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FT. ATKINSON

Dr. Mike Hutjens has no doubt.

'Lameness is going to be a factor on dairy farms,' the University of Illinois dairy specialist told over 100 listeners during the July Hoard's Dairyman Webinar co-hosted by Steve Larson, Hoard's Dairyman, and University of Illinois. It was sponsored by Zinpro.

Research shows that, on average, between 21 and 55 percent of dairy cows are dealing with lameness. The range for individual farms runs from less than 3 percent (usually pasture situations) to 80 percent.

Unfortunately, dairy farmers' perception of lameness is 2.5 to 4 times lower than estimated by researchers

'Farmers are only seeing one quarter of their lame cows', Hutjens said. 'It's really a tough thing to do anything about if you don't even see it. It's hard to treat, hard to help that cow survive.'

He traced failures to deal with cases of lameness in a timely fashion to a lack of awareness, failure to detect the problem and inadequate facilities for examination and treatment.

'Sometimes, we don't see the lameness and don't react as fast as we could and should,' he said. 'The question is how often are we looking at our cows' hooves?'

Besides hoof shape, locomotion and posture, lameness has negative effects on a dairy farm's culling rate, milk production and reproductive performance.

The data raises lots of red flags. The culling rate for nonlame cows is 5.4 percent versus 31 percent for lame cows before the start of breeding events at 95 days, Hutjens reported, and cows developing lameness within 30 days post-calving were 2.6 times more likely than normal cows to develop cystic ovarian disease before breeding.

'Lameness is a highly visible and important animal welfare issue. It is the last thing consumers need to see,' he pointed out.

It is also the last thing a farmer's pocketbook needs. Research puts the bill for a case of lameness around $500, which includes $170 for milk loss and a culling cost of $192.

'Lameness is a big, big factor economically,' Hutjens said. 'It's right in league with mastitis now.'

Cows with a locomotion score above 2 are nearly three times more likely to have increased days to first service, almost 16 times more likely to have increased days open, nine times more likely to have more services per conception and 8.4 times more likely to be culled than their herd mates.

'The take-home message here is to have a sort pen to take a closer look at suspect cows and see if there's anything you can do before they get to locomotion scores of 3, 4 or 5,' Hutjens said.

He defined a cow with a locomotion score of 3 as a lame cow. She stands and walks with an arched back and takes short strides. 'She's permanently roached. It's a different gait,' he said, noting such a cow will also have a 5 percent drop in milk and a 3 percent drop in dry matter intake.

One big culprit is laminitis, an inflammation of the vascular hoof tissues or laminae. Animals feel pain from pressure inside the hoof wall caused by inflammation and edema and walk less, further reducing the natural pumping action within the hoof. Blood flow stagnates inside the hoof, causing further damage to the sensitive laminae.

Feeding strategies

While exposure to concrete and heat stress are huge factors, Hutjens said the 'big gorilla in the room' is excess rapidly fermentable carbohydrates, meaning sugars and starches.

The scenario: volatile fatty acid exceeds rumen wall absorption, reducing rumen pH below 5.5. Lactic acid bacteria proliferate, vasoactive substances are released into the blood and damage to vessels in the sensitive laminae occur.

'It is a cascade of problems,' Hutjens said.

A cow's transition phase, in particular, poses risks for laminitis. It may take 10 to 14 days to stabilize rumen microbial populations, Hutjens pointed out, and rumen papillae, the surface area for VFA absorption, require 6 to 8 weeks to develop. In addition, every acidotic episode sets them back.

The physical form of the ration is an important factor in managing lameness, as is slug feeding, rumen fermentable carbohydrate levels, the rate of feed passage and polyunsaturated fatty acids.

Starch and sugar levels need to be considered. Hutjens advised starch levels between 22-30 percent, rumen starch availability of 55-85 percent and using wheat, barley and corn in descending order of preference. Sugar levels should be between 5-7 percent.

Fiber is another factor. He advised a minimum of 450 minutes of cud chewing using rumen monitoring devices, 5 pounds of feed particles over 3/4 inch and 50 percent of total dry matter in the top two boxes of a Penn State Box.

Reduce feed sorting by keeping forage particle size below 2 inches, increasing forage quality and reducing the amount of hay. Try adding 5-7 pounds of water and evaluating the effect.

Consider adding liquid molasses, corn distillers solubles or other wet ingredients and feeding more frequently each day, Hutjens added.

He also likes the idea of going in with some sort of feed conveyor/mixer unit to lift and remix the feed.

Protein can be a factor. Higher levels of RDP (<11 percent RDP) or total quantity of protein (<16.5 percent) may produce rumen fermentation that impacts hoof hardness, he noted, while sulfur containing amino acids can have an impact of hoof health. Aim for a 0.25 to 0.28 percent DM, he advised.

PUFA (polyunsaturated fatty acids) are also gaining attention because they appear to reduce fiber digestion in the rumen and shift rumen microbial populations. They shift the rumen VFA pattern to less acetate, Hutjens said, advising <500 grams of total ration PUFA/cow/day and <225 grams of vegetable oil in the free form and/or under 50 grams of fish oil.

Copper helps the synthesis and maintenance of tendons, improves hoof hardness and boosts immunity. Aim for 10 to 15 ppm with 1/4 from organic sources.

Zinc, a component of 300 enzyme systems, improves wound healing, hoof hardness and hoof health. Go for 40 to 60 ppm. A study with organic zinc and 3,000 cows showed a 34 percent reduction in while line, a 33 percent reduction in digital dermatitis and an 11 percent reduction in sole ulcers.

Biotin improves hooves by reducing heel warts, claw lesions, white line separations, sand cracks and sole ulcers. It also increases milk yield, Hutjens added. Feed 10-20 mg/cow/day, which will cost from 4 to 10 cents/cow/day for six months to a year.

'It takes about six months for the biological effect on hoof health, although it is much quicker on milk production,' he noted.

For feed additives, Hutjens likes rumen buffers (0.75 percent ration dry matter), monensin (300 to 450 mg), yeast products, organic zinc and biotin. 'Remember, for hoof health, this has to be continuous,' he said.

New research

Interestingly, research shows the thickness of a cow's digital cushion is a critical element in lameness. 'Cows with the highest DCT (digital cushion thickness) had 15 percent lower lameness scores compared to the lowest DCT scored cows,' Hutjens reported.

The DTC, which provides cushion to the hoof structure, continues to drop after calving with the lowest level at 120 days after calving.

'The target is to avoid dropping more than 0.5 BCS (body condition score) after calving, which reflects dry matter intake and environment,' he advised.

Looking ahead, Hutjens believes technology will help with early detection of lameness. For now, focus on minimizing lameness on the farm by paying attention to nutrition and cow comfort, footbath management and corrective hoof trimming.

Continue to improve the cows' environment and management, he counseled, and use genetics/genomics/gene technology for better feet and legs with good hoof quality.

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