Lame sheep adjust behavior to cope with their condition

Automated technology suggests lameness alters other behaviors besides walking.

January 16, 2020

3 Min Read
Nottingham lame Sheep_x53514a40.jpg
University of Nottingham

Using novel sensing technology, researchers from the University of Nottingham have found that lame sheep adjust how they carry out certain actives, such as walking, standing or lying down, rather than simply reducing the amount of activities they do.

In the first-of-its-kind study, published in the Journal of the Royal Society Open Science, a team of experts from the School of Veterinary Medicine & Science at the University of Nottingham was able to demonstrate the automated detection of lameness in sheep when standing, lying and walking using a new prototype tagging and monitoring system.

The technology was developed by Dr. Jasmeet Kaler, associate professor in epidemiology and farm animal health from the university, along with Intel and agricultural software developer Farm Wizard.

As sheep are a prey species, they are likely to mask signs of lameness when they feel threatened or enlivened by the presence of observing farmers and veterinarians. It means that up until now, diagnosis has been difficult and relied on visual inspection because no validated commercial tools have been available, the researchers explained.

The wearable smart technology consists of a sensing device worn on a sheep’s ear tag that gathers accelerometer and gyroscope data, effectively tracking the animal’s behavior and movement and its way of walking. The algorithms are used to create different alerts for farmers.

For all three activities (standing, walking and lying), the study identified features that differed between lame and non-lame sheep. This is particularly novel in lying and standing activities, which have not-so-obvious lameness-related behaviors that previously were difficult to spot with the human eye, Nottingham said.

The results suggest that instead of affecting how much of an activity lame sheep do, they actually carry out activities differently, leading to a change in acceleration and rotational movement, according to the announcement.

Detecting features that significantly differentiate lame from non-lame animals was not surprising because of visual differences previously reported in the gait patterns of lame and non-lame sheep, the researchers said.

Five out of the top six characteristics when walking were related to rhythm and pace. These differences could be linked to reduced mobility because of the lameness, which also resulted in differences in the regularity and frequency of head movements, according to the announcement.

Lame sheep also showed a change in gait -- with peculiar head nodding in line with stride -- compared to non-lame sheep, which had a smoother stride pattern.

A particularly interesting finding was that the results for classification of lameness had greater accuracy within lying and standing activities, Nottingham said.

The top features include a mixture of frequency and time-domain features, which suggest differences in in the variability and smoothness of movements for both standing and lying down between lame and non-lame sheep. In lame sheep, this could be the animal's attempt to reduce discomfort caused by the lameness, the researchers suggested.

The research also suggests that lame sheep possibly lie down differently from non-lame sheep, which also could be related to the animal’s attempt to alleviate pain.

Kaler said, “Our study has shown conclusively that there are behavioral differences between lame and non-lame sheep when walking, standing and lying. This has been the first report of its kind, and given lameness classification is possible within all these activities, this helps to improve the accuracy as well as flexibility in terms of energy requirements. This automated system for the lameness detection can help improve sheep health and welfare on farms.”

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