MADISON, Wis. – Reducing and preventing lameness is a constant goal of most dairies and one Gerard Cramer, DVM, thinks is attainable.
    “Aiming for zero percent new lame cases in a day is not complicated,” Cramer said.
    Cramer presented, “Let the hoof chips fly,” at the Professional Dairy Producers of Wisconsin Virtual Business Conference March 18-19 in Madison.
    Cramer, an associate professor in the department of veterinary population medicine at the University of Minnesota College of Veterinary Medicine, discussed ways to reduce lameness on dairies while focusing the conversation on digital dermatitis and corkscrew lesions.
    “Dairies need to find an approach that works for them,” Cramer said. “The goal is to keep cows mobile.”
    One of the most common hoof ailments on dairies everywhere and a leading cause of lameness is digital dermatitis.
    “Digital dermatitis is a lifelong infection,” Cramer said. “If an animal gets it, she’s going to have it for life. Therefore, the goal with digital dermatitis is not a cure. Rather, we want to get it to a certain level and maintain it. It’s actually the easiest of the foot diseases to control. We know what we have to do.”
    Digital dermatitis prevention and control begins in heifers. Heifers that contract DD are set up for a lifetime of hoof problems. A 2015 study by Gomez et al., found that 80% of heifers that never had DD pre-calving stay clean in the next lactation. In those treated for one case pre-calving, about 50% stay clean, while the other half become repeat offenders. For heifers with more than one case before calving, 70% will get repeat cases in their first lactation.
    “We can control it in our lactating herd, but if we don’t control it in heifers, they come in with new lesions and continuously introduce new cases into the herd,” Cramer said. “The footbath is one strategy for controlling the disease in heifers. Zinpro also has a (feed additive) product that has shown efficacy towards reducing the incidence of new lesions in heifers.”
    The key is to treat DD early and aggressively, and then rely on the footbath for control.
    “Our goal for treatment is to reduce the pain,” Cramer said. “The next part of treatment involves the footbath in which we try to progress the lesion to where it’s healing or at least maintain it at a chronic stage without making it worse.”
    Cramer has found tetracycline to be effective in treating DD when spread over the whole lesion in a liquid or paste solution. To use responsibly, Cramer said it needs to be applied at the lowest possible dose.
    “You can see success using as little as 2 grams of tetracycline and likely get away with using even less,” Cramer said.
    Tetracycline shows up in milk, and the higher the dose, the longer the residue. This has led people to try other products. However, Cramer said the efficacy of some of these products is questionable.
    “If you only have one or two cases, treating a cow with antibiotics wouldn’t be an issue,” Cramer said. “There are herds where we see very low levels – less than 1% of DD cases – so then treating the odd cow isn’t as much of an issue as treating a lot of cows in one herd. You can also use pastes and copper-based products. We have to consider what we are trying to do. Does it harm the cow? Digital dermatitis is very painful, and we need to reduce that pain as fast as possible.”
    The control of digital dermatitis focuses on two things – hygiene and footbath, with hygiene being the biggest driver. Cramer is not a fan of alley scrapers, which he refers to as a foot bath with a manure tsunami in front.
    “Hygiene is a key component and something we need to focus on when it comes to digital dermatitis,” Cramer said. “The goal is to have clean, dry feet, and there are different strategies for achieving that. If you have alley scrapers, look at the timing. Are they running on herd check day? Does the vet have to jump over the alley scraper when cows are in head locks? Are cows left standing in too much manure or crossing when there’s a huge wave of manure to travel through?”
    When designing a footbath, make sure it is at least 10 feet long. This helps increase contact time. To get appropriate volumes and save money, a farm might create a narrower footbath. A typical width is 20-24 inches. The bath should feature tall sides to prevent loss of solution. Footbaths may incorporate a tunnel design for tighter product containment. Footbath frequency depends on the farm’s goals, what the footbath looks like, products used and hygiene of cows’ feet.
    “There is no simple answer,” Cramer said. “Run it as frequently as you need to get to the level of DD that you want. If you’re not happy with the number of cases, crank up your footbath frequency. If you are happy, then start looking for opportunities to save costs on product and start switching out products or reducing frequency. For example, you could switch out copper sulfate for soap or rock salts.”
    Formalin is a footbath product that can be used at 1%-2 % with no handling when pumped from a barrel into a vat. The key is to minimize exposure for the sake of human health. If people are carrying the product back and forth, they should wear a gas mask.
    “I don’t think we need to stop using formalin, we just need to use it wisely,” Cramer said. “I think it’s the most cost-effective solution we have at this point with the lowest environmental impact post-foot bath.”
    Copper sulfate is another popular footbath product. Cramer recommends using it with acid to reduce the pH to between 3 and 5. There is some concern with driving the pH too low, however, which could actually create more chronic lesions.
    In discussing corkscrew lesions, Cramer said they occur when the P3 bone rotates all the way through the foot. Corkscrews can result in thin soles. A toe that is curved is not necessarily a corkscrew – it may be a long toe. A true corkscrew exhibits curvature all the way from the coronary band on down. Normal corkscrews occur on the lateral hoof whereas reverse corkscrews affect the medial hoof on both back and front feet.
    The overcrowding of heifers combined with the use of headlocks and sand bedding is a common cause of corkscrews. If a heifer is put under pressure while reaching for feed during a critical growth period, it can change the foot’s bone structure. The bone rotates as the animal pushes forward, putting tension on ligaments. The more she reaches, the more it rotates, and the more severe the damage. On sand, animals have added traction, allowing them to put even more pressure against the headlock when reaching for feed. This places additional pressure on the inside of the hoof, putting tension on a bone that is loose and developing.
    Pushing feed up more often can help alleviate the issue. But some experts believe the only way to truly eliminate the problem is to not raise heifers on sand.
    Corkscrew feet should be trimmed like normal, trimming flat and then 90 degrees to the cannon bone with more aggressive trimming on the modeling to remove pressure. Trimming a reverse corkscrew in the medial hoof requires great care. Because the bone is turned, it is difficult to judge the foot’s thickness.
    “Removing the curvature is the worst thing we can do for the corkscrew,” Cramer said. “Although it’s tempting to want to remove this loose horn, it actually provides stability. Removing it would reduce the surface area and decrease stability, and I would argue the cow is going to grow it back as fast as possible. Hooves grow around the shape of the foot, and in this case, the bone is rounded so the hoof grows at an angle.”
    Cramer recommends looking cows over systematically every couple weeks and putting someone in charge of finding lame animals.
    “We need to find these cows way before that point,” Cramer said. “We need to find lame cows as early as possible. Once they are three-legged lame, damage has been done inside the foot.”
    Lesions found early have less inflammation. A block can be applied, and within four weeks, evidence of a prior lesion could be non-existent. But if left untreated, inflammation and bony changes are guaranteed, resulting in an ulcer that returns every lactation.
    Cramer identified three groups of cows to trim on dairies – routine maintenance trim, lame cows and cows with a history of lameness. A healthy cow on a larger dairy probably only requires a maintenance trim at dry-off. A cow with a history of lameness should be trimmed every three to four months. Treat lame cows immediately. Create a foot trim recheck list to follow up with certain cows in about four weeks.  
    Addressing lameness requires teamwork. The dairy producer, nutritionist, hoof trimmer and veterinarian must all work together to identify bottlenecks on the farm that contribute to lameness – whether trimming, hygiene, footbath or other – and make necessary changes.
    “We all like working with healthy cows and see lameness as an impediment to your dairy’s progress, productivity and sustainability,” Cramer said. “Getting these people to talk and communicate as a team is the first step in addressing lameness and maintaining good hoof health on your dairy.”