The Schlitz Brewing Company was founded by a German immigrant in the mid 19th century and became very successful in the early 20th century. It was the biggest brewery in the US for some time and had swapped that position with their greatest competitor, the Anheuser Busch Co., until the latter took that position definitely since the 1950's.
The Malt Liquor that is advertised here is a lager with a kick. The 6% alcohol was probably responsible for that kick. It was one of their top products and the bull became a famous trademark.
When this deck was published the decline of the Schlitz company had already set in. In promotional TV clips bands like The Four Tops and Kool & The Gang were used.
So maybe it's not such a surprise that an advertising deck with Afro-American faces was published too. Milwaukee, where the main Schlitz brewery was located, had a large Afro-American population. If your goal is to become or remain the largest brewery in the US then it's wise to address that part of the market in sound and image too.

Our deck came in a plastic box, so there's only the ace of spades to provide information. The deck was "printed in U.S.A.", but the name of the printer isn't mentioned, nor that of the designer. The Schlitz Brewing Co. applied for copyright in 1970, so the deck was most likely published that year too. It consists of 52 cards and 2 jokers. The courts show Afro-American faces. On the Kings the same face is repeated in 3 suits, only in the Diamond suit the face is en profile. All the faces of the Queens are the same, but 2 of the Jacks are similarly "one-eyed" and the other 2 have the same face, but in a slightly different position. All the courts hold a beer, the queens in a glass.