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rBST: Adoptions and Concerns Of California's Dairy Producers

by L.J. (Bees) Butler, University of California Cooperative Extension specialist

What is rBST?

Bovine somatotropin is a naturally occurring (peptide) hormone produced in the pituitary gland of cows. It was discovered in the 1920s, and originally called bovine growth hormone or BGH. Experiments in the 1930s revealed that BGH, when extracted from the pituitary gland of a cow and injected into another cow, could increase milk production in the recipient cow.

In the late 1970s, Dale Bauman, Ph.D., an animal scientist at Cornell University, successfully transferred the gene responsible for BGH production in cows to a bacterium. The resulting product was called recombinant bovine growth hormone, or rBGH. Simple multiplication of the bacterium meant that it could easily be produced in commercial quantities at a very reasonable cost. Several pharmaceutical and nonpharmaceutical companies became very interested in the product in the early 1980s. Despite the fact that rBGH is a peptide hormone and not a (much-maligned) steroidal hormone, to avoid the stigma associated with hormones, the industry agreed to change its name to bovine somatotropin (BST). Thus, its synthetic analog would be called recombinant bovine somatotropin, or rBST. Today, both names (rBGH and rBST) are still used.

Effects on Cow Productivity

Four companies involved in rBST research applied for patents for their particular brands of rBST in the early 1980s, which resulted in many misstatements, exaggerations and misunderstandings. Congressional hearings were held in June 1986. From these hearings emerged the alleged last word on rBST. The basic findings were:

  • rBST, when injected into a cow, could cause a 10-25 percent increase in milk production.
  • There was also a 10-15 percent increase in feed efficiency. This means that there was an effective decrease in feed costs per unit of milk produced, and therefore a lower average cost of production.
  • rBST appeared to be safe both for human milk consumption and for cows.

It took until November of 1993 to gain FDA approval, and rBST was not released commercially until February of 1994. However, the controversy surrounding rBST that has existed since 1983 continued. Specifically, questions were raised about adverse health effects on animals treated with rBST, the appropriateness of the technology for an industry plagued with surpluses, the effects of increased milk production on milk prices, and the plight of the family farm in the United States. Media coverage about the impacts of rBST has been intermittent since 1983, but increased substantially from 1988-1993.

Adoption in California's Dairy Industry

In 1987, a survey of California dairy producers was carried out to determine their attitudes and concerns about rBST. A sample of 152 producers (about 7 percent of the total) was drawn randomly from a complete list of all Grade A dairy producers in California.1 Grants from the Giannini Foundation and the University of California Biotechnology Research and Education Program allowed the author to continue to survey the same producers every year (except 1995) to the present. In 1990, the original survey sample was increased to 262 producers to represent approximately 10 percent of the total California dairy producer population.

The overall objective of this long-term research was to survey a continuous sample of California dairy producers prior to, during, and after the commercial availability of rBST to determine a timetable of adoption and diffusion patterns. A review of the results collected to date provides an interesting perspective on the prospective adoption of the new technology prior to and during its release. For example, the results indicate that as more information regarding a new technology becomes available, opinions and attitudes toward the new technology change, thus significantly modifying the responses to the survey.

Survey Results Before rBST Availability (1987-1993)
Prospective Adoption Rates

Survey participants were asked whether they would use rBST immediately after it became available, wait to use it, or would not use it at all. Over the seven years of the survey prior to the commercial availability of rBST, responses to this question varied considerably. As more information became available and as the controversy surrounding rBST increased, survey respondents dramatically reduced their desire to use it immediately after it became available.

The proportion of respondents who said they would not use rBST at all increased 33 percentage points between 1987 and 1993. Similarly, the number of those who said they would use rBST dropped from a high of 55 percent in 1988 to 30 percent in 1993.

Three major concerns consistently emerged over the seven years of the survey prior to commercial availability. Most prospective users worried over public opinion and potentially negative consumer reactions to the use of rBST. This concern increased dramatically over the years of the survey and was considered by many to be the major reason why the California dairy industry was skeptical about the use of rBST. Many producers expressed concern over rBST's potential to increase milk production, resulting in increased surpluses of milk and a consequent decline in milk prices. Producers also expressed an increasing concern about cow "burn out" reflecting the continuing uncertainty about this issue. Others questioned the cost effectiveness of rBST and the administration method.

1994 and 1996 Preliminary Survey Results
Adoption and Use of rBST

With the FDA approval of rBST in November 1993, and its commercial availability in February 1994, the survey was modified to solicit responses about current use of rBST, its use in the past, or consideration of its future use. Table 1 is a tabulation of the adoption and use of rBST in 1994 and 1996. Overall we could conclude that about 20 percent of California dairy producers were currently using rBST. Another 8 percent had used it in the past for a total rBST adoption rate of about 28 percent. Another 20-30 percent of producers reported that they would consider using rBST in the future, defined as prospective users.

In 1994 and 1996 there was clearly still some uncertainty about rBST among its current and prospective users. Apart from concerns about the health of their herds, concern about adverse prices due to increased milk production also increased slightly in 1994 but decreased in 1996. And although concerns about the cost effectiveness of rBST decreased from 31 percent in 1993 to 21 percent in 1994 and 25 percent in 1996, this concern still ranked fourth among the concerns of current and prospective users.

Among those who were currently using rBST, have used it in the past, or were considering using it in the future, over 68 percent still had concerns about it. Table 2 tabulates these concerns.


A panel survey of about 260 California dairy producers between 1987 and 1993 indicated a declining interest in using rBST immediately after it became available. Preliminary results of the survey (of the continuous sample) in 1994 and 1996 indicated that about 10 percent of the total California herd was currently being treated with rBST. Average milk yield response appeared to be about 11 percent. Therefore, rBST use in California in 1994 and 1996 probably resulted in an increase in milk production of less than 1 percent per year.

Future use of rBST will depend largely on how producers adapt the new technology to their current management styles and the effect that it will have on their profit margins in the next 2-3 years. A 1997-98 study is in progress, in which a greater number of dairy producers are included in the survey.

Publications Cited

  1. Zepeda, L. The Potential Economic Effects of Bovine Somatotropin on the California Dairy Industry. Ph.D. Thesis. Davis: University of California Department of Agricultural Economics, 1988.

L.J. (Bees) Butler is a UC Cooperative Extension economist with interests in dairy and poultry marketing, food and agricultural policy, market structure and technological change, and intellectual property rights. For a complete report on the rBST surveys, contact L.J. (Bees) Butler at (530) 752-3681.