Dairy herds can feed toward foot health

After mastitis, lameness is the most costly disorder of dairy cows. There are several factors that have an influence on hoof health, a few of which I'll explain below.

Producers tend to underestimate hoof health problems via lack of accurate records. Do you track loses on cows with hoof issues? Do your records show the extent of the problem? And, how you identify and define a lame cow? A too-strict definition won't make these losses go away. So for our purposes, is a 1-to-5 scale that comes in handy for finding where the herd stands.

For a score 1: The cow's top line remains flat or level while standing and walking; 3 out of 4 cows should be scored as 1.

A score 2: The cow's top line remains flat while standing and hunches up when walking. There should be less than one out of every six cows that are scored as 2. Score 2 cows will have slightly less dry matter intake than score one cows—say 99 percent as much as score 1
cows.

A score 3 cow has a hunched back when standing still and more pronounced hump when moving. A herd should have under 10 percent cows as score 3. Cows with a 3 score will have lower feed intake, and about 5 percent lower milk production than cows scoring as 1 or 2.

Cows that distinctly favor a foot are score 4, these cows will be 15 to 20 percent down on milk, and close to 10 percent down on feed
intake.

A score 5 cow is a severely limping cow, a cow that has limited interest in moving to the feed bunk or the parlor. These cows are often off a third of their milk, and 20 percent down on feed intake. Milk cows usually find a lameness score 5 to be lethal.

A leading cause of hoof problems is infectious agents or bacteria that can cause foot rot, hairy heel warts, etc.

Wisconsin researchers reported that 6 out of 10 cases of lameness were associated with infectious agents, 4 out of 10 cases are associated with laminitis—which is an inflammation of the foot. Laminitis changes blood flow to the hoof. One of the principal causes of laminitis is acidosis, where heavy grain feeding results in substantial production of lactic acid. This shifts rumen pH lower, which results in histamine increased after the death of gram-negative bacteria release endotoxin-causing blood pooling in the hoof claw.

Rumen protein degradation adds to the histamine load. Acidosis will result in breakdown in the bond between the epidermis of the hoof wall and soft tissue in the corium. It gives an increased incidence of sole ulcers and white line abscesses.

Of course, we can protect our herds from hoof problems through improving cow comfort, walking distances, walking surfaces, concrete exposure, heat stress, and exposure to frozen, slick surfaces, small rocks and yard wetness. And we can select genetics that boost sound foot and leg confirmation.
Feeding options to promote hoof health are as complicated as most "beneficial" rations.

Nutrients that seem to have little influence on hoof health are: salt, potassium, calcium, phosphorous, cobalt and magnesium. Rations do affect hoof health. Starch and sugar, the rapidly fermentable carbohydrates, are key factors leading to lower rumen pH and acidosis.

These carbohydrates can shift fermentation away from fiber digestion and increase levels of propionic and lactic acids. Finely ground, high-moisture grains or rapidly available sugars affect the rate of fermentation.

Sugars have the fastest rates of rumen fermentation. If you have a ration with a very fast fermentation rate of the fast-digesting feed, and a slow rate of the slow-digesting feed (which is common when we try to make up for low forage quality by bringing in a lot of grain), you're setting up the cows for acidosis. Expect Christmas presents from the hoof trimmer.

As a guideline, it is good to keep starch around 24 percent of the diet. Of course, it might move up or down from there by a couple of points. Sugar will usually be 2 to 4 percent of the diet DM.
Protein quality, protein solubility and protein degradability can influence lameness. As mentioned earlier, protein breakdown can lead to histamines.

Adequate effective fiber maintains a rumen forage mat, reduces the likelihood of laminitis, helps maintain butterfat percent and encourages cud chewing or rumination. There are a couple of general rules for effective fiber: maintain NDF and have at least 5 pounds a day of fiber over an inch of length. If butterfat is fine, the cows are getting bred and feet are good, effective fiber is adequate.

Fat does not ferment, it will not produce lactic acid. Overfeeding occurs sooner with oils than with animal fat, reducing fiber digestion. This reduction in fiber digestion tends to swing rumen pH lower. Not feeding more than a pound of additional fat is a good place to stop
with feeding fat.

Copper has some effect. We tend to get greedy on feeding copper, except to Jerseys, and especially when we are feeding fescue. Copper-short animals are more susceptible to heel cracks, foot rot and sole abscesses. Zinc, especially protected-chelated zinc, such as that used in MFA dairy feeds has been shown to improve hoof integrity, wound healing, epithelium maintenance and keratin synthesis.

Additionally it has been shown to be associated with lower somatic cell counts.

Classically it was argued that adult ruminants did not need, require, nor like water-soluble vitamins added to their feed. Research and field work has shown instances where ruminants have responded to niacin, biotin and B12. Biotin is requisite for keratin formation and claw horn development. University work on lame cows has reported that cows fed biotin will improve their lameness score by about one when fed 20 mg of biotin a day. The response to feeding biotin is not immediate, plan on doing it at least six weeks before seeing a response. Seeing a response in 6 months is more likely. Likewise, if you are feeding biotin, and pull it, the milk nor hoof health response is immediate.

Dr. Jim White is ruminant nutritionist for MFA Incorporated.