At least 12 horses at a national equestrian event in Hastings have become ill from dehydration.
The horses have been treated by vet staff during the Land Rover Horse of the Year at Tomoana Showgrounds after refusing to drink water (or not drinking enough) at the event, which has been running this week.
Vet Services Hawke's Bay veterinarian Richard McKenzie said it was common for horses to refuse to drink water when they travelled to new areas for events due to the different taste but this was exacerbated by the length of the show.
Usually people would take their own water but because horses were away from home for more than a week this was impossible and at least 12 horses had ended up with dehydration which had caused colic in some, he said.
While horses had been treated for dehydration in previous years this time was worse because of the good weather.
"The heat and humidity probably doesn't help with the horses sweating a lot."
A remedy for the issue was flavouring the water with something like molasses but without getting a horse used to it for a few weeks before the event some had refused this, too.
"Luckily we haven't lost any horses."
Although the number of dehydration cases was small and most were mild it was disappointing for owners because their horses either weren't performing at their best or had to pull out of the competition, McKenzie said.
About six horses were unable to be treated on site and had to be referred to secondary clinics such as Massey University Equine Veterinary Clinic in Palmerston North for further investigation and treatment due to other underlying issues which were made worse from the dehydration.
Vet Services staff had seen 10-15 horses a day since the start of the event for various reasons including cuts and transport injuries.
Horse of the Year board chair Cynthia Bowers said she hadn't heard of any problems but expected the horses didn't like the taste of chlorine in the water.
Chlorine was added to the town's water supply in 2016 and may not have been so much of an issue last year because the weather was wet and not as warm.
Chlorination of water supplies was not uncommon and would be something that would have to be managed by owners of horses at events in terms of flavouring the water, she said.
"It's the way of the future.
"I think it's just something that we really need to be aware of and do whatever we need to do particularly when we are dealing with animals like horses."
A Hastings District Council (HDC) spokesperson said Tomoana Showgrounds has both a private bore and HDC water connection.
A Bombay resident, who doesn't want to be named, said she had come down to the event with her daughter and niece's horses and had heard of at least eight horses getting colic from refusing to drink the water.
"On Tuesday night one of the ponies was unsettled in the yard, luckily he was being watched closely.
"They thought it was colic and got the vet out.
"This little pony nearly died…it was just about falling over."
It was almost sent to Massey University for surgery but was able to be treated on site, she said.
The vet had been going from one end of the grounds to the other dealing with colicky horses that night.
"Everyone was panicking, we didn't know what was causing the colic.
"They were all from Auckland so I thought it must have been a bad batch of feed but the vet said it's the water.
"They won't drink it and are getting dehydrated."