Sutter fell ill on Friday and was rushed to an animal hospital by the governor and first lady, Brown spokesman Evan Westrup said in a written statement. According to Westrup, Sutter underwent emergency surgery, during which "numerous masses," were discovered in his intestines, lymph nodes and liver. The masses are most likely cancer, he said.

"While Sutter pulled through surgery, the vets were not able to remove all of the cancer and his condition remains critical," he said. "While we do not have the results from the biopsies yet, the prognosis is likely to be very poor. He will continue to rest and recover at the animal hospital in the days ahead. The focus is on getting him well enough to come home, so he can spend time with his family, including Colusa, whose spirits have been very low with her brother gone."

Colusa is Sutter's adoptive sister, who joined the first family in 2015.