Two-year-old Rolo arrived at Vets Now in Sutton unable to eat, drink or move. With the cat’s red blood cell count at 7% and no feline blood immediately available, emergency vet Paige Walker turned to her four-year-old cocker spaniel, Gin, as a one-time donor.
Rolo had collapsed after a flea infestation caused severe anaemia. Walker also found that the cat’s gums were very pale, a common sign of the condition, and said a normal red blood cell level is about 30%.
We did tests and her red blood cell count was down to seven per cent, which is one of the lowest levels I’ve ever seen in an adult cat, Walker said.
Walker considered an emergency transfusion the only potential way to keep Rolo alive. Gin happened to be at the clinic that Sunday afternoon, allowing the team to collect approximately 60 millilitres of the dog’s blood and give it to Rolo.
Rolo was monitored closely overnight as her red blood cell count gradually rose. By the next morning, she was well enough to return to her daytime veterinary practice, and she later went home to her owner, Louise Wood.
Why dog blood can be used only in exceptional cases
Transfusing blood between different species is called xenotransfusion. Pet Blood Bank UK guidance says canine blood may be considered when a critically ill cat urgently needs greater oxygen-carrying capacity and feline blood cannot be obtained quickly.
That does not make dog blood an equivalent substitute for compatible feline blood. Canine red cells are cleared from a cat’s circulation within roughly four to seven days, so the benefit is short-lived. A second dog-to-cat transfusion is contraindicated because repeat procedures have proved fatal; any later transfusion would require compatible feline blood.
A 2023 retrospective study of 311 cats found that transfusion-related adverse effects were more frequent among cats receiving canine blood than among those receiving matched feline blood. Delayed destruction of red blood cells was also more common in the xenotransfusion group.
The study’s authors concluded that canine blood may save lives when feline blood is unavailable or blood typing cannot be completed in an emergency. They also cautioned that the findings came from a retrospective study at one veterinary teaching hospital, limiting how broadly its results can be applied.
Close observation is essential with any transfusion. International Society of Feline Medicine guidelines say reactions can range from mild to severe and that patients require frequent checks, especially during the first 30 minutes. Rolo’s overnight monitoring was therefore a central part of the emergency care, not simply a waiting period.
How fleas can lead to severe anaemia
Fleas feed on blood. A heavy, uncontrolled burden can remove enough blood to cause life-threatening anaemia, according to Veterinary Partner’s flea-anaemia guidance. Very young kittens, outdoor puppies and older outdoor cats are identified as particularly vulnerable, although Rolo’s case involved an adult cat.
An infestation may also be easy to underestimate. Cats that are not allergic to flea bites may not scratch, while grooming can make live fleas difficult to find. Dark, pepper-like material in the coat can be flea dirt and indicates that fleas are present.
Pale gums, weakness and listlessness can accompany advanced anaemia. A pet that collapses, cannot move or stops eating and drinking needs prompt veterinary assessment; owners cannot determine the severity of anaemia by appearance alone.
Wood said she had regularly used nonprescription flea treatments but later learned that the products she chose had not controlled Rolo’s infestation. Principal vet Sam King said modern prescription-only options produce the best results, but treatment selection should be discussed with a veterinarian rather than assuming that every nonprescription product will fail.
For Wood, the outcome followed a visit she believed might be Rolo’s last. “I really thought we were going to lose Rolo and it felt at the vets like we were saying goodbye to her,” she said.
Rolo’s return home also carried an unusual connection: she was named after Roly, a dog in Disney’s 101 Dalmatians. In this emergency, a cocker spaniel’s blood gave the cat named after a dog a short window to recover.
What would you do if your dog were in this situation? Share your thoughts in the comments.
By Sarah Mitchell — 8 years as a local-news reporter covering animal welfare, shelters, neighborhood disputes, and public-safety pet stories.
