Australia's peak shearing body says animal cruelty cases heard in western Victoria this week have forever changed the industry.

Four men pleaded guilty to a combined total of 60 animal cruelty charges in the Horsham Magistrates Court on Monday.

Evidence against the shearers included hidden camera footage obtained by animal rights group PETA.

A packed court room was shown videos of sheep being repeatedly punched in the face, beaten with shearing handpieces, gouged in the eyes sockets, lifted and slammed to the ground and stomped on by shearers.

Many of the animals were seen stumbling away bleeding from the eyes, nose and mouth.

Shearing Contractors Association of Australia secretary Jason Letchford said the footage was an embarrassment for the industry.

"We're all shocked, upset and embarrassed as an industry. It's been a wake-up call," he said.

Mr Letchford said industry bodies had been working together to improve industry standards since the footage was published.

"None of us from wool growers to shearing contractors to the union are sitting around thinking it's just a case of mongrel shearers doing a mongrel job," Mr Letchford said.

"It's all of us that need to pull up our socks and head towards a zero tolerance policy."

Long-term problem in industry

Witness for the defence and wool producer Tom Silcock said historically, the Australian wool industry had seen sheep being abused for a long time.

The case began in 2013 when two people fitted with video cameras obtained work as roustabouts in shearing sheds in locations including Rupanyup, Nurrabiel and Moyston, and documented what they described as cruel shearing practices.

The footage was posted online by PETA, prompting Agriculture Victoria to launch a full-scale investigation.

In a statement, PETA said justice was finally coming to shearing sheds around Australia, and that violent abuse should be met with maximum penalties, starting with a ban on being in charge of farmed animals.

The Agriculture Victoria investigation resulted in a number of shearers being referred for prosecution.

In December, a 60-year-old Lucindale man was the first to be successfully prosecuted.

Authorities will continue to prosecute abusers

Victoria's senior veterinary officer Robert Suter said as much as animal activists were "a thorn in everyone's side", their work had resulted in positive outcomes for animal welfare.

Dr Suter warned authorities would continue to prosecute people in the sheep industry who abused animals.

"This is a reminder to everyone that allegations into cruelty will be investigated," Dr Suter said.

This week's cases included Natimuk man Bradley James Arnold, 39, Horsham man Jake Lachlan Williams, 23, Keith man Graham Ivan Batson, 49, and Hamilton man Lindsay David Gillin, 61.

Magistrate Mark Stratmann said the men's behaviour was "confronting, offensive and very serious".

"It offends community standards to treat animals this way," he said.

The men will return to the Horsham Magistrates' Court on March 31 for sentencing.