Hoof diseases in dairy cattle
Bovine lameness is predominantly caused by diseases of the hoof. These can be subdivided into non-infectious and infectious diseases.
Non-infectious diseases
Surface and deep ulcers on the soles of the hooves are one of the main non-infectious diseases of the hoof. A variety of non-infectious hoof diseases arise as a complication of chronic laminitis. During laminitis, the pedal bone sinks into the hoof. The sensitive corium is compressed, which in turn leads to circulatory and diffusion disorders. Horn development is impaired, which can be ascertained during hoof trimming after approximately six weeks through yellowish and reddish discolouration of the sole horn (haemorrhaging) or their cracked consistency (double sole formation).
[Source: Kerstin E. Müller, Tilmann G. Eilers, 2008]
Infectious diseases of the hoof
Infectious diseases of the hoof generally affect the sensitive area of skin between the hoof wall and sole along with the adjacent layers of horn. The most widespread infectious diseases of the hoof are interdigital dermatitis, digital dermatitis, Mortellaro disease and interdigital phlegmon.
[Source: Kerstin E. Müller, Tilmann G. Eilers, 2008]
Interdigital dermatitis (heel horn erosion and hoof rot)
Unlike strawberry heel, heel horn erosion impairs horn growth, leading to fissured, in part severely inflamed heels and a characteristic rotting smell. The hooves of the hind legs are more commonly affected. Excessive hoof horn formation at the bulbs caused by bacteria is exacerbated by a moist, warm cattle shed climate. The hard sole horn slides over the bulbs that have been radically changed by the decomposing enzyme in the bacteria. Pockets form in which the optimal conditions for germs prevail.
Hoof rot occurs in the interdigital space. The abovementioned bacteria also play a central role here. Moist, unclean ground conditions and a lack of "cow comfort" must first do the groundwork though. The skin in the interdigital space softens, germs penetrate and the tissue begins to rot away. Calluses often form on the surface.
[Source: Andrea Fiedler, 2007]
Digital dermatitis (Mortellaro disease, strawberry heel)
This extremely painful disease of the dermis mainly appears as round to oval, raw lesions with a raised appearance. However, outbreaks of so-called proliferative, wart-like lesions are also observed in some herds. The disease – predominantly on the hind legs – usually occurs at the juncture between the coronary band and soles of the hooves, and in the hoof bulbs. They range from pea-sized to the size of a fist.
This infectious disease is a mixed infection with different characteristic germs. It occurs when combined with stress factors, which weaken the body's immune defences. Excessive moisture, both on the walkways/standing areas and in the air (humidity) lead to an increased bacterial load. Further stress factors that "weaken" the cow can be due to illness or herd management (e.g. IBR/BVD infections, hierarchical fights, a lack of "cow comfort"). Several cows in a herd tend to then be affected; the lesions are large and extremely painful.
[Source: Dr. Andrea Fiedler, 2007]
Interdigital phlegmon (interdigital necrosis, acute interdigital necrobacillosis, panaritium)
This disease is defined as acute phlegmonous inflammation of the interdigital skin involving the underlying tissues, which is accompanied by hyperkeratotic and parakeratotic changes to the bulb horn. Espinasse et al (1984) and Dirksen (2002) speak of secondary spread of interdigital dermatitis, which is also caused by inflammation of the skin in the interdigital space, but in the case of interdigital dermatitis, no underlying tissues are affected. Interdigital necrosis is widespread around the work and primarily develops during phases of stall keeping. In tethered animals, it is primarily the hooves of the hind legs that are affected; decay in the front legs is far more common in animals kept in pens. Several animals in one herd often contract the disease one after the other. A notable increase in the number of cases can be observed in heifers and cows around the time of birthing as well as in beef cattle (Dirksen 2002). This disease caused by raising of the bulb area can be kept to a minimum by means of species-friendly hoof care (Toussaint Raven 1998).
[Source: www.intervet.de]
Further information
The German Agricultural Society (Deutsche Landwirtschafts-Gesellschaft, DLG) has published guidelines on the diagnosis of disease of the hoof: "Klauenkrankheiten" – Praxisanleitung für eine sichere Diagnose (www.dlg.org)