Australian CCF member - triggersmob - recently started a thread "Bovine Coins - Post Yours" over in the "Post Your..." Galleries area. I contributed what I could from the classic-era US commemorative coin series. There aren't too many series coins that meet the criteria, so rather than create an Index to my posts, I thought a "Quick Bits" post would be a better option.
Note: Common bovines include: cattle, bison, buffalo, antelopes, goats and sheep.So, here we go!
The 1935 Old Spanish Trail Half Dollar features the skull of a cow on its obverse. The skull serves as a metaphor for Cabeza de Vaca, the Spanish explorer who allegedly traversed the trail in 1535; "Cabeza de Vaca" translates from Spanish to English as "Head of a cow").
To paraphrase Billy Crystal in Princess Bride - the cow depicted is not "Mostly dead." it's "All dead." But it's still classifed in the bovine family!

One of the most popular classic-era US commemorative coins is the Oregon Trail Memorial Half Dollar; it was struck intermittently between 1926 and 1939.
The obverse (officially, per the US Mint) depicts an ox-drawn wagon being guided by a male figure (father?) leading his family to a new life in the American West.

The 1938 New Rochelle, NY Half Dollar marks the 300th Anniversary of the settlement of the present-day city.
It's obverse features a "fatte calfe" which - regardless of its old-time spelling - is squarely in the bovine category!
BONUSHere's a medal whose obverse was designed by Avard Tennyson Fairbanks. The design began life as a 2-D logo for the Old Oregon Trail Association (OOTA) in the early 1920s, but was then sculpted into a large-format, 3-D, uniface plaque that was intended as an Oregon Trail Marker for use all along the Trail (though it was ultimately only installed at two locations - Seaside, Oregon and Baker City, Oregon - at the time [circa 1924]. In following years, markers were erected in Independence (Missouri), Vancouver (Washington), Boise (Idaho) and Meridian (Idaho.).
Decades later, Medallic Art Company (MACO) created commissioned commemorative medals with Fairbanks' design (or a variation on it) on the obverse and a sponsor-driven design on the reverse. Shown here is one such medal; the reverse commemorates the centennial of RM Wade in 1965. (RM Wade is an Oregon-based company with "a rich history of distribution of farm equipment and the manufacture of irrigation systems in the Northwest;" (RM Wade Company web site). The Company has ties - through its founder Robert Marshall Wade - to the Oregon Trail - a 15-year-old Wade went west on the Trail with his family in 1850.)

If you have an interest in "bovine coins," I recommend visiting triggersmob's thread to view a variety of such coins issued by countries around the world:
Bovine Coins - Post Yours.
For much more on each of the coins (or medal) presented here, see:
Commems Collection.