Newsletters - July'14

July 2014

An Introduction to Equine Sarcoids

Sarcoids are the most common skin tumour affecting horses. They do not seem to affect particular ages, breeds or genders. Their appearance is variable, as there are several types. The types are as follows: occult (flat, grey, and hairless), verrucose (scabby or warty), nodular (solid small tumour-like masses), fibroblastic (large bleeding masses that look like proud flesh), mixed (a combination of any of the types), and the rarely seen very aggressive malevolent type that spreads over the horse. Sarcoids can occur individually, or a horse can have multiple sarcoids affecting an area. The areas they tend to pop up in most commonly include the face (particularly the ears), neck, and abdomen. The bovine papillomavirus is considered to be the main cause of sarcoids, however the mode of transmission is poorly understood, but flies are believed to be involved. Sarcoids frequently occur at sites of previous injury or scarring.

Sarcoids are usually diagnosed based on their appearance. Given the variety of types, it can sometimes be hard to differentiate sarcoids from other skin tumours or conditions. Sometimes a sample is taken from the presumed sarcoid and submitted for analysis. The risk of taking a biopsy from a sarcoid is that it will trigger expansion of the lesion, often making the sarcoid worse.

There are a wide variety of treatment options available for sarcoids. Benign neglect, which is simply leaving it alone, is an option so long as it does not seem to be bothering the horse (or the owner). One of the more common treatment options is surgical removal of the sarcoid(s). This technique is most useful for nodular or fibroblastic sarcoids, but surgery alone is not always effective and other adjunct therapies are often needed. In our experience, the occult and verrucose sarcoids tend to respond well to topical medications. Other treatment options that are available include: immune stimulant medications, injections of chemotherapeutic agents into the sarcoid, cryotherapy (freezing), vaccination using pieces of the sarcoid, and radiation therapy. Unfortunately there is no treatment that is curative in 100% of cases, which is the reason that there are so many treatment options available.


Left Displaced Abomasum (LDA's) – A Climbing Trend

This spring our practice has experienced an increase in the number of cattle treated for DA's (displaced abomasum), primarily left sided. It appeared that most displacements we were called out for were cows experiencing metritis (uterine infection). This is often caused by retaining some or all of the placenta after calving for long enough time that the placenta begins to rot. This illness leads to fever and systemic infection, resulting in the cow being off feed and getting a displacement. Regardless of the cause of displacements, this condition is costly to the producer and the cow. Generally these cows will have a decreased milk production even after treatment, at least for the first month.

Transition Period
The transition period is a very critical time for heifers and cows, so optimal management practices should be adopted in order to decrease the incidence of DA's. This time period encompasses the dry period prior to calving and the first few weeks after calving. During this time it is natural to see a decrease in dry matter intake (DMI) prior to calving, followed by a slow rate of increase in DMI postpartum. With fewer intakes the rumen won't be as full and motility will slow down, increasing the chances of a displacement. Prepartum Transition Period
There is a more substantial decrease in DMI pre and postpartum if the cow is over conditioned. Over conditioning leads to a higher incidence of ketosis and fatty liver driving the decrease in DMI. To decrease the risk of these conditions the target body condition for cows about to calve is 3.5-3.75 out of 5. On top of body condition, ensuring higher forage diets at this time will allow for more rumen fill and motility. This will promote regular abomasal emptying and keep the GI system moving, decreasing gas build up in the abomasum. Slowly introducing a bit of starchy grain concentrate will help the rumen microbes adapt and decrease the risk of fatty liver, ketosis and ruminal acidosis.

Postpartum Transition Period
The major events that can occur in the first few weeks postpartum will heavily influence the risk of displacements. Negative events including retained placenta, metritis, ketosis and hypocalcemia will greatly increase the individual cow's risk of displacing. Therefore, trying to deal with retained placenta (oxytocin injections, ECP, selenium, etc) and metritis (oxytocin, antibiotic infusions, etc) cases early on are important. Proper preparation of TMR and bunk management will decrease risk of ketosis. For example, if the TMR is too fine it will decrease chewing activity, as well as rumen fill and motility. If a TMR is not used on farm, ensuring proper forage consumption is important. Regardless of feed practice, encouraging a steady DMI is important. Preventative measures such as administering B vitamins to help stimulate appetite may be warranted in some cattle as well. If ketosis is suspected, supplementing the cow with oral glycol or IV dextrose may help get her back on track. Lastly, proper prevention of hypocalcemia via diet and early supplementation/ treatment should be second nature for producers, with most attention placed on older, multiparous cows. Hypocalcemia (even subclinical) will slow rumen and abomasal motility leading to a higher risk of a displacement.

Treatment
Despite proper management, prevention and treatment of the above negative events, displacements will still occur. Up to 80% of displacements are detected within the first 2 weeks after calving. Left displacements are most common (80-90% of cases) and can be corrected surgically or in some cases by rolling the cow. Rolling often is only a temporary fix and within a few days the abomasum will flip back to the left side. At our clinic we surgically correct the displacement by entering the cow's right flank and manually bringing the abomasum back to the natural position on the right side. We then suture the fatty omentum surrounding the abomasum to the body wall. If the displacement is detected on the right side it can only be corrected surgically. In a few unfortunate cases the stomach can twist on its self in a more emergent manner creating a torsion. These are the most challenging to correct and require emergency surgery before the blood supply is cut off for too long and the stomach dies.

In conclusion, displacements are costly to the cow and the producer. Trying to manage the transition period of cattle with heavy emphasis on proper nutrition will help decrease the risk of negative events that would promote displacements.