Got your message of 2/24. . .perhaps I should give you a
bunch of materials on rbGH, as some of your info is misleading.
In particular, the notion that rbgh only increases mastitis by
15%. This is not true!!!
If you look at the FDA FOI summary, you'll see that the
relative risk of clinical mastitis in rbgh-treated cows compared
to controls during the treatment period is 1.79 overall. That
means that there is a 79% increase in the rate of clinical
mastitis during the treatment period. Furthermore, if we look at
first calf heifers (i.e. cows going through their first
lactation), the relative risk is 1.97, or a 97% increase!!! In
addition, if we look at the data on relative risk of cases of
subclinical mastitis, the number is 1.81, an 81% increase!! I
think that what FDA is referring to as only a 15% increase in
clinical mastitis might be if you lumped the data from the entire
lactational cycle (i.e. if you include the first 9 weeks of data).
This is not good science. To compare the effect of bGH on
mastitis, one should only look at data from the treatment period.
If you wanted to look at the entire lactational cycle, you should
have data on cows treated for the entire lactational cycle. I've
never seen any such data, but would be willing to bet that the
increase in clinical mastitis would be higher than 100% if it were
given during the entire lactational cycle.
Further, you should know that the data FDA used is a very
selective rendering of all the studies. For example, they didn't
include the Vermont Jersey study which demonstrated a four-fold
increase in the number of cows treated for clinical mastitis and a
seven-fold increase in the number of cases of clinical mastitis.
This study is a pivotal study, but it is only pivotal for
injection site syndrome. Further, there has been much suppression
on any adverse health effects. A big example is the Cornell
trials (which involved 84 animals--42 controls and 42 treated).
When Bauman et al. published the results in the J. of Dairy
Science, they said that they observed no catastrophic adverse
health effects. They also made a point of saying that to detect
"subtle" differences in effects on cow health requires larger
sample sizes and that they would lump the data from the Cornell
trials with other data so that the sample sizes would be larger.
It turns out, from looking at info in the FDA FOI summary and from
slides from the VMAC (Vet. Med. Advisory Cmtee) meeting on March
31, that the real data on clinical mastitis from Cornell is pretty
bad: cases of clinical mastitis went from 4 out of 42 in controls
to 14 out of 42 in rbGH-treated animal!! I think that a 3.5-fold
difference is more than a "subtle" health effect. I mean, 33% of
all rbGH-treated animals getting mastitis is pretty significant
and should constitute a catastrophic increase.