterone at the end of the study suggests a long term effect of scrotal insulation on Leydig cell function.

Effects of injectable trace minerals administered concurrently with a modified live virus vaccine on long-term protection against bovine viral diarrhea virus acute infection in dairy calves.

The objective was to evaluate the effects of injectable trace minerals (ITM) concurrent with modified-live virus (MLV) vaccination on protection from bovine viral diarrhea virus (BVDV) infection in dairy calves. In a previous study (Palomares et al., 2016), thirty dairy calves received two doses of a MLV vaccine subcutaneously (SC), concurrently with ITM (n = 15) or saline (n = 15), SC. Five months later, 20 of these calves received ITM (G1, n = 10) or saline (G2, n = 10) according to their previous groups and were challenged intranasally with BVDV2. Five unvaccinated calves were also challenged with BVDV2 (G3). Blood samples were collected on days 0 (BVDV challenge), 3, 5, 6, 7, 8, 9, 11, 14, 18, 21, 32 and 61 for leukocyte count, virus isolation and BVDV serum neutralizing antibodies (SNA). Mild-moderate clinical signs were observed in G3 after BVDV challenge. Group 1 showed lower sum health score and nasal score on d5 and fecal score on d8 compared to G2. Rectal temperature and leukocyte counts were not different between G1 and G2. In contrast, G3 calves had significant leukopenia and lymphopenia from d3 to d7 (P < .05) and higher rectal temperatures on d6 to d8, compared to values on d0 (P < .05). All unvaccinated calves became viremic, while viremia was not detected in G1 or G2. Average daily gain was not different between vaccinated groups, however, only G1 calves had significantly greater (P = .04) ADG compared to non-vaccinated calves during the first 14 days post challenge. Vaccinated calves treated or not with ITM were protected from BVDV2 infection five months post-vaccination.

Clinical response after chitosan microparticle administration and preliminary assessment of efficacy in preventing metritis in lactating dairy cows.

The objectives were to evaluate the clinical response to intrauterine administration of chitosan microparticles (CM) and to assess efficacy for preventing metritis in dairy cows. Holstein cows (n=104; 40 primiparous and 64 multiparous) at increased risk for metritis (cows that had abortion, dystocia, twins, stillbirth, or retained placenta) were randomly assigned to 1 of 2 treatments at 1d in milk (DIM; 24h postpartum): CM group (n=52), daily intrauterine infusion of 8g of CM dissolved in 40mL of sterile water for 5d; control (CON) group (n=52), daily intrauterine infusion of 40mL of sterile water for 5d. Clinical response was assessed by evaluation of parameters associated with inflammation (rectal temperature and plasma haptoglobin concentration) and metabolism [plasma nonesterified fatty acid (NEFA) and ß-hydroxybutyrate (BHB) concentrations] up to 14 DIM, and daily milk yield up to 30 DIM. Uterine discharge pH was evaluated at 4, 7, 10, and 14 DIM as an indicator of bacterial load and acid byproduct production. The cumulative incidence of metritis was evaluated up to 4, 7, 10, and 14 DIM. Continuous and dichotomous outcomes were evaluated with mixed linear and logistic regression analysis, respectively. Treatment with CM did not affect rectal temperature (39.17±0.04 vs. 39.14±0.04°C), haptoglobin (1.10±0.05 vs. 1.07±0.05mg/mL), NEFA (0.64±0.04 vs. 0.63±0.04mmol/L), BHB (0.61±0.03 vs. 0.57±0.03mmol/L), or milk yield (30.3±0.92 vs. 30.1±0.97kg/d) compared with CON. An interaction between treatment and time showed that NEFA concentrations were lower for CM than CON at 10 DIM (0.46±0.06 vs. 0.64±0.06mmol/L). Treatment with CM resulted in greater uterine discharge pH than CON (6.91±0.03 vs. 6.83±0.02). Cows that developed metritis had increased concentrations of haptoglobin and BHB, and decreased uterine discharge pH and milk yield. Treatment with CM resulted in decreased incidence of metritis up to 7 DIM compared with CON (46.2 vs. 65.4%); however, no differences were found at 4 (11.5 vs. 17.3%), 10 (61.5 vs. 73.1%), and 14 DIM (63.5 vs. 73.1%) for CM versus CON, respectively. In conclusion, CM did not alter clinical parameters of cows at risk for metritis, and may merit further investigation for prevention of metritis. However, the duration of treatment may have to be extended to effectively reduce the incidence of metritis during the high-risk period.

Effects of injectable trace minerals on humoral and cell-mediated immune responses to Bovine viral diarrhea virus, Bovine herpes virus 1 and Bovine respiratory syncytial virus following administration of a modified-live virus vaccine in dairy calves.

Our objective was to evaluate the effect of an injectable trace mineral (ITM) supplement containing zinc, manganese, selenium, and copper on the humoral and cell mediated immune (CMI) responses to vaccine antigens in dairy calves receiving a modified-live viral (MLV) vaccine containing BVDV, BHV1, PI3V and BRSV. A total of 30 dairy calves (3.5 months of age) were administered a priming dose of the MLV vaccine containing BHV1, BVDV1 & 2, BRSV, PI3V, and an attenuated-live Mannheimia-Pasteurella bacterin subcutaneously (SQ). Calves were randomly assigned to 1 of 2 groups: (1) administration of ITM SQ (ITM, n=15) or (2) injection of sterile saline SQ (Control; n=15). Three weeks later, calves received a booster of the same vaccine combination SQ, and a second administration of ITM, or sterile saline, according to the treatment group. Blood samples were collected on days 0, 7, 14, 21, 28, 42, 56, and 90 post-vaccination for determination of antibody titer, viral recall antigen-induced IFN-γ production, and viral antigen-induced proliferation by peripheral blood mononuclear cells (PBMC). Administration of ITM concurrently with MLV vaccination resulted in higher antibody titers to BVDV1 on day 28 after priming vaccination compared to the control group (P=0.03). Calves treated with ITM showed an earlier enhancement in PBMC proliferation to BVDV1 following vaccination compared to the control group. Proliferation of PBMC after BVDV stimulation tended to be higher on day 14 after priming vaccination in calves treated with ITM than in the control group (P=0.08). Calves that received ITM showed higher PBMC proliferation to BRSV stimulation on day 7 after priming vaccination compared to the control group (P=0.01). Moreover, calves in the ITM group also had an enhanced production IFN-γ by PBMC after stimulation with BRSV on day 21 after priming vaccination compared to day 0 (P<0.01). In conclusion, administration of ITM concurrently with MLV vaccination in dairy calves resulted in increased antibody titer to BVDV1, and greater PBMC proliferation to BVDV1 and BRSV recall stimulation compared to the control group, suggesting that ITM might represent a promising tool to enhance the humoral and CMI responses to MLV vaccines in cattle.

Combined use of progesterone inserts, ultrasongraphy, and GnRH to identify and resynchronize nonpregnant cows and heifers 21 days after timed artificial insemination.

The objective was to decrease the reinsemination interval (RI) when dairy cows and heifers are inseminated using all timed artificial insemination (TAI) programs. Holstein cows (n = 211) and heifers (n = 153) were randomly assigned to a control or 21-day Resynch (21dRES) at 13 days after TAI. Animals in 21dRES (n = 109 cows and 77 heifers) had a progesterone device inserted on Day 13 and removed on Day 20 after TAI and ovaries scanned by ultrasonography. Animals found not to have an active CL (<15 mm) or a CL that decreased 10 mm or greater from Days 13 to 20, and to have a follicle of 12 mm or greater received GnRH and TAI on Day 21. Pregnancy diagnosis was performed on Day 32. Nonpregnant control cows (n = 102) were resynchronized immediately using Ovsynch-56, and control heifers (n = 76) were resynchronized using 5-day Cosynch starting on Day 34; therefore, cows and heifers were reinseminated on Day 42. Nonpregnant 21dRES animals that had not been reinseminated on Day 21 were resynchronized concurrently with the control animals. Pregnancy per AI (PAI) for the initial TAI was similar (P = 0.80) for 21dRES and control cows (30.3% vs. 29.4%) and heifers (49.4% vs. 51.3%). Of the nonpregnant 21dRES animals, 33 of 76 cows (43.4%) and 22 of 39 heifers (56.4%) had been reinseminated on Day 21. Therefore, the RI was decreased by 9.9 days (33.3 ± 1.0 vs. 43.2 ± 1.0 days; P < 0.001) in 21dRES cows and by 12.2 days in 21dRES heifers (30.1 ± 1.3 vs. 42.3 ± 1.3 days; P < 0.001) compared with controls. The overall resynchronized PAI was similar for 21dRES cows compared with controls (31.6% vs. 25.0%; P = 0.23). The PAI was 24.2% for 21dRES cows reinseminated on Day 21 and 37.2% for 21dRES cows reinseminated on Day 42. The overall resynchronized PAI was increased for 21dRES heifers compared with controls (57.5% vs. 32.4%; P = 0.03) because 21dRES heifers reinseminated on Day 21 had similar PAI compared with controls (43.5% vs. 32.4%; P = 0.39), but PAI was increased for 21dRES heifers reinseminated on Day 42 compared with controls (76.5% vs. 32.4%; P = 0.003). Consequently, the proportion of animals pregnant from the initial and resynchronized TAI tended to be increased in 21dRES heifers (79.0% vs. 67.1%; P = 0.09). Cost per pregnancy was decreased for the 21dRES in heifers. In conclusion, 21dRES provided a useful method to decrease the RI in cows and heifers, and to increase PAI and decrease cost per pregnancy in heifers.

Factors associated with early cyclicity in postpartum dairy cows.

The objective of this study was to evaluate factors associated with resumption of ovarian cyclicity within 21 days in milk (DIM) in dairy cows. Cows (n=768) from 2 herds in north Florida had their ovaries scanned at 17±3, 21±3, and 24±3 DIM. Cows that had a corpus luteum ≥20mm at 17±3 or at 21±3 DIM or that had a corpus luteum <20mm in 2 consecutive examinations were determined to be cyclic by 21±3 DIM. The following information was collected for up to 14 DIM: calving season, parity, calving problems, metabolic problems, metritis, mastitis, digestive problems, lameness, body weight loss, dry period length, and average daily milk yield. Body condition was scored at 17±3 DIM. Multivariable mixed logistic regression analysis was performed using the GLIMMIX procedure of SAS. Variables with P≤0.2 were considered in each model. Herd was included as a random variable. Three models were constructed: model 1 included all cows, model 2 included only cows from dairy 1 that had daily body weights available, and model 3 included only multiparous cows with a previous dry period length recorded. In model 1, variables associated with greater cyclicity by 21±3 DIM were calving in the summer and fall rather than in the winter or spring, being multiparous rather than primiparous, and not having metabolic or digestive problems. In model 2, variables associated with greater cyclicity by 21±3 DIM were calving in the summer and fall, not having metritis or digestive problems and not losing >28 kg of BW within 14 DIM. In model 3, variables associated with greater cyclicity by 21±3 DIM were absence of metabolic problems and dry period ≤76 d. In summary, cyclicity by 21±3 DIM was negatively associated with calving in winter or spring, primiparity, metritis, metabolic or digestive problems, loss of >28 kg of body weight, and a dry period >76d. Strategies preventing extended dry period length and loss of BW, together with reductions in the incidence of metritis as well as metabolic and digestive problems should improve early cyclicity postpartum.

Individual and combined effects of anovulation and cytological endometritis on the reproductive performance of dairy cows.

The objective was to evaluate the individual and combined effect of anovulation and cytological endometritis (CTE) on the reproductive performance of dairy cows. A total of 1,569 cows from 3 data sets were used. In data set 1, 403 Holstein cows from 5 dairies in New York were used. In data set 2, 750 Holstein cows from 2 dairies, one in Florida and one in California were used. In data set 3, 416 dairy cows, 165 Holsteins, 36 Jerseys, and 215 Holstein-Jersey crossbreeds from a grazing dairy in Florida were used. Cyclicity and CTE was determined at 35±3 (data set 2) or 49±3 d in milk (data sets 1 and 3). A variable (VarCycCTE) containing all 4 possible permutations between cyclicity (cyclic = Cyc; anovular = Anov) and CTE (present = CTE; absent = Healthy) was created. In the combined data set (sets 1, 2, and 3), pregnancy per artificial insemination (P/AI) diagnosed at 30 to 38 d after first AI was affected by VarCycCTE, with AnovCTE cows having decreased P/AI compared with CycHealthy cows (21.3 vs. 46.7%), whereas AnovHealthy (37.9%) and CycCTE cows (36.0%) had intermediate P/AI. Pregnancy per artificial insemination for the individual data sets and for pregnancy diagnosed at 63 to 74 d after artificial insemination followed a similar pattern. Pregnancy loss was not affected by VarCycCTE. Hazard of pregnancy up to 300 d in milk was affected by VarCycCTE in the combined data sets 1 and 2, with AnovCTE [hazard ratio (HR)=0.55], AnovHealthy cows (HR=0.71), and CycCTE (HR=0.8) having decreased hazard of pregnancy compared with CycHealthy cows. Median days open were 200, 159, 145, and 121 for AnovCTE, AnovHealthy, CycCTE, and CycHealthy, respectively. Hazard of pregnancy for the individual data sets followed a similar pattern. In summary, both anovulation and CTE were negatively associated with reproductive performance and, when combined, they had an additive negative effect.

Inducing ovulation early postpartum influences uterine health and fertility in dairy cows.

The objective of the current study was to evaluate the effect of GnRH early postpartum on induction of ovulation, uterine health, and fertility in dairy cows. Holstein cows without a corpus luteum (CL) at 17 ± 3 DIM were assigned randomly to receive i.m. GnRH (n = 245) at 17 ± 3 and 20 ± 3 DIM or remain as controls (n = 245). Ovaries were scanned by ultrasonography twice weekly totaling 4 examinations. Ovulation was characterized by the appearance of a CL ≥ 20 mm at any ultrasound or CL <20mm in 2 consecutive examinations. Clinical and cytological endometritis were diagnosed at 35 DIM. Compared with control, GnRH increased ovulation up to 3.5d after the last treatment (78.7 vs. 45.0%) and did not affect the prevalence of clinical endometritis (23.9 vs. 18.6%) or cytological endometritis (30.9 vs. 32.8%). Prevalence of clinical endometritis increased in cows that had calving problems (32.6 vs. 15.9%) and metritis (40.6 vs. 15.8%). Metritis increased prevalence of cytological endometritis (50.7 vs. 23.5%). Treatment with GnRH did not affect pregnancy per artificial insemination at 32 (37.6 vs. 38.6%) or 74 d after artificial insemination (35.0 vs. 31.5%), but reduced pregnancy loss (6.8 vs. 18.1%). No overall effect of GnRH treatment on hazard of pregnancy was observed; however, an interaction between GnRH treatment and ovulation showed that GnRH-treated cows that ovulated had increased hazard of pregnancy by 300 DIM compared with GnRH-treated and control cows that did not ovulate (hazard ratio=2.0 and 1.3, respectively), but similar to control cows that ovulated (hazard ratio=1.1). Gonadotropin-releasing hormone early postpartum induced ovulation without affecting uterine health, but failed to improve pregnancy per artificial insemination or time to pregnancy, although it reduced pregnancy loss.

Effect of feeding maternal colostrum or plasma-derived or colostrum-derived colostrum replacer on passive transfer of immunity, health, and performance of preweaning heifer calves.

The objective of this study was to evaluate the effect of feeding maternal colostrum (MC), a plasma-derived (PDCR) or colostrum-derived colostrum replacer (CDCR) on passive transfer of immunity, health, and performance of preweaning heifer calves. Preplanned contrasts were performed for MC versus CR (PDCR combined with CDCR) and PDCR versus CDCR. At birth, calves were randomly assigned to 1 of 3 treatment groups: MC (n=49), 3.8L of maternal colostrum; PDCR (n=49), 550 g (1 dose; 150 g of IgG) of a PDCR; or CDCR (n=49), 470 g (1 dose; 100g IgG) of a CDCR. The best total protein cutoff for determining passive transfer was >5.2, 5.6, and 5.1g/dL for MC, PDCR, and CDCR, respectively. Serum total protein was greater for calves fed MC (mean ± SE; 6.14 ± 0.11 g/dL) than for calves fed PDCR (5.29 ± 0.11 g/dL) and CDCR (5.27 ± 0.11 g/dL). Serum IgG concentrations were greater for calves fed MC (2,098 ± 108 g/dL) than for calves fed PDCR (927 ± 107 g/dL) or CDCR (1,139 ± 108 g/dL). Apparent efficiency of absorption was greater for CDCR than PDCR (38.8 ± 3.0 vs. 21.6 ± 3.0%). Adequate passive transfer was greatest for MC (91.8%), followed by CDCR (49%) and PDCR (28.6%). Calves fed MC had greater weaning weights and body weight gain than calves fed CR. Morbidity was lower for calves fed MC (46.9%) than for calves fed PDCR (71.4%) or CDCR (67.3%). Calves fed MC tended to have lower mortality than calves fed CR. Given the conditions of this trial, feeding 3.8L of MC was superior to feeding one dose of CR. Further research is needed to evaluate calf performance when a higher dose of CR is fed.

The effect of intrauterine administration of mannose or bacteriophage on uterine health and fertility of dairy cows with special focus on Escherichia coli and Arcanobacterium pyogenes.

The objective of this study was to evaluate the effects of intrauterine administration of 50 g of ultrapure mannose or a bacteriophage cocktail and the presence of Escherichia coli and Arcanobacterium pyogenes in the uterine lumen on uterine health and reproductive performance of lactating dairy cows. The study was conducted on a commercial dairy farm located near Ithaca, New York, from May 4 to January 20, 2011, and 597 cows were enrolled. The cows were divided randomly into 3 treatment groups, and treatments were administered at 2 ± 1 d in milk (DIM). Treatment 1 consisted of intrauterine administration of 50 g of ultrapure mannose powder divided in 4 pills; treatment 2 consisted of intrauterine administration of a bacteriophage cocktail that included 4 different phages in one pill, with a dose of approximately 107 plaque-forming units; and treatment 3 consisted of intrauterine administration of one empty pill (control). Intrauterine fluid swabs were collected on day of treatment and at 10 ± 3 DIM; uterine lavage samples were collected at 35 ± 3 DIM. Swabs and uterine lavage samples were cultured for E. coli and A. pyogenes. The intrauterine administration of mannose and bacteriophage did not affect uterine health, reproduction performance, or outcome of intrauterine secretion cultures for E. coli and A. pyogenes. Prevalence of intrauterine E. coli at 2 ± 1 DIM and A. pyogenes at 2 ± 1, 10 ± 3, and 35 ± 3 were affected by retained placenta. Additionally, prevalence of intrauterine E. coli at 10 ± 3 and A. pyogenes at 35 ± 3 DIM were associated with metritis, and cows that were diagnosed with clinical endometritis at 35 ± 3 DIM had greater prevalence of intrauterine E. coli at 2 ± 1 DIM and A. pyogenes at 35 ± 3 DIM. Furthermore, cows positive for E. coli at 2 ± 1 and 10 ± 3 DIM and for A. pyogenes at 10 ± 3 DIM had 1.63, 2.34, and 1.54 increased odds of having metritis. Cows positive for A. pyogenes at 35 ± 3 DIM and for E. coli at 2 ± 1 DIM had 19.8 and 2.66 higher odds of being diagnosed with clinical endometritis, respectively. Additionally, cows negative for E. coli at 2 ± 1 DIM were 1.39 times more likely to conceive than cows positive cows for E. coli.