As an Equine Therapist, I follow the Veterinary Act as shown below.

Therefore, must obtain your Veterinaries permission to treat your horse before any appointment.

The Veterinary Act is in place to protect and safe guard sick and injured animals, it is a parliamentary act passed in order to protect their welfare. 

It is an offence for any individual, other than the one owning the animal to treat the animal, unless permission has been given by the vet dealing with the case has been obtained. 

Section 19

'Subject to the following provisions of this section, no individual shall practice or hold him/herself out as practicing or as being prepared to practice veterinary surgery unless he/she is registered in the register of veterinary surgeons or the supplementary veterinary register.'

Section 27

'Veterinary Surgery' is the act and science of veterinary surgery and medicine.

This therefore includes:

a) The diagnosis of disease and injuries to animals, this would include performing tests on these animals for diagnostic purposes.

b) The giving of advice based on information obtained via diagnosis.

c) The medical or surgical testament on animals.

d) The performance of surgical operations on animals.