Dan Zawisza, VMD
October 15, 2009 I graduated veterinary school in 2006. As in many other professions, veterinarians are required to attend continuing education meetings. These meetings cover a variety of topics and can focus on one or more animal species. They are designed to keep veterinarians up to date on current research and veterinary topics and ensure that we are offering the very best in care to our patients. Recently, I attended a continuing education conference that took me to Minnesota. It was a conference about mastitis and was attended by about 20 vets from the eastern US. Mastitis is an infection or inflammation of the udder-the milk producing organ of a cow. Since our practice specializes in livestock, and in particular dairy cattle, this is a very important topic for us. Additionally, our obligation to ensure that American agriculture continues to provide the safest food supply in the world dictates that we do our best to produce quality milk. The facility I visited in Minnesota is part of a 6,000 cow dairy. This particular facility housed about half of those cows. Just as there are breeds of dogs, there are also breeds of cows. The primary breeds of dairy cows include Holsteins, which generally weigh 1200-1500 pounds, and are the black and white cows that you probably see most commonly; there are also red and white Holsteins; Jerseys, which are a smaller breed (900-1000 lb) and have a higher fat content in their milk; Brown Swiss cows (~1200 lb), which have big, furry ears; Ayrshires, which are darker red and white; and Milking Shorthorns, which tend to be more common in warmer climates as they seem to be a more heat tolerant breed. The cows at the Minnesota dairy are Jersey cows. They are generally curious, friendly, and doe-eyed and their appearance and temperament makes them a favorite breed to many people. The conference focused on various aspects of milk production as a means to ensure milk quality and healthy cows. For starters, we discussed and analyzed the components of a milking system. Most cows today are milked by systems involving a vacuum pump and a series of vacuum lines which pulls the milk into a pipeline which leads to a bulk tank. This is the large, cooled tank where the milk is stored until the milk truck comes to collect it and haul it to the milk processor. The system is very complex and needs to be evaluated regularly to ensure that the appropriate vacuum level is present for the cow to avoid damaging its teats. Additionally, the cow’s udder must be prepared correctly to prevent introducing an infection during milking. Such an infection can make cows very sick. So as part of our conference, we evaluated milking routines and their effect on a cow’s udder. In addition to udder prep, stimulating milk letdown is crucial to avoiding improper milking. One thing many people might not realize about dairy farmers is that many of them keep detailed records about cow health using computer programs. Part of our coursework involved analyzing computer records to look for cows with chronic cases of mastitis, which can be difficult to treat. We also look for patterns of mastitis such as at what stage of lactation many cows become infected on a given farm. This can suggest management changes on a farm to prevent new infections. Additionally, many dairy farmers can earn monetary bonuses related to the production of higher quality milk, and in the current tough economic times, these bonuses can be very important. Mastitis is often caused by a bacterial infection, but not always. In our clinic, I am in charge of the mastitis lab. In this lab, I culture abnormal milk to see what pathogenic bacteria will grow. By identifying these organisms, I can make treatment recommendations about what antibiotic to use to treat the infection, as well as how long to treat it. I can also suggest milking practices to prevent the spread of contagious organisms. Of course, when we use antibiotics, we must always consider food safety. That means not only keeping pathogenic organisms out of the food supply; it also means keeping cows healthy and ensuring that antibiotics are not entering the food supply. So, as food animal veterinarians, when we use an antibiotic, we prescribe withholding times for meat and milk. For instance, if a drug has a 48 hour milk withhold, the milk taken within 48 hours after the last treatment will be discarded to keep that antibiotic out of the food supply. Additionally, every tank of milk that is taken to a dairy is tested for antibiotics in the penicillin class, and tankers are screened at random for other drugs, with very high sensitivity. Milk samples are taken from every farm when the milk is collected, and any farm with drug residues in the milk is given a hefty fine. This is all done to ensure that milk is safe. So now I am back from Minnesota and looking for opportunities to incorporate the things I learned into my work to help dairy farmers. Milk quality is so important in our work and my goal is to do what I can to aid in the production of the best possible milk. At this job, I learn something every day. And some days, that means learning new things I can do as a person at the front lines of food quality and safety. /> June 19, 2009: Farming is very seasonal work. Because livestock veterinarians work so closely with farmers, this profession also tends to follow very seasonal patterns during the year. With the onset of spring, farmers head out to the fields to start planting. As the weather gets nicer, cows and heifers are let out of the barn to get some exercise in the pasture. This week, I got called out to look at a heifer that had recently been turned out on pasture. A heifer is a female bovine who has not had a calf yet. Once she has had a calf, we call her a cow. Heifers are young and curious, and this particular heifer got tangled up with a wire fence. The wire had cut through her leg above her hoof and broken the bone in her lower leg. She had gotten the wound very dirty. I cleaned her wound and set the fracture temporarily while waiting for a consult with the orthopedic surgeon to determine if this wound could be repaired. Due to the contamination in the wound and the extent and severity of the fracture, the prognosis for repair was hopeless. The fracture had a poor chance for healing and a high chance of infection. This heifer had to be humanely euthanized. Later that evening, I looked at a deer fawn with a lame front leg. It was difficult to tell in such a young animal whether or not it was broken. Additionally, in the field, we work without the benefit of radiographs. I placed a splint on the baby deer’s leg. A week later, I removed the splint, and the fawn is making progress. This story looks like it will have a happier ending. I have never worked on a deer before. I have not studied them and do not know very much about them. One of the challenges of being a large animal veterinarian is adapting to situations like these. Though I don’t know much about deer, the principles of wound healing are similar across all species of mammals. I have splinted many injuries in calves, dogs, and cats. I expect this injury to heal the same way. I was glad for the neat opportunity to work on this little deer. My job provides many opportunities to think through new problems. And when encountering these new problems, it is rarely acceptable to say ‘I don’t know’. It is much more acceptable to say ‘we’ll figure it out’. It is a constant reminder that in spite of all the equipment that I carry on my vet truck, my mind is the biggest asset I have with me every single time I step on a farm. Summer is show season. I spent a lot of time last week inspecting animals for clinical signs of contagious diseases. Animals may get infected with diseases such as ringworm, sore mouth, pneumonia, foot rot, and others. Before they go to a show, animals must be inspected by a veterinarian for evidence of disease. This is to prevent a sick animal from spreading disease to other animals. Preventing illness among livestock is a major part of our work. Additionally, some diseases, such as ringworm, are zoonotic, meaning they can be spread to people. It is very important to treat these diseases to prevent sickness among people as well. And it is always fun to look at young sheep and goats and pigs and cattle.