Turner and Hooch
In 1989 Tom Hanks starred in the film “Turner and Hooch” (starred by “Beasley the Dog”) where he is an overly neat (OCD?) police officer who ends up having to take care of a dog who may be a witness to a murder. “Hooch” was a Dogue de Bordeaux (a.k.a . French Mastiff). Of course this set sup the conflict between the overly neat human and his excessively messy and destructive canine companion.
They most likely used the Dogue de Bordeax for many reasons – it’s size, it’s dirty look, as well as its “slobberyness”.
Clint Rowe (also an animal (wolf) trainer for “Men In Black“, “The X-Files“, and “Dr. Dolittle 2“) is credited for being Hooch’s owner and Scott Rowe (who has also done work in “True Lies“, “Cats & Dogs“, “Star Trek Enterprise“, and “Beverly Hills Chihuahua“) was credited as being the animal trainer.
K-911
In 1999 James Belushi (Mike Dooley) starred with a German shepherd (“Jerry Lee” played by Mac) in the sequel to “K-9″, “K911″. Jerry Lee is an older and close to retirement K9 office that the captain thinks should be retired but Mike refuses a younger K9 officer has his new partner.
German shepherds are not only the most recognizable breed of dog in the world, they have also been the most popular breed for a pet (or working-pet) dog for almost 100 years. Due to their intelligence, loyalty, ruggedness, and stamina they are also often used in police and military work.
The film also featured a Doberman pincher being used as a younger and more outgoing K9 officer.
Karl Lewis Miller is credited for being the “animal action coordinator” yet the credits do not list any trainers or handlers. Mac is not credited for being in any other film at this time.
Stargate SG-1: Emancipation
The third episode of the first season of Stargate SG-1 featured the episode “Emancipation”. When the team first exists the gate, they hear dogs barking and later see a boy being chased, and later attacked by a series of dogs. The team rescues the boy form his attackers with a few shots of their guns into the air. Continue reading
Star Trek: Enterprise – Porthos
At the age of six weeks (a little early IMO) Captain Johnathan Archer had his trusty English Beagle, Porthos. In Season 1 Porthos was played by a male beagle named Prada, whom also played a beagle named Lou in the film Cats and Dogs (voiced by Toby Maguire). In later seasons two female beagles shared the honor, Breezy and Windy (although Porthos was always a male).
In one of the final episodes of Enterprise, “In a Mirror Darkly” (a “evil twin universe episode”), Porthos was replaced with a Rottweiler. While they tried to find a dog that would be a polar opposite to the Beagle (and Rotties do have that look), on set reports that the Rottweiler was even a bigger baby than the Beagle – writer Mike Sussman noted that he was “The sweetest dog I Have ever met”.
In the new Star Trek Film (2009) there is reference to Montgomery Scott having a “transporter accident” with Admiral Archer’s dog. I highly doubt it was the beloved beagle since he would have been over 70 years old when Scotty was born. 
The Vitagraph Dog
Jean, the Vitagraph Dog, was the first canine film star. Owned by Laurence Trimble (also owned Strongheart) where he ended up at the Vitagraph Studios to do a story for a local magazine on film making. His timing was perfect, he was there with his pet, Jean, when they needed a dog on the set to play opposite of Florence Turner
Jean became quite popular and was soon known as “the Vitagraph Dog”, starring in her own films along with “the Vitagraph Girl” all directed by Larry Trimble. One- and two-reelers with titles such as, Jean and the Calico Doll, Jean and the Waif, and Jean Goes Fishing were made by Trimble as their troupe filmed along the coastline in his native Maine.
Jean died in 1916.