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Claw diseases often lead to lameness in dairy cattle and are the result of many causes. Therefore, claw diseases are often divided into two primary groups, infectious and non-infectious foot disorders. Claw trimming is usually done for several purposes in addition to alleviating the problem. The question addressed in this study by Dr Alsaaod and co-workers was to establish the magnitude of alleviation, using the possible useful tool of infrared thermography. Their study was published in the Journal of Dairy Science, Volume 98 of 2015, pages 2381 to 2388, with the title:Effect of routine claw trimming on claw temperature in dairy cows measured by infrared thermography
What is the background?
In cattle, the lateral digits of the hind feet are significantly longer than the medial digits, which are considered a risk factor for chronic overload and claw lameness. In addition, the lateral claws of the hind feet are larger and bear more weight than the medial claws. Moreover, increasing pressure concentration on the corium has been attributed to damage of the dermal papillae, followed by disturbance and partial discontinuation of horn production, which increases the risk of developing sole lesions. The lateral claws of the hind feet are mainly affected by such lesions. In contrast, in the front feet, sole ulcers occur less frequently and, when they do occur, mainly involve the medial claws.
As mentioned, claw trimming in dairy cows is performed as a routine management procedure to prevent the development of claw disorders. Numerous studies have shown that prevalence of claw disorders and lameness is decreased in farms that follow a routine claw-trimming protocol. Claw trimming is achieved by removal of excess horn material. The contact area of the claws with the hard surface is increased and the weight-bearing balance between the medial and lateral claw of the foot is improved, with a partial shift from the lateral to the medial claw in the hind feet. Measurements of ground reaction forces during standing showed that the lateral claws of the hind feet and the medial claws of the front feet are exposed to higher maximal pressures compared with the non-trimmed partner claws. Another contributing factor is the weight-bearing area and pressure distribution of the solar surface of the claw which is mainly affected by abrasiveness of the flooring systems. On rough floors, such as asphalt, the sole zone plays a main role in weight bearing (although pressure is lesser due to the increased contact area of the sole), whereas on floors with low abrasion such as rubber mats, the contact area of the claw and the floor is reduced, which results in greater average contact pressure exerted on the claws.
Increasing mechanical pressure over the metatarsal heads, great toe, and heel has been associated with elevated surface temperature of the respective region in humans, which has been picked up by the non-invasive technique of infrared thermography. The local skin surface temperature is increased in cases of elevated metabolic activity or inflammatory conditions. In horses, an even thermal pattern of the hoof was found when weight bearing within the hoof was balanced, and the thermal bands were unilaterally enlarged at the site of increased pressure in unbalanced hooves. Infrared thermography has also detected digital dermatitis (DD) lesions of dairy cows with a high sensitivity and specificity.
In this study the authors were of the opinion that the difference in superficial temperatures between the medial and lateral claws of the hind feet would be decreased by routine claw trimming. This would, in turn, make visible the purpose of routine foot trimming (temporary shift of weight bearing from the lateral to the medial claw), using infrared thermography. This technique might support objective, automated, and non-invasive assessment of the success of claw trimming and, where applicable, the professional activity of foot-trimmers.
How did the study progress?
They used the technique of infrared thermography to assess the effect of routine claw trimming on claw temperature. In total, 648 infrared thermography observations each were collected from 81 cows housed in 6 tie-stalls before and 21 days after claw trimming. The feet were classified as either healthy (the non-lesion group) or affected with infectious foot disorders (group IFD). The maximum surface temperatures of the coronary band and skin and the temperature difference between the lateral and medial claws of the respective foot were assessed. Front feet and hind feet were analyzed separately. Ambient temperature and infectious foot status were identified as external and internal factors, respectively, that significantly affected claw temperature, and were corrected for in the statistical analysis.
The results showed that before claw trimming, the lateral claws of the hind feet were significantly warmer compared with the medial claws, whereas such a difference was not evident for the claws of the front feet. At day 21, the temperature of the hind feet was reduced by equal or more than 0.25°C, whereas it was increased by equal or less than 0.13°C in the front feet compared with the day before trimming. This shows that trimming was associated with a remarkable decrease of temperature of the hind claws.
The authors concluded that the effort to balance the weight bearing of the hind feet by routine claw trimming is accompanied by a measurable reduction in temperature. Secondly, it was concluded that infrared thermography may be a useful tool for non-invasive assessment of claw-trimming.