October 2012

Vaginal Prolapse in Sheep

Vaginal prolapses are a condition of heavily pregnant ewes (last 2-4 weeks of gestation) where the vagina, sometimes up to and including the cervix, is pushed through the vulva and ends up outside the body. The causes of vaginal prolapses are many and prevention is aimed at reducing some of them.

Treatment by your vet will include replacing the vagina and sewing up the vulva or using a spoon/harness to keep the vagina in.

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Bovine Respiratory Disease Complex

As we enter into fall and winter, a disease that always becomes more prominent in cattle is pneumonia. Pneumonia in both cows and calves can be caused by many different agents and can be frustrating to treat as re- lapses are common.

Pneumonia is a disease that shows up in cattle after a number of factors have occurred. Stress or another illness will alter the lungs normal defense mechanisms. At this point viruses have a much easier time invading and sticking around. The virus will then immune suppress the cow/calf further making it much easier for some bacte- ria to also infect the cattle. The bacte- rial infection overwhelms the lungs and the body then sends an influx of white blood cells to the area. The purpose of this response is to destroy the bacteria. In this process the white blood cells may be effective at killing the bacteria but the end result is a lot of inflamma- tion, which then makes breathing even more difficult and painful. This is why we refer to this process most com- monly as "bovine respiratory disease complex or shipping fever", as it often is causing illness from a few different pathogens and disease processes oc- curring at the same time.

The main viruses that play a part are Infectious Bovine Rhinotracheitis, Parainfluenza type 3, Bovine Viral Diarrhea, Respiratory Syncytial Virus. Others include Bovine Herpes Virus type 4 and Bovine Corona Virus. The most common bacteria that get in- volved are Mannheimia hemolytica, Pasteurella multocida, Histophilus somni, and Mycoplasma bovis. Many of these pathogens can be involved at once.

Common signs that producers may observe are fever initially and then stabilization of temperature, marked increase in respiratory rate, depres- sion, off feed, dry muzzle, nasal discharge, shallow abdominal breath- ing, increased lung sounds, and mouth breathing. Early detection and diag- nosis has a much better prognosis for the cow as less damage has been done to the lungs and they are more suscep- tible to medical therapy.

In treatment of respiratory disease there are a couple of key factors that are important to consider. Everyone always focuses on getting the cow/calf on an antibiotic. Although this is im- portant and beneficial, especially early on, we must consider what antibiotic to use and the duration to treat for. There are many different classes of antibiotics that are effective against different types of bacteria. Within the different groups of antibiotics some penetrate the lungs better than others. In any case (beef or dairy) the cost of the drug, how often it is given and the withdrawal times for both meat and milk become other im- portant details. Aside from antibiotics, as previously mentioned, inflammation from the immune response to patho- gens in the lungs can make the lungsworse temporarily and lead to more severe breathing difficulties. Anti-in- flammatory medications can help with this inflammation and in some cases with the fever. The two most common anti-inflammatories are corticosteroids and NSAIDS (non-steroidal anti- inflammatories). In treatment it is easy to get caught up with the drugs but we must also remember the simple steps to help the cow recover faster. These include encouraging water consump- tion as the higher respiration rate will cause cows to lose more fluids more rapidly and lead to dehydration andin severe cases shock. Also decreasing stress in the cow's environment will be very beneficial.

Failures to treatment or chronic cases could be due to choosing an an- tibiotic that is not effective against the bacteria in this case. Some bacteria are able to hide within cells and can be dif- ficult to reach. Other chronic cases may be due to significant permanent lung damage, continuous stress or another underlying disease process.

As you can see there is no clear cut definition for bovine pneumonia and in veterinary medicine we base a lot off the signs producers tell us and we ob- serve in our physical exam. Ultimately prevention is the key to decreasing morbidity and this can be done by reducing stress where possible and using strategic timing of preventative vaccinations.

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Pastern Dermatitis in Horses

With the arrival of wet weather in the fall (and spring!) comes a common skin condition affecting the pastern area and heel bulbs of horses. Pastern dermatitis, also called mud fever, scratches or greasy heel, generally affects horses with white limbs, but can occuron any colour of horse. It starts out as redness and scaling and can progress to crusting, scabs and oozing of serum and can be quite painful.

Most cases are due to bacterial infection, but other causes of pastern dermatitis include fungal infection, mites, contact irritation, photosensitivity, or any combination of these. Excess moisture in the environment precipitates the development of pastern dermatitis.

Treatment is aimed at keeping affected horses clean and dry. Ideally, paddocks shouldbe designed to prevent the development of mud and puddles but if not possible, keep horses inside when the paddocks are really wet. Once a horse has developed pastern dermatitis, any long hairs on the lower limbs should be clipped and the affected areas should be washed with a chlorhexidine or iodine scrub and then dried well. Application of medicated ointments is recommended after the area has been cleaned and dried. We have a product available at the clinic that contains an anti-inflammatory, an anti-bacterial agent, and a moisture barrier that we have found to work in most cases. However, sometimes trial and error is needed to find a medication that helps. If you have any questions or concerns about treating pastern dermatitis, please do not hesitate to call the office and speak with one of the veterinarians.