Respiratory Disease In Preweaned Calves Research Articles

A systematic review of the relationship between housing environmental factors and bovine respiratory disease in preweaned calves – Part 1: Ammonia, air microbial count, particulate matter and endotoxins

Bovine respiratory disease (BRD) is one of the leading causes of mortality and morbidity in calves across diverse management systems. Despite expert opinion often citing the influence of housing environment on the level of respiratory disease in calf groups, there have been few reviews of environmental factors that predispose to BRD. This systematic review was undertaken to identify the measurable environmental variables associated with respiratory disease in housed preweaned calves. To achieve this Pubmed, CAB Direct and Scopus databases were searched. To be considered for inclusion, publications had to be fully published in English, published before 24 November, 2022 and include at least one measurable/ manipulated environmental variable and a standardized method of BRD detection.Twelve publications were included in this review. These examined a wide range of risk factors including air microbial count (four publications), air particulate matter (one publication); air endotoxins (one publication) and air ammonia (four publications). From the included publications, a statistically significant relationship to BRD was identified in 2/4 examining air microbial count, 1/1 examining air particulate matter, 1/1 examining air endotoxins and 2/4 examining air ammonia. This review indicated a paucity of evidence from the peer-review literature demonstrating a significant association between the many investigated exposure factors and BRD occurrence. An optimal environment for housed calves could not be clearly identified in this review.

A systematic review of the relationship between housing environmental factors and bovine respiratory disease in preweaned calves - Part 2: Temperature, relative humidity and bedding

Bovine respiratory disease (BRD) is a challenge in all housed farming systems that raise calves. Farm to farm variation in BRD prevalence can be partially attributed to variation in host immunity, pathogens and housing environment. Unlike host immunity and BRD pathogens, housing environment has not been well investigated. The objective of this systematic review was to identify the measurable environmental variables associated with BRD in housed preweaned calves. Pubmed, CAB Direct and Scopus databases were searched. To be considered for inclusion publications had to be published in English, before 24 November, 2022 and include at least one measurable/ manipulated environmental variable and a standardized method of BRD detection. In total 12 publications were included in this review. In this second part of the systematic review the environmental variables identified were; temperature (9 publications); relative humidity (8 publications); bedding (5 publications); ventilation (1 publication); air CO2 concentration (1 publication) and air velocity (4 publications). Of the publications that were examined a statistically significant relationship to BRD was identified in 4/9 publications examining temperature, 3/8 examining relative humidity, 2/4 examining air velocity, 2/5 examining bedding, 0/1 examining ventilation rates and 0/1 examining CO2 concentration. From this review it is clear high airspeed at calf level should be avoided as should deep, wet pack bedding. The relationship between BRD prevalence and both high and low temperature requires more investigation to identify temperature thresholds associated with increased risk of BRD as well as the most influential modifiers. An optimal environment for housed calves could not be clearly identified in this review.

Subcutaneous Bacillus Calmette-Guérin Administration Induces Innate Training in Monocytes in Preweaned Holstein Calves.

The bacillus Calmette-Guérin (BCG) vaccine, administered to prevent tuberculosis, is a well-studied inducer of trained immunity in human and mouse monocytes. We have previously demonstrated that aerosol BCG administration induces innate training in calves. The current study aimed to determine whether s.c. BCG administration could induce innate training, identify the cell type involved, and determine whether innate training promoted resistance to bovine respiratory syncytial virus (BRSV) infection, a major cause of bovine respiratory disease in preweaned calves. A total of 24 calves were enrolled at 1-3 d of age and blocked by age into two treatment groups (BCG, n = 12; control, n = 12). BCG was given s.c. to preweaned calves. The control calves received PBS. We observed a trained phenotype, demonstrated by enhanced cytokine production in response to invitro stimulation with LPS (TLR-4 agonist) in PBMCs and CD14+ monocytes from the BCG group 2 wk (IL-1β, p = 0.002) and 4 wk (IL-1β, p = 0.005; IL-6, p = 0.013) after BCG administration, respectively. Calves were experimentally infected via aerosol inoculation with BRSV strain 375 at 5 wk after BCG administration and necropsied on day 8 postinfection. There were no differences in disease manifestation between the treatment groups. Restimulation of bronchoalveolar lavage fluid cells isolated on day 8 after BRSV infection revealed enhanced IL-1β (p = 0.014) and IL-6 (p = 0.010) production by the BCG group compared with controls. In conclusion, results from our study show that s.c. administration of the BCG vaccine can induce trained immunity in bovine monocytes and influence cytokine production in the lung environment after BRSV infection.

Etiology and risk factors for bovine respiratory disease in pre-weaned calves on California dairies and calf ranches

Our study objective was to estimate the magnitude of association of BRD risk factors including failure of passive immunity transfer, sex, age, and the detection of suspected BRD etiological pathogens in pre-weaned dairy calves in California. A conditional logistic regression model and a mixed-effects logistic regression model were used to estimate the association of these potential risk factors with BRD from a matched and nested case-control studies, respectively. For each exposure covariate, the odds ratio (OR) is the ratio of odds of an exposure in a BRD calf (case) to that in a non-BRD calf (control).In the matched case-control study, an interaction term between failure of transfer of passive immunity and sex of calf showed that female calves were more negatively impacted by failure of transfer of passive immunity compared to male calves. The odds ratios comparing failure of transfer of passive immunity in BRD score positive calves versus controls for male calves was 1.34 (95 % CI: 0.87, 2.06) and was 2.47 (95 % CI: 1.54, 3.96) for female calves. The model odds ratios varied from 1.74 (95 % CI: 1.26, 2.42) for Mycoplasma spp. to 9.18 (95 % CI: 2.60, 32.40) for Histophilus somni, with Mannheimia haemolytica and Pasteurella multocida having an OR of 6.64 (95 % CI: 4.39, 10.03) and 6.53 (95 % CI: 4.44, 9.59), respectively. For bovine respiratory syncytial virus positive calves, the OR was 4.60 (95 % CI: 3.04, 6.97).Findings from the nested case-control study showed that based on thoracic ultrasonography findings consistent with BRD, the odds of a calf being 1 day older compared to a day younger were 1.01 (95 % CI: 1.00, 1.02) among BRD cases. For the bacterial and viral pathogens, the OR for Mycoplasma spp. and Pasteurella multocida were 1.85 (95 % CI: 1.24, 2.75) and 1.86 (95 % CI: 1.28, 2.71), respectively. The OR values for these pathogens were similar when both thoracic auscultation and ultrasound findings were used to detect cases of BRD. Based on positive scores for BRD using the California BRD scoring system, the OR for facility type, calf ranch versus dairy farm, was 3.17 (95 % CI: 1.43, 7.01), Mannheimia haemolytica was 3.50 (95 % CI: 2.00, 6.11), Pasteurella multocida was 1.78 (95 % CI: 1.21, 2.60), and bovine coronavirus was 2.61 (95 % CI: 1.85, 3.70).Results from both study designs showed the difference in relative contributions of age, sex, immune status, and pathogens in BRD occurrence between cases and controls in pre-weaned dairy calves.

Management factors associated with bovine respiratory disease in preweaned calves on California dairies: The BRD 100 study

The objective of this cross-sectional study was to determine how management practices on California dairies may be associated with bovine respiratory disease (BRD) in preweaned calves. A convenience sample of 100 dairies throughout California, providing a study population of 4,636 calves, were visited between May 2014 and April 2016. During each farm visit, in-person interviews with the herd manager or calf caretaker were conducted to collect information about herd demographics, maternity pen, colostrum and calf management, herd vaccinations, and dust abatement. A random sample of preweaned calves was identified and evaluated for the presence of BRD using a standardized tool. A survey-adjusted generalized linear mixed model with a logit link function was fitted with calf as the unit of analysis and dairy as the random effect. Mean study herd size (±SE) was 1,718 (±189.9) cows. Survey-adjusted estimates of breed types in the sample were 81.6% (±0.6) Holstein, 13.1% (±0.4) Jersey, and 5.3% (±0.5) crossbred or other purebred breeds, and calf sex proportions were 73.8% (±1.0) female and 26.2% (±1.0) male. Overall survey-adjusted BRD prevalence in the study herds was 6.91% (±0.69). Housing factors positively associated with BRD were metal hutches compared with wood hutches [odds ratio (OR) = 11.19; 95% confidence interval (CI) = 2.80–44.78], calf-to-calf contact in calves >75 d of age (OR = 9.95, 95% CI = 1.50–65.86), feeding Holstein calves <2.84 L of milk or replacer per day (OR = 7.16, 95% CI = 1.23–41.68), and lagoon water used for flushing manure under hutches compared with no flush (OR = 12.06, 95% CI = 1.93–75.47). Providing extra shade over hutches (OR = 0.08; 95% CI = 0.02–0.37), feeding calves at least 90% saleable milk (OR = 0.27, 95% CI = 0.13–0.54) or pasteurized milk (OR = 0.10; 95% CI = 0.03–0.36), and feeding >5.68 L of milk or replacer per day to Jersey calves (OR = 0.04; 95% CI = 0.01–0.28) were negatively associated with BRD. Our study identified management practices on California dairies with variability and that may contribute to differences in BRD prevalence, which will be incorporated into a risk-assessment tool to control and prevent BRD in preweaned dairy calves.

Bayesian estimation of sensitivity and specificity of systematic thoracic ultrasound exam for diagnosis of bovine respiratory disease in pre-weaned calves

Among the different clinical presentations of bovine respiratory disease, active pneumonia, defined as an infection of the lower airway with signs of inflammation, is the most important to diagnose correctly so appropriate treatment can be initiated. Diagnostic tests that accurately identify cases of active pneumonia are lacking; however, thoracic ultrasonography (TUS) seems promising. The primary objective of this study was to estimate the accuracy of TUS compared to reference tests for the diagnosis of active pneumonia in pre-weaned calves, using a latent-class model method (LCM). The tests used for comparison were the Wisconsin Clinical Respiratory Scoring Chart (CRSC, positive if ≥5) and serum haptoglobin concentration (Hap, positive if ≥15 mg/dL). Secondary objectives were to assess the incremental value on TUS accuracy of combining TUS of the right cranial part and caudal parts, and to determine the accuracy of various thresholds for depth of consolidation (≥0 cm, ≥1 cm, or ≥3 cm) for diagnosis of active pneumonia. One population of veal calves (n = 209) and one of dairy calves (n = 301) were enrolled. TUS, CRSC and Hap were all performed on each calf on the same day. TUS was performed by screening the mid to ventral portion of the lung caudal of the heart (the caudal sites), as well as the right parenchyma cranial to the heart (the cranial site). The maximal depth of consolidation (DEPTH) on TUS was recorded and noted separately for caudal and cranial sites. Different TUS cases were defined according to site and DEPTH. The accuracy of TUS was estimated by LCM for three tests conducted in two populations. Prevalence of active pneumonia was low (0.05) in both populations. In general, higher minimal consolidation depth thresholds led to increased TUS specificity (Sp) estimates, with minimal effects on TUS sensitivity (Se). With a TUS DEPTH threshold of ≥3 cm, adding TUS of the cranial site had little effect on accuracy. Using the ≥3 cm threshold with caudal sites only, posterior Se and Sp median estimates of 0.89 (95%BCI: 0.55, 1.0) and 0.95 (95%BCI: 0.92, 0.98), respectively, were obtained. In conclusion, in populations with low active pneumonia prevalence, adding TUS of the cranial site did not enhance the performance of the test. We suggest using a DEPTH threshold of ≥3 cm solely on caudal sites to detect active pneumonia.

Cost of bovine respiratory disease in preweaned calves on US beef cow-calf operations (2011-2015).

OBJECTIVE To develop a partial budget analysis of direct costs associated with bovine respiratory disease (BRD) in preweaned calves on US beef cow-calf operations and identify factors that strongly influence those costs. DESIGN Risk analysis model. ANIMALS US preweaned beef calf inventory from 2011 through 2015. PROCEDURES A stochastic simulation model was developed by use of a computer spreadsheet and add-in software. Input data were obtained from the USDA, peer-reviewed literature, and a survey of beef cow-calf producers. A simulation consisting of 10,000 iterations was used to account for either uncertainty or variability in model inputs. The median (90% confidence interval) was reported for each output variable. Global and local sensitivity analyses were performed to identify the most influential factors and quantitatively evaluate the effects of inputs on the estimated costs. RESULTS From 2011 through 2015, BRD in preweaned calves cost the US beef cow-calf industry approximately $165 million annually, of which costs associated with the death, treatment, and decreased weaning weight of BRD-affected calves were approximately $126, $25, and $15 million, respectively. CONCLUSIONS AND CLINICAL RELEVANCE Although BRD in preweaned calves may have a fairly small effect on the total gross income for the US beef cow-calf industry as a whole, it can have a substantial adverse effect on the net profit of BRD-affected herds. The model developed provided important information regarding the cost of BRD in preweaned calves on US beef cow-calf operations and identified factors that had an import effect on those costs.

Beef producer survey of the cost to prevent and treat bovine respiratory disease in preweaned calves.

OBJECTIVE To estimate costs associated with prevention and treatment of bovine respiratory disease (BRD) in preweaned calves on US beef cow-calf operations. DESIGN Cross-sectional survey. SAMPLE 43 beef cow-calf producers whose operations had a history of BRD in preweaned calves. PROCEDURES Mail and electronic surveys were developed and administered to producers in Nebraska, North Dakota, and South Dakota to obtain information regarding costs of BRD prevention and treatment. Descriptive statistics were generated. Mixed linear regression models were used to assess factors associated with the costs of vaccines, medicine, and labor and percentage time spent on prevention and treatment of BRD in cows, replacement heifers, and preweaned calves. RESULTS 7 mail and 36 electronic surveys were completed. Median annual costs for BRD vaccines were $2.25, $4.00, and $6.25/animal, and median annual labor costs for vaccination were $4.58, $3.00, and $5.00/animal for cows, heifers, and preweaned calves, respectively. Median annual costs for medicine and labor to treat preweaned calves for BRD were $11.00 and $15.00/ affected calf, respectively. Adjusted mean annual BRD vaccine cost for preweaned calves ($7.67/animal) was significantly greater than that for cows ($3.18/animal) and heifers ($4.48/animal). CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that labor costs associated with BRD vaccination and treatment were similar to or exceeded the cost of vaccines and medicine, and most of those labor costs were associated with gathering and sorting cattle. Therefore, costs associated with labor as well as medicine and vaccines should be considered during the development of BRD prevention and treatment plans.

Development of a risk assessment tool for prevention of bovine respiratory disease in pre-weaned calves on California dairies

Bovine respiratory disease (BRD) has been estimated as the cause of death in 22.5 % of pre-weaned and 46.5 % in post-weaned heifers. In 2010, 18.1 % of pre-weaned heifers on dairy heifer raising operations were reportedly affected by pneumonia, the second most common illness after diarrhea. Despite the availability of numerous vaccines and antibiotics specifically approved for the prevention and treatment of BRD, morbidity and mortality in dairy calves have remained static over the past 25 years. The objective of this cross-sectional study was to determine how management practices on California dairies are associated with BRD in pre-weaned calves.

Short communication: Automated detection of behavioral changes from respiratory disease in pre-weaned calves

Group housing of calves can pose a challenge in identifying respiratory disease; therefore, it is necessary to develop tools that can identify these disease events. In this experiment, pre-weaned calves (n = 30) were housed in groups with an automatic calf feeder and were fitted with an accelerometer. Step activity, lying behaviors, and feeding behaviors were recorded to determine the effect of respiratory disease. All calves were health scored twice daily, and calves with respiratory scores ≥5 were diagnosed with respiratory disease (n = 10). Each diseased calf was match paired with a healthy control based on the date of disease diagnosis, breed, and age. Control calves were determined to be healthy if they had respiratory scores ≤4, as well as fecal, navel, and joint scores of 0 or 1. Diseased calves were less active before, on the day of, and after respiratory disease diagnosis. Furthermore, diseased calves had reduced lying frequencies starting 2 d before diagnosis, as well as after diagnosis. Last, diseased calves consumed less milk on the day of diagnosis when compared with healthy controls. Step activity, lying bouts, and milk intake may prove to be a useful tool in identifying respiratory disease under practical farming, but this requires further research.

Survey of management practices related to bovine respiratory disease in preweaned calves on California dairies

In the spring of 2013, a survey of California (CA) dairies was performed to characterize management practices related to bovine respiratory disease in preweaned calves, compare these practices across geographic regions of the state, and determine the principal components that explain the variability in management between herds. The questionnaire consisted of 53 questions divided into 6 sections to assess management practices affecting dairy calves from precalving to weaning. The questionnaire was mailed to 1,523grade A licensed dairies in CA and 224 responses (14.7%) were collected. Survey response rates were similar over the 3 defined regions of CA: northern CA, northern San Joaquin Valley, and the greater southern CA region. The mean size of respondent herds was 1,423 milking cows. Most dairies reported raising preweaned calves on-site (59.7%). In 93.3% of dairies, preweaned calves were raised in some form of individual housing. Nonsaleable milk was the most frequent liquid diet fed to preweaned heifers (75.2%). Several important differences were identified between calf-raising practices in CA and practices reported in recent nationwide studies, including herd sizes, housing practices, and sources of milk fed to heifers. The differences between the CA and nationwide studies may be explained by differences in herd size. Regional differences within CA were also identified. Compared with the 2 other regions, northern CA dairies were found to have smaller herds, less Holstein cattle, calves remained with dams for longer periods of time after calving, were more likely to be certified organic dairies, and raised their own calves more often. Principal component analysis was performed and identified 11 components composed of 28 variables (questions) that explained 66.5% of the variability in the data. The identified components and questions will contribute to developing a risk assessment tool for bovine respiratory disease in preweaned dairy calves.

Evaluation of fixed sources of variation and estimation of genetic parameters for incidence of bovine respiratory disease in preweaned calves and feedlot cattle12

ABSTRACTThe primary objective of this study was to estimate variance components and heritability of bovine respiratory disease (BRD) incidence in beef calves before weaning and during the finishing phase. The second objective was to investigate the impact of BRD incidence and treatment frequency on performance and carcass traits. Bovine respiratory disease is the biggest and most costly health challenge facing the cattle industry. The 2 populations used consisted of 1,519 preweaned calves and 3,277 head of feedlot cattle. The incidence rate of BRD in preweaned calves was 11.39%, and among treated cattle, 82.1% were treated once, 13.9% were treated twice, and 4.0% were treated 3 times or more. The incidence of BRD (P = 0.35) and the number of treatments (P = 0.77) had no significant effect on weaning BW. Heritability estimates of the entire preweaned population for BRD resistance and number of treatments were 0.11 ± 0.06 and 0.08 ± 0.05, respectively. The genetic correlation estimates for BRD incidence with weaning BW and birth BW were low (−0.02 ± 0.32 and 0.07 ± 0.27, respectively). The same estimate for the number of BRD treatments with weaning BW and birth BW was 0.25 ± 0.35 and 0.30 ± 0.27, respectively. The observed BRD incidence rate for feedlot cattle was observed at 9.43%. Incidence of BRD significantly (P < 0.01) decreased overall and acclimation ADG by 0.06 ± 0.01 kg/d and 0.28 ± 0.03 kg/d, respectively. Carcass traits were also significantly (P < 0.05) affected by BRD incidence; untreated cattle had a 9.1 ± 1.7-kg heavier HCW. Results were similar in the analysis of treatment frequency. The heritability estimate of BRD incidence and the number of treatments were 0.07 ± 0.04 and 0.02 ± 0.03, respectively. Estimates of genetic correlations of BRD incidence with production traits were −0.63 ± 0.22 for acclimation ADG, −0.04 ± 0.23 for on-test ADG, −0.31 ± 0.21 for overall ADG, −0.39 ± 0.21 for final BW, −0.22 ± 0.22 for HCW, −0.03 ± 0.22 for LM area, 0.24 ± 0.25 for fat, and −0.43 ± 0.20 for marbling score. Similar results for the number of treatments and production traits were −1.00 ± 0.68 for acclimation ADG, −0.04 ± 0.39 for on-test ADG, −0.47 ± 0.41 for overall ADG, −0.66 ± 0.40 for final BW, −0.58 ± 0.45 for HCW, −0.12 ± 0.38 for LM area, 0.42 ± 0.50 for fat, and −0.32 ± 0.37 for marbling score. Because of the high economic cost associated with BRD incidence, even these modest estimates for heritability of BRD resistance should be considered for incorporation into beef cattle breeding programs.