| dc.description.abstract | The acute phase response (APR) represents a protective, coordinated response of the host with the aim of eliminating the inciting stimuli and re-establishing homeostasis. Produced by activated immune cells, proinflammatory cytokines serve as effector signals for communication between the immune system and other parts of the body, including the brain. The APR is comprised of complex neurologic, immune, endocrine, and metabolic changes. The actions of proinflammatory cytokines also elicit behavioral changes. These sickness behaviors include depression, lethargy, anorexia, and reduced activity. Detection of disease in livestock species is challenging, given the nature of these prey species to conceal signs of illness to human observers. Improvement in the health, welfare, and production of cattle has included the development and application of remote monitoring technologies. These technologies are capable of objectively quantifying physiological parameters and behaviors. One such technology used to measure sickness behavior in cattle is the three-dimensional (3-D) accelerometer, which can be applied and used to quantify lying, standing, walking behaviors, under various experimental and naturally occurring conditions.
Use of remote monitoring technologies to detect behavioral changes indicative of disease was the objective of our experimental studies. In the first experiment, the objective was to assess sickness behaviors during mild experimental endotoxemia. Lipopolysaccharide (LPS) was delivered using implanted osmotic mini-pumps (OMP) to weaned beef calves. The LPS (E. coli O55:B5) was delivered at 30 μg/(kg · d) for 7 days to principal calves, with an equivalent volume of saline delivered to control calves implanted with OMPs. Use of OMP was novel for the low-dose, prolonged time course of LPS administration in cattle. Changes in traditional markers of inflammation were observed, including significant differences in rectal temperature, body weight, fibrinogen, albumin, and platelets between groups. Objective quantification of behavioral changes, using accelerometers, demonstrated significant differences between groups, with LPS calves spending more time lying, less time standing, and more time walking post-LPS infusion.
In our second study, sickness behaviors using 3-D accelerometers were evaluated in weaned beef calves following experimental infection with bovine viral diarrhea virus (BVDV). Ten weaned beef calves were inoculated intranasally with 4 x 106 TCID50 with the low-virulent BVDV strain 134F, and control calves (n = 10) were intranasally administered BVDV-free medium. The challenge model was very mild, with mean time allotted to each activity not differing significantly between groups on any day except day 8 post-inoculation. On day 8, BVDV calves spent less time standing than controls. Following virus inoculation, calves in both groups tended to spend more time lying and less time walking and standing compared to their respective baselines. Although subtle changes in behavior were appreciable in BVDV-infected calves, the use of accelerometers could not distinguish calves subclinically infected with BVDV from healthy controls.
Use of remote monitoring technologies to demonstrate deviation from normal baseline behavior has been applied for the detection of normal physiological states, including estrus and parturition. Use of accelerometer-based activity data for the prediction of parturition has been primarily evaluated in housed dairy cattle. The aim of our third study was to characterize behavioral changes using accelerometers during the peripartum period in pastured beef cattle. Activity data were collected from 40 multiparous and 40 primiparous mixed-breed beef cows using accelerometers, housed on pasture. Data represented two successive fall calving seasons. Within 24 hours of parturition, changes in activity indices were demonstrably different from baseline. Time spent lying and standing decreased and increased, respectively, as well as increases in lying bouts frequency and steps.
The fourth study, paired with the peripartum cow behavior study, characterized the behavior of neonatal calves during the first 7 days of life, using accelerometers. There is limited research utilizing remote monitoring technologies in young calves, especially pastured beef animals. Concurrently, measures of transfer of passive immunity and weight gain were assessed. Activity data and other parameters were collected from a total of 70 mixed-breed beef calves. During the first week of life, calves gradually spent more time standing, less time lying, and a reduction in lying bout duration. Calves born to multiparous dams had significantly higher IgG concentrations and increased weight gains compared to calves born to primiparous dams. A positive correlation between change in body weight and IgG status on day 7 was present in both primiparous and multiparous groups. Correlations between behavioral indices and IgG were found in calves of multiparous dams only. Calves with greater IgG concentrations demonstrated reduced activity.
Overall, accelerometers were successfully applied and tolerated by pastured beef cows and calves. The results of our research indicate accelerometers were useful in the quantification of behavioral changes during naturally occurring physiological changes as well as during experimental subclinical disease incidents in cattle. | en_US |
