Evaluating Alternatives to Locomotion Scoring for Lameness Detection in Pasture-Based Dairy Cows in New Zealand: Infra-Red Thermography

Abstract

Lameness in cattle is a complex condition with huge impacts on welfare, and its detection is challenging for the dairy industry. The present study aimed to evaluate the association between foot skin temperature (FST) measured using infrared thermography (IRT) and locomotion scoring (LS) in dairy cattle kept at pasture. Data were collected from a 940-cow dairy farm in New Zealand. Cows were observed at two consecutive afternoon milkings where LS was undertaken at the first milking (4-point scale (0–3), DairyNZ). The next day, cows were thermally imaged from the plantar aspect of the hind feet using a handheld T650sc forward-looking infrared camera (IRT). The association between FST and locomotion score was analysed using a generalised linear model with an identity link function and robust estimators. ROC curves were performed to determine optimal threshold temperature cut-off values by maximising sensitivity and specificity for detecting locomotion score ≥ 2. There was a linear association between individual locomotion scores and FST. For mean temperature (MT), each one-unit locomotion score increase was associated with a 0.944 °C rise in MT. Using MT at a cut-off point of 34.5 °C produced a sensitivity of 80.0% and a specificity of 92.4% for identifying cows with a locomotion score ≥ 2 (lame). Thus, IRT has a substantial potential to be used on-farm for lameness detection. However, automation of the process will likely be necessary for IRT to be used without interfering with farm operations.

Assessing Alternatives to Locomotion Scoring for Detecting Lameness in Dairy Cattle in Tanzania: Infrared Thermography

“…The speci city and sensitivity of IRT at our 38.0 cut-off point for identifying cows with a locomotion score of ≥ 2 were both moderate (86.0 and 73.2%, respectively) and lower than the speci city and sensitivity we reported in New Zealand of 92.4 and 80.0%, respectively (Werema et al, 2021). However, as with the difference between the two studies in relation to optimal cut-off, the difference between our two studies is much less than the differences between previous studies, which have reported the speci city and sensitivity of IRT.…”

“…Additionally, the order was consistent across claws, such as if on the lateral claw, zone 1 had a higher mean temperature than zone 2, the same applied to zones 5 and 6 on the medial claw. However, the order was not the same as that reported by Werema et al (2021). In the current study, zones 1 and 5 (coronary band) had a higher mean temperature than zones 3 and 7 (below accessory digit), whereas Werema et al (2021) reported that zones 3 and 7 had a higher temperature than zones 1 and 5.…”

“…However, the order was not the same as that reported by Werema et al (2021). In the current study, zones 1 and 5 (coronary band) had a higher mean temperature than zones 3 and 7 (below accessory digit), whereas Werema et al (2021) reported that zones 3 and 7 had a higher temperature than zones 1 and 5. The reason for this difference is unclear.…”

“…1). The maximum temperature for each zone was used for analysis in line with previous infrared studies aimed at lameness detection in the cow (Stokes et al, 2012;Werema et al, 2021;Whay et al, 2004).…”

“…On all three farms, unlike in New Zealand (Werema et al, 2021), there was su cient time during milking to collect thermal images from all cows. Hand milking increased the time available for image collection as it was slower than when the machine was used, but during hand milking, the milker obstructed the cow's feet, and the cows were more restless, leading to frequent changes in foot posture.…”