Laminitis (founder) is associated with sole ulcers, white line separation, and heel horn erosion. Laminitis is an inflammation of the sensitive tissues (lamellae) of the hoof. It is caused by both nutritional and management problems.
Hoof infections are generally related to environmental conditions and the presence of causative organisms. These diseases generally affect the skin of the hoof. Nutrition does impact skin integrity, the first line of defense against infections.
When acid production exceeds the rumen’s ability to buffer and absorb the acids, rumen pH drops and acidosis and laminitis can develop. Nutritionists control ration non-fiber carbohydrate, effective fiber, buffers, and DCAD to reduce rumen acidosis.
Management is involved with laminitis. Pay attention to exercise, cow comfort, hoof trimming, and general stress reduction.
General hoof health can be improved with biotin and zinc supplementation.
Lameness is a serious economic issue on many dairy farms. Lameness is associated with several disease conditions and can have a number of causes. Laminitis (founder) is associated with sole ulcers, white line separation, and heel horn erosion. Laminitis is an inflammation of the sensitive tissues (lamellae) of the hoof. It is associated with both nutritional and management problems. Hoof infections, such as inter-digital dermatitis (heel cracks and quitters), digital dermatitis (hairy heel warts, strawberry heel), and foot rot are generally related to environmental conditions and the presence of causative organisms. These diseases generally affect the skin of the hoof rather than the claw itself. Control of these diseases is accomplished mostly through management and aggressive therapy but nutrition impacts skin integrity, the first line of defense against infections.
Systemic or metabolic acidosisoccurs when the cow’s blood becomes acidic from too much acid being absorbed from the rumen into the blood (see Acidosis). Acidic blood cannot carry as much oxygen. The cow’s feet, being at the farthest points of the cow’s body, receive the least oxygen. Histamine, a vasodilator and arterial constrictor, is released in response to the damage. The small blood vessels that supply the horn-producing tissues suffer the most and the cow’s feet swell. The sensitive tissues (lamellae) that are located in between the outside wall of the hoof and the coffin bone (on the inside) become inflamed. Pressure between the hoof wall and bone inside results in the pain, hemorrhages, and ulcers associated with laminitis.
Keratinocytes up in the living layer of the foot (the corium or “quick”) produce the keratin (a protein) and the “intracellular cementing substance” which bind together in a fibrous complex to make the hoof horn. As the tissue moves, it hardens and cements together until it eventually dies, forming the hard outer layer of the hoof horn. Hoof horn protects against the invasion of bacteria into the tissues underneath. Any time the hoof becomes inflamed, as in the case of metabolic acidosis, the keratinocytes do not receive the nutrients and oxygen that they need. The result is the production of poor quality, soft hoof horn. Between the hoof wall and the sole is the white line that is around the circumference of the bottom of the hoof. Often, when the hoof horn is poor quality, the white line gets damaged, separates, and bacteria invade there.
It takes 15-20 months for hoof wall tissue to migrate down from the living layer to the weight-bearing part of the hoof (like in a fingernail). A horizontal ridge found 2/3 of the way down the hoof wall tells you that the keratinocytes were negatively affected by something 8-9 months previously. Hoof horn in the sole and heel takes about 2-3 months to reach the bottom of the hoof. So, any hemorrhages there indicate a problem 4-8 weeks before.
Signs of Laminitis:
- Cows “plod” as they walk or they look like they are “walking on eggs”
- Cows stand with their feet close together or crossed
- Above the coronary band, it is pink and puffy
- Hemorrhages appear as pink striations in the hoof
- White line separation and sole ulcers are seen
- Hooves become wide and flat and develop ridges
Laminitis and Nutrition
A byproduct of carbohydrate fermentation in the rumen is acid. Highly digestible carbohydrate produces large amounts of acid. Rumen acids are buffered by saliva and by added dietary buffers such as sodium bicarbonate. The acids are absorbed from the rumen via the rumen papillae located on the rumen wall. When acid production exceeds the rumen’s ability to buffer and absorb the acids, rumen pH drops. With the reduction in rumen pH, bacteria that produce a stronger acid called lactic acid become a larger part of the bacterial population. They cause rumen pH to drop even more.
Rumen pH less than 5.8 will reduce growth of the fiber-digesting bacteria. Acute acidosis is associated with a rumen pH less than 5.0. Acute acidosis is rarely seen in dairy cattle. Periods of sub-clinical rumen acidosis (pH < 5.8) are very common during some hours of the day in today’s high-producing dairy cattle. Minimizing hourly swings in rumen pH will improve dry matter intake, improve microbial growth, and limit acidosis. Rates of carbohydrate fermentation, meal size and frequency, and fiber length all impact hourly rumen pH.
It is important to watch for the signs of sub-clinical acidosis. These signs should be evident before laminitis is seen. They include:
- Daily roller-coaster intake and milk production
- Inconsistent manure (some stiff, some loose, some pasty with bubbles)
- Lack of cud-chewing
- General cow depression
- Decreased efficiency of milk production
- Reduced milk fat test
- Poor body condition
Balancing Rations to Avoid Sub-Clinical Acidosis and Laminitis
The job of the nutritionist is to balance the ration to provide enough energy for milk production by maximizing carbohydrate fermentation while maintaining rumen health and avoiding acidosis.
1. Non-Fiber Carbohydrates.
High-producing dairy cattle require large amounts of energy. Unfortunately, grains, which are energy-dense, produce large amounts of acid. Grain (or NFC) levels must be controlled. Attention must also be paid to the rate of NFC fermentation in the rumen.
- Do not exceed 40% dietary NFC
- Avoid slug-feeding grain (no more than 10 pounds (4.5 kg) at one time)
- Limit rapidly degradable starches and sugars to less than 20-30% of the NFC
- Adapt the rumen microbes and rumen papillae to larger amounts of NFC before calving using a pre-fresh diet with 32-33% NFC
- Provide adequate soluble and degradable protein (SIP and DIP) to ferment in conjunction with NFC. This enhances microbial growth and reduces fermentation of energy to acids
2. Effective Fiber.
Adequate effective (chewable) fiber must be provided to induce cud-chewing and saliva production. Long fiber also stimulates the movement of rumen contents to increase the absorption of acid out of the rumen. More digestible fiber will be consumed to a greater extent and will provide more energy. Non-forage fiber sources such as citrus pulp, beet pulp, or soy hulls can help to improve overall fiber digestibility of a ration and reduce acid production but they provide little effective fiber.
- 15% of the ration particles should exceed 1.5 inches (3.8 cm) in length
- Forage NDF should exceed 21% of the DM if forage is fairly digestible and there is inclusion of little non-forage fiber in the diet
- Forage NDF should exceed 19% of the DM if forage is poorly digestible and there is inclusion of significant non-forage fiber in the diet.
- Feed forage before grain if not using a TMR
- Forage or TMR should be available 24 hours per day
- At least 50-60% of cows that aren’t eating should be chewing their cuds a few hours after feeding time
Buffers like sodium bicarbonate should be added to high-production diets
- Buffers should be included at 1-1.5% of the diet dry matter
- Offer buffers and salt to cows on a free-choice basis
Increasing the Dietary Cation-Anion Difference (DCAD = (Sodium + Potassium) – (Chloride + Sulfur)), increases the ability of the cow’s blood to buffer acids and raises blood pH. This is especially helpful in hot weather when cows lose potassium via sweat.
- Increase DCAD to 35-40 by raising dietary potassium to at least 1.6%
- Increase buffer in the ration to 0.75 pounds (0.34 kg)/cow/day
- Add 4 oz. of potassium carbonate
- Maintain the potassium:magnesium ratio at 4 to 1.
Laminitis and Management
At one time, it was common to consider laminitis as solely a nutrition problem. It is now recognized that management is one of the factors associated with laminitis. The same ration may result in laminitis in one herd but not in another because of differences in management. When major management stresses are imposed on the cow, more protection must be built into the ration to avoid laminitis.
When a cow stands without moving, blood pools in the hoof, hoof blood pressure rises and less oxygen and nutrients are supplied to the hoof tissues. Movement increases blood circulation.
2. Cow Comfort.
With poor cow comfort, cows stand more and blood pools in their feet. Cows also tend to ruminate more when they are lying down. If 10-15% of cows are standing at 2 hours after feeding time, there may be a cow comfort problem. Hard stall surfaces, improper stall dimensions, high curb height (over 10 inches (25.4 cm)), too few stalls, and lack of bedding can all be cow comfort problems. When cows stand on concrete a lot, the corium can become irritated and hoof growth can increase. Cows also don’t exercise as much on concrete. Wet concrete is as much as 83% more abrasive than dry concrete and the moisture also increases hoof softness. Grooving concrete is helpful.
3. Functional Hoof Trimming.
Routine hoof trimming should preserve the hoof wall and make the sole concave. Poor trimming results in poor weight distribution and more stress on the hoof.
4. General Stress Reduction.
Histamines are produced not only when nutritional problems result in acidosis but also any time a cow is stressed. Cows can be stressed by their environment, by poor handling by people, and by overcrowding. Heifers are often stressed when they are introduced to concrete floors after being on pasture.
Histamines are also released when cows experience infectious diseases like mastitis, foot rot, or metritis.
Biotin Supplementation for Hoof Health
Biotin is a water-soluble B-complex vitamin. The rumen microbes manufacture all of the water-soluble B-complex vitamins, including niacin, thiamin and riboflavin. In the past, nutritionists believed that a sufficient amount of biotin was made in the rumen to supply all of the cow’s needs. It was difficult to create a clinical biotin deficiency in cows. New studies have shown that rumen biotin production decreases as the level of grain in the diet increases above 35% in the ration. The rumen makes only 2 to 4 mg of biotin per day. Typically, diets that aren’t supplemented with biotin will supply 4 to 10 mg of biotin per day. The biotin found in feeds is generally not as available to the cow as microbial biotin. Cows fed 20 mg of supplemental biotin per day have had blood serum concentrations that were twice as high as control cows and milk concentrations two or three times as high.
Recent research has shown that biotin supplements can improve hoof health. Hooves require special nutrients to grow and function, including biotin, copper, zinc, calcium, phosphorus, magnesium, vitamins A and D, and the two sulfur amino acids (cystine and methionine). If the cow receives a limited supply of any of these nutrients either due to a limited concentration in the blood or when blood circulation is disrupted (as in laminitis), the hoof horn will weaken and the cow will be more likely to get hoof lesions. Researchers have created biotin deficiencies in calves. The signs of biotin deficiency include: soft, crumbly hooves, hair loss, and skin lesions.
More than 10 controlled research trials have been completed in which veterinarians carefully evaluated hoof health. For most studies, biotin was fed at 20 mg per cow per day. The average time of response was 8 to 12 months because hooves grow so slowly. In all of the studies, there were significant reductions in at least one type of hoof disorder (sole ulcers or heel erosion, heel warts, claw lesions, and sand cracks).
At the American Dairy Science Association Meetings in 1999, the results of a controlled 12-month field trial in the state of Washington were presented. Half of the cows on a 150-cow dairy farm were supplemented with 20 mg per day of biotin and the other half were not supplemented. The cows were housed in a free stall barn, fed a high corn silage ration, and averaged 72 pounds (32.7 kg) of milk. Feet were trimmed every 6 months. At the final foot trimming, 20 of 40 control cows (50%) and 10 of 42 biotin-fed cows (24%) had sole hemorrhages. The difference was statistically significant. The percentages of control cows having double soles, ridges, and heel horn erosion were 28%, 43%, and 53% and for biotin-fed cows 31%, 24%, and 52%, respectively. Those differences weren’t statistically significant. Unfortunately, this study didn’t evaluate heel warts. In general, there is less data on heel warts. However, there are two German studies with small numbers of animals showing a reduction in heel warts with biotin supplementation.
Zinc Supplementation for Hoof Health
Like biotin, zinc is also important for keratin production and hoof growth. In one study, cows had sounder hooves when they were supplemented with 200 mg of zinc methionine per day during their lactation. Similar results were seen when heifers were supplemented with 100 mg/head/day of zinc proteinate.
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