After mastitis and reproductive failure, lameness is the most important problem in cows. Lameness not only causes economic loss to farmers but is also an important animal welfare issue. There are a large number of factors contributing to lameness in cattle. Nutrition and feeding, housing and environment, concurrent disease, genetic makeup, and management are some of the main predisposing factors to foot problems. The most frequent causes of lameness are: laminitis, claw disease, digital dermatitis, and foot rot. A proper understanding of lameness conditions in terms of what they are, how or why they occur, and what to do with them is essential to minimize production losses as well as the loss of cows from lameness and related problems. |
Anatomy of the cow foot The cow foot is made up of two digits. These digits are covered by horn, which is cornified epidermal tissue, also called hoof capsule. It has both biological and mechanical functions and it wear the weight of the cow to the floor. The main tissue components of cow digit are: the horny capsule of hoof composed of hard keratinized tissue, subcutaneous connective tissue, tendons, ligaments, blood vessels, nerves, fatty tissue and bones. Each digit has three bones, the distal, middle and proximal phalanges. The distal phalanx also called as pedal bone contacts the laminar corium of the sole. Anatomical deformities of digits can also lead to an increased rate of lameness. Majority of the body weight is placed over the hoof wall. Diseases causing the lameness In Cows the greatest incidence (90 percent) of lameness involves the foot, and of these, 90 percent involve the rear feet. Below is a brief account of some of the main diseases that cause lameness in cows. Diseases of horn of hoof Laminitis Acute or chronic inflammation of the laminae of the hoof is called laminitis. Laminitis itself may cause lameness in cows, often in all four feet, but it is a predisposing cause for other diseases causing lameness, such as sole ulcer and white line abscesses. Laminitis may be caused by various factors like housing systems and management factors that force animal to stand instead of lying down and increase the stress on the feet. Improper nutrition is also a factor for predisposing the cows to laminitis. A predisposing feed includes a feed high in starch and low in fiber, leading to ruminal acidosis particularly in overweighing cows, diets high in crude protein content and sudden change of diet e.g. from low to high concentrate. Laminitis caused byexcessive concentrate diet is called as grain founder and if caused by abrasive surface of floor it is called as road founder and if caused by eating of lush green grass it is called grass founder. Sole ulcer Laminitis in cows predisposes the hoof to sole ulcers. In laminitis, the pedal bone drops and puncture the sole thus an ulcer appears in the center of the sole towards the heel. The ulcer may progress to necrosis of sole and often infection. This infection may travel to nearby tissue and joints thus further complicating the condition. Lumps of granulation tissue (proud flesh) may protrude from the ulcer area. Sole ulcers typically occur in the lateral claw of the hind foot. Sole ulcers are most common disease condition of foot and may lead to severe economic loss and decline in fertility. White line disease Part where the wall of the hoof joins the sole is called white line. It is a weaker area in the hoof and cracks in it can allow dirt and infection to enter, leading to pus formation (mainly on the outside of the lateral claw of the rear foot) or other diseases and ultimately the lameness. Laminitis, abnormal hoof conformation and improper nutrition may lead to weakness of the white line. White line disease is most common on the concrete but abrasive floor of the cowsheds. Such flooring causes bruising in the white line and makes the entrance for bacteria. Slurry heel This condition is most common in older cows and is also known as heel erosion. In slurry heel damage to the bulb of heel may occur in all four feet, but it may only affect the hind feet. The lateral digit is most commonly involved. The bacterium Dichelobacter (Bacteroides) nodosus, which is an obligate anaerobic bacterium, is considered to be involved in slurry heel. This bacteria produce keratolytic enzymes that erode the horn thus leading to rotation of pedal bone and the toe may no longer be able to bear the weight. The predisposing factors for slurry heel are the moist conditions. More moisture leads to softening of the horn tissue thus more prone to infection. Diseases of skin causing lameness Digital dermatitis Digital dermatitis is a contagious inflammation of the epidermis and is associated with housing. It mainly affects the bulbs of the heels, but the interdigital space may also be affected. In its severe form coronary band (horn/skin junction) may be involved thus increasing the lameness. Mostly it is caused by bacterial infection of Spirochaetes, which also produce keratolytic toxin. It can produce two types of lesion: erosive (strawberry-like) or proliferative (wart-like). The erosive form is very painful and has a pungent smell. Because of chronic irritation of skin, wart-like lesions may occur when it is not treated. Foot rot The most frequent causes of foot rot in cattle are Fusobacterium necrophorum or Spherophorus necrophorus, bacteria that are widespread in the animal's environment, especially in mud and manure. In addition, yeasts and molds may also be the contributing organisms. Bacteria gain entry following the damage to the interdigital skin by a foreign body such as sharp pieces of stone, metal, wood, stubble, or frozen manure, continuous exposure to mud or moist manure that causes irritation and erosion, excessive dryness of the hoof and skin that cause cracking, or injuries. The infection results in sudden lameness, often in one limb. The signs of foot rot in cattle include increase in body temperature, lameness, the holding or raising of a foot, reluctance to move, impaired locomotion, loss of appetite and weight, and reduction in milk production. There may be bad smell because of the necrosis of skin. Severe illness or death can occur in prolonged cases. Diseases of joints causing lameness Septic arthritis Infection in foot, because of sole ulcer or foot rot, may involve the surrounding tissues and reach the digital joints leading to septic arthritis, It commonly involves the pedal joint between the pedal bone and the second phalangeal bone. Main clinical signs of septic arthritis are the swelling of the joints, acute pain, reduced appetite, weight loss and longer periods of recumbency. Joint ill In newborn calves any general infection can involve the joints of limbs thus leading to lameness. The most common causative agents encountered are E. coli and Streptococcus, which are found in great numbers in damp, dirty bedding. It causes severe lameness. Usually the naval ill leads to joint ill in calves. So care of naval cord should be taken to avoid lameness in early life. Lameness due to Injuries Carpal Hygromas Hock and Damage A hygroma is a swelling on the joint and is produced by the excessive fluid accumulation in the acquired bursa. Hock damage, such as hygroma and traumatic arthritis, primarily results from chronic mechanical irritation due to rough floors with little or no bedding, poor floor or building design, and poor hygienic conditions. The skin over a hygroma may change and may be hairless, thickened and flaky. A hygroma may contain blood clots and serum, but infection often produces an abscess, which eventually bursts and drains leaving behind a fibrous lump. Control and Prevention of lameness Cowsheds In housing, type of flooring is one of the major factors to be considered with respect to lameness. Hard concrete floors may cause abrasions in the hoof. Floor surfaces must not be too smooth nor too rough. Smooth floors may be slippery leading to injury to the animals and lameness. If floor is not good animal will not lie down and prefer to stand and walk around thus increasing the stress on the feet. To prevent lameness proper bedding of wheat straw or any other soft straw should be provided. It has been observed that cows housed in straw padded sheds lie more, ruminate more thus get better rest and have improved digestion for increased production. Cow sheds and fences should be made carefully so that they do not cause injury and do provide comfort to cows. Overcrowding should be avoided in the cowsheds and sheds should be kept clean and dry by scraping out slurry at least twice a day and providing new bedding material. If sheds are different for heifer, pregnant and lactating cows, then the cows should be acclimatized by moving a few days forehand to new shed. If pastures are used for cows, it should be ensured that cows are not hurried while walking. Cows should not walk for more than 500 meters on concrete roads. Nutrition Many of the foot diseases are of nutritional origin, e.g. more concentrate may lead to ruminal acidosis and thus laminitis. Laminitis is a root cause to many problems of hoof and may lead to chronic conditions. Excess of proteins in diet may also cause laminitis. This may be due to more ammonia production in rumen. So cows should be fed as per their requirements and body weight. Sudden change in diet should be avoided and there should always be tapering and gradual shift to new feed. Straw and hey should also be included in diet along with the concentrates as it helps to limit the ruminal acidity. Some other elements also play a major part in preventing foot diseases. Selenium is such a mineral. Both excess and deficiency of selenium is harmful. Selenium toxicity may lead to overgrown hoofs which may slough off in severe cases. Some of the other mineral deficiencies, such as sulphur and zinc deficiencies, may contribute to poor horn formation, and these minerals may need supplementation when dietary supply is insufficient. Vitamins such as biotin have been shown to reduce lameness and improve healing of sole ulcers and wall cracks. Foot Care Routine foot inspection should be performed and any anomaly should be managed immediately. Regular foot trimming can be beneficial, as it reduces the risk of lameness due to misshapen and overgrown hooves. The development of overgrown feet is the result of foot conformation, type of environment and rate of horn growth versus wear. On a herd basis, trimming allows regular examination of the feet and hence early diagnosis of any lameness lesion. Animals with disfigured feet, and those with a history of clinical lameness, should be given priority. It is important that cows are not driven immediately after trimming along stony or poorly constructed and maintained tracks. The dry period is the most convenient period for hoof trimming. Foot trimming is a skilled job and it must not be attempted without proper training and handling facilities (e.g. a crush). Foot Bathing Footbaths are important tool for hoof care. Their use can clean feet, kill bacteria and help to harden horn. Footbaths help to reduce lameness associated with foot rot, heel erosion and digital dermatitis when used with the suitable treatment. Solutions of 5–10% zinc or copper sulphate are most commonly used in organic farming. A footbath should be included in the design of the housing system, generally near the exit from the milking parlour in a position through which cows normally move or in an adjacent area through which cows can be diverted when necessary with minimal disturbance to their normal routine. Ideally, two footbaths should be used in tandem: the first containing water to clean the feet and the second a suitable chemical. If the herd is suffering from contagious foot rot, the use of footbaths should be carefully considered as they may spread the disease in the herd. To prevent excessive hardening of the feet, dairy cattle should not be put through a footbath on a daily basis but as required or as recommended by a veterinarian. Breeding Selection of sire and dam plays important role in long-term management of lameness in cows. Sires with good linear scores for shape of foot, depth of heel, depth of hock and pastern angle should be selected. Cows with severe clinical lameness or with hoof/limb deformity (such as sole ulcers and corkscrew claws) should not be used for breeding purpose. However a lot more research is required to establish breed predilection of lameness among the exotic, crossbred and indigenous breeds. There are many other factors that can help in reducing the suffering of cow by checking the lameness. A proper record of lameness and other hoof and limb diseases should be kept. Newly purchased animals should be given a footbath in zinc or copper sulphate and hoof should be checked for any lesion. Preference should be given to purchase the animals from disease free or lameness free herd. Young heifers and cows in first lactation should be monitored carefully for any foot lesion and any disease should be controlled in early stage. Veterinarian should be consulted if lameness is severe, protracted or very frequent within a herd. Top |