When New York State dairy farmer Peter
Dueppengiesser pulled the plug on Posilac in
September, 1994, he expected to see his milk
production go down the drain as well. It didn't,
but the exercise was part of a learning curve for
the young producer who milks 550 cows with his two
brothers in Perry, 50 miles south of Lake Ontario
between Rochester and Buffalo. 
"We were averaging in the low 60s (pounds per cow
per day) on three-times-a-day milking, and said
this is not cost-effective," says the young farmer
who has since given Posilac, Monsanto's bovine
somatotropin product, another try. Once the plug
was pulled, "everybody told us the cows would
crash," Dueppengiesser told more than 250 producers
and industry officials gathered in Toronto last
month for the first-ever National Conference on
Dairying. 
The Dueppengiessers jumped on the BST bandwagon
immediately, once the Posilac was cleared for use
in the U.S. in February, 1994. It remains under
review in Canada, along with an Eli Lilly product. 
Production on the Dueppengiesser farm jumped
quickly by 10 to 12 pounds per cow. "We were very
pleased with that, but as time went on, cows were
not maintaining production as we thought they
should. We had 268 cows on Posilac in September
when we decided to quit," says the American
producer, who gets just under US$13 per
hundredweight for his milk. 
The month Posilac was dropped, cows on BST averaged
63 pounds. In October, production rose to 67, and
in November dropped to 65. 
A more careful number crunching by Cornell
University and Monsanto, however, told another
story. Production was dropping, but other factors
were masking the drop. Cows that had been on BST
from day one fell to 54 pounds in November. 
Today, Dueppengiesser is a lot more discriminating
about his BST use, but he still hasn't got his
herd's reproductive performance where he'd like it.
"Reproduction is suffering drastically, but we're
not blaming this on BST," he said, citing an
average 3.5 to four services per conception, and a
25 to 28-per-cent success rate. "Our target is 40
(per cent)," he said. "This is costing us money.
It's not enough just to inject cows and say you
have a milk response. You have to have an economic
response. 
"What's your optimum calving interval, pregnancy
rating, and services per conception? We are
positive about BST, but our strategies are
different. BST forces us to be at the top of our
game. It's important to know the real numbers,
what's happening on your farm." 
Reproductive performance of BST-treated cows also
poses a question mark for renowned BST guru Elliot
Block of MacDonald College, who has completed more
on-farm BST trials than any other research
scientist Canada. In trials over three years, Block
could find no effect on days of gestation, calf
birth weight, or calf performance after birth, and
no increase in abortions. He did, however, find
more open days and higher services per conception. 
"The only effect that appears to be on the negative
side is the effect on open animals for reproductive
cycles," he said. In trials, cows on BST averaged
161.4 days open and 3.1 services per conception,
versus 137.3 days open and 2.3 services per
conception for control cows. 
Block surmised that heat detection is more
difficult to detect in BST-treated cows possibly
because an increase in progesterone masks signs of
heat. To compensate, he recommended not using BST
prior to conception. As there is no increase in
production at the lactation peak, farmers could
start BST after the peak, "hopefully convenient
with the time the animal has conceived."
Over all trials, Block noted a consistent
five-kilo-per-cow advantage to BST. Feed intake
also rose an average six per cent, but any increase
in feed efficiency is simply due to increased milk
production, he said. "There's nothing magic about
BST. The only reason the cows are more efficient is
because they are making more milk. It's the same as
changing the components of the diet and getting an
increase in efficiency." 
Milk composition from BST-treated cows was
unaltered, as was the somatic cell count. With a
slower drop in the lactation curve, animals
regained weight more slowly. 
Between February and August, 1995, the Food and
Drug Administration (FDA) cited 509 "adverse
reactions" in U.S. herds on BST, said Jean
Szkotnicki, who represents Monsanto and other
pharmaceutical companies on the Canadian Animal
Health Institute. Of those, 300 were thought to
have been relevant to Posilac, but FDA also found
that all of the conditions are known in dairy
cattle not on BST. In its first year, 14 million
doses of Posilac were administered on 13,000 U.S.
farms, representing 11 per cent of U.S. milk
producers, she said. 
Block admitted to having an anti-BST bias when he
started investigating. "When BST came around, I was
eager to work on it because I was almost certain
that this would happen," said Block, flashing up a
cartoon slide of bone-rack cows. "But Mother Nature
has her tricks," allowing cows to maintain
condition. 
As for the safety of the milk, "my
two-and-a-half-year-old is drinking milk," said
Block. "Am I 100-per-cent sure that we won't find
anything in the next 20 years relating to BST? No.
But you won't find anything related to BST that
will be harmful to humans. 
"BST is the most researched drug, animal or human,
on the planet. It's more researched than aspirin.
Do I think it's for everyone? No. Do I think it's
safe? Yes." 
While U.S. producers were fearful of a consumer
backlash, the opposite actually occurred, said
University of Guelph agricultural economist George
Brinkman. While there were pockets in Wisconsin and
Vermont where consumption declined, overall
consumption rose a slight 0.6 per cent in the year
following BST's introduction to the U.S. Two per
cent of all fluid milk sold in the U.S. is labelled
"rBST-free," Brinkman said. 
"It is important that we distinguish between the
publicity and concern and the actions of consumers
when they vote with their pocket book." 
He attributes BST's relatively smooth ride in the
U.S. to strict labelling requirements, and giving
consumers a choice. The FDA requires labelling to
indicate "there is no significant difference in
milk from rBST/rBGH-treated and untreated cows." 
New York producer Willard DeGolyer, who farms in
Castile, to the south of the Dueppengiessers, has
no doubts about BST's benefits. DeGolyer, who milks
850 cows in a double-14 Germania herringbone
parlour, and expects to expand to 20 a side,
compares the switch to BST to the switch to 15-inch
rows of silage corn. "We went to a
22.34-tonne-per-acre average at 35-per-cent dry
matter. We're harvesting more sun per acre." 
While BST also incurred extra costs, production has
risen 12 to 15 pounds per cow per day, bringing
production from 21,000 to 24,500 pounds of milk
sold per cow. At press-time prices of US$12.52 per
cwt, that's an extra US$438 per cow.
DeGolyer added, however, that BST takes careful
management of every cow. "BST will only work with
good feed, good air, and a comfortable place for
the cow to lie down." 
While few at the Toronto conference doubted the
production benefits, there were questions about
BST's effect on Canada's world-class reputation in
dairy genetics. "Are we breeding a breed of cows
that can only produce if we have supplemental BST?"
asked Chris Judd, who milks cows in Shawville,
Quebec. "We all know the cows that milk well up to
100 days, and then it's off to McDonalds...I'm
afraid that in 15 years after we have changed the
genetics of animals, you're going to pull it." 
The industry will have to come up with criteria for
genetic evaluation if BST is registered in Canada,
said Beamsville, Ont., producer Peter Oosterhoff, a
member of the federal BST task force which issued a
report in May. In the area of genetics, Oosterhoff
said "further work needs to be done to determine
whether we can find additional criteria on BST
herds to determine the effect. 
"But if we're afraid to be afraid, then we're not
going to get ahead." While the task force called
for "auxiliary genetic evaluations", including
100-day evaluations for sires and a complex
evaluation over the whole lactation pre and
post-BST, Oosterhoff said "there is a limit to the
amount of data we as producers are going to collect
through milk recording programs.
"Breeding strategies are going to be critically
important in the future, even more than in the
past...The challenge will be to choose and
implement, and...modify the programs that move us
along faster than the competition. 
"BST will only be used...if we can assure the
public, the industry and our customers that the
technology is deemed necessary and safe...Frankly,
I think we're on the right track." 
Elliot Block said the industry "can adjust" and has
"no intention of using 100-day records." 
"We have a lot more to lose than the Americans. The
Americans are ignoring it, and I think that's
incorrect. We have to be a lot more careful." 
Where does that leave American producer Peter
Dueppengiesser? He left the Toronto meeting to go
shopping at the Royal Winter Fair for another 100
cows. The genetics are good, and the dollar's even
better. - JMM 

   

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