Randomized field trial on the effects of body weight and short transport on stress and immune variables in 2‐ to 4‐week‐old dairy calves

BACKGROUND: Whether underweight calves respond differently to transport stress, enhancing their disease risk, is currently unknown. OBJECTIVE: To determine the effects of low body weight and transport stress on immune variables. ANIMALS: Twenty-one 2- to 4-week-old male Holstein calves, housed on a commercial farm. METHODS: Randomized clinical trial. Full factorial design with 4 treatment groups: low body weight (≤46 kg)/no transport (LOWCON); low body weight/transport (LOWTRANS); normal body weight (>46 kg)/no transport (NORMCON), and normal body weight/transport (NORMTRANS). Transport duration was 2 hours. RESULTS: Transport significantly increased serum cortisol concentration (77.8 μg/mL; 95% confidence interval [CI], 37.8-131.6; P < .001), interleukin (IL)-17A (344.9 pg/mL; 95% CI, 32.2-556.5; P = .04), and tumor necrosis factor-α (TNF-α) (218.2 pg/mL; 95% CI, 32.5-368.3; P = .03) production after lipopolysaccharide (LPS) stimulation. Body weight did not affect any of the studied variables. However, the interaction of transport and body weight was significant. LOWTRANS calves showed increased monocyte count (2.0 × 109 /L; 95% CI, 0.6-4.2; P < .05) and interleukin IL-17A production (106.0 pg/mL; 95% CI, 4.2-306.9; P = .03) compared to normal weight calves and increased TNF-α production (275.6 pg/mL; 95% CI, 2.6-463.0; P = .02) compared to LOWCON calves in unstimulated peripheral blood mononuclear cells (PBMCs) after transport. CONCLUSION AND CLINICAL IMPORTANCE: These findings contribute to our understanding of increased disease susceptibility of underweight calves when transported. Gamma globulin concentration was identified as important interfering factor in studies on immune variables in neonatal calves

Effects of short transport and body condition on stress and immune parameters in 2 to-4-week old dairy calves

C

Associations of barn air quality parameters with ultrasonographic lung lesions, airway inflammation and infection in group-housed calves

Barn climate is believed to play a major role in the bovine respiratory disease complex. However, the exact air quality parameters associated with (sub)clinical pneumonia or airway inflammation in calves are currently unknown. The objective of this cross-sectional study was to assess associations of air quality parameters with clinical signs, lung consolidation, pulmonary inflammation and infection in group-housed calves. In total, 60 beef and dairy farms were visited from January to April 2017 and 428 calves sampled. Measured air quality parameters included continuous 24-h measurements of ammonia concentration, relative humidity and temperature and punctual measurements of air velocity, ammonia, CO2 and bacterial air load. Calf sampling consisted of clinical examination, thoracic ultrasonography and broncho-alveolar lavage sampling for bacteriological and cytological analysis of broncho-alveolar lavage fluid (BALf). Average air temperature was 14.2 degrees C (standard deviation (SD) 4.4, range 5.5-23.9) and relative humidity 68.8 % (SD 8.9, range 52.2-91.6). Average ammonia concentration was 1.7 ppm (SD 0.9, range 0-10.0). Lung consolidations of >= 1 cm, >= 3 cm and >= 6 cm in depth were present in 41.1 % (176/428), 27.1 % (116/428) and 16.1 % (69/428) of the calves, respectively. Average pen temperature was positively associated with consolidations of >= 1 cm (P = 0.005), >= 3 cm (P = 0.002) and >= 6 cm (P 4 ppm, was associated with lung consolidation >= 1 cm (odds ratio (OR) = 1.73; confidence interval (CI) = 1.02-3.07; P = 0.04). Ammonia concentration was positively associated with BALf epithelial cell percentage (P= 0.01). Air velocity> 0.8 m/s was associated with increased odds of lung consolidation of >= 3 cm (OR= 6.8; CI= 1.2-38.5; P= 0.04) and >= 6 cm (OR = 15.9; CI = 1.2-200.0; P = 0.03). The prevalence of lung consolidations >= 1 cm was higher in the draught (81.8 %; P = 0.0092) and warm, dry and ammonia accumulation clusters (54.2 %; P = 0.02) compared to the presumably normal cluster (31.6 %). In addition, in the warm, dry and ammonia cluster the prevalence of lung consolidations >= 3 cm (38.1 %; P = 0.04) and >= 6 cm (31.4 %; P = 0.01) in depth were higher compared to the presumably normal climate cluster (18.2 % and 9.1 %, respectively). Of all frequently measured indoor air quality parameters, only average temperature, ammonia concentration and air velocity were associated with pneumonia and might therefore be preferable for cost-effective evaluation of calf barn climate

Arrival cortisol measurement in veal calves and its association with body weight, protein fractions, animal health and performance

Male dairy calves are exposed to an accumulation of transport, social and environmental stressors while transferred to fattening units. As a consequence, calves show high cortisol concentrations upon arrival at the veal facility. Whether cortisol levels as measured on arrival can be associated with animal health, welfare and production results is currently unknown. The first objective of this prospective cohort study was to determine possible associations of arrival serum cortisol concentration with health and production variables of veal calves and other arrival predictors like body weight and gamma-globulin concentration. The second aim was to investigate potential clustering of arrival risk factors in veal calves for developing bovine respiratory disease (BRD) based on arrival body weight, serum cortisol concentration, total protein and protein fractions. In total, 105 male Holstein calves from two consecutive production cycles in a single, commercial white veal farm were blood sampled directly at arrival on the farm to determine serum cortisol, total protein and protein fractions. All calves were weighed the day after arrival and clinical signs, average daily weight gain (ADG) and carcass weight were collected. Also, all calves of both production cohorts were repeatedly examined by thoracic ultrasonography at the onset of group respiratory disease symptoms (2 3 weeks after arrival) and four weeks later. Linear and logistic mixed models together with k-means clustering were used for statistical analyses. Calves showed on average high, but individually variable serum cortisol concentrations (mean value = 96.6 ng/mL +/- standard deviation (SD) = 48.8; Range (R) = 50.0-317 ng/mL). Arrival cortisol, body weight and gamma-globulin content were not significantly associated. Serum cortisol and albumin concentrations at arrival were associated with chronic, unresponsive pneumonia. For each increase of serum cortisol concentration by 10 ng/mL, the odds for lung consolidation of >= 1 cm in depth at the second ultrasonography increased, odds ratio (OR) = 1.03 (95 % confidence interval (CI) = 1.01-1.06; P = 1 cm in depth at week 6 7 after arrival (OR= 3.93 (95 % CI=1.34 11.53; P < 0.013)). Avoiding high cortisol levels upon arrival of calves is important for animal welfare, but also for reduction of the prevalence of chronic, unresponsive pneumonia and the associated need for (repeated) antimicrobial treatment and production losses