US TV host Cesar Millan is being investigated for possible animal cruelty over a clip showing a dog attacking a pig, US media report.
Officials visited his training facility in California following complaints over the footage from his Cesar 911 show, according to NBC and others.
The TV presenter known for his Dog Whisperer series has not commented.
But the channel which carries Cesar 911, Nat Geo Wild, sought to defend the video in a statement.
The host had taken precautions for the segment, which had taken place in a “safe and controlled environment”, Nat Geo Wild said in remarks carried by the Wrap website.
“The clip caused some concern for viewers who did not see or understand the full context of the encounter,” it said.
The case apparently stems from an episode in which a pig was used in a behavioural training session with a dog said to have attacked and killed two other pet pigs.
In the clip posted online, the dog – a French bulldog/terrier mix – bites the pig’s ear, causing it to bleed. The dog is then restrained.
Nat Geo Wild said the injured pig had recovered quickly after treatment and showed no lasting signs of distress.
Officials from LA County Animal Control visited Millan’s centre in Santa Clarita on Thursday, reports say.
NBC says the TV host was not there at the time and a 24-hour notice was issued, requiring him to contact officials.
Millan is a self-taught dog behaviourist who rose to fame with Dog Whisperer, reportedly broadcast in more than 80 countries.
In that series, he rehabilitated dogs and trained people to improve their relationship with their pets.