Borrowdale Park Veterinary Hospital

24/02/2021

These are sialoliths. Or stones that have formed in the parotid salivary duct. Usually forms in the cheek area of horses. Bacteria invade the duct from the mouth to form a nidus or scaffolding for calsium to get deposited. They grow slowly over time. The nose band can put pressure on them causing riding issues. They are removed by means of a simple sugery thru the mouth called a marsupialization approach I find these stones occasionally when working dental cases up as they are easy to feel under the skin on the cheeks or mandibles

28/01/2021

We see donkeys with slipper feet laminitis in Botswana quite commonly. Oddly this slipper feet can affect anything from one to all four hooves but more commonly less than four. It can even affect one front and one back foot.

Our project was to see if we could get this donkey sounder. To this end we took some xrays. These showed rotation in the front feet and due to increased weight going down the outside of the back feet the pedal bone had lateral sinking causing the donkey to walk on the outside of both back feet! The soles were rotated medically and were viable as the hoof wall had rotated through 90 degrees. Together with the help of the farrier Charles and Elias and some meditomidine sedation, as doing donkeys back feet is not easy, we managed to correct the deformity and reduce the sole depth in the front feet in three farrier visits. The back feet are better but not 100%. But we have a happy donkey and a happy owner. Thanks to the new owner for bringing this donkey into town and seeking some professional assistance which we were happy to supply at no charge. Pain needs a solution!

In Botswana this condition is thought to be as a result of a toxic plant called Crotalaria. However, no one can explain to me how a toxic plant can affect one front hoof and not the other or one front foot and one back foot. So the explanation seems somewhat dubious in my opinion. This Zimbabwean donkey had access to a wheat field so had too much luxury and then become overweight and therefore got secondary laminitis. It is easy to get donkeys overweight. However I deal with some thin donkeys that, try as one may, never recover. I wish we could do more extensive work ups and blood testing and possibly even, glucose absorption tests and a histopath to understand severe weight loss in donkeys better.

06/10/2020

Please note that there has been a confirmed AHS case reported in the Germiston state vet area, GP. Permits for movement into the AHS controlled area will be retracted/ declined. movement restrictions will remain in place for 40 days at least for the 30km radius around the case or larger if more cases are reported.

04/10/2020

STOP PRESS. Wrote to Prof Martin Nielson the parasitologist at Kentucky university about increasing prevalence of anthelmintic resistance in young horses. He is the co-author of the book “ Handbook of equine parasite control “ They have just diagnosed Ivermectin and moxidectin resistance too in a big group of imported Irish TB yearlings earlier this year. Paper Released three days ago on their findings They overcame this by tubing with moxidectin plus oxibendaxole ( not available in RSA ) plus pyrantel pomoate. Note. Piperazine is not registered anymore for use in horses in the USA . As the yearlings were isolated from USA bred yearlings on importation the problem may have been contained for now. They were suspecting a looming problem as
In a paper evaluating the parasite soundness of the Irish breeding industry ( Elghryani 2019) only 12.9% had ever used a wec reduction testing when considering deworming stratergy We have been seeing strongyle resistance since 2016 in Zbw but the big concern is that the prevalence is on the increase. Take home message. Global movement of horses likely to spread resistant strains of parasites. Dr Karl van Laeren

16/08/2020

AHS vaccinations continued.
Many of our clients insist in vaccinating late in the year. Either because they claim to get clinical cases late in the rainy season or because they don’t want to
Vaccinate while their horses are in work and not “on Christmas holiday “. Most of the trials on immune response to vaccination get stopped at about 12 weeks after vaccination (due to the costs involved) and the antibody titers are still on a steady rise. Onderstepoort Vet Institute, who manufacture the vaccine, say that their testing has shown the antibody titer to steadily climb and only reach its plateau levels at 11 months after vaccination! So vaccinating earlier in late winter to autumn months would suggest a higher antibody level when it really counts than leaving ones vaccinations till Christmas. Not even considering the real risks of vaccinating when midges are already enjoying blood meals with living vaccine virus in abundance in the blood stream!

29/06/2020

Dear clients, this is the first on three or four articles that we will write on understanding oral health and dental abnormalities we are seeing in our case load. After attending the two practical courses laid on by EQUINE DENTAL CLINIC UK my passion for performing good dentistry has improved due to my own better understanding of dental anatomy. Let me share this with you

18/04/2020

AHS VACCINATION NOTES APRIL 2020
Our visiting vet and good friend Dr Karl van Laeren BVSc MRCVS of Borrowdale Park Veterinary Hospital, Harare attended an AHS vaccination seminar in Kruger National Park in February 2020 and shared key info from that talk with us in early March. Following a Zoom chat on the outcomes with Karl and other clients of his in Botswana and Zimbabwe, I’d like to expand upon it as below.
Please note that these notes refer to the use of AHS vaccine from Ondersterpoort, South Africa. They are for the information and interest of horse owners and do not replace your own veterinarian’s advice.
New thinking in AHS vaccination
• The meeting was to discuss the current theory that no less than six sets of vaccination per horse are necessary to provide immunity.
• Therefore the recommendation is to give two full sets per year for three years in a row in previously unvaccinated horses.
• One full set is both bottles AHS 1 and AHS 2.
• This schedule will greatly enhance a horse’s chances of survival.
In the 19th century, some 70,000 horses died of AHS in South Africa in one ten year period, so although the vaccine is expensive to buy and can be challenging to source in some African countries, it is a big life saver when correctly used. More recently, in 2019, 50 race horses were lost in Thailand following the import of some zebra from South Africa. Thailand’s epidemic continues. https://asiatimes.com/2020/04/the-other-viral-plague-stalking-thailand/
Vaccination notes
• AHS is an attenuated (modified) live vaccine.
• To remain viable, the cold chain of above 4oC to 8oC MUST be preserved.
It cannot be frozen as this will kill it.
• When you are preparing it for use, it must be used within 10 minutes of
mixing, so when vaccinating big yards, do not mix too many doses at once.
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• Ideally, vaccination of the pregnant mare will start 3 months before the foal is born to provide it with passive immunity. This may last from 3 to 6 months, depending on the strains being examined.
• Knowing due date is therefore of key importance.
• Vaccination of any horse should take place outside the midge season i.e.
before the rains, as it is possible for the vaccine to cause a mild case of AHS which is transmissible by midges to other horses - because it is a live vaccine. This is known as viral recrudescence. It is more likely to occur in horses being vaccinated for the first time than in older horses being revaccinated.
• Vaccinate foals at age 6 months.
• Always use Bottle 2 before Bottle 1 to avoid reactions in sensitive
animals. Mild AHS symptoms are sometimes observed the very first time a youngster or mature horse receives AHS vaccine and these are usually less with Bottle 2 than Bottle 1.
Viral recrudescence was the cause of no less than 3 outbreaks of AHS in the Cape. Vaccine virus entered the midge population and rearranged itself into a more virulent strain which was then transmitted to adjacent unvaccinated horses with dire consequences. So – vaccinating in the non-midge season is very desirable in Southern Africa (June to end of October).
In East Africa where there are two rainy seasons, it may be necessary to use Bottle 2 in one dry season and Bottle 1 in the other, but local knowledge is required here to determine best practice.
Do not think that vaccinating your horses during an outbreak is going to save
them. It will not as they won’t have developed sufficient antibodies. Vaccine response is quite slow and one does not know which strain is at work. One may have been unlucky and started vaccinating with the wrong bottle.
For example, in 2020, strains 1, 4, 7 and 8 were all incriminated in the northern Transvaal and Gauteng (Limpopo province) outbreak. There are 9 serotypes in nature. Strains 1, 3 and 4 are in Bottle 1. Strains 2, 6, 7 and 8 are in Bottle 2. Strains 5 and 9 are not in but there is some cross protection from the strains that are present in the vaccine, between 8>5 and 6>9.
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A 2012 weanling study by Guthrie et all showed:
• 50% response to Serotype 1 within 3 weeks
• Serotype 3 response detected at 4 weeks
• Serotype 4 response detected at 7 weeks
• If Bottle 2 first only 27% response to Serotype 8!
• Foals born within 6 weeks of their dam’s vaccination had no response to
the vaccine
Research continues at Ondersterpoort (University of Pretoria, South Africa) and in Dubai at the Central Veterinary Research Laboratory.
SHN 16.4.2020
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BANGKOK – For the first time in Thailand, another rapidly spreading “cruel” and “devastating” virus has killed at least 186 horses by attacking the animals’ lung…

18/04/2020

African Horse Sickness Outbreak in Thailand
The World Animal Health Organisation (OIE) was notified on 27 March by the Department of Livestock Development (DLD), the veterinary authority of Thailand, of an outbreak of African Horse Sickness (AHS) in the Pak Chong district, Nakorn in the north-east of the country. In the initial notification, 341 horses were reported susceptible, of which 62 were confirmed infected. Out of these 62 horses, 42 are reported to have died.

A further two outbreaks were reported to the OIE on 3 April. One outbreak occurred in Hua Hin district, in the Prachuap Khiri Khan province where 10 horses out of a group of 15 susceptible horses have died. In the Ko Chan district of the Chon Buri province, there were 33 susceptible horses of which 6 were infectious. Five out of the 6 horses died.

As a result of the outbreak, the OIE has suspended the AHS-free status of Thailand.

AHS is spread by insect vectors such as midges and some types of mosquitos and ticks. All species of equidae can be infected by the disease. Horses and mules often die from the infection, while donkeys are much less susceptible and zebras rarely show clinical signs. The disease can be caused by any of nine serotypes of the virus. The serotype in this outbreak has not yet been communicated by DLD.

Dr Karl M.A. van Laeren (BVSc)

21/01/2020

Just to keep everyone informed that their are some cases of AHS around in Rsa. None so far that I know of in Zimbabwe though

AHS confirmed case East London area.
AHS confirmed case Bergville area
KZN. And suspect north of Pietermaritzburg

14/11/2019

THE "FAT LEG" DISEASE

Raise your hand if this has ever happened to you: you walk into the field or stall to catch your horse, and there he stands, in a lot of pain, with one leg swollen from the stifle down to twice its normal size (the famous "stovepipe" leg).

What is unscientifically called a “fat leg” is usually an inflammation: of subcutaneous connective tissue (in that case it's called cellulitis); of the lymphatic system (called lymphangitis, a severe form of cellulitis); or of blood vessels (called vasculitis).

A "fat leg" with no obvious trauma can be very frustrating for both horse owner and veterinarian due to its confusing nature. It can sideline a horse for days, weeks, or even months; and severe or untreated cases can become chronic, which can in turn result in fibrosis and hardened spots on the legs. Please note that lymphangitis/cellulitis is a dramatically different condition than your everyday "stocking up" (fluid swelling), which normally resolves with exercise.

While causes may vary, once a horse has cellulitis, it’s easy to spot. If you think your equine friend has cellulitis or even if you're not sure, we encourage you to seek professional help promptly. Your horse doctor will make the best treatment recommendations, both to reduce swelling and to address any sort of bacterial infection that might be active or that could occur due to the edema in the soft tissue.
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Related resource: https://aaep.org/horsehealth/lymphangitis-frustrating-condition
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