Bill Gross, co-founder of bond fund giant Pimco and widely known as the "Bond King," has had a rough start to the year.

He's still dealing with the waves caused by a public falling-out with former heir-apparent Mohamed El-Erian, while in March the flagship Pimco Total Return Fund suffered an 11th straight month of outflows and its performance lagged 95 percent of its peers.

Now Gross's cat, Bob, has died.

On Thursday, Gross dedicated the first half of his widely followed Investment Outlook letter to the cat and headlined it "Bob."

"Treasure your pets and all living things. Eventually we all stop living," said Gross, who will celebrate his 70th birthday this month.

The cat, a female despite the name, died last week. The pet had been with Gross and his wife for 14 years.

"Aside from sleeping, Bob loved nothing more than to follow me from room to room making sure I was OK," wrote Gross. "It got to be a little much at times, especially when entering and exiting the shower."

Gross said Bob's "obsession carried over to the TV, sensing when I was on CNBC and paying apt attention no less. I often asked her about her recommendations for pet food stocks, and she frequently responded - one meow for 'no,' two meows for a 'you bet.' She was less certain about interest rates, but then it never hurt to ask."

Gross, who included in the letter an old photo of Bob watching Gross on TV, has canceled two planned CNBC appearances in March, according to the station.