Meat&Poultry -- April 2014 - 82

From the Corral
By Dr. Temple GranDin
meatpoultry@sosland.com

Detrimental effects
of beta-agonists
A

massive study with data collected

Zilpaterol is fed at a single dose and the

from numerous commercial feedlots

label on ractopomine allows freedom to

indicates that Zilpaterol increases both

raise or lower the dose.

death losses and dark cutters. Ractopamine
had an effect on death losses, and little or

Epidemiology approach

no effect on dark cutters. The study was

The ractopomine data was set up as a

conducted by Guy Loneragan from
Texas Tech Univ. and Dan Thomson
from Kansas State Univ.
The detrimental effects of both

controlled experimental design. The
Zilpaterol data set used the observational
approach that was used in epidemiology.
Some people in the industry have criticized

beta-agonists were greatest in the

the Zilpaterol data because the cattle

summer months. The data sets

were not randomly assigned to treatment.

were huge with 79,171 cattle in

Dr. Loneragan is an epidemiologist and

the ractopomine data set and in two
Zilpaterol data sets there was 722,704
and 149,636 cattle. The entire paper is
available free online.
The dark-cutter percentages for cattle

observational data is a solid scientific
approach when the data is carefully
scrutinized for confounding factors.
Epidemiology is used to track down causes
of food poisoning or bovine spongiform

on Zilpaterol were 0.53 percent for cattle

encephalopathy (BSE or mad cow disease).

fed regular feed and 1.59 percent for steers

It is also the same method that is used by

fed Zilpaterol. Steers seem to be more likely

data mining companies to collect customer

to have dark-cutter problems on Zilpaterol

information. Powerful statistics and

than heifers. In the ractopomine data set,

computer programs mine data, and when

there was one out of nine feedlots that

you click on your favorite shopping sites

had 0 percent death losses on both the

they know what you like.

ractopomine group and the regular feed

The first observations I made of lame,

group. All of the other feedlots had death

heat-stressed cattle were dismissed as

losses for both groups.

anecdotal by many people in the industry.
At a packing plant in the summer of 2006,

Further investigation
There is a need to find out what this one

with strange new problems I had never

feedlot was doing differently. I have talked

seen before. Half of the pen of cattle was

to two feedlot managers who reduced

normal, about one-third of the animals were

lameness problems with Zilpaterol by

sore footed and there were a few down with

adding more light bulky roughage to the

their tongues sticking way out. The sore-

rations. Other factors that may increase

footed animals acted like the stockyard floor

adverse effects might be poor feed mixing,

was red hot. The downed animals showed

rough handling or lack of bunk space. Some

severe heat-stress symptoms I had NEVER

animals will eat more Zilpaterol feed than

seen before in heat-tolerant Brahman

others. Dose is a further possible factor.

82

I observed a pen of Brahman cross cattle

cross cattle. The only new thing that was

* Meat&Poultry * April 2014 * www.MeatPoultry.com
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Meat&Poultry -- April 2014

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