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Equine Articles

Kowhai Tree. RIP Tree.Kowhai Tree. RIP Tree.

During April 2019, Louisa visited an interesting case in the Wairarapa.

The owner’s 5 year old dressage mare had recently had treatment for an orthopaedic problem and was being returned to ridden work. The owner noticed that she was behaving oddly – perhaps a case of too much grass and not enough work?

She noticed that she was spooking more than usual, was more highly strung and was not her usual placid self to handle. On the day of the visit, the behaviour had become even more pronounced to the point of being dangerous. She was high stepping with her hind legs, with stringhalt like symptoms, and she appeared to have lack of co-ordination. She did not appear to have an obvious lameness, but when put on the lunge to assess this further, the mare attempted to run off toward a fence in a blind panic! The mare also displayed muscle fasciculations (tremors) most pronounced over her rump and sides. Sensibly, the owner decided to call out the vet as some form of injury to horse or handler seemed imminent.

The mare presented to Louisa much the same as the owner had reported. Her heart rate and respiratory rate were increased, her temperature was normal, her gut sounds were increased in all quadrants and she displayed obvious muscle fasciculations over her body. Her mucous membrane colour and capillary refill times were normal (a measure of hydration). A brief orthopaedic exam showed no obvious lameness but did show intermittent high steps with the back legs and was cut short due to safety. She was in excellent body condition weight wise and her coat was healthy, plus she was on a vet monitored worming program.

Other than returning to work, her management hadn’t really changed. She had moved to a new paddock in the last week or two, which she shared with her usual cow friends. There was no excessive grass cover; she was getting the same hard feed and a small amount of baleage, which the owner was careful to check for moulds.

Sadly, horses don’t always read the text books! What on earth was happening? Colic? Gastric ulcers? ‘Grass affected’? Simple lack of work and fresh grass? Low magnesium? Botulism from baleage?

A presumptive diagnosis of colic +/- ulcers seemed sensible as a starting point and so she was given anti spasmodics, pain relief, ulcer treatment and a mild sedative for her own safety. Bloods were taken for further investigation.

While we waited to check that the medications were going to help, we took a walk around the property. Fortunately, Louisa has become a ‘tree geek’ whilst planting her own lifestyle block and so she noted that the horse was being grazed under a kowhai tree, which are toxic. Neither the mare nor the cows had any history of eating the tree.

All parts of the kowhai tree are toxic, with the seeds being most toxic to all stock and people. They apparently are bitter and so animals usually choose to avoid them. In this case, the owner was kindly using the shelter of the tree to give the mare a nice place to eat her hard feed, which she had a habit of tipping out of her bucket... onto endless numbers of Kowhai seeds!

Removal of animals from the paddock and conservative treatment seem to have effected a full recovery. We spoke to Kathy Parton, a toxicologist at Massey University, about the case for any advice. It would appear it does not take many seeds to provide a lethal dose; this mare appears to have no long lasting effects but it did take her some weeks to get her normal laid back behaviour back. Lucky escape.

If you’re not sure about planting trees or shrubs, there are great resources available online to find out about their potentially toxic effects. There are also excellent plant ID apps and Facebook groups if you’re trying to investigate plants at a new property – Sycamores, Yew, Tutu, Rangiora, Ngaio, Rhododendrons are just a few plants that a well meaning gardener may have planted within reach..

Sadly, but understandably, the only victim in this whole episode was the kowhai tree. RIP tree!


Wolf teeth in horses

Read more >Thursday 18th of July 2019: Wolf teeth are technically known as the first premolar teeth in horses. They usually erupt into the mouth at between five and twelve months of age, but do not continue to grow or erupt into the mouth as do the rest of the cheek teeth. It has been estimated that approximately seventy percent of horses will develop wolf teeth.

Equine Insurance – should I bother?

Read more >Thursday 18th of July 2019: It's a question that's come up time and time again for me over the last year or two. Often, clients will explain that their horses or ponies are not worth very much money, and so they don't think it's worthwhile. I thought I'd put together some of the aspects to consider, and some of the questions to ask about your potential cover. I'll also summarise some of the costs you might expect for treatment for various conditions - you might be surprised!

The Importance of Vaccinations – What’s it all about?!

Read more >Thursday 18th of July 2019: Vaccination provides your horse with important protection against some serious and potentially life-threatening diseases. Vaccines act to stimulate the body's natural response to a disease, allowing a rapid and effective response if that disease is encountered later in life. This could be the difference between severe clinical disease and a healthy horse!


Read more >Thursday 18th of July 2019: This is the name given not to "affectionate backs" but to over-riding or impinging of the dorsal spinous processes of the vertebrae commonly in thoracic [chest] or lumbar [lower back] region of the horse.

Often it is in the region of wither or saddle and can be associated with a poor saddle fit or trauma/damage often from as far back as when the horse was being broken in or weaning. Horses that rear up and over backwards and land on their withers is a common "accident" that can cause injury in this area. Sometimes we'll never know the cause.

Coughing and Wheezy Horses

Read more >Thursday 7th of March 2019: The classic âcoughing horseâ is a common sight and sound at this time of year, and often transient viral respiratory disease is to blame. But as much as we love to blame a virus, they are not always the cause!

Stomach Ulcers and Gastroscopy

Read more >Thursday 7th of March 2019: Stomach ulcers (gastric ulcers) are a hot topic! Stomach ulceration is a somewhat confusing syndrome â the syndrome can have a multitude of clinical signs, ranging from very subtle performance issues, or picky eating, to weight loss and colic. There is also a multitude of products on the market which claim to help with ulcers, not all being equal.

Encysted Strongyles – Small worms, big problems

Read more >Thursday 7th of March 2019: âSmall Strongylesâ or âCyathostomesâ are the terms used for a group of over forty different species of parasites affecting horses. They tend to be the most prevalent parasite within the horsesâ gastrointestinal tract and although small, heavy burdens can result in big problems!


Read more >Friday 27th of July 2018:

Equine Annual Warrant of Fitness

Read more >Friday 27th of July 2018: With the equestrian season kicking off in most disciplines, Spring is a good time for your horse to have its annual âwarrant of fitnessâ.


Read more >Wednesday 25th of July 2018: We have had a couple of interesting cases over the last few months where our Vets have been able to use the endoscope to help diagnose and address issues.

The endoscope is a flexible camera/video /light source that we can use to help investigate respiratory tract in horses as they allow us to gain access visually to some of the nooks and crannyâs that make up a horses upper and lower respiratory tract.


Read more >Thursday 8th of March 2018: The transportation of horse to events in NZ [such as HOY] is commonplace but in saying that it needs to be managed to maximise athletic performance, and minimise the risk of any negative impact on horse health. After all it is a long expensive and disappointing trip to an event to have your horse perform below their best.

Road transport can be detrimental to horse's lungs, muscles, gut function and weight


Read more >Thursday 8th of March 2018: Alfie is a 22 year old Kaimanawa gelding who had the misfortune of getting the wrong end of a stick during a wind-storm.

He presented with acute right eye pain â eyelids tightly closed with profuse tearing.


Read more >Thursday 27th of July 2017: The first five years of a horse's life are critical in regards to dental development. Like us, horses have two sets of teeth, the deciduous being shed from about two and a half years until the permanent teeth have erupted at around five years.

Drenching your horse

Read more >Thursday 27th of July 2017: Some horse owners are still drenching their animals on a six to eight weekly basis regardless of age or worm burden. This was a traditional approach which is outdated and possibly detrimental in terms of developing resistance to drenches.

Equine Dentistry

Read more >Friday 1st of April 2016: With the current surge in interest in equine dentistry, more than a few myths have crept into popular belief. Find out more.


Read more >Friday 1st of April 2016: Spring and early summer are the high risk periods for pasture - induced laminitis, so this is a timely reminder of what this disease is and how you can avoid it.