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OBJECTIVE To test a unique electronic ear tag designed to collect movement data to determine whether physical activity of sick steers differed from that of healthy steers. ANIMALS 206 steers. PROCEDURES Physical activity in 2 groups of steers during November and December of 2010 (101 steers; the tag of I steer failed, and thus that steer was removed from the study, which resulted in data for 100 steers) and 201 1 (105 steers) was monitored with an electronic ear tag device with an on-board triple-axis accelerometer.The accelerometer recorded motion in all 3 axes in the form of counts per minute. A radio-frequency transmitter on the ear tag delivered serial packets of motion data to a local server. An algorithm was developed to analyze the activity data to determine whether this technique could be used to assess health status with high accuracy. RESULTS Steers that became sick had significantly fewer activity counts (approx 25% fewer), compared with the activity counts of steers that remained healthy the entire time. CONCLUSIONS AND CLINICAL RELEVANCE In this study, automated detection of health status in growing cattle was feasible through remote monitoring of animal activity. Early identification of sick animals should lead to improved health outcomes, increased marketability, and improved animal well-being and help to minimize the use of antimicrobials that could contribute to resistant bacteria. [ABSTRACT FROM AUTHOR]

Objective--To determine the relationship between rectal temperature at first treatment for bovine respiratory disease complex (BRDC) in feedlot calves and the probability of not finishing the production cycle. Design--Retrospective data analysis. Animals--344,982 calves identified as having BRDC from 19 US feedlots from 2000 to 2009. Procedures--For each calf, data for rectal temperature at initial treatment for BRDC and various performance and outcome variables were analyzed. A binary variable was created to identify calves that did not finish (DNF) the production cycle (died or culled prior to cohort slaughter). A mixed general linear model and receiver operating characteristic curve were created to evaluate associations of rectal temperature, number of days in the feedlot at time of BRDC diagnosis, body weight, quarter of year at feedlot arrival, sex, and all 2-way interactions with rectal temperature with the probability that calves DNF. Results--27,495 of 344,982 (7.97%) calves DNF. Mean rectal temperature at first treatment for BRDC was 40.0°C (104°F). As rectal temperature increased, the probability that a calf DNF increased; however, that relationship was not linear and was influenced by quarter of year at feedlot arrival, sex, and number of days in the feedlot at time of BRDC diagnosis. Area under the receiver operating characteristic curve for correct identification of a calf that DNF was 0.646. Conclusions and Clinical Relevance--Rectal temperature of feedlot calves at first treatment for BRDC had limited value as a prognostic indicator of whether those calves would finish the production cycle. [ABSTRACT FROM AUTHOR]

Objective--To evaluate the endocrine and immune responses of steers challenged with infectious bovine rhinotracheitis virus (IBRV). Animals--12 crossbred beef steers. Procedures--Steers were randomly assigned to IBRV- (control) or IBRV+ treatment groups. Experimentally challenged steers (IBRV+) received a dose of IBRV intranasally (8.0 50% tissue culture infective doses), IBRV- steers received a saline (0.9% NaCI) solution placebo intranasally, and each group was placed in an isolated paddock. At 72 hours after challenge, all steers were fitted with indwelling jugular catheters and placed into individual stanchions. Blood samples were collected on days 4 through 8. Serum was analyzed for concentrations of cortisol, interleukin-6, interferon-y, tumor necrosis factor-cc, growth hormone, and insulin-like growth factor I. Results--From 72 to 144 hours after challenge inoculation, the IBRV+ group had significantly greater mean rectal temperature, compared with the IBRV-group; the greatest temperatures in both groups were observed at 72 hours. Serum cortisol concentrations were increased in both groups from hours 72 to 136 and serum interferon-y concentrations were greater in the IBRV+ from 94 to 112 hours after inoculation. Growth hormone concentration was greater in the IBRV+ group at various time points, but no difference in insulin-like growth factor-I concentration was observed. Conclusions and Clinical Relevance--Results indicated that IBVR challenge altered growth hormone concentration at some time points but was not associated with large increases in circulating proinflammatory cytokines. [ABSTRACT FROM AUTHOR]

Objective--To determine the usefulness of physiologic, behavioral, and pathological changes as objective indicators of early respiratory disease in calves with Mannheimia haemolytica pneumonia. Animals--14 crossbred beef steers. Procedures--Disease was experimentally induced in healthy calves through endoscopic pulmonary inoculation of M haemolytica. Calves were necropsied on days 1, 2, 3, 5, 7, and 9 after inoculation. Physical examination variables (rectal temperature, heart rate, and respiration characteristics), clinical illness score, and degree of activity were assessed 3 times daily beginning 4 days prior to inoculation and continuing throughout the study. Twice before inoculation and on days 1, 2, 3, 5, 7, and 9, arterial blood gas measurements, serum biochemical analyses, and CBCs were performed. Pedometers and accelerometers were used to monitor cattle behavior and activity throughout the trial. Results--All calves became clinically ill after inoculation and had gross and histopathologic signs of bronchopneumonia. No variable was a reliable indicator of disease progression as judged by percentage of pulmonary involvement. However, activity as measured by total steps taken in a 24-hour period was lower after versus before disease induction. Conclusions and Clinical Relevance--This single-pathogen challenge model successfully yielded clinical signs and pathological effects consistent with naturally acquired respiratory disease. Routine laboratory variables and subjective measures were not reliable indicators of lung involvement or the progression of pneumonia. However, activity, objectively measured with pedometers and accelerometers, appeared to be a promising indicator for early recognition of bovine respiratory disease. (Am J Vet Res 2010;71:359) [ABSTRACT FROM AUTHOR]

Objective--To compare sensitivity of a complement fixation (CF) test and competitive ELISA (cELISA) for detection of Anaplasma marginale in experimentally infected steers. Animals--40 crossbred (Angus-Simmental) steers. Procedures--Steers were inoculated with 2.6 X 109 A marginale-infected erythrocytes (day 0). Blood samples were collected on days 9, 13, 20, 28, 34, 41, 61, 96, 126, and 156 days after inoculation. The percentage of parasitized erythrocytes (PPE) was determined by microscopic examination of stained blood films, and sera were evaluated with the CF test and cELISA by use of USDA-approved methods. Sensitivity and agreement (κ statistic) between the 2 methods were determined. Persistent infections were confirmed by inoculation of blood obtained from infected steers into susceptible, splenectomized calves. Results--9 days after inoculation, sensitivity of the cELISA was 475%, whereas the CF test failed to identify seropositive steers. After day 13, sensitivity of the cELISA and CF test was 100% and 20%, respectively During peak parasitemia (day 20), sensitivity of the cELISA and CF test was 100%, Thereafter, sensitivity of the CF test fluctuated between 75% and 375%, whereas sensitivity of the cELISA remained at 100% Overall sensitivity of the cELISA and CF test was 94.8% and 265%, respectively (κ statistic, 0.039). Conclusions and Clinical Relevance--The cELISA had superior sensitivity for serologic detection of A marginale. The CF test and cELISA each had a high percentage of false-negative results during the prepatent period. These findings are relevant for export certification and anaplasmosis prevention or eradication programs. [ABSTRACT FROM AUTHOR]

Objective—To determine the prevalence and effect of Neospora caninum infection and persistent infection (P1) with bovine viral diarrhea virus (BVDV) on weight gain, morbidity, and mortality rate in dairy-breed steer calves located on a feedlot in California. Design—Prospective cohort observational study. Animals—900 dairy-breed steer calves in 2 pens. Procedures—The 3- to 4-month-old calves were evaluated for serum antibodies against N caninum and infection with BVDV at entry to the feedlot. Five months later, sera were again analyzed for anti-N caninum antibodies; calves that were determined to have BVDV infection initially were retested to evaluate Pt status. Average daily gain, morbidity, and deaths were recorded for all calves. Results—Among 900 calves, prevalence of N caninum infection was 16.7% (95% confidence interval, 14.3% to 19.3%); prevalence of BVDV-associated P1 was 0.2% (95% confidence interval, 0.03% to 0.9%). Morbidity rate and time to first illness were not significantly different between calves that were seropositive or seronegative for N caninum. At the second sample collection, weight and average daily gain of calves that were seropositive for N caninum was less than that of seronegative steers in 1 pen, whereas these measures did not differ between groups in the other pen. Statistical power was insufficient to evaluate the effect of BVDV P1 on any outcome measurement. Conclusions and Clinical Relevance—Although N caninum serostatus had no significant effect on morbidity rate, some seropositive calves had reduced growth, compared with seronegative calves, 5 months after entry to the feedlot. [ABSTRACT FROM AUTHOR]

A letter to the editor is presented in response to the article "Description of a novel fatigue syndrome of finished feedlot cattle following transportation" by D.U. Thomson and colleagues, that was published in a 2015 issue.