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Development
of Objective Lamb Tail-dock Measurement Device “De-tail”
Device Jeff Goodwin University of Idaho Jan
Busboom, Washington State University Ross
Jacobson, Utah State University Bob
Peterson, University of Arizona Barney
Cosner, Wyoming State Fair Michele
Pike, University of Idaho Bill
Shulaw, Ohio State University Jim
Jenson, Utah State University Jean
Woloshuk, West Virginia Cooperative Extension Willard
Lemaster, Maryland
Cooperative Extension Troy
Ott, University of Idaho Paul
Kuber, University of Idaho
Situation Over
the course of the last 20-30 years, many club lamb producers and
exhibitors have promoted the docking of show lambs that result in no
tail (or shorter in the case of ultra short docks) being left on the
lamb. This popular
practice is carried out because it creates the appearance of a lamb
with a more level rump and a fuller, squarer leg.
Therefore, a lamb with any tail is seen as having a distinct
disadvantage at many livestock shows. To
address this issue, in 1999 The United States Animal Health
Association (USAHA) passed a resolution recommending that lambs should
only be accepted for exhibition if “tails are not docked shorter
than the level of the distal end of the caudal fold”.
Then in 2000, The American Association of Small Ruminant
Practitioners (AASRP) and the American Veterinary Medical Association
(AVMA) passed supporting resolutions.
Since that time ASI (American Sheep Industry Association), the
American Farm Bureau Federation, and the National Institute for Animal
Agriculture (NIAA) have also passed resolutions to support the
original USAHA recommendation. Several
state Extension Systems and/or State Fairs (Utah, Wyoming, California,
West Virginia, Idaho, Washington) have taken positions to support the
USAHA/AASRP/AVMA recommendation.
Hence, it could be argued that the “distal end of the caudal
fold” recommendation regarding lamb dock length is an industry
position with broad support. One
of the reasons behind the industry recommendations against ultra-short
docked lambs is the issue of increased rectal prolapse observed in
those animals. In a study
conducted by Dave Thomas of the University of Wisconsin, the following
preliminary results were reported:
lambs docked at the distal end of the caudal fold had a rectal
prolapse rate of 1.8 %; mid web 4 %; and lambs with no tail 7.8 %.
Granted there are other factors that influence rectal prolapse
in lambs such as genetics and feeding programs; however, the Thomas
study focuses on tail length and its influence.
When
the study by Dave Thomas is published by a peer reviewed journal in
the near future, Extension will have to decide if it will promote and
educate based on what the research base tells us, or whether it will
promote and educate based on what some club lamb producers tell us.
These are often two divergent trains of thought.
It
must also be remembered that the short tail docking issue in show
lambs is not just about rectal prolapse.
Other factors such as re-docking large lambs (weighing 100
pounds or more that were originally docked at mid to full web) in
order to conform to show ring pressures is an example of another
aspect of this issue that is often ignored.
With
the AASRP and AVMA recommended lamb tail-docking length of “distal
end of the caudal fold”, a controversy has erupted in the show lamb
industry. The AASRP/AVMA
recommended length provides an excellent visual landmark for the site
of the tail docking procedure to occur. However, once the procedure is
carried out, the landmark is destroyed. This
presents a problem for individuals and states striving to implement
the AASRP/AVMA recommendation. How
do you identify an acceptably docked lamb months after the procedure
is carried out? After
the fact, lambs docked at the distal end of the caudal fold are many
times indistinguishable from those docked at 1, 2, or 3 tenths of an
inch shorter that the distal end of the caudal fold.
In short, while the distal end of the caudal fold provides a
great landmark of where to dock, it is useless when it comes to
enforcement of guidelines or rules related to appropriately docked
lambs. Objectives of the Study Research Objective 1 The
purpose of the proposed study is to develop a device that can be used
by show management to objectively assess appropriately docked lambs.
Such a device could also be used by 4-H and/or FFA members to
assess the ability of prospect lambs to pass such a test at show
and/or market ready time. Phase
I of this study will:
Research
Objective 2 Probably
the must important component of this study will be to describe a
population of lambs that have been docked at the distal end of the
caudal fold in terms of a linear measurement.
This is the critical link in taking the AASRP/AVMA
recommendation to some measurable and enforceable standard that can be
utilized by livestock shows. This
will also provide an educational standard for youth development
programs such as 4-H and FFA that utilize a lamb as a youth
development vehicle. Research Objective 3 The
secondary objective of this study is to determine if the length of the
tail (as measured with the proposed device) changes between docking,
weaning, and market ready time frames.
This information will be extremely useful as states and
individual livestock shows explore implementation of guidelines and
rules regarding appropriately docked lambs. Procedure This
study will be conducted at various locations on the following breed
types as available in order of priority.
The
study will also attempt to have equal representation between wether
and ewe lambs in each of the breed types identified above in order to
explore sex differences. All
lambs in the study will be docked at the distal end of the caudal
fold. Description of “Detail” Device The
ultimate outcome of this study is to arrive at a standard length
measuring device (post study device) that all people involved in lamb
showing nationwide could use as a guide or “standard” to determine
acceptably docked lambs. A
2 inch diameter PVC pipe cut in half to form a trough of a length to
be determined during the course of this study will be used to measure
lambs, (Figure 1). A half
round flange (extending 1 inch on the side and 3 inches below the PVC
pipe) will be attached to the end of the PVC pipe that makes contact
with the body of the lamb. The purpose of this flange is to minimize variation during
measurement. The flange
actually makes contact with the pin bones on the lamb, thus
establishing solid point of contact and allowing very little variation
in the measurement. A
second part of the device made of slightly smaller diameter PVC pipe,
acts as a plunger as it fits inside the main body of the device.
With the device in position and a lamb’s tail resting in the
main body, the plunger is slid up the main body of the device until
contact is made with the end of the tail.
The scale on the side of device is read and the appropriate
mark on the scale recorded. Measurements
are made on a tenth of an inch scale.
The device must be held in a level position and a small level
is mounted on the device itself to aid in this.
The version of the device to be used to collect data for this
study will be four inches long. The device will be constructed from materials to allow for
use of disinfectant on the device between uses.
This
standard would also apply to genetic lines and breeds of lambs, which
may have a very short caudal fold.
If this standard can be developed that fits a statistically
significant number of lambs then all breeders would be aware of the
standard regardless of unusual lengths of caudal folds in their own
lambs. Measurements
will be made on each lamb with the study version of the device at
docking and at market ready time frame.
This is being done in order to explore the claim that the tail
can actually appear shorter at show time than at docking.
This is claimed by some club lamb producers to be due to less
tail extension because of leg development during the course of growth
and development of the lamb. If
there is a significant difference in docking time and market ready
time frame of measurements, this may indicate a need for different
lengths of prospect and market ready devices. Study Methodology
Phase
I – Establishment of Device/Rater Accuracy Each state involved in this project will conduct a pre-study analysis of device/rater accuracy. Ten lambs that have previously been docked at the distal end of the caudal fold and six raters (device operators) will be used in the phase I part of the study. Three of the raters will have been trained and practiced in the proper use of the device. Three of the raters will only have written instructions to guide their use of the device. Each rater will have ten lambs that have been docked at the distal end of the caudal fold presented to him/her, one at a time. The lamb ID number/ear tag number will not be communicated to the rater, only the person recording lamb ID and measurements. Once the rater has measured all ten lambs and measurements have been recorded for each lamb, the rater will a second time measure all ten lambs in random order. The rater will have his/her back to the pen of lambs as someone else will catch and present each lamb to the rater. It is important to keep the ID of each lamb unknown by the rater. This same process will be carried out by each of the 6 raters. Data from Phase I of the study will be analyzed for:
If possible, phase I data from each state will be utilized to select the operator for the device in collecting data from that state in Phase II, if that data suggests there is significant variation in operator reliability.
At Docking All
lambs should be docked at less than two weeks of age by one of the
following methods: 1) hot iron, 2) knife, 3) or burdizzo. Due to the design of the “de-tail device” tails
must be removed at docking time in order to make the docking time
measurement. If a
test site must use another docking method in order to participate in
the study an allowance will be made.
Data for alternative docking will be analyzed in a manner to
identify or remove possible variation in measurements due to docking
method. Each
lamb will be restrained on its hindquarters with tail extending, in a
position typically used for vaccinations and sheering.
The lamb will rest on a hard flat surface to aid in
implementation of the procedure.
A narrow tipped felt-tip pen will be used to draw a line in the
ventral side of tail indicating the location of the distal end of the
caudal fold. The docking
procedure will be carried out exactly on this line drawn on the
underside of the tail. If
one caudal fold is shorter than the other, the line should be drawn on
the shorter of the two and procedure carried out at this location. Measurement
at Docking After
the tail is removed from the lamb, it will be returned to its feet.
The detail device will be placed under the tail with the tail
contained in the trough created by the PVC pipe.
Ensure that the flange is in firm contact with the pin bones
and that the device is held level. Slide the plunger into the device until contact is made with
the tail. Record the
graduated mark on the device that the distance indicator completely
extends beyond (not the closest mark).
If the distance indicator lies exactly on a graduated mark on
the device, record that mark.
Measurement At Prospect lamb Selection/Weaning Time Frame In
order to assess research objective 3, the tail length at the weaning
or prospect lamb selection time frame will need to be obtained if
possible. The process for
obtaining this measurement will be the same as described below for the
market-ready time frame. Measurement
At Market Ready Time Frame All
lambs in the study will have the wool slick sheared from the tip of
the tail at market ready measurement.
With the lamb on its feet, The detail device will be placed
under the tail with the tail contained in the trough created by the
PVC pipe. Ensure that the flange is in firm contact with the pin bones
and that the device is held level.
Slide the plunger into the device until contact is made with
the end of the tail. Record
the graduated mark on the device that the distance indicator
completely extends beyond (not the closest mark).
If the distance indicator lies exactly on a graduated mark on
the device, record that mark.
Breed
and muscling differences of study animals will be recorded. Possible Outcomes Resulting From the Study Analysis
of the data collected in the study will aid in the description of the
normal distribution of lambs (by linear measurement) that have been
docked at the distal end of the caudal fold.
Once a relationship has been established between the distal end
of the caudal fold and a linear measurement that can be accurately and
consistently obtained, that information can be utilized to determine a
minimum accepted tail length that is both enforceable and
educationally sound. Data
collected in this study will be essential in subsequent possible legal
challenges directed to states and to livestock shows that choose to
adopt and utilize the tail measurement device proposed and developed
in this study. The
Cooperative Extension System is in the business of extending
research-based information through its educational programs.
Therefore, this study will provide Extension educators
nationwide and show management nationwide with objective,
research-supported information on which to base enforcement and
educational efforts related to this contentious and volatile issue
currently being faced by the livestock show industry.
Click on the following for:
Phase I Data Collection Page (Device/Rater Accuracy Instruction)
Phase II Data Collection Page Instruction
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