Some politicians and farming community members have reacted angrily to a High Court decision to quash a destruction order on a "sacred" bullock Shambo.
Shambo tested positive for bovine TB in late April
Shambo, who lives at the Skanda Vale multi-faith temple in Carmarthenshire, tested positive for bovine TB after a routine screening.
A High Court judge ruled that the assembly government acted unlawfully in ordering his slaughter.
The Farmers' Union of Wales (FUW) said it could set back disease control.
"This ludicrous ruling contradicts the principles upon which successful TB eradication programmes throughout the world have been based for generations," said Evan R Thomas from the FUW.
"It flies in the face of common sense. It seems that the British justice system is now content to put human health and animal welfare at grave risk.
"Today's ruling could set disease control in Britain back by 70 years," Mr Thomas added.
Veterinary officials were scheduled to slaughter the six-year-old Frisian after the Hindu monks were given notification on 5 May.
Monks at the temple and supporters launched a campaign to save Shambo, saying it would violate their religious principles and human rights.
On 3 July, Rural Development Minister, Jane Davidson, announced he would be slaughtered but allowed the monks time to launch an application for a judicial review.
But farmers and some AMs have said Shambo should face the same fate as other cattle.
Last year, 5,220 cattle in Wales alone were culled because they failed the TB test.
Labour AM Alun Davies, chair of the assembly's rural development sub-committee, said: "It's one of the most ludicrous rulings I've heard from any judge for quite some time.
"It drives a coach and horses through the policy which is addressing bovine TB at the moment in Wales. "
Other members of the opposition parties including Montgomeryshire farmer and Liberal Democrat AM, Mick Bates, have questioned the decision to spare Shambo.
"This decision is a blow to every farmer in Wales who have lost animals to bovine TB.
"The High Court decision puts assembly government plans to control the disease in jeopardy," Mr Bates added.
"The farming industry is already reaching crisis point because of bovine TB. To allow decisions like this allows the crisis to get worse.
Tory shadow rural affairs minister Brynle Williams said: "This is an incomprehensible decision.
"It sends out completely the wrong message to the farming industry and those working and living in the countryside."
He said he recognised the sensitivity of the case but fully expected the High Court to endorse the assembly's position.
The National Farmers' Union (NFU) also expressed concern at the High Court decision.
"This decision is an absolute kick in the teeth for all those farmers who have had animals destroyed as part of the bovine TB controls," Dai Davies, president of NFU Cymru said.
He added that farmers had faced culling animals which had often taken generations of careful selective breed improvement to produce.
"Bovine TB is running wild in the livestock industry in this country and everyone is working towards eradicating this awful disease.
"This is a decision which saves one animal but at the expense of hundreds if not thousands of other animals," Mr Davies said.