The Edinburgh event has been organised by The Hunter Foundation.
£1,000 Reward After Horse Attack
The owner of a horse which was stabbed and "sexually violated'' in a field is urging people to help police catch whoever did it.
The "beautiful'' female horse, named Blaze, had to be put down following the attack in the New Pitsligo area of Aberdeenshire overnight on Sunday.
Police have launched an investigation into the incident.
Owner Zoe Wright is offering a £1,000 reward to anyone who provides information that results in an arrest.
She described the incident in a Facebook post which has been shared more than 10,400 times.
She wrote: "On the 16th / 17th of August between the hours of 9pm and 6am someone came into my horse's field and stabbed my beautiful old girl Blaze twice in the chest before sexually violating her.
"Blaze was put to sleep after succumbing to her injuries.
"My lovely Blaze was the nicest pony, she has been part of our family for 18 years, the complete low-life scum who did this to her needs to face justice for what they have done.''
She also urged other horse owners in the area to check their animals and look out for any suspicious cuts.
Police Scotland said the horse was aged 23.
The incident is understood to have happened between 9pm on Sunday, August 16 and 8pm on Monday August 17.
Detective Inspector Norman Stevenson said: "Enquiries are ongoing to establish what has happened to the horse but I would appeal directly to any neighbours or residents in the area who may have seen anything unusual or suspicious in the days before this happened.
"As a result of this cruel act a horse has died and a family have now lost a much-loved animal.
"We have not received any reports of similar incidents in the area but I would urge horse owners to check their animals regularly and report anything unusual to police.
"Patrols are carried out frequently in rural areas but we do rely on residents, land owners and people who work in the area to contact us to report anything unusual or suspicious.''
Temperatures in Aboyne reached 27C.
72 year old Isabella Jackson sent the abuse when Mrs May was Home Secretary.
Police Scotland Chief Constable Phil Gormley said officers had been deployed to find witnesses.
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