Physiological and behavioral responses as indicators for early disease detection in dairy calves

Abstract

This study investigated physiological and behavioral responses associated with the onset of neonatal calf diarrhea (NCD) in calves experimentally infected with rotavirus and assessed the suitability of these responses as early disease indicators. The suitability of infrared thermography (IRT) as a noninvasive, automated method for early disease detection was also assessed. Forty-three calves either (1) were experimentally infected with rotavirus (n = 20) or (2) acted as uninfected controls (n = 23). Health checks were conducted on a daily basis to identify when calves presented overt clinical signs of disease. In addition, fecal samples were collected to verify NCD as the cause of illness. Feeding behavior was recorded continuously as calves fed from an automated calf feeder, and IRT temperatures were recorded once per day across 5 anatomical locations using a hand-held IRT camera. Lying behavior was recorded continuously using accelerometers. Drinking behavior at the water trough was filmed continuously to determine the number and duration of visits. Respiration rate was recorded once per day by observing flank movements. The effectiveness of inoculating calves with rotavirus was limited because not all calves in the infected group contracted the virus; further, an unexpected outbreak of Salmonella during the trial led to all calves developing NCD, including those in the healthy control group. Therefore, treatment was ignored and instead each calf was analyzed as its own control, with data analyzed with respect to when each calf displayed clinical signs of disease regardless of the causative pathogen. Milk consumption decreased before clinical signs of disease appeared. The IRT temperatures were also found to change before clinical signs of disease appeared, with a decrease in shoulder temperature and an increase in side temperature. There were no changes in respiration rate or lying time before clinical signs of disease appeared. However, the number of lying bouts decreased and lying bout duration increased before and following clinical signs of disease. There was no change in the number of visits to the water trough, but visit duration increased before clinical signs of disease appeared. Results indicate that milk consumption, IRT temperatures of the side and shoulder, number and duration of lying bouts, and duration of time spent at the water trough show potential as suitable early indicators of disease.

Automated Collection and Analysis of Infrared Thermograms for Measuring Eye and Cheek Temperatures in Calves

“…Over time, the livestock industry has seen a significant change in response to an increasing reliance on automated systems. This reliance has largely been driven by a need to reduce labour costs and has resulted in the development of automated systems such as the robotic milking and automated calf feeder systems seen in modern dairy farming systems [1]. This increasing level of automation in the livestock industry [2] has resulted in a less "hands-on" approach to farming, and additionally, there are fewer experienced stock people in the industry [3].…”

“…With specific relevance to cattle welfare, some of the applications that IRT has been used for include diagnosing mastitis [15] and lameness [16,17] by detecting areas of inflammation and as a method for measuring stress and pain responses to procedures such as disbudding [18], castration [19], handling [20] and transport [21]. IRT has also been used in previous studies as a method for the early detection of diseases such as bovine viral diarrhea (BVD), bovine respiratory disease (BRD) [22][23][24] and neonatal calf diarrhea (NCD) [1,25] and, additionally, as a method for detecting differences in feed efficiency [26][27][28]. Previous studies have collected infrared images from various anatomical regions.…”

“…Generally, thermal infrared images are collected and analysed manually, where an observer collects images using a handheld infrared camera (e.g., ThermaCAM S60; FLIR systems AB, Danderyd, Sweden) [1,26]. These images are then analysed using specific analysis software (e.g., ThermaCAM Researcher; FLIR systems AB, Danderyd, Sweden).…”

“…Furthermore, the development of algorithms is necessary for the successful integration of IRT into automated systems where it could then be utilized for noninvasive monitoring of animal health and welfare. The integration of IRT into automated systems could potentially enable diseased animals to be identified sooner than is currently possible based on overt clinical signs [1]. This would enable sick animals to be identified and isolated from their pen mates to prevent the spread of disease and would enable treatments to be administered sooner [1].…”

“…The integration of IRT into automated systems could potentially enable diseased animals to be identified sooner than is currently possible based on overt clinical signs [1]. This would enable sick animals to be identified and isolated from their pen mates to prevent the spread of disease and would enable treatments to be administered sooner [1]. A system providing the ability to detect early disease onset would also facilitate decision-making abilities for farmers, reducing costs on-farm and for the industry as a whole through reduced labour, mortalities and veterinary costs, and, overall, would lead to improvements in both production and animal welfare [1].…”