Quick Links

The Beat Goes On - Report on Research Studying Heart Disturbances In Horses

posted by Horse Owner Today    |   January 11, 2012 14:08

Normal heart rhythm and sounds in a horse are difficult to define because of the fascinating array of strange sounds and rhythms which can be found in apparently healthy animals and which change with exercise.  Also, even when sounds or rhythms do reflect heart problems, most horse owners will not notice signs, until there is an inability to perform work at a level previously achieved successfully, when the horse shows an unusual tendency to tire.

 

Owners of performance horses understand the economic impact of a horse that can no longer work, or in the worst-case scenario, where sudden loss becomes a serious issue.  University of Guelph researcher Dr Physick-Sheard states, “After safety issues and welfare issues are discussed there is still a need to put an economic value on the horse, which is decided by the client”.  One aspect of research Dr. Physick-Sheard and Dr. Kim McGurrin look at is atrial fibrillation, the most common clinically significant rhythm disturbance horses can have.   An arrhythmia is technically defined as an abnormal heart rhythm, however, irregular heart rhythm is commonplace in horses and the endeavor to define normal, continues to be a complex and fascinating journey.  A completely steady rhythm can be considered abnormal.

 

Before a diagnosis of heart problems can be made, Dr. Physick-Sheard explains, a logical process where the client is asked the history of the horse (breed, use, how long it has been in training) is followed before conducting a general physical examination.  Future use would also be discussed before deciding on diagnostics.  An Electrocardiogram may be the next step to determine the heart’s rhythm and possibly an ultrasound to look at how efficiently the muscle and valves work.  They look for enlargement or abnormal structure in the heart and check for normal blood flow around the valves. 

 

Dr. Physick-Sheard describes two types of rhythm disturbance that can be found:   

 

1.  Benign variations on normal (mostly involving the top part of the heart).

 

2. Ventricular rhythm disturbances, which can be serious and even life threatening.

 When found, they look first for problems outside the heart, disturbances in homoeostasis, which involves keeping the environment around cells constant:  dehydration, electrolyte and acid base imbalance.  Under these circumstances secondary arrhythmias are often detected.  Situations where the cardiac problem is primary are rare but sometimes serious.

 

McGurrin and Physick-Sheard have had enormous success treating arrhythmia with transvenous electrical cardioversion. The response rate has been 100%!  Electrodes are placed into the heart to deliver an electric shock, while the horse is under anesthesia, to convert the rhythm to normal. 

 

Dr. McGurrin and Dr. Physick-Sheard developed this technique before their first Standardbred track study, where they collected heart rhythm data during racing using an electrocardiogram.  Dr. Physick-Sheard explains how the technology works, “The heart is a bag of muscle, a slave pump which does what the system tells it, contracting at a rate that reflects the body’s needs. The heart gives off an electrical signal when it contracts which reaches the skin and can be detected by the electrocardiogram (ECG).  This is then used to monitor heart rhythm.”

 

Dr. Physick-Sheard has developed specialized equipment and software for the current intensive Thoroughbred study, which he is hoping will give more insights into causes of sudden death.

 

Research funding has been provided by Equine Guelph, Grayson Jockey Club Foundation and OMAFRA.

 

                                                            -30-

Story by:  Jackie Bellamy

 

Web Link: http://www.equineguelph.ca/news/index.php?content=315

 

Links to the Utube Videos:

Report on Research: http://www.youtube.com/watch?v=fXI3Q0pMl34&lr=1&feature=mhee

Help for Horse Owners:

http://www.youtube.com/equineguelphuofg#p/c/595FECA446307F6A/0/BQSdkSsbmE8

Potential for Anthrax

posted by Horse Owner Today    |   December 3, 2011 09:33

     Since widespread flooding has occurred on the Prairies this year, livestock producers and horse owners living near areas where anthrax cases were previously reported may be considering vaccinations as a preventive measure.

But before horse owners make a decision about vaccinating, Dr. Chris Clark of the Western College of Veterinary Medicine (WCVM) recommends that they talk to their veterinarians first.

“Horses are relatively resistant to anthrax, and they’re even more unlikely to get exposed to the bacteria because of the way most owners keep their horses in smaller pastures or paddocks. Consequently the risk is typically very low,” explains Clark, a specialist in large animal medicine who has been involved in previous anthrax investigations in the United Kingdom and in Western Canada.

     “Only people who live in high risk areas and manage horses like cattle and other livestock are at a high risk for anthrax.”

Anthrax is a reportable disease in Canada that’s caused by the bacteria Bacillus anthracis whose spores can survive in soil for decades. Cattle, horses, bison or deer can ingest anthrax when they graze in areas where flooding or digging has brought the bacterial spores to the surface.

Once ingested, the spores germinate and grow in an animal’s intestinal tract — releasing potent toxins that cause the animal to die if left untreated. Clinical signs of anthrax include bloody discharge from the animal’s nose, mouth, anus or vagina, abdominal swelling and a carcass that decomposes very quickly. The mortality rate in the early stages of an anthrax outbreak is nearly 100 per cent.

According to veterinarians at the Canadian Food Inspection Agency (CFIA), anthrax is different from other reportable diseases. It’s considered to be an environmental disease since its spores are in the soil and they’re available in a wide, geographic region.

Although anthrax is a non-contagious disease, the bacterial spores can “spread” to other areas through scavengers, migrating birds or flies. Excessive moisture and flooding can also wash anthrax spores from one area to another.

The only anthrax vaccine that’s licensed in North America is manufactured by the Colorado Serum Company (www.colorado-serum.com). The vaccine is available for cattle, horses, mules, sheep, goats and pigs, while off-label use can be considered for bison and farmed elk and deer. The live culture anthrax spore vaccine, which was introduced in the 1950s, is highly effective and considered to be safe with minimal risk to animals and to humans.

However, Clark points out that the anthrax vaccine typically causes significant reaction (such as local swelling) at the injection site — an issue that can be particularly upsetting for horse owners. As well, the vaccine company and the WCVM advise owners of miniature horses and young foals to use other alternatives for preventing the disease.

Once animals receive the vaccine, it takes from seven to eight days for them to build up enough immunity against the disease. In circumstances where an animal is already exposed to anthrax, Clark says that it’s better to treat with antibiotics such as oxytetracycline or penicillin, then vaccinate the animal later. “What’s important to remember is that you can not give the vaccine and treat with antibiotics at the same time.”

Visit the Canadian Food Inspection Agency (www.inspection.gc.ca) for more information. 

Reprinted with permission from Horse Health Lines, publication for the Western College of Veterinary Medicine’s Equine Health Research Fund. Visit www.ehrf.usask.ca to sign up for our e-newsletter.

 


    

Interpreting Feed Test Results

posted by Horse Owner Today    |   November 12, 2011 08:23


by:Chelsey Carruthers, M.Sc., AAg

Regional Livestock Specialist, Saskatchewan Ministry of Agriculture

Watrous

It’s that time of year again when cows are coming in from pasture, and beef producers must begin the task of planning their winter feeding strategy. A great first step is to have forages tested by an accredited laboratory. A standard forage quality test provides the information necessary to decide whether the feed you have available will meet the requirements of the cow herd during the winter months. You can then decide when each feed can be used to best meet the cows’ requirements, and if supplementation of energy, protein, or minerals will be necessary.

Forage tests provide information on the moisture, energy, fiber, protein and mineral content of feeds. These may be reported on an “as is” or “as received” basis, or on a “dry matter” basis. Dry matter values are reported as if the feed contained no moisture, and this is important when comparing values between feeds that have different moisture contents. The values discussed in this article are reported on a dry matter basis.

Energy is reported in feed tests in a number of ways: total digestible nutrients (TDN), digestible energy, and relative feed value. TDN is the most common, and is expressed as a percentage. On average, mature beef cows require 55 per cent TDN in mid pregnancy, 60 per cent in late pregnancy, and 65 per cent after calving in order to maintain their body condition. Energy requirements will be higher during very cold weather, for cows that are underweight, and for young cows that are still growing. Average quality hay often contains 50 to 60 per cent TDN, while poor quality hay can be less than 45 per cent. Straw contains 35 to 40 per cent TDN. If cows are fed a diet containing only forage, that forage must meet their energy requirement. If not, feeds higher in energy (such as grain or pellets) can be added to the diet to provide the energy required.

The fiber content of feed is related to the amount of energy that is available to the cows. Fiber is expressed on forage test results as neutral detergent fiber (NDF). A higher number indicates more fiber in the feed. When NDF is higher than 60 per cent the feed will be very fibrous and bulky. Cows may have trouble physically consuming enough feed to meet their energy requirement.

Protein is measured as crude protein (CP). Cows require approximately 7 per cent CP in mid-pregnancy, 9 per cent in late pregnancy, and 11 per cent after calving. Forages will vary greatly in protein content, but in general, legume hay such as alfalfa or clover will be higher protein than grass hay, and cereal green feeds will be lower in protein than hay. Grains are also relatively low in protein. Protein is often supplemented in the form of pellets or lick tanks, which can be used to increase the protein content of the total diet. It is important to keep in mind that protein supplements will not compensate for forage that does not contain sufficient energy.

Most feed tests also report the mineral content of the forage. Calcium and phosphorus are the most important minerals to consider. The complete diet should contain at least 0.25 per cent calcium and 0.17 per cent phosphorus. More importantly, the diet should contain at least 1.5

times more calcium than phosphorus. Minerals often need to be supplemented using one of the many products available. Speaking with a nutritionist can solve the mystery of which mineral supplement to use with your forages.

As with many things, the first step to planning a winter feeding program is to know what you have to work with. Forage testing is a valuable tool for determining the most effective way to use your feed resources.

For more information on this or other topics please call me at (306) 946-3237, the Agriculture Knowledge Centre at 1-866-457-2377 or visit our website: http://www.agriculture.gov.sk.ca/