Newsletters - October 2016

October 2016

What's New at the Clinic?

Welcome back to Dr. Allison Doherty! Her maternity leave has just ended, and she will be working full-time again. We also welcome back Pam, one of our customer service staff, after she was off for the summer. We have some new faces at the office too. On the weekends you might run into our newest part-time staff member Ari. Many of you have probably met Emily on your farms; she has been working with us part-time as a veterinary technician over the past few months.

We owe all of our clients a big thank you for accommodating all of the veterinary and university students who visited your farms this past summer. We really appreciate that you allowed for these students to gain valuable hands on experience and knowledge during your appointments with us.

In the coming weeks we will be transitioning to using a new laboratory called Antech for many of the blood and lab tests we run. This change should not affect you in any way, with cost and turnaround time for results being essentially the same. Certain tests such as milk cultures and Coggins will continue to be sent to the labs that you are accustomed to.

Lastly, we are excited to announce our upcoming equine client education meeting. This year's meeting featuring Drs. Allison Doherty and Erin Branigan, focuses on Lameness in Horses including the lameness exam, diagnostic and treatment options, and an interactive case discussion. Please join us on Thursday, November 24 from 7-9 p.m. at the Scugog Community Recreation Centre in Port Perry. All are welcome, so bring your friends and come learn something new (or come for the food and prizes!)

Caseous Lymphadenitis in Small Ruminants

Caseous Lymphadenitis (CL) is caused by the bacteria Corynebacterium psuedotuberculosis and is a huge problem in flocks in Ontario due to its highly contagious nature and potentially devastating consequences. Once it is on a farm, it becomes endemic to that farm quickly because it is shed by infected animals either through open draining abscesses or from animals infected with the internal type shedding via nasal discharge and coughing. It can survive harsh environmental conditions for up to 8 months. The bacteria causing CL enters an animal through wounds to the skin and also by inhalation or ingestion.

Once an animal is infected by the bacteria it goes to their lymph nodes, generally to external ones typically in the submandibular area (under the chin), prescapular area (in front of the shoulder) and mammary area (near the udder). These will eventually rupture and release pus that contains the bacteria into the environment so it can infect other animals. It can also go to internal lymph nodes in the intestinal and respiratory tracts. This will cause chronic wasting (thin animals) or condemnation at slaughter. The external variety is more common in goats while the internal type is more common in sheep.

There is no treatment for CL. Once a diagnosis has been made on the farm, preventing spread of the disease is the most important next step. Animals with draining lesions should be separated from the herd and ideally culled. Blood testing the herd is possible; however you have to keep in mind that the test has a high chance of a false negative result, meaning that it will miss some of the infected animals. Separating babies from known infected mothers at birth is a good way to decrease the vertical spread in a herd. There are also vaccines available for CL that are very effective at decreasing the amount of active lesions on the farm.

If you are having suspected CL issues, give us a call to discuss management options for your flock.

Equine Allergies

In the simplest of terms, an allergic reaction is the immune system over-reacting to normal stimuli. These over-reactions can range from a few small bumps, or hives to a full on anaphylactic reaction. Anaphylaxis is a serious emergency, but luckily we rarely see these types of reactions in horses. Other common signs of allergies include swollen eyes with clear to white discharge and respiratory problems (heaves). As the seasons change, so too do the allergens our horses are exposed to and it is therefore at these times of year that allergies tend to cause the most headaches.

There are a wide number of things in a horse's world that can be the cause of allergies. Some of the most common culprits include inhaled environmental allergens (such as dust, pollen and mold), bug bites, and contact allergies (shampoos, sprays and stall bedding). The most frustrating part of allergies can be figuring out what it is that your horse is reacting to.

Although many of the signs (symptoms) of allergies will disappear just as suddenly as they appear, for some unlucky horse owners, dealing with allergies can be frustrating when signs last or progress to causing our equine friends discomfort. Since allergies are not something that can be cured, but rather managed, once signs occur, the question is always - what now?

Ideally, we would figure out exactly what the horse is reacting to. The "easiest" way to get rid of allergies is to eliminate the offending stimulus. If something new has been introduced into your horse's environment, be it a new shampoo, fly spray or change in pasture, eliminating the issue might be simple. This isn't always the case, however, since getting rid of all the dust or all the insects in a barn is just a laughable proposition. Although elimination of these allergens might not be possible, reduction of exposure most often times is. Keeping dust to a minimum with good ventilation of the barn or keeping horses outside as much as possible, as well as wetting down hay or feeding hay cubes can reduce inhaled allergens and be helpful to a horse with heaves. A horse who is sensitive to bug bites might benefit from a turnout schedule that minimizes the amount of time outside when flies are at their worst.

There are tests (albeit expensive) to determine what specifically your horse is allergic to. One of these tests is a skin test where small amounts of different allergens are injected under the skin. If swelling occurs at the injection site, this would be called a positive test and an allergy vaccine can be created to desensitize the horse. Although these tests are specific and can help us determine what we should be trying to eliminate from the environment, there are effective treatments that can be tried before goingdown that road. The most commonly used medications used to treat the signs of allergies are corticosteroids. They work at relatively low doses to reduce inflammation and give horses a good deal of relief from the inflammation caused by allergic responses.

Antihistamines are also sometimes effective for more minor allergies or to give to an animal before signs occur if they have, in the past, had minor allergies as the seasons change.

Overall, dealing with allergies can be very frustrating for all of those involved. Although there is no cure, there are definitely ways to make your equine companion more comfortable during the spring and summer months when allergies seem to be most prevalent.

Zelnate for Cattle

'Tis the season for cattle to develop respiratory issues including pneumonia, as the result of bovine respiratory disease (BRD). BRD is a condition usually caused by a number of viral and bacterial pathogens working together. One of the primary bacterial invaders is Mannheimia haemolytica. The risk factors for developing BRD include recent weaning, feed or weather changes, shipping, and comingling of animals (especially calves) from different sources. BRD can affect calves as well as adult cattle and accounts for huge economic losses - loss of animals, costs of treatment, decreased weight gain, and reduced production in dairy animals.

There is a new product available from Bayer called Zelnate that offers a novel approach to helping combat BRD caused by the bacteria Mannheimia haemolytica. We haven't started carrying this product yet, but we look forward to trying it in the coming months. Zelnate is not a vaccine or an antibiotic; it is an immunostimulant that works by helping kickstart the animal's immune system by mimicking a pathogen. This promotes a stronger immune response against the bacteria commonly implicated in BRD cases. Use of this product reduces mortality and severity of lung lesions which in turn can reduce the need for antibiotics or other medications.

Zelnate is an intramuscular injection intended for cattle 4 months of age or older, and is given at the time of, or within 24 hours of a stressful event. It has a meat withdrawal of 21 days. This product can be used in conjunction with vaccination protocols, metaphylactic antibiotic protocols, or as an adjunct treatment to animals already showing signs of respiratory disease. If you are interested in learning more about whether Zelnate could be useful for your herd, please do not hesitate to speak with one of the veterinarians.