May 5, 2012 10:29
Leah Clark – Regional Livestock Specialist, Weyburn
Colby Elford – Regional Livestock Specialist, Moose Jaw
Although most cattle producers are in the midst of calving season, it is not too early to start thinking about getting pairs out to pasture. Many producers have a system of grass management that they put a lot of time and thought into. Often water quality and availability is an afterthought, but because water can have such a drastic impact on production and performance it is a good idea to ensure lots of good quality water is available to all animals.
Using a dugout as a summer water source is common practice in this part of the province. Getting the dugout ready for the grazing season is extremely important and can have big influences on the quality and availability of water for your livestock. There are a few things to consider when preparing a dugout for use.
The first, is addressing the issue of dugout nutrient loading. Nutrient loading of dugouts leads to increased bacterial and algae growth. Some of the bacteria and algae that grow in our dugouts can cause off tastes in the water, sickness and in some cases death. The best way to limit nutrient addition to dugouts is limiting livestock accessibility to the dugout. Restricting direct access to dugouts from livestock not only extends the dugout life by reducing trampling and collapsing of banks, it allows forage growth which helps to trap nutrient run off. Restricting access also reduces fecal and urine addition to water. Some producers are eligible for funding to install an offsite watering system. Research has shown that cattle will choose to drink from a trough rather than the source. Using an offsite watering system improves both dugout health and animal productivity.
Summer heat, nutrients and sitting water is the perfect combination for algae growth in our dugouts. This may be a concern, as cyanobacteria, commonly called blue green algae, produces toxins that have the potential to cause sickness, and in some cases death, when consumed by our livestock. Algae is easy to prevent with the addition of one of the registered copper sulphate treatments available for dugouts. Growth of algae occurs as water warms so prevention entails an initial dose followed by visually inspecting dugouts and adding the treatment when necessary as algae growth is observed. It’s important to note that correct doses should be used as toxicity can occur if too much product is added.
Aeration can also have tremendous long term positive effects on dugout water quality. In a study done at WBDC near Lanigan, SK. Yearlings gained 0.2lbs per day more when drinking aerated water compared to water straight from the dugout. Aeration helps to prevent algae growth as well as decreases the population of anaerobic bacteria in our dugouts. Examples of anaerobic bacteria effects in dugouts include ammonia formation and hydrogen sulfide gas which are associated with odor and poor palatability.
For more information, you can contact the agriculture knowledge center at 1-866-457-2377 or visit our website at www.agriculture.gov.sk.ca.
January 6, 2012 10:37
An 11-year-old Arab mare defies the odds and survives more than 12 hours in surgery to remove one side of her jaw along with a grapefruit-sized, cancerous tumour.
When Dr. James Carmalt examined the grey Arabian mare named Noor for the first time at the WCVM’s Veterinary Medical Centre last fall, the first thing that surprised him about the horse was her body condition.
“You could tell that Mr. Abidi (her caregiver) had been working hard to ensure that she had the right type of feed available and had managed to keep her weight on,” explains Carmalt, an equine surgeon at the WCVM. “She looked like a relatively normal horse — other than having this huge growth on the side of her face.”
The grapefruit-sized growth, about 26 centimetres (cm) in width and 20 cm in height, had been developing on the back curve of the horse’s right jaw ever since an accident occurred when she was two or three years old. Earlier in 2010, Syed Abidi found the disfigured mare on a farm in B.C. while searching for a specialized bloodline of Arab breeding stock.
He knew time was running out for the tough little horse that had managed to adapt and survive for so many years: “I saw a horse that needed help and I went for it,” says Abidi.
With the owners’ consent, Abidi brought the horse to Dr. Ryan Shoemaker of Delaney Veterinary Services in Sherwood Park, Alta. But after the cancer diagnosis was confirmed, Shoemaker referred the case to Carmalt.
“I think Dr. Shoemaker knows that if I could concentrate on equine head and teeth cases for the rest of my career, I would be a very happy man,” jokes Carmalt. “But he also knows that we’ve got many willing hands to help with post-operative care — something that’s very difficult to manage in private practice.”
“She wanted to go for it”
After several phone and email discussions, Abidi and Noor met Carmalt for the first time in November 2010. For two days, Noor underwent a battery of tests at the WCVM: a physical examination, a full mouth oral examination, an endoscopy of her upper airway and both of her guttural pouches, and radiographs of her skull and chest.
“Everything culminated with the CT scans. That allowed us to do a 3-D reconstruction of the tumour and that’s when we found out how large and invasive it really was,” explains Carmalt, adding that the tests showed no metastasis in the horse’s lungs.
Then Noor went home for three weeks — giving Abidi time to consider the risks and expense of the experimental procedure. “We talked at length about the risks. We also made a lot of effort to discuss the potential endpoints beforehand because we all wanted to consider the horse’s welfare,” says Carmalt.
“If she reached endpoint X or she suddenly decided that she had enough, we agreed that I would be the ultimate decision maker about euthanasia.”
“Dr. Carmalt and I — we think alike. We’re cautiously optimistic. We understand the risks involved but we’re willing to continue moving forward,” adds Abidi. “More than a dozen times, I was told to just put her down because it was too risky and too much money. But Noor is a smart horse — she let me know that she wanted to go for it.”
In the meantime, Carmalt prepared for a surgery that, based on veterinary literature, had never been done before. Besides experimenting on equine cadavers, Carmalt consulted with colleagues in the U.S. “Almost universally, the answer was, ‘Good luck with that,’” says Carmalt, who found invaluable advice closer to home.
Dr. Kathleen Linn is one of the WCVM’s small animal surgical specialists and routinely removes parts of the jaw in dogs diagnosed with cancer. But the surgeons had to plan for a different scenario with Noor. Instead of performing most of the surgery inside the mouth (the practice used for canine patients), the surgical team — consisting of Carmalt, Linn and Drs. Imma Roquet and Holly Sparks — would need to do most of the procedure from the outside because of the tight space inside the horse’s mouth.
“Like digging out a fossil”
Once Noor was prepped for surgery, the team inserted a tube through a tracheotomy in her neck. As well, they isolated her carotid artery in case a large bleed occurred and they needed to block the artery — an emergency procedure that slows down blood loss and buys time for surgeons.
The team used that emergency option four times during Noor’s marathon surgery that lasted for more than 12 hours. The procedure began with a 30 cm incision just below the tempomandibular joint (TMJ), curving around the bottom of the jaw to the front. The surgeons dissected their way down to the bone, lifting the tenuous tissues and facial nerves up like a flap until they could see the bone.
“Then we made a horizontal cut just below the TMJ at the top and a vertical cut between the second and third cheek tooth and lifted out the jaw,” describes Carmalt. “And that left us with a massive hole.”
The actual removal of the jaw bone took less than 15 minutes. What took time was cutting through the complex web of blood vessels — a process that Carmalt compares to digging out a fossil with painstaking care. “With a tumour, there’s a massive amount of new blood vessels. We knew where the major blood vessels were but there were so many vessels involved in the tumour — it was a whole entity on its own.”
After removing Noor’s swollen lymph nodes and any cancerous tissue, the surgical team began the laborious process of closing the hole with five layers of tissue and skin. Two catheters were left in the hole: one suctioned fluid out of the closed area while the other was a “soaker” catheter that allowed clinicians to put painkilling drugs directly into the wound.
As expected, Noor was wobbly in the recovery room but showed no ill effects of being under general anesthesia for so long. Within six hours, her post-surgery care team was offering her a variety of feed to choose from.
Horizontal to vertical chewing
When surgeons remove one side of a dog’s jaw, the animal can still chew its food up and down on the opposite side of its mouth. “But horses chew their feed horizontally so they need both sides to chew,” explains Carmalt. “We had no idea what Noor was going to do, but in retrospect, I should have held more stock in my physical exam and the CT findings.”
What the CT scan had shown was that Noor’s cheek tooth angles were flat as opposed to 15 degrees — the normal angle found in horses. Carmalt and his team eventually realized that Noor had already adapted to her disability before the surgery, learning how to chew vertically.
Three days after the procedure, Noor was eating enough to maintain her body weight. The rest of her three-week stay went relatively smoothly — thanks to the hard work of veterinary students who cared for Noor around the clock.
Noor returned home to Alberta just before Christmas. Since then, her recovery has had its challenges especially because of the harsh winter conditions on the Prairies. Noor also had some trouble eating because of dental issues, requiring Abidi to try different feeding options for her.
But the fact that Noor is alive and now has the chance to live a relatively normal life is still a miracle to Abidi who credits Carmalt for taking the chance on Noor. While he acknowledges that it was costly to save Noor, Abidi points out that he also spent the money to give the WCVM surgical team a chance.
“Dr. Carmalt told me it was a great learning experience for everyone involved. And by talking about this surgery, maybe others will read about it and be more confident about taking on these kinds of challenging cases in the future.”
For veterinary students, Carmalt says Noor’s case emphasizes the importance of referring cases to teaching centres like the WCVM once they’re in practice. It has also led to some intensive discussions about medical ethics at the veterinary college.
“From an ethical standpoint, I think we were very close to the edge with this horse. And if she hadn’t recovered as quickly as she did, we may have wished we hadn’t done it,” admits Carmalt. “I think as long as you have the welfare of the horse absolutely paramount and you aren’t swayed by the financial and emotional investments of the client, then I think you can try. You just need to know when to stop.”
Besides Noor’s strong will to survive and adapt, the other factor in the mare’s favour was Abidi: “He had already put in a massive amount of work to care for Noor plus he was willing to invest thousands of dollars in her surgery. After all that, I knew he wasn’t going to back off on his care,” says Carmalt. “He was in it for the long haul.”
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.
December 2, 2011 07:26
Hyracotherium - today's equine ancestor
November 12, 2011 08:23
by:Chelsey Carruthers, M.Sc., AAg
Regional Livestock Specialist, Saskatchewan Ministry of Agriculture
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/
September 21, 2011 06:16
Properly dispose of deadstock
Plan and control the disposal of carcasses according to municipal and provincial regulations. Carcasses should be disposed of in a timely manner.
Manage manure according to regulations
Plan and control manure management according to municipal and provincial regulations. Planning should include measures for collecting, storing, moving, and disposing of manure in ways that minimize the chance of spreading any disease organisms.
Keep the premises, buildings, equipment and vehicles clean
Buildings, equipment and vehicles should be cleaned regularly to prevent the introduction of disease and pests. Consider applying disinfectants when practical.
Maintain the facilities in a state of good repair
Maintain all facilities in a state of good repair so that your biosecurity plan can be effectively implemented.
This may include:
- buildings and fences to prevent wildlife and people from entering the premises,
- feed storage areas to prevent access by wildlife and vermin, and
- laneways to allow for cleaning and disinfecting vehicles.
Obtain production inputs from a reliable source
Purchase production inputs such as feed and bedding from reliable sources. Ensure the water supply is free of contamination.
Ensure a pest management program is in place to prevent the spread of disease.
Plan and train
Have a written biosecurity plan that is updated regularly. Ensure that employees receive proper training and training materials so they can continue to follow the plan.
for more information http://www.inspection.gc.ca
September 20, 2011 10:40
Equine infectious anemia (EIA), also commonly referred to as swamp fever or Coggins disease, is a viral disease of horses and other equidae that affects the immune system. It is transmitted by blood, mainly via blood-sucking insects, and by needles contaminated with blood containing the virus, or through breeding. The EIA virus can only reproduce in living cells, and in this way spreads throughout the animal. All infected horses carry the virus for life. The fact that the virus lives within the cell is the reason treatment and vaccination are ineffective.
In general, there are three forms of EIA in which the virus can be detected by the presence of antibodies produced by the horse in response to the EIA infection. In EIA's acute form, the virus actively multiplies and attacks the immune system and other body organs. Some of these horses may die suddenly, others may appear constantly and severely ill and harbor heavy concentrations of the virus in their blood. Horses afflicted by the chronic form of the disease may also contain high concentrations of the virus, but they tend to alternate between periods of appearing healthy and the disease state seen in the acute form. Some of these animals will debilitate over time, and present poor body condition. Acute and chronically infected horses always pose a high risk of infection to EIA-free horses because they have a high concentration of virus in their blood. The third form of EIA involves unapparent carriers. These are seemingly healthy horses that also carry the virus, but in a low or undetectable concentration in the blood. Inapparent carriers may never become acute or infectious; however, stress and other diseases or treatments can activate the acute form resulting in a high concentration of virus in the bloodstream. This third form of the disease is often the source of debate about the meaning of the Coggins test and the fate of the unapparent carriers among horse owners who are not well-informed about the disease.
The clinical symptoms of EIA depend on the severity of infection and vary from horse to horse. They can include one or more of the following: fever, depression, decreased appetite, fatigue or reduced stamina, rapid breathing, sweating, weight loss, bloody or watery eye discharge, swelling of legs, lower chest and abdomen, general weakness, wobbly gait, pale or yellowish mucous membranes, signs of abdominal pain, and abortion in pregnant mares.
The origin and evolution of the EIA control program
EIA has been recognized in Canada since 1881, originally as swamp fever. Initial efforts to control this disease based on the elimination of clinically ill horses were largely unsuccessful because infected but unapparent carriers perpetuated the disease within the horse population and served as a continuous source of infection for disease-free horses. In 1970, Dr. Leroy Coggins developed a diagnostic test for EIA using an agar-gel immunodiffusion (AGID) reaction. The Coggins' test is consistently reliable in detecting the presence of antibodies regardless of whether the infection is acute, chronic or unapparent. The test's reliability and the identification of unapparent carriers paved the way for implementation of more successful EIA control programs.
In 1971, EIA was made a reportable disease in Canada, and the first EIA program was introduced in 1972. Agriculture Canada offered the Coggins test to Canadian horse owners and voluntary testing was performed by accredited veterinarians. The government was only involved in trace-out investigations and testing after a reactor was reported. EIA reactors were either permanently quarantined or destroyed. There was no compensation paid for any destroyed horses during the first seven years of the program, but in 1978 the federal government introduced the compensation payment of $200 to owners whose horses were euthanised. In 1989, Agriculture Canada began to accredit private laboratories to perform the Coggins test although all atypical or positive results were confirmed in a federal laboratory before any quarantine and investigation activities were implemented.
From 1972 to 1993, of the approximately 1.8 million horses tested, some 14,000 were confirmed positive for EIA. Although some owners chose permanent quarantine for their animals, the majority of horses were destroyed. During the same time period, the rate of infection among horses tested dropped from 2.9% to 0.39%, indicating that the program reduced the number of infected horses and was successful in controlling the spread of the disease in all but some remote and high risk areas.
In 1994, the government reprioritized its activities and reduced its involvement in the program by modifying the EIA control policy. EIA remained a reportable disease and testing procedures and requirements did not change; however, Agriculture Canada notified the owners and "contact animal" owners instead of investigating reactors and testing positive animals. Horses in contact with reactors were not quarantined and their testing was conducted at the owner's expense by Canadian Food Inspection Agency (CFIA)-accredited veterinarians. Owners required a federal licence to remove infected animals from a premises. At this time the government also discontinued ordering the destruction of infected horses and the payment of compensation. Between 1994 and 1998, approximately 337,000 horses were tested and close to 550 reactors were either voluntarily destroyed or permanently isolated. During that period, the rate of infection among tested horses increased from 0.39% in 1993 to 0.66% as recorded in 1999.
The current EIA control program
In April 1998, the newly created CFIA was approached by the equine industry to modify the EIA program. EIA does not pose a risk to food safety or human health; however, the CFIA agreed that unless EIA was controlled there could be devastating effects on the Canadian horse industry including those related to international trade. Consequently the CFIA agreed to participate in the control of EIA providing the new program was industry-driven and self-funded.
This current program consists of two components. Under the first component, horse owners voluntarily pay to have their horses tested when they are identified by the industry (i.e. movement into shows, point of sale, etc.). Testing is conducted by private veterinary practitioners and EIA private laboratories accredited by CFIA for that function. The second component of the program is the mandatory response, for which the CFIA is responsible. Each time an EIA positive horse is discovered, it must be reported to the CFIA and disease control measures are implemented. The premises on which a reactor is discovered is declared an infected place and all susceptible animals must test negative to be allowed to move off the property. Horses in contact with the reactor within 30 days of the sampling date are also tested. All EIA test-positive horses are retested and reactors with clinical signs are ordered destroyed. Owners of horses that are confirmed positive for EIA without clinical signs must choose whether to either keep the horse in a permanent quarantine or have it destroyed. In the later case, the CFIA orders the horse destroyed and pays compensation. The government's part of the program is delivered at no charge to owners.
When the program was introduced in 1998, the maximum amounts payable were set at $500 and $1000 for grade and pure-bred horses respectively. To further promote the program and encourage testing, compensation has increased to a maximum amount payable of $2000 per horse.
Accredited laboratories charge owners $2 for each animal tested to offset the cost of the CFIA's mandatory response. While this amount may, in some years, cover the cost of compensation, it does not cover CFIA's cost in terms of manpower and operating cost. This is provided as a service to the industry.
The CFIA's position on EIA control program
The CFIA has not imposed the EIA program on horse owners, but has responded to a request from the industry to administer a program that the majority of horse owners support. Participation in the program is voluntary and all elements of the program have been developed in conjunction with the industry. The program is based on internationally recognized disease control standards, current knowledge of the disease, and diagnostic methods. As there is no effective treatment for EIA and no vaccine to prevent it, the disease can be successfully controlled by testing and the elimination of reactors including unapparent ones. The Coggins test is an integral part of the CFIA control program.
EIA does not pose a food safety risk and is not a public health concern, therefore the CFIA's involvement is based on the furtherance of animal health in Canada.
for more information: www.inspection.gc.ca
August 19, 2011 07:48
Animals (particularly horses) infected with the virus show neurological disturbances. Clinical signs may include:
- ataxia (lack of coordination);
- depression or lethargy;
- head pressing or tilt;
- impaired vision;
- inability to swallow;
- loss of appetite;
- muscle weakness or twitching;
- partial paralysis;
- coma; and
The clinical signs of WNV in mammals can be confused with rabies.
Most infected domestic birds do not show signs of infection, and only domestic geese appear to be particularly susceptible to disease and/or death when infected.
WNV-infected geese will show signs of depression, loss of appetite, inability to stand, weight loss and death. The virus can be difficult to distinguish from Newcastle Disease and Avian Influenza in domestic birds.
March 10, 2011 18:05
“It’s really cold outside, it’s starting to snow again, and the wind is howling. Is my pasture-kept horse all right?” In all but the most extreme winter weather, the answer is “Yes.” Most horses are well-suited for staying healthy and comfortable in cold weather as long as owners provide them with proper care. Some horses may need additional help staying warm in bitterly cold, wet, windy weather.
The equine hindgut acts as an enormous furnace where the digestion of hay and other fibrous feeds produces a constant supply of heat from microbial fermentation. Owners need to be sure horses have an adequate supply of hay, increasing the amount as the temperature drops.
More heat can be produced by activity, including shivering. Pastured horses can be seen playing, bucking, and running from time to time, and this muscular exertion helps to keep body temperature stable. Short bouts of shivering do the same thing. Horses that shiver continuously in cold, wet weather probably need more hay, possibly a bit more grain, and access to shelter.
The horse’s winter coat is thick and dense. As long as it stays dry, it provides superior insulation. Natural oil tends to let rain and snow slide off, keeping moisture from penetrating deep into the coat. If you see snow building up on your horse’s back or rump, you are looking at proof that his body heat is not escaping through the hair to melt the snow.
When rain or wet snow manages to soak through to the horse’s skin, heat will be lost as the coat’s insulating ability decreases. Under these conditions, horses may need to wear a well-fitting waterproof blanket or have access to a windbreak or covered shelter.
Though horses sometimes stand in deep snow, their lower limbs and hooves almost never suffer damage from the cold. This is because the legs below the knees and hocks are made up mostly of bones and tendons, tissues that don’t freeze easily. In extreme cold temperatures, blood-shunting mechanisms in the hooves alter circulation patterns to preserve body warmth.
Regardless of the adaptations mentioned above, some horses may need additional help staying warm in bitterly cold, wet, windy weather. Very old, very young, sick, or extremely thin horses may need to be blanketed or brought into deep-bedded stalls to keep them from becoming dangerously chilled.
to read further: http://www.equinews.com/article/
March 2, 2011 21:30
Western Canada’s most common (and not so common) skin conditions.
Dr. Sue Ashburner still shudders when she describes the sight of one of her equine patients covered with thousands of bloodsucking ticks last winter. “We occasionally see wood ticks on horses during May and June, but I didn’t know what kind of ticks would be on horses in February,” admits Ashburner, a veterinary clinician at WCVM’s Large Animal Clinic in Saskatoon, Sask. Dr. Lydden Polley, a parasitologist at the College, soon solved the mystery: he identified the parasites as Dermacentor albipictus (Acari: Ixodidae), more commonly known as moose ticks. “It was the first time I ever saw a horse in this area covered in moose ticks,” says Ashburner. “That’s what I like about working on dermatology cases. There are always new things, and those cases challenge you to find out what you’re dealing with. Sometimes we never know the cause, but we usually know how to treat what we see.” At least once a week, Ashburner gets a chance to use her dermatological know-how on equine patients living around Saskatoon — an area that’s populated with horses of all breeds and disciplines. The clinic’s number of dermatology cases usually rises in the spring after horses shed their coats and owners suddenly notice lumps, bumps, growths or parasites that have shown up during the winter. Thanks to advances in diagnosing and treating equine skin conditions, veterinarians can offer clients more effective therapies and more understanding of what causes skin problems to develop. Most clients call for advice or to arrange for a veterinary visit, but some still insist on using their own home remedies that often makes Ashburner’s job tougher. “After they’ve scraped it, treated it or used ointments that burn the skin, it doesn’t look anything like it originally did. These remedies usually just make things worse.” While Ashburner isn’t expecting another moose tick infestation case soon, here are some common skin conditions that she and veterinary pathologist Dr. Ted Clark regularly see out in the field and in the pathology laboratory. Their comments accompany some additional information gleaned from the text, Equine Dermatology, co-authored by Drs. Danny Scott and William Miller Jr. • Dermatophytosis or ringworm is a fungal infection that’s transmitted by contact with infected hair, bedding, tack and grooming equipment. Ashburner often diagnoses multiple cases of ringworm in young horses living in close quarters throughout the winter months: the infection often goes unnoticed until horses shed their winter coats. The most consistent clinical sign is one or many circular patches of alopecia (hair loss) with variable scaling and crusting. But horses may also develop the classic ring lesion with a healed centre and fine follicular papules and crusts on the ring’s edges. Lesions are usually multiple, and they’re most commonly found on the face, neck, the sides and girth. The lesions usually go away within three months, but veterinarians often use topical and systemic treatments to help their patients’ response to the infection, to reduce the spread of the fungus and to speed up the healing process. • Sarcoids are the most common skin tumour of horses around the world. Veterinary researchers believe the cause of sarcoids is viral, and research has shown that bovine papillomaviruses (BVP) are commonly involved in sarcoid development. Lesions frequently show up in areas of a horse’s body after a wound or trauma, or they may also spread to other areas of the same horse or to other horses through biting, rubbing, tack, equipment and insects. Sarcoids occur anywhere on a horse’s body, but most lesions are found on the head, neck and ventral body surface. The lesions’ appearance can be verrucous (wart-like), fibroblastic (proud flesh-like), mixed verrucous and fibroblastic, and occult (flat). Sarcoids do not metastasize, and some tumours may disappear after several years. Depending on available resources, veterinarians can choose from surgical excision, cryosurgery, radio-frequency hyperthermia, laser therapy, radiotherapy, chemotherapy, immunotherapy or combinations of treatments. • Papillomas present in two different forms: as warts (viral papillomatosis) or as aural plaque (ear papillomas). Viral papillomas spread through direct contact or indirectly through contact with contaminated equipment or housing. Young horses often develop clusters of warts, usually on their muzzles or lips. “They bother the owner much more than horses,” says Ashburner. “If left alone, they tend to go away and you can’t rush them. People always buys potions and lotions, but they usually make no difference.” Aural plaques — white-greyish crusts commonly found in horses’ inner ears — don’t respond very well to topical treatments, and they rarely go away. Fortunately, these lesions are only a cosmetic problem. • Eosinophilic granuloma or nodular necrobiosis is an equine dermatosis most commonly seen in the spring and summer. These nodules are round, elevated, and occur as single or multiple lesions on the back, withers and neck. The lesions aren’t painful or itchy, and the overlying skin and hair coat are normal. Veterinarians can surgically remove one or several lesions, or treat multiple lesions with systemic glucocorticoids over several weeks. Some lesions undergo spontaneous remission in three to six months, while older or larger lesions must be surgically removed. • Allergic reactions show up as anything from bumps and wheals in all shapes and patterns to angioedema (swelling) involving the muzzle, eyelids, under the belly, legs or the entire body. These reactions result from insect bites, plants, drugs or vaccines, a change in feed, bedding or the horse’s environment. Gathering a thorough medical history is how veterinarians usually track down the source, says Ashburner. “It could be caused by a minor environmental change, a sudden hatch of bugs in the area. It really pays off to ask a lot of questions.” Ashburner and her colleagues usually try to eliminate the source of hypersensitivity or generally treat the horse to try and decrease its immune response. “One treatment that has worked quite well is to feed the horse raw linseed oil: its Omega 3 fatty acids help to decrease the animal’s hypersensitive response in the skin. That seems to calm things down and it helps to make the other treatments work better.” • Scratches or pastern dermatitis most commonly affects one or both hind limbs with varying levels of pain and itchiness. The condition initially shows up as erythema (dew poisoning), swelling and scaling on the pastern, then progresses to discharge, matting of hair and crusting. Veterinarians usually diagnose this problem when there’s abrasive mud in corrals, or when ice crystals are mixed in the snow and dirt. “We think the moisture content has something to do with it: something seems to set up the right environmental conditions to induce scratches, particularly in the spring,” says Ashburner, adding that the condition usually shows up on a white leg. “It responds very well if treated early, but it’s often missed by the owners until the horse’s pastern is very sore or very swollen. And the longer they have it, the harder it is to treat.” Severe cases of scratches can also lead to a longstanding, immune-mediated infection called vasculitis that can take months to cure. If diagnosed early, the ideal treatment is to clean the area very well with mild soap (no abrasive cleaners) then remove as much of the scabby debris as possible. Clipping the hair can help to remove the scabs. “We keep the area dry and use a topical cream — a combination of antibiotic and steroid cream — to fight the mixed infection,” explains Ashburner. Clark adds that it’s important for veterinarians to be aware that scratches isn’t “one specific disease with one specific cause.” If certain horses or horse herds continue to be plagued by this type of dermatitis, practitioners need to look at the animals’ environment, their habits and what they’re used for to learn more about probable causes. • Rain scald (dermatophilosis) is a bacterial skin infection that causes superficial, pustular and crusting dermatitis in horses. These lesions are most commonly found on horses’ rumps, saddle area, face and neck — or on pasterns, coronets and heels (in the form of scratches). The two most important factors that lead to rain scald are skin damage and moisture. The condition is often diagnosed in horses after intense rain, and when temperatures and humidity are high. Veterinarians on the Prairies don’t often see rain rot, but it’s a common problem in B.C. While most cases of rain rot go away within a month, the best treatments include keeping the animal dry, removing crusts, and using topical treatments and using systemic therapy if the infection is chronic or severe. • Melanomas are malignant skin tumours that are most commonly — but not exclusively — found in grey or white horses over six years of age. Arabians, Percherons and Lippizaners commonly develop these tumours that are often found on the undersurface of the tail and the perianal region. Tumours can also be found on the lips, base of the ear, on the legs, or anywhere else on the horse’s body. The melanomas are usually firm, nodular to plaque-like, and they may or may not be alopecic (hair loss), hyperpigmented or ulcerated. Veterinarians can use surgical excision or cryotherapy to remove solitary tumours, but in most cases, the tumours require no treatment. • Insect hypersensitivity: Western Canadian horse owners and veterinarians deal with fewer parasitic problems than in other parts of the world because of the region’s cooler climate, but insect hypersensitivity is still a common problem in the spring and summer months. Controlling insects and using anti-itching agents can help to manage insect hypersensitivity. The use of ivermectin, moxidectin and other dewormers has also helped to reduce the occurrence of conditions like sweet itch, says Ashburner. - Sweet itch or Summer Seasonal Recurrent Dermatitis (SSRD): The most important cause of equine insect hypersensitivity is Culicoides gnats (sandflies, no-see-ums, biting midges). Affected horses develop itchy, crusted papules on the top of their tails, along their mane, neck, withers, hips, ears and forehead. The disease’s itchy nature causes horses to scratch and chew at themselves, or they may rub against stalls or fences. That can lead to hair loss, ulcer development and damage to the animals’ manes and tails. - Mange is caused by mite infestations in horses’ coats. Owners and veterinarians usually see these infestations during the late winter and early spring, and contributing factors include crowding, prolonged stabling, and poor nutrition. - Lice infestations are commonly found in horses during the winter when the animals’ coats are longer and they may be in close contact with their herd mates. Biting lice are usually found on the horses’ dorsolateral trunk, while sucking lice prefer the animals’ mane, tail and fetlocks. Clinical signs include scaling, a dishevelled coat, hair loss and mild to moderate itchiness. Reprinted with permission of Horse Health Lines, news publication for the Western College of Veterinary Medicine's Equine Health Research Fund. 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February 3, 2011 08:14
Horses are living long lives on acreages, farms and ranches across North America. That reality is reflected in statistics: it’s estimated that geriatric horses (animals more than 20 years old) account for somewhere between seven and 20 per cent of the entire equine population.
Owners and veterinarians are growing more aware that proper management and medical care can expand the lifespan of these horses. Many age-related issues like dental disease or parasite problems can also be prevented through regular veterinary care that’s provided throughout a horse’s life.
Dr. Katharina Lohmann is an internal medicine specialist and an associate professor in the Western College of Veterinary Medicine’s Department of Large Animal Clinical Sciences. Since many of her regular patients at the College’s Veterinary Teaching Hospital are equine senior citizens, Lohmann has gathered together a wealth of health management tips that are specific for geriatric horses.
The following story is an abridged version of a comprehensive article that Lohmann wrote for a national veterinary publication called Large Animal Veterinary Rounds that’s written at the WCVM. Visit www.canadianveterinarians.net/larounds (click on “Archives” for the complete title list) to read the entire article that was published in June 2007. Plus, make sure to read another helpful article called “Diseases Affecting the Geriatric Horse” (published in September 2007).
FOOD AND WATER
A common challenge in caring for older horses is maintaining their weight. Several factors can cause a horse to lose pounds or adequate body condition: underfeeding, protein-calorie malnutrition, nutrient loss, the inability to eat, a lack of appetite, or a physiologic condition or illness.
In many cases, it’s not enough to simply increase the amount of feed: it may take some research to understand the root of the problem. For example, if an older horse is underfed with protein-calorie malnutrition, the animal may have trouble eating the existing feed. In that case, you may need to find an alternate feed that’s easier for the horse to chew or digest. Or, if younger herdmates are preventing the senior horse from getting enough access to food, you may need to rearrange the herd and provide more accessible feed sources to avoid competition.
Q. How much fuel does a senior need?
An older horse’s feeding regimen generally needs little or no adjustments as long as the animal maintains its weight and body condition. The National Research Council’s (NRC) energy recommendations for adult horses equates to about 7.5 to 11 kilograms of hay per day — depending on feed quality and energy content. However, these ration estimates are only a starting point and need adjusting to account for exercising, chronic illness or conditions, or cold weather.
Use body conditioning scoring systems or weight tapes to monitor an older horse’s body condition. While weight loss is a common concern, you also need to be sure that obesity doesn’t become a problem.
Q. What are the best energy sources?
While good quality forage is the ideal maintenance feed source, older animals with dental issues may need alternate feed to maintain body condition. Complete pelleted feeds meet all dietary requirements for senior horses including higher protein and fat content along with balanced mineral supplementation. If a horse doesn’t have a condition like recurrent choke, you can also feed supplemental hay to satisfy your horses’ chewing needs and to prevent boredom or bad vices.
Make the switch from hay to pellets gradually, and adjust feed amounts for the individual horse. As well, consider cost before deciding to make the switch: based on maintenance requirements, a horse will need about 15 to 20 pounds of complete feed per day.
One cheaper alternative: feed energy-packed beet pulp and grains or sweet feeds to senior horses along with their daily hay ration. But these high-carbohydrate diets aren’t recommended if a horse has chronic laminitis or insulin resistance (a common condition associated with pituitary dysfunction).
While supplemental feeds with higher fat content are available in feed stores, you can also add vegetable oils to your animals’ diets. You can feed up to two cups of oil to an average-sized horse in two or more daily feedings with small amounts of beet pulp and grain, but start with smaller volumes and gradually increase to oil amounts over two to three weeks.
Q. What are changes in digestive capacity?
The energy requirements of older horses may not change, but their ability to digest certain nutrients may be reduced. Geriatric horses may prefer feeds with higher protein concentrations with less fibre content, and it may also be advisable to increase mineral supplementation so the horse gets enough phosphorus. But be careful about making these kinds of changes if horses have been diagnosed with renal or liver disease.
Since chronic parasitism can cause decreased feed digestibility in older horses, it’s important to maintain a good deworming program. If a horse has trouble maintaining its body condition, use extruded feeds or add Brewer’s yeast that has the added benefit of providing supplemental B-vitamins.
Q. What are changes in water intake?
Dental pain or decreased thirst perception may cause older horses to reduce their water intake. That can cause low-grade chronic dehydration that leads to reduced exercise tolerance and a predisposition to impaction colic or renal dysfunction. As well, older horses can develop choke if they don’t drink enough water along with alfalfa pellets or other pelleted diets.
How can you increase your horses’ water intake? One option is to soak their hay or roughage, but that’s not a long-term solution since it reduces the feed’s nutrient content. Adding salt to a horse’s diet may increase thirst, but animals must have free access to water and it’s advisable to test for adequate renal function before using this option. Another suggestion: feed mashes or slurries to geriatric horses — a good way to ensure that they ingest some fluids.
If horses aren’t drinking as much because of oral pain, it’s important to correct the dental problem. Heated water sources will also help to reduce the pain of cold water on a sensitive mouth. If an older horse has a chronic condition like laminitis, it’s also important to make it as easy as possible to give the animal ready access to clean water.
Regular exercise can improve a horse’s mobility and slow down the effects of age on cardiopulmonary and musculoskeletal function, but exercise regimens should be tailored to the horse. As well, be aware that older horses may be prone to overheating during strenuous exercise and may become dehydrated. As the horse’s body changes, it may also be necessary to adjust the animal’s regular saddle and tack.
Common causes of reduced athletic capacity in older horses include: • musculoskeletal problems that are caused by the cumulative “wear and tear” of athletic activities versus acute conditions.
• decreased range of joint motion that can lead to further lameness problems if a horse tries to perform strenuous exercise.
• age-related changes in body conformation such as swayback.
Some musculoskeletal conditions in older horses can’t be cured. Instead, they require long-term management and pain control through the use of non-steroidal anti-inflammatory drugs (NSAIDs) or other systemic medications, supplements (such as glucosamine or hyaluronic acid) or arthrodesis of low-motion joints. Specialized trimming and shoeing can also be helpful in managing musculoskeletal issues.
PREVENTIVE CARE AND VACCINATIONS
Geriatric horses may be more susceptible to infections based on declining immune responses with age, concurrent diseases, general debilitation and poor nutritional status. Researchers have demonstrated that declining immune responses with age primarily affect the adaptive immune responses, specifically antibody formation, while the innate immune system remains relatively stable throughout life.
Here are some recommendations about vaccination practices with older horses:
• routine vaccination against viral diseases like influenza should continue throughout life.
• continue vaccinating against life-threatening conditions like encephalomyelitis, tetanus and rabies. In contrast, some scientists recommend that owners discontinue vaccination against equine herpes virus infection since it may provide little benefit and may favour reactivation of latent infections.
• inactivated vaccines are thought to be safer for geriatric horses compared with attenuated live vaccines.
• optimizing a horse’s overall health status can help to achieve the maximum benefit of vaccination.
Since chronic parasitism is a common problem in geriatric horses, review your deworming strategies — especially in animals with a perceived loss of body weight and/or condition, or with pituitary dysfunction. Monitor parasite load in an older horse through regular examinations of body weight, body condition and fecal egg counts.
Lohmann, Katharina L. “Management and Care of the Geriatric Horse.” Large Animal Veterinary Rounds 7(5), 1-6. Reprinted with permission of 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 a free e-newlsetter.