Serial evaluation of physiologic, pathological, and behavioral changes related to disease progression of experimentally induced Mannheimia haemolytica pneumonia in postweaned calves

Abstract

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.

Blood Gases, Acid-Base Status And Plasma Lactate Concentrations In Calves With Respiratory Diseases

“…However, the results were inconsistent for all days after challenge and generally obtained lactate levels were within normal reported ranges and values higher than 2 mmol/l were found only in affected calves with pO 2 values lower than 50 mmHg (6.65 kPa). An experimentally induced Mannheimia haemolytica pneumonia successfully yielded clinical signs and pathological effects consistent with the naturally acquired respiratory disease but without a signifi cant increase of lactate concentration [14]. The authors did not fi nd blood lactate concentration to be useful in identifying early BRD, possibly because generalized body-tissue anaerobic metabolism did not have a chance to develop due to the low percentage of pulmonary involvement.…”

“…Decreased delivery to the brain or heart can lead to collapse, and decreased delivery to other tissues leads to lactic acidosis and metabolic abnormalities [12]. However, there are only few data about the effects of hypoxia on blood lactate levels and, consequently, hypoxic lactacidemia and changes in acid-base balance in calves suffering from respiratory diseases [13][14][15][16].…”

Remote Noninvasive Assessment of Pain and Health Status in Cattle

“…In another respiratory disease trial, there was no difference in the amount of time morbid calves spent lying down or walking compared with baseline data collected prior to challenge. 3 These findings suggest that the postural activity of cattle may be influenced by disease or pain state, but changes in standing and lying behavior may not be a specific response to changes in wellness status.…”

“…11 Scoring systems that assign a value based on degrees of illness are relatively common, 12 and are frequently used in disease research. 3,10,13 Even when quantitative measurements, such as rectal temperature, are combined with subjective assessment, the final disease classification remains subjective. 14,15 This subjectivity may impact how the results are interpreted if the CIS is used as one of the criteria in a treatment or preventative health program.…”

“…Objective, continuous behavioral monitoring using accelerometers and pedometers has been used to assess cattle behavior in a variety of scenarios. [3][4][5][6][7][8][9] Monitoring cattle location within a defined environment has also been used in an effort to identify and monitor potential behavioral changes. 8,10 The objective of this review is to describe potential benefits and challenges of remotely monitoring cattle behavior with available methodologies including clinical illness scores, visual monitoring, accelerometers, pedometers, feed intake and behavioral monitoring, global position systems, and real time location systems.…”