Melbourne Magistrates Court was on Wednesday shown photos of emaciated horses, their rib cages visible, which were among those taken from Christine Weisheit's property near Ararat in 2016.

Ms Weisheit has pleaded not guilty to more than 60 animal cruelty offences, brought by the RSPCA, for allegedly mistreating horses.

She is accused of starving the animals and keeping them inside contaminated paddocks.

The court heard 11 horses were among those brought to Golden Plains Equine hospital, where principal veterinarian Simon Pearce determined most of them had not received sufficient food.

Some had a body condition score as low as zero out of five, and one in particular had a painful and chronic hoof condition, which meant it was walking on its heel.

Dr Pearce said horses' hooves normally grew at a rate of 1cm a month if they were well fed, but in this case, the horse's 25cm hoof growth would have taken at least 50 months.

"I don't recall seeing one (of these conditions) quite so bad in my clinical experience," Dr Pearce said.

The horse was also emaciated and an assessment showed it was recently lactating, but it had no foal.

"It makes me wonder what happened to the foal," Dr Pearce said.

One of the horses suffered an "insanely painful occurrence" called laminitis, whereby its pedal bone - the bottommost bone within a horse's leg - had rotated away from its hoof wall.

Dr Pearce said horses with the condition required much more frequent care by a farrier, and it was incumbent on the owner to minimise their pain.

Another of the horses appeared to have pain in its hooves, and veterinary staff noticed a smell reminiscent of thrush coming from them - an infection normally caused when horses' hooves were not regularly cleaned.

Dr Pearce's practice managed to resolve the horse's pain, and found another horse - named "Squeak" - was in need of urgent dental care, given it had significant difficulty eating.

The veterinarian said the horse's mouth would squeak when it ate, and its sharp enamel points and expired teeth showed it had gone without dental care.

He said it was "inconceivable" to him that a horse owner would not notice their animal was unable to eat properly for a long time.

"This horse might have performed badly even with reasonable nutrition given how poor the mouth was," Dr Pearce said.

Defence barrister Luke Howson pointed out that some of Ms Weisheit's horses taken to Golden Plains Equine had a higher body condition score than others.

The horse hospital took care of 21 animals from the property.

Some of the horses came in at about three on the scale, which dictates zero as emaciated and five as extremely fat.

The hearing continues.

Australian Associated Press