The phrase "susceptible cats" means cats that are more prone to being affected by something, such as a disease or illness.
Sentences with «susceptible cats»
In addition to causing allergies in susceptible cats, they can also transmit other diseases. (pethealthnetwork.com)
Some cats, especially older ones, may have no signs of illness at all but can be a source of infection for more susceptible cats in the same household or shelter. (morrisanimalfoundation.org)
Particularly susceptible cats may even get sick, or develop behavioral problems such as aggression. (petpeoplestores.com)