The fact that about 90% of lameness is caused by claw-related diseases accentuates the impact of laminitis. The average percentage of lame cows in herds differs, depending on country and stable management. Financial losses are high, because one lame cow can cost between 200 and 300 Euros/lactation. This means a financial loss of 4,000 to 6,000 Euros in a herd with 100 cows and an average lameness prevalence of 20 %.
Economic costs consist of:
- Treatment costs (veterinary, medical costs, working time of the farmer)
- Decreased milk yield (up to 400 kg/cow for every 305 lactation days)
- Decreased body weight
- Lower reproductive performance
- Higher susceptibility to other diseases
- Increased involuntary culling rates
A lot of factors can influence the prevalence and severity of laminitis. Most of them can be avoided by appropriate feed and health management strategies.
Role of endotoxins in development of laminitis
Endotoxins are parts of the cell wall of Gram-negative bacteria, and are released when bacteria multiply, lyse and die. Sources of endotoxins are in the environment as well as in the rumen and gut. If an excessive amount of carbohydrates is ingested, they cannot be digested in the foregut, and are digested in the hindgut. This leads to an imbalance in the bacteria population in the gut. Gram-positive bacteria (e.g. Streptococcus bovis) proliferate rapidly, which consequently results in the death of Gramnegative bacteria (family Enterobacteriaceae). As endotoxins are released when bacteria die, the amount of endotoxins can dramatically increase during carbohydrate overload. In addition to the release of endotoxins, acidity is increased and affects the gut permeability. Endotoxins are absorbed into the bloodstream, together with other toxins, such as mycotoxins and exotoxins as well as histamine. This worsens the blood supply of the lamella tissue, and increases the blood pressure in the feet.
Processes in the hoof/claw
If toxins reach the hoof/claw tissue, an inflammation process starts. Specific cells activate cytokines (e.g. TNF-alpha, IL-6) and enzymes (e.g. matrix metalloproteinases), which weaken or even destroy the tissue. In the worst cases, the connective tissue of the pedal bone completely separates from the lamellar tissue, which causes the rotating, and eventually, the sinking of the pedal bone. This process causes a lot of pain, and is irreversible.
Treatment and prevention
In acute cases, non-steroidal anti-inflammatory drugs, vasodilators and pain killers are given to the animal. Furthermore, claws/ hooves can be trimmed to minimize the pressure on the affected tissue. In addition, foot baths and cooling of the claws/hooves can be helpful. The animal needs to rest on deep and soft bedding material until it has recovered. In the worst cases, the animal has to be euthanized.
To minimize the trigger factors, and therefore reduce the risk of laminitis, some points have to be considered:
- Appropriate feeding management: avoid excessive amounts of carbohydrates
- Bedding material
- Good hygiene management
- Regularly hoof/claw trimming
- Grazing management (especially in horses)
- Avoid obesity in horses
- Supplementation of minerals
- Application of proper mycotoxins and endotoxins risk management