National Park (YNP) bison are not needed for human consumption so some adjuvants not approved for cattle might be useful in bison and elk.

B. abortus strain 19 is a low-virulence, live vaccine developed for use in cattle. It is cleared from the body of the cow more quickly than is the virulent field strain from which it was derived. S19 lacks the eri gene for erythritol metabolism, but it is uncertain whether that gene is associated with virulence. S19 was the cornerstone of the United States Department of Agriculture program of brucellosis eradication in cattle from the 1930s to 1996. When given to cattle in calfhood, S19 has been shown to be only 67% effective in preventing infection and abortion. It has several disadvantages: it is infectious for and causes disease in humans; when given to pregnant cattle, it infects the placenta and can cause abortion; and it induces serologic responses in vaccinated calves that cannot be discriminated from serologic responses caused by field infections.

In commercial bison herds, S19 has been used for calfhood vaccination since the 1960s without important clinical sequelae. Commercial producers using S19 in bison typically use vaccine doses established for cattle. The standard dose of S19 for cattle was originally required to contain at least 10 billion live cells per milliliter (50-billion dose) on initial test and at least 5 billion per milliliter (25-billion dose) at expiration date. A reduced dose of S19 was later established as 0.3-3 billion live cells with age limits of 4-12 months for use. The reduced dose range was based on data for minimal protective doses of 0.09-4.5 billion colony-forming units (CFU) for calves 3-6 months old (Davies et al. 1980) and 0.1-90 billion for calves 4-6 months old (Deyoe 1980).

In South Dakota, which has more bison than any other state, many of the 200 small commercial bison herds are vaccinated according to state regulations. Bison are moved through chutes and vaccinated subcutaneously. One commercial herd of some 5,000 bison in South Dakota (Triple U) was vaccinated with S19 beginning in the 1960s and with RB51 since 1996.

Attempts were made in the 1940s to control brucellosis in YNP bison. A vaccination program with S19 was begun and was believed to have achieved some success in reducing the incidence of brucellosis (Barmore 1968).