Effects of transport age and calf and maternal characteristics on health and performance of veal calves

The objective of this study was to investigate effects of calf transport age (14 vs. 28 d) and calf (e.g., sex and breed) and dam characteristics (e.g., parity and ease of birth) on health and performance of veal calves until slaughter age. Calves (n = 683) originated from 13 dairy farms in the Netherlands and were transported at either 14 or 28 d of age from the dairy farm to 8 Dutch veal farms. A health assessment of calves was performed on a weekly basis at the dairy farm and in wk 2, 10, 18, and 24 at the veal farm. Body weight of calves was measured on a weekly basis at the dairy farm and upon arrival at the veal farm. At the veal farm, use of antibiotics and other medicines during the rearing period (both at herd and individual level) was recorded and carcass weights were obtained from the slaughterhouse. Body weight upon arrival (Δ = 11.8 kg) and carcass weight at slaughter (Δ = 14.8 kg) were greater, and mortality risk (Δ = ?3.1%) and prevalence of animals treated with medicines other than antibiotics (e.g., antiinflammatories, multivitamins, and anticoccidial drugs; Δ = ?5.4%) were lower in calves transported at 28 d compared with calves transported at 14 d. Crossbreds other than Belgian Blue × Holstein Friesian received a higher number of individual treatments with antibiotics and other medicines (Δ = 14.8% and Δ = 15.1%, respectively) at the veal farm compared with Belgian Blue × Holstein Friesian calves. These findings suggest that calves transported at 28 d were more robust compared with calves transported at 14 d.     

Risk factors associated with mortality at a milk-fed veal calf facility: A prospective cohort study

The veal industry experiences calf losses during the growing period, which represents a challenge to animal welfare and profitability. Health status at arrival may be an important predictor of calf mortality. The objectives of this prospective cohort study were to describe the health status of calves arriving at a veal farm and determine the risk factors associated with early and late mortality. Using a standardized health scoring system, calves were evaluated immediately at arrival to a commercial milk-fed veal facility in Ontario, Canada. Weight at arrival and supplier of the calf were recorded. The calves were followed until death or the end of their production cycle. Two Cox proportional hazard models were built to explore factors associated with early (≤21 d following arrival) and late mortality (>21 d following arrival). A total of 4,825 calves were evaluated from November 2015 to September 2016. The overall mortality risk was 7%, with 42% of the deaths occurring in the first 21 d after arrival. An abnormal navel, dehydration, housing location within the farm, arriving in the summer, and the presence of a sunken flank were associated with increased hazard of early mortality. Drover-derived calves and calves with a greater body weight at arrival had lower hazard of early mortality. Housing location within the farm, being derived from auction facilities, and an abnormal navel were associated with higher hazard of late mortality. These results demonstrate that risk factors for mortality can be identified at arrival, which represents a potential opportunity to selectively intervene on these calves to reduce mortality. However, methods of preventing the development of these conditions before arrival need to be explored and encouraged to improve the welfare of the calves entering the veal industry.     

Risk factors identified on arrival associated with morbidity and mortality at a grain-fed veal facility: A prospective,single-cohort study

High levels of morbidity, mortality, and antimicrobial use are common in the veal industry. For the sustainability of the industry, it is important to address these challenges and determine factors that can be used to improve animal health and welfare. The objectives of this prospective observational cohort study were to describe the health status of calves on arrival at a grain-fed veal facility and determine characteristics that were associated with morbidity and mortality. On arrival, the calves were assessed for health abnormalities, weighed, measured for hip height and length from withers to lumbosacral junction, and had blood collected to determine serum total protein level. Body mass index (BMI) was calculated using weight on arrival divided by the sum of the calf's length from withers to lumbosacral junction and hip height. The calves were observed for 77 d after arrival, during which the producer was responsible for recording all antibiotic treatments and mortality. We built Cox proportional hazard models for morbidity and mortality variables. We created 2 morbidity models: 1 for calves that were treated <21 d after arrival at the facility, and 1 for calves that were treated during the 11 wk at the facility. From January to December 2017, 998 calves were evaluated on arrival at the veal rearing facility. A large proportion (68%) were treated with antibiotics in the first 21 d after arrival. The only explanatory variable in the final <21 d morbidity model was BMI: calves with a higher BMI had a lower hazard of being treated for disease in the first 21 d after arrival. A total of 872 calves (87%) were treated at least once over the 11-wk housing period. A calf arriving with a BMI >371.46 g/cm or a serum total protein between 5.8 and 6.2 g/dL had a lower level of morbidity during the observation period. Over the 11-wk housing period, 74 calves (7.5%) died. Calves that arrived at the facility with a fecal score of 2 or a rectal temperature between 38.9 and 39.1°C had a higher hazard of dying; calves that had a BMI of >371 g/cm were less likely to die than calves that had a BMI <330 g/cm. These results point to the importance of assessing calves on arrival at a veal facility as a measure of identifying those at high risk for morbidity and mortality.     

Characterization of fecal branched-chain fatty acid profiles and their associations with fecal microbiota in diarrheic and healthy dairy calves

Branched-chain fatty acids (BCFA) have recently been reported to play a role in human gut health during early life. However, little information is available on the fecal BCFA profiles in young ruminants and whether they are associated with the development of neonatal calf diarrhea. The objectives of this study were to (1) characterize BCFA profiles in feces collected from young calves, (2) compare the fecal BCFA composition between diarrheic and nondiarrheic dairy calves, and (3) explore the potential relationships between BCFA and microbiota in the feces. A total of 32 male Holstein dairy calves (13 ± 3 d old) with the same diet management were grouped as diarrheic (n = 16) or healthy (n = 16) based on fecal score (determined by liquid fecal consistency with some solid particles); diarrhea cases were defined as fecal score ≥2 for at least 2 d. Fecal samples were collected on the seventh day after calf arrival, and the fecal BCFA and microbial profiles were assessed using gas chromatograph and amplicon sequencing, respectively. In total, 7 BCFA were detected in the feces of all dairy calves; however, the concentrations of fecal BCFA differed between diarrheic and nondiarrheic calves. Specifically, the concentrations of iso-C16:0, iso-C17:0, anteiso-C17:0, and total even-chain BCFA were significantly higher in the feces of diarrheic calves. When the associations between BCFA and bacteria were studied, the relative abundance of Eggerthella was positively correlated with the concentrations of iso-C16:0 (ρ = 0.67), iso-17:0 (ρ = 0.77), anteiso-C17:0 (ρ = 0.73), and iso-C18:0 (ρ = 0.65), whereas the relative abundance of Subdoligranulum was positively correlated with the concentrations of iso-C14:0 (ρ = 0.62), iso-C15:0 (ρ = 0.78), and anteiso-C15:0 (ρ = 0.63). Use of random forest algorithm showed that BCFA such as anteiso-C15:0, iso-C16:0, iso-C17:0, iso-C18:0, and total even-chain BCFA could be used as biomarkers to differentiate diarrheic calves from healthy ones. Our findings generated fundamental knowledge on the potential roles of BCFA in neonatal calf gut health. Follow-up studies with larger animal populations are warranted to validate the feasibility of using BCFA as indicators of health status in neonatal calves.     

Short communication: Validation of methods for practically evaluating failed passive transfer of immunity in calves arriving at a veal facility

Providing a sufficient quantity of high-quality colostrum to male and female calves soon after birth is critical to reduce the risk of disease and mortality. Practical tests have not been validated to determine failed passive transfer of immunity upon arrival at veal facilities. There are many challenges to validation, including the lack of information on the age of the calf and the high prevalence of dehydration. The objective of this study was to validate a semiquantitative IgG antibody test using whole blood and a digital refractometer using serum to determine passive transfer of immunity status. A total of 149 Holstein calves were evaluated upon arrival at a milk-fed veal facility for dehydration status and had blood drawn to evaluate passive transfer of immunity. Serum IgG determined by radial immunodiffusion was used as the gold standard for the validation of the tests, and a cut-off point of <1,000 mg/dL of IgG was used to indicate failed passive transfer of immunity. Serum total protein (STP) was evaluated using a digital refractometer (Misco Palm Abbe no. PA202x, Misco, Solon, OH), and a semiquantitative test (ZAPvet Bovine IgG test, NOWDiagnostics, Toronto, Ontario, Canada) was used on whole blood. A nonparametric receiver operating characteristic curve was generated to compare STP and IgG levels. Sensitivity, specificity, positive predictive values, and negative predictive values were calculated for STP and the semiquantitative IgG test. A total of 31 calves (21%) had serum IgG <1,000 mg/dL. Twelve percent of calves were showing signs of clinical dehydration when assessed upon arrival. The serum total protein (STP) was very well correlated with the concentration of IgG (R² = 0.75). The STP cut point to determine passive transfer was ≥5.1 g/dL, yielding a sensitivity of 84% and a specificity of 90%. The semiquantitative antibody test on whole blood performed poorly, with a sensitivity of 77% and a specificity of 44%. This study demonstrates that serum total protein is a reliable measure for evaluating passive transfer of immunity and can be used despite a high prevalence of dehydration.     

Characteristics of veal calves upon arrival, at 28 and 84 days, and at end of the production cycle

Holstein bull calves arriving at five special-fed veal farms (eight production groups) were scored for various physical condition traits and blood-sampled within 2 h after arrival and at 28 d, 84 d, and 1 wk prior to slaughter at 116 to 143 d. Of 1179 total calves in the production groups, 758 calves were scored and evaluated. Blood cell analyses (red and white blood cell counts, hemoglobin, and packed cell volume) were conducted at all four sampling times; total serum protein concentration was obtained at 0 and 28 d. The study was initiated in autumn and ended the following autumn. Mean initial and final body weights were 46.3+/-0.17 and 209.7+/-0.77 kg; mean mortality was 2.5%. Average daily gain of the eight groups ranged from 1.23 to 1.70 kg/d. Subjective scores of 5 = excellent to 1 = very poor condition were used to evaluate 16 different physical condition characteristics. With the exception of leg joint, hoof, and foot scores, most of the physical condition scores exhibited improvement during the first 28 d. Foot and leg impairments did not appear to hinder the ambulatory ability of the calves during the production period. Physical condition scores at d 0 and 28 were generally not related to numbers or types of medical treatments (enteric, respiratory, other, or total) or to average daily gain during the production period. Means for most erythrocytic and leukocytic traits upon arrival (d 0) were within normal ranges, although 27.4% of the calves were clinically or marginally anemic. Final mean hemoglobin and packed cell volume were 8.53 g/dl and 26.1%. Forty-three percent of the calves at d 0 were colostral deficient, assuming that total serum protein concentrations of <5.5 g/dl indicate colostral deficiency. No blood trait was consistently correlated with body weight gain when gain during the production period was divided into quartiles and the blood traits were averaged by gain quartile. Calves in the lowest serum total protein quartile (mean 4.58 g/dl) had more respiratory and total medical treatments than quartiles with higher total protein means. Dairy bull calves arriving at veal production units after transporting from the dairy farm to the auction market (or other collection facility) have several physical impairments. However, most of these physical impairments are improved early in the veal feeding period and are not generally related to subsequent growth rate or medical treatment.     

Clinical and metabolic indicators associated with early mortality at a milk-fed veal facility: A prospective case-control study

Antimicrobial use and resistance, in combination with high levels of mortality, are important challenges facing the veal industry. To improve both the economic sustainability of the industry and animal welfare, measures need to be taken to explore and address reasons for these challenges. Health status at arrival may be an important predictor of calf mortality because substantial mortality occurs early in the growing period on veal operations. The objective of this observational case-control study was to identify clinically measurable variables and metabolic indicators associated with mortality in the first 21 d following arrival at a veal facility. Calves were evaluated using a standardized health scoring system, blood was collected, calves were weighed, and the supplier of the calf was recorded at arrival. The calves were followed until death or 21 d after arrival. Cases were defined as calves that died ≤21 d following arrival. Two controls for every case were randomly selected from calves that survived >21 d, arrived on the same day, and were housed in the same barn as cases. Stored serum harvested at arrival from cases and controls was submitted for measurement of concentrations of nonesterified fatty acids, β-hydroxybutyrate, glucose, cholesterol, urea, haptoglobin, and immunoglobulin G. A conditional logistic regression model was built to evaluate factors associated with mortality ≤21 d following arrival. A total of 4,825 calves were evaluated from November 2015 to September 2016. The mortality risk in the first 21 d was 2.8%, giving 135 cases, which were compared with 270 controls. Six variables were significant in the final multivariable model. Calves with a slightly enlarged navel with slight pain or moisture, and those with severe dehydration had increased odds of mortality ≤21 d following arrival. Drover-derived calves, calves that weighed more, and calves that had higher concentration of immunoglobulin G or cholesterol at arrival were less likely to die. The results demonstrate that calves at elevated risk for early mortality can be identified at arrival using both health and hematological factors. Early recognition of high-risk calves may allow for an intervention that could result in improvement in survival rates; however, prevention of these abnormalities before arrival at veal facilities needs to be further explored.     

Effect of health status upon arrival at a single milk-fed veal facility on breakeven purchase price of calves

Male calves are purchased from the dairy industry in North America to produce red meat. The price paid for male calves varies widely, and it is unclear which variables influence the price paid for each calf. The objective of this study was to assess how the health traits of calves at the time of arrival and demographic variables affect the breakeven purchase price of a male calf entering the veal industry. A financial model was constructed using the prevalence of health abnormalities, weight at arrival, source of the calf, number of days in the barn, base carcass price, days to mortality, feed costs, season at arrival, interest rate, housing location, carcass dressing percentage, and costs associated with housing, labor, utilities, trucking, and health to calculate the breakeven purchase price and an estimate of profit. Sensitivity analysis was conducted using health variables measured at arrival and demographic variables, including season at arrival and housing location, to identify the factors with the largest impact on the predicted average daily gain, early and late mortality risk, breakeven purchase price, and profit. At the baseline inputs, the average calculated profit was ?$5.36 per calf and it was most sensitive to the location of housing where calves were fed and the body weight of the arriving calf. The mortality risk in the first 21 d after arrival (early) was calculated to be 2.2%, whereas the risk of mortality after 21 d (late) was 3.7%. The risks of early and late mortality were most sensitive to the level of dehydration measured at arrival and the season at arrival for the purchased calves, respectively. The calculated average daily gain was 1.12 kg/d and it was most sensitive to housing location. The breakeven purchase price was calculated to be $242.49 per calf, which was most sensitive to the housing location where the calves were fed. The results of this analysis demonstrate that veal producers need to consider many variables before purchasing calves. In addition to overall market conditions, veal producers should factor health characteristics and the expected performance of the calves they purchase into what they are willing to pay for them.     

Calf and dam characteristics and calf transport age affect immunoglobulin titers and hematological parameters of veal calves

This study aimed to investigate effects of transport age of calves (14 vs. 28 d), and of calf and dam characteristics, on immunoglobulin titers and hematological variables of veal calves. Calves (n = 683) were transported to a veal farm at 14 or 28 d of age. Natural antibodies N-IgG, N-IgM, and N-IgA against phosphorylcholine conjugated to bovine serum albumin (PC-BSA) were measured in serum of the dams 1 wk before calving and in first colostrum. These antibodies were also measured in serum of calves 1 wk after birth, 1 d before transport, and in wk 2 and 10 posttransport at the veal farm. Hematological variables were assessed in calves 1 d before transport and in wk 2 posttransport. One day before transport, titers of N-IgG, N-IgM, N-IgA, and neutrophil counts were higher, and lymphocyte counts were lower in 14-d-old calves compared with 28-d-old calves. In wk 2 at the veal farm, calves transported at 14 d of age had higher N-IgG titers and neutrophil counts, but lower N-IgM and N-IgA titers, and lymphocyte counts than calves transported at 28 d. In wk 1 and 1 d before transport, N-Ig in calves were positively related to N-Ig in colostrum. In wk 2 and 10 at the veal farm, N-IgG in calves was positively related to N-IgG in colostrum. The N-IgG titers in calves at the dairy farm were negatively related to the likelihood of being individually treated with antibiotics or other medicines at the veal farm. Our results suggest that calves transported to the veal farm at 28 d of age showed a more advanced development of their adaptive immunity than calves transported at 14 d of age. Quality of colostrum might have long-term consequences for N-IgG titers and immunity in veal calves.     

Identification of biomarkers measured upon arrival associated with morbidity,mortality, and average daily gain in grain-fed veal calves

There is a strong need for management strategies that help reduce the incidence of disease and subsequent antimicrobial use in the veal industry. Biomarkers could serve as useful tools that allow producers to take preventative measures before clinical problems occur. The objective of this prospective cohort study was to identify biomarkers measured upon arrival associated with morbidity, mortality, and average daily gain (ADG) in grain-fed veal calves. Upon arrival at a grain-fed veal facility in Ontario, Canada, calves were weighed and health-scored using a standardized health-scoring system. Several metabolites were measured including creatine kinase (CK), cholesterol, haptoglobin, manganese, serum total protein, iron, cobalt, zinc, selenium, molybdenum, and IgG. Farm personnel treated calves according to their farm protocol and weighed them at 78 d after arrival. Performance, treatment, and mortality records from the facility were used for analysis. Multivariable Cox proportional hazard models were created to evaluate metabolic biomarkers associated with morbidity and mortality. A mixed linear regression model was created to determine biomarkers associated with ADG. A total of 992 male dairy calves were evaluated at arrival from January to December 2017. Of the calves evaluated, 74 calves (7.5%) died and 877 (88.4%) were treated for illness over the 11-wk period under observation. Higher levels of haptoglobin and molybdenum were associated with a greater hazard of morbidity, whereas higher weight upon arrival and higher levels of both CK and IgG were associated with a reduced hazard of morbidity. For mortality, higher weight upon arrival and higher levels of cholesterol and IgG were associated with a lower hazard of mortality occurring over the 78-d period of observation. Higher weight, cholesterol, copper, CK, iron, and IgG were associated with increased ADG, whereas increased zinc and haptoglobin were negatively associated with ADG. These results demonstrate that certain biomarkers could be used to identify high-risk calves when measured upon arrival at a veal facility. Future research should focus on determining the utility of these biomarkers to selectively target intervention strategies to improve ADG and reduce morbidity and mortality.     

Effect of treatment of pneumonia and otitis media with tildipirosin or florfenicol + flunixin meglumine on health and upper respiratory tract microbiota of preweaned Holstein dairy heifers

The objective of this randomized clinical study was to compare the effect of 2 antimicrobial interventions, tildipirosin or florfenicol + flunixin meglumine, used for treatment of pneumonia and extralabel treatment for otitis on health parameters and upper respiratory tract (URT) microbiota of preweaned Holstein calves. Housed preweaned Holstein heifers diagnosed with either otitis or pneumonia were assigned into 1 of 2 treatment groups, receiving a single subcutaneous injection of either 4 mg/kg of tildipirosin (TLD; n = 444) or 40 mg/kg of florfenicol combined with 2.2 mg/kg of a nonsteroidal anti-inflammatory, flunixin meglumine (FLF; n = 442). Calves were enrolled and treated on the day of diagnosis of the first case of pneumonia or otitis. If a calf had a recurrent case, the opposite drug was administered, respecting an interval of 5 d between drug injections. Blood samples for leukocyte counts were collected at 0, 2, 4, and 6 d after treatment, and rectal temperature was measured daily during the 5 d after treatment. Ear scores were observed from calves with otitis. Additionally, swabs of the URT were collected from a subset of 20 calves in each treatment group at d 0, 3, 6, 9, and 11 following enrollment for analysis of URT microbiota through next-generation sequencing of the 16S rRNA gene and quantitative PCR. Swabs were also collected from a comparative group of 20 healthy calves that did not receive any drug. No differences were observed between groups for recurrence risk of either pneumonia (TLD = 32.4%; FLF = 29.7%) or otitis (TLD = 72.7%; FLF = 73.6%). Similarly, no differences were observed for the total number of treatments for pneumonia (TLD = 1.45; FLF = 1.42) or otitis (TLD = 2.96; FLF = 3.07). On the other hand, both drugs reduced rectal temperature, ear scores, and leukocyte counts, with FLF calves having a greater reduction in rectal temperature within 4 d after treatment. Both TLD and FLF reduced the total bacterial load when compared with healthy untreated calves, but no differences were observed between treatment groups. Furthermore, compared with the untreated group, treated calves had lower mean relative abundances (MRA) of the genera Mannheimia, Moraxella, and Pasteurella within 11, 9, and 3 d after treatment, respectively; however, no significant differences were observed between TLD and FLF. On the other hand, MRA of Mycoplasma was not decreased by both treatments compared to untreated animals, and a higher MRA was observed in the TLD group during 11 d after treatment in comparison to FLF and untreated calves. Based on this data, we concluded that both drugs used in the study were effective in reducing rectal temperature, ear scores, leukocyte counts, and MRA of the genera Mannheimia, Pasteurella, and Moraxella in the URT, and calves treated with FLF had a greater reduction in rectal temperature.     

Improved performance and heightened neutrophil responses during the neonatal and weaning periods among outdoor group-housed Holstein calves

The objective was to determine if outdoor group housing of Holstein calves influences metabolic status, leukocyte responses, and behavior compared with individually housed calves. Forty-nine Holstein heifer calves (2 ± 1 d of age) were randomly assigned to 1 of 2 treatments: individually housed (G1; n = 22) or group housed [3 calves per pen (G3); n = 27]. The space allowances per calf were 4.8 and 7.0 m² for G1 and G3, respectively. All calves were offered an identical plane of milk replacer nutrition (747 and 1,010 g of DM/d of a 28% CP:20% fat milk replacer from wk 1 to 2 and wk 3 to 6, respectively). Weaning was initiated during wk 7 by removing the p.m. feeding and calves were completely weaned when they consumed 900 g of calf starter/d (as fed) for 2 consecutive days after d 54. At d 90, calves were commingled into random outdoor groups of 5 calves per pen. Peripheral blood was collected during the neonatal (d 3, 10, and 21), weaning (d 46, 48, and 54), and commingling periods (d 90, 93, and 98) and was analyzed for neutrophil oxidative burst (OB) capacity when cocultured with Escherichia coli, neutrophil surface L-selectin protein expression, and whole-blood secretion of tumor necrosis factor-α when cocultured with lipopolysaccharide. Starter intake was greater for G3 during the postweaning period (wk 8 to 12). Average daily gain was greater for G3 than G1 from d 54 to 68 and tended to be greater after commingling from d 113 to 133. During the neonatal period, G3 calves had more activated neutrophils, as evidenced by increased neutrophil L-selectin protein expression and a tendency for increased percentage of neutrophils producing an OB than G1 calves. During weaning, G3 calves continued to have more activated neutrophils with increased L-selectin expression on d 46 and 48 and a greater OB intensity throughout the period. No differences were observed among leukocyte responses between treatments at d 93 and 98. Outdoor group-housed Holstein calves had improved performance and heightened neutrophil responses compared with individually housed calves.     

Prevalence of respiratory disorders in veal calves and potential risk factors

The study aimed to assess the in vivo and postmortem prevalence of respiratory disorders in veal calves and investigate risk factors associated with them. A cross-sectional study was carried out in 174 farms in the 3 major veal meat-producing countries in Europe (50 in France, 100 in the Netherlands, and 24 in Italy). Trained veterinarians visually evaluated individual calves of 1 batch per farm at 3 and 13 wk after arrival and at 2 wk before slaughter to assess the prevalence of hampered respiration, nasal discharge, and coughing. A random sample of lungs belonging to calves of the same batch was monitored at the slaughterhouse for mild to moderate or severe signs of pneumonia, and presence of pleuritis. Data regarding veal calf housing, feeding, and management and specific characteristics of the batch were collected through an interview with the stockperson, and the potential of these as respiratory disease risk factors was assessed. Regardless of the stage of fattening, the prevalence of in vivo signs of respiratory disorders in calves was always <7%. This low prevalence was likely the outcome of the general implementation by veal producers of standardized practices such as prophylaxis, all-in/all-out, and individual daily checks of the calves, which are recognized tools for effective disease prevention and management. However, at postmortem inspection, 13.9% and 7.7% of lungs showed mild to moderate and severe signs of pneumonia, respectively, and 21.4% of the inspected lungs had pleuritis. Thus, even mild clinical signs of respiratory disorder in calves at specific time points during the fattening period may be associated with high prevalence of lungs with lesions at slaughter. Alternatively, clinical symptoms recorded during routine visual inspections of veal calves on-farm may be poor predictors of the true prevalence of respiratory disease in calves. Among all potential risk factors considered, those concerning the characteristics of the batch were predominant but factors related to housing, management and feeding equipment were also relevant. Different risk factors were involved at different stages of the fattening period. Therefore, to overcome respiratory disorders in veal calves, different solutions may apply to different stages of the fattening period.     

Evaluation of inter-rater agreement of the clinical signs used to diagnose bovine respiratory disease in individually housed veal calves

In dairy calves raised for veal, typical clinical signs of bovine respiratory disease (BRD) are ocular discharge, nasal discharge, ear droop or head tilt, abnormal respiration, cough, and increased rectal temperature. Despite the existence of several clinical scoring systems, there are few studies on the variability of human recognition of individual BRD clinical signs. The objective of this study was therefore to assess the inter-rater agreement of BRD clinical signs in veal calves. We hypothesized that BRD clinical signs were not detected equally between veterinarians, technicians, and producers of the veal industry and that some clinical signs have higher inter-rater agreement than others. During 2017–2018, we prospectively recorded 524 videos of physical examinations of random veal calves from 48 different batches in Québec, Canada. A researcher, not involved in the inter-rater assessment, classified each video as presence/absence of each BRD clinical sign except rectal temperature. For each of the 5 clinical signs, 15 videos with and 15 videos without the clinical signs were randomly selected to avoid kappa paradoxes. Those 30 videos were then presented in a random order to experienced raters of BRD in veal calves: 6 veterinarians, 6 technicians, and 6 producers. The raters assessed the clinical signs using scores based on the Wisconsin and California scoring system with modifications (0 = absent, 1 = mild, 2 = moderate, 3 = severe for nasal discharge, ocular discharge, and ear droop or head tilt; and 0 = absent, 1 = moderate, 2 = severe for abnormal respiration and induced cough). We used median percentage agreement (Pa), median Cohen's kappa (κ), and Gwet's agreement coefficient 1 (AC1) to assess inter-rater agreement. The effect of scale combination was also tested to determine the optimal combination (4-scale 0/1/2/3 vs. 3-scale 0/1/2 vs. 2-scale 0/1,2,3; 0,1/2,3; or 0/1,2). The differences of inter-rater agreement between veterinarians, technicians, and producers were estimated by a Wilcoxon rank-sum test. The 2-scale combination (0,1/2,3 or 0/1,2) had the highest inter-rater agreement for all clinical signs. With this combination, induced cough was the clinical sign with the highest inter-rater agreement (Pa = 0.93; κ = 0.79; AC1 = 0.87) and abnormal respiration was the sign with the lowest inter-rater agreement (Pa = 0.77; κ = 0.20; AC1 = 0.74). According to Pa and AC1 values, the 2-scale inter-rater agreement of the 5 clinical signs was good (value > 0.6). According to κ, only ear droop or head tilt and induced cough had a substantial 2-scale inter-rater agreement (κ > 0.6). In general, the 2-scale inter-rater agreement was better among veterinarians than among technicians and producers, except for the ear droop/head tilt, where agreement was better among producers. We concluded that with severity scores assessed on a scale of 2 (0,1/2,3 or 0/1,2), the inter-rater agreement of BRD clinical signs was variable according to the sign in veal calves. BRD clinical signs were not detected equally between veterinarians, technicians, and producers of the veal industry. Future research could determine if this discrepancy could be improved by standardization training.     

Effect of health status evaluated at arrival on growth in milk-fed veal calves: A prospective single cohort study

The objective of this prospective single cohort study was to determine the effect of health status at arrival on growth in milk-fed veal calves. Upon arrival at the veal facility, calves were evaluated using a standardized health scoring system and weighed, and the supplier of the calf was recorded. The calves were followed until slaughter, when the hot carcass weight (HCW) was reported. To calculate average daily gain (ADG), the HCW was transformed into an estimated live weight, weight at arrival was subtracted, and this value was divided by the number of days on feed. A mixed linear regression model was created to evaluate the association of health status on arrival with the ADG throughout the production period. A total of 4,825 calves were evaluated at arrival; however, due to inconsistent HCW data from one slaughter plant, and 357 calves dying during the production period, 2,283 calves were used for analysis. In the final model, 7 variables were significantly associated with ADG. Housing location within the farm, method of calf procurement (drover or auction-derived calves versus direct delivery from local farms) and having a higher body weight at arrival were associated with a higher ADG. The season of arrival (summer or fall compared with winter) and being dehydrated at arrival were associated with a lower ADG. Days on feed was also significant in the multivariable model and had a quadratic relationship with ADG. The associations identified suggest that there may be value in scoring dehydration and body weight at arrival to a veal facility.     

Short communication: The effect of diarrhea and navel inflammation on the lying behavior of veal calves

Many veal calves arrive to growing facilities with diseases, including diarrhea and navel inflammation. Observing neonatal calf behavior, such as lying behavior, can be used to better detect and determine the implications of these diseases. The aim of this study was to determine the effect of navel inflammation and diarrhea on lying behavior in neonatal veal calves. This study was part of a larger experiment that included a total of 360 male Holstein calves from 3 cohorts; from these calves, we selected a subset of 125 calves (every third calf as they entered the barn) to be fitted with 3-dimensional accelerometers (Hobo Pendant G data loggers; Onset Computer Corp., Bourne, MA) on 1 hind leg to continuously measure lying time, number of lying bouts, and lying bout duration. Calves were housed individually on slatted flooring (Tenderfoot; Tandem Products Inc., Minneapolis, MN) in 3 rooms of a mechanically ventilated barn. Health exams were conducted twice weekly for 2 wk starting the day after arrival. Exams included rectal temperature, navel score (0 = normal, 1 = mildly inflamed, 2 = moderately inflamed, 3 = severely inflamed), and fecal score (0 = normal, 1 = semiformed, 2 = loose, 3 = watery). Calves were considered to have navel inflammation (n = 22) or diarrhea (n = 15) if they scored ≥2 during at least 3 of the 4 health exams. The lying behavior of these calves was compared with that of normal calves (n = 18) that had no signs of illness and rectal temperatures <39.4°C during at least 3 of the 4 health exams. Data were analyzed using a repeated-measures ANOVA; models included cohort (1, 2, or 3), health status (normal, navel inflammation, or diarrhea), week (1 or 2), and a health by week interaction. There was an effect of health status on lying time, whereby normal calves spent more time lying compared with calves with inflamed navels and tended to spend more time lying compared with calves with diarrhea. There was no effect of health status on the number of lying bouts per day or on the duration of lying bouts. There were no health by week interactions. Results indicate that neonatal veal calves with navel inflammation and diarrhea may be less comfortable than calves without these conditions. Veal producers should consider adapting their facilities to create more comfortable lying environments to help calves better recover from disease, such as by adding a hospital pen with comfortable bedding.     

Development and validation of a clinical respiratory disease scoring system for guiding treatment decisions in veal calves using a Bayesian framework

Active infectious bovine respiratory disease (BRD) is an infection of the airways that needs to be diagnosed correctly so that appropriate treatment can be initiated. The simplest and most practical test to detect active BRD in dairy calves raised for veal is the detection and interpretation of clinical signs by producers or technicians. However, the clinical scoring system currently available for veal calves lacks sensitivity and specificity, contributing to economic losses and high use of antimicrobials. An accurate and reliable batch-level test to detect active BRD is essential to tailor antimicrobial use and reduce economic losses in veal calves. The objective of this study was therefore to develop and validate a new veal calf respiratory clinical scoring system (VcCRS), including reliable clinical signs (cough, ear droop or head tilt) and increased rectal temperature to detect active BRD in batches of veal calves housed individually, and to describe the accuracy of the scoring system for identifying batches of veal calves to treat. During 2017 to 2018, clinical examination, thoracic ultrasonography (TUS) and a haptoglobin concentration (Hap) were prospectively performed on 800 veal calves housed individually in Québec, Canada. Deep nasopharyngeal swabs were performed on 250 veal calves. A Bayesian latent class model accounting for imperfect accuracy of TUS and Hap was used to obtain weights for the clinical signs and develop the VcCRS. The VcCRS was then validated externally in 3 separate data sets. Finally, the applicability of the VcCRS at batch level was determined. We found that calves with 2 of the following findings—cough, unilateral or bilateral ear droop or head tilt, or increased rectal temperature ≥39.7°C—were considered positive and had a 31% chance of having active BRD. Without at least 2 of these 2 findings, a calf had a 100% chance of not having active BRD. At the batch level, we found that a batch with ≥3 positive calves among 10 calves sampled 2 wk after arrival at the fattening unit had a 94% chance of having an active BRD prevalence ≥10%. A batch with <3 positive calves had a 95% chance of not having an active BRD prevalence ≥10%. In this study, we developed a simple individual and batch-level score that is reliable across examiners and performs effectively in the detection of active BRD in veal calves. The implementation of this VcCRS in the veal calf industry would promote the elaboration of a protocol tailoring antimicrobial use.     

Calf management risk factors on dairy farms associated with male calf mortality on veal farms

The objective of this cross-sectional herd-level study was to assess the association of calf management practices on source dairy farms with mortality risk on veal farms. From April to October 2016, 52 source dairy farms supplying male calves to 2 veal operations were visited once. A questionnaire was administered that covered all areas of calf management, calves between 1 and 10 d of age were examined using a standardized health scoring system, and blood was taken to evaluate passive transfer of immunoglobulins. The mortality risk for calves from each dairy farm was calculated based on the number of male calves sold from the dairy farm and that died during 2016 at the veal operations. The mean mortality risk was calculated for both veal farms and, based on the veal facility-adjusted mortality risk, dairy farms were classified as high- or low-mortality source farms. Using the information gathered at the 52 source dairy farms, a logistic regression model was used to assess factors associated with being a high-mortality source farm. Suppliers to veal farm 1 had a mean mortality risk of 9.6% and suppliers to veal farm 2 had a mean mortality risk of 4.2%. The lower mortality risk at veal farm 2 was partially influenced by a shorter period of observation. Of the 182 calves examined during the single visit to the source dairy farms, 41% of male calves and 29% of female calves had at least one identifiable health abnormality. The risk of failure of passive transfer on source dairy farms was low, with only 13% of calves tested having <10 mg of IgG/mL of serum. The subset of calves examined at the source dairy farm was not followed prospectively to the veal farms. Using a tube feeder or pail to feed colostrum, bedding male calves on wood shavings or chopped straw at the source dairy farm, and the herd veterinarian not routinely and actively inquiring about the health and performance of calves during regular herd visits were significantly associated with the farm being classified as a high-mortality source dairy farm. Checking the calving pen at an interval of every 3 h or more during the day was associated with a lower probability of being classified as a high-mortality source dairy farm. The results of this study suggest that there are management practices on the source farm that contribute to the risk of mortality on veal farms.     

Effects of feeding heat-treated colostrum on passive transfer of immune and nutritional parameters in neonatal dairy calves

The first objective of this study was to describe the effect of on-farm heat treatment of colostrum on colostral bacteria counts and IgG concentrations. The second objective was to describe the effect of feeding heat-treated (vs. raw) colostrum on passive transfer of colostral immune and nutritional parameters in neonatal calves. Pooled batches of colostrum were mixed and divided equally: one half was fed raw whereas the other half was fed after heat treatment at 60°C for 60 min using a commercial on-farm batch pasteurizer. Colostrum samples were cultured for total bacteria count and total coliform count and analyzed for total IgG concentration. Forty-nine Holstein calves were fed either raw colostrum (n = 24) or heat-treated colostrums (n = 25) within 1 to 2 h after birth. Serum samples collected from calves at 0 h (precolostrum) and 24 h (postcolostrum) were assayed for serum total protein; IgG, IgA, and IgM concentrations; peripheral total leukocyte counts; neutrophil counts; lymphocyte counts; lymphocyte phenotypes; vitamin A, vitamin E, cholesterol, and β-carotene concentrations. Serum samples collected from 2- to 5-d-old calves were tested for immunoglobulin function via a bovine viral diarrhea virus type I serum neutralization titer and for neutrophil bacterial opsonization activity. On-farm batch heat treatment of colostrum at 60°C for 60 min resulted in lower colostrum bacteria concentrations while maintaining colostral IgG concentration. Calves fed heat-treated colostrum had significantly greater serum total protein and IgG concentrations at 24 h, plus greater apparent efficiency of IgG absorption (total protein = 6.3 mg/dL; IgG = 22.3 mg/mL; apparent efficiency of absorption = 35.6%) compared with calves fed raw colostrum (TP = 5.9 mg/dL; IgG = 18.1 mg/mL; apparent efficiency of absorption = 26.1%). There was no effect of treatment on serum concentrations of IgA, IgM, vitamin A, vitamin E, cholesterol, β-carotene or vitamin E:cholesterol ratio, or on serum bovine viral diarrhea virus type I serum neutralization titers. There was no difference between treatment groups when examining calf plasma total leukocyte counts, neutrophil counts, lymphocyte counts, or neutrophil opsonization activity. However, the latter results were considered inconclusive.     

Effects of Echinacea purpurea supplementation on markers of immunity,health, intake,and growth of dairy calves

Echinacea purpurea (EP) is an herb that has demonstrated immunostimulatory and anti-inflammatory effects with the potential to improve immunity, health, and performance in animals. The objective of this study was to investigate how supplementing calves with EP affects their blood immunity marker profile, health, intake, and growth. Male Holstein calves (n = 240), sourced from local dairy farms or auction, arrived at a rearing facility between 5 and 14 d of age and were kept in individual pens in 1 of 3 rooms (80/room) for 56 d, and then put into groups for the remaining 21 d of the trial. Calves received milk replacer (MR) 2× per day for 56 d (total = 36 kg of MR) and had ab libitum water and starter access. Within room, calves were randomly assigned to 1 of 3 treatments: (1) control (n = 80), (2) 3g of dried (powder) EP extract per day split over 2 milk feedings from experiment d 14–28 (n = 80), and (3) 3 g of dried (powder) EP extract per day split over 2 milk feedings from experiment d 1–56 (E56; n = 80). The powdered EP treatments were mixed into the liquid MR. On d 1, 14, 28, and 57 rectal temperatures and blood were collected from a subset of calves (n = 117; 39 calves/treatment), and blood serum was assessed for serum total protein (d 1), haptoglobin, white blood cells, and cytokines. Failed transfer of passive immunity was defined as serum total protein <5.2 g/dL. Calves were health scored 2× per day, receiving fecal and respiratory scores until d 28 and 77, respectively. Calves were weighed on arrival and then weekly until d 77. Milk replacer and feed refusals were recorded. Supplementation of EP was associated with lower haptoglobin levels, segmented neutrophil counts, segmented neutrophil per lymphocyte ratio, respiratory scores in auction derived calves, and higher lymphocyte counts and d 28 rectal temperature. Of calves with heavier arrival body weight, E56 calves had greater postweaning weekly body weight. There was no detected effect of EP supplementation on total white blood cells, band neutrophil, monocyte, and basophil counts, IL-10, IL-6, and TNF-α levels, fecal scores, risk of receiving diarrhea and respiratory treatment, risk of bovine respiratory disease (calves were deemed at risk for bovine respiratory disease if they had at least 1 respiratory score ≥5), risk of mortality, MR and feed intake, average daily gain, and feed conversion ratio. Overall, EP supplementation to dairy calves was associated with immunomodulation and reduced inflammation, evidenced through blood markers, although only few minor health and growth improvements were observed. Benefits were observed particularly when fed across the whole milk feeding period.