Puppies taken through Gloucestershire died with canine coronavirus
Puppies died with canine coronavirus after being transported in crammed cages, a court was told.
The dogs were found malnourished and dehydrated while being transported in a van from Cheltenham to Stoke-on-Trent.
Patrick Stokes, 24, who lives on a traveller site in Durham, was driving the unventilated vehicle and told police he "wasn't selling the puppies".
Appearing at Cheltenham Magistrates' Court he admitted failing to ensure the welfare of animals in his care.
Stokes was stopped by police on the M6 heading northbound on 22 August.
He was found to have 44 puppies and two dogs, including 10 beagles, seven border collies, three chihuahuas and one shih tzu, in his van.
The animals were being transported in 4ft by 3ft (1.21m by 0.91m) crates, which Stokes said was "plenty of space" but a vet said was too small.
They were taken to Northside Veterinary Clinic in Birmingham, where one of the puppies collapsed and fell into a coma.
The rest were taken to the Brookend Kennels in Malvern where they were put into quarantine after showing signs of a virus.
The dogs were tested for canine coronavirus a week after arriving and 20 of the results came back positive.
Prosecutor Cathy Thornton said the infected puppies died in the following weeks, many by euthanasia.
Stokes told police he spent £2,500 buying the animals for his nieces and nephews.
He said he also paid £2,400 to All Star Pet Transport, owned by Mark Hirst, to take them by ferry from Belfast to Cheltenham at 03:30 BST on 22 August.
Stokes told police he picked the puppies up from Mr Hirst 45 minutes before being pulled over.
The court was told, at his hearing on 22 April, the two men were spotted in Cheltenham by a "furious" member of the public who alerted the authorities.
Michael Levy, defending Stokes, said his client had "employed a proper firm" and could have had no way of knowing the dogs had contracted canine coronavirus.
But he admitted Stokes "should have known" they were in a distressed state.
Stokes is due to be sentenced on 7 June.
Mr Hirst, 43, of Ley Farm, Huddersfield, denied one count of causing unnecessary suffering to a protected animal and one count of failing to ensure the welfare of an animal in his care.
A two-day trial has been set for 13 September at Cirencester Magistrates' Court.