In citing claims which were made by M. Hansen in a communication to C.
Benbrook and then posted on sanet-mg, you state:
> They simply represent
> another case of misinformation where Hansen has told only part of
> the story.
It was my impression from reading the posting to which you refer here that
it had been a private, informal communication from Mr. Hansen, one that
Mr. Hansen may not have intended as a formal, public, and complete
representation of his views or the data on which they are based. Be that
as it may, your own formal response also leaves us with only part of the
story. Nothing wrong with that. Space and time are limited. But here are
some of the questions that immediately spring to mind.
1) Hansen had indicated that in the Cornell study the incidence of
mastitis was 3.5 times higher in the rBST treated herd. You indicate that
the pretreatment incidence of mastitis was higher in that herd. However,
you do not indicate how much higher. Why not? Similarly, in your other
statements regarding coincidental inclusion of animals in rBST treatment
groups who were apparently more susceptible than controls to mastitis,
your posting does not provide the needed data to allow us an adequate
interpretation.
2) You state the following:
> Other studies have summarized even larger sets of data and in
> all cases these evaluations have concluded that bST does not affect
> mastitis or mastitis-related variables (1, 2, 4, 5, 6, 7, 8, 9, 10,
> 11, 12, 13). These summaries demonstrated that somatic cell
> counts and incidence of mastitis were related to many herd factors,
> especially environment and milking management practices, and these
> effects were equally evident in both control and bST-treated
> groups.
Your first reference above is to this study:
> 1. Craven, N. 1991. Milk production and mastitis susceptibility:
> genetic relationships and influence of bovine somatotropin
> treatment. In: J. Espinasse (ed). Mammites des Vaches
> Laitieres. Societe Francaise de Buiatrie. Dec. 18-19, 1991.
> Paris, pp 55-59.
Here is what the GAO said referring to this same study:
"Concerning the indirect (nonresidue) human food safety issue that is
neither reflected in FDA guidelines nor addressed in the rBGH review, we
have concluded that rBGH treatment does increase the incidence of
mastitis in cows. We have two bases for our conclusion. First are the
results of studies that were submitted to the FDA. The specific data,
however, are proprietary and cannot be presented in our report. Second is
a published report (discussed in appendix III) which, although focused on
the incidence of mastitis as a function of the natural production level
of cows, demonstrates that rBGH treatment does increase mastitis.
[Craven, 1991]. In comparing the treatment and control groups, the number
of cows experiencing mastitis was approximately 33 percent higher in the
treatment group (28 percent versus 21.2 percent), while the incidence of
mastitis was also greater in the treatment group (0.415 cases per cow
versus 0.361 cases per cow)."
Your quote from Dr. Koop does little to clear up the apparent discrepancy
between your analysis and that of GAO.
BTW, any suggestions as to how I may obtain a copy of the Craven article?
I know someone who has tried unsuccessfully through inter-library loan.
3) You state:
> any technology which increases milk yield would increase mastitis
> incidence per cow.
This does not make sense to me. After all, techniques/technologies that
improve pre- and postmilking disinfection of the udder, proper milking
machine function and use, identification and diagnosis of infected
animals, prophylactic therapy of nonlacting animals, etc., might all
decrease mastitis incidence and thereby increase milk yield, right?
It is strange to me how blithely some people state that rBST is not the
only way to make animals a little sicker while producing a good deal more
milk, as if that made it O.K. I would concur with you that incidence of
mastitis per unit of milk is an appropriate focus of analysis in regard to
consumer health. I am not convinced, however, that it is as appropriate a
focus as the incidence of mastitis per cow when one consider the impact of
POSILAC on animal welfare and farmer quality of life.
Stephen Ronan sbr@world.std.com