Eye Muscle Scanner’s Workshop
FITT FINAL REPORT 13FT14
Year of trial: 2014
Group that proposed the trial: Eye Muscle Scanner’s Workshop
Region: South Canterbury
Farmer Initiator: David McCulloch
KEY ‘TAKE HOME’ MESSAGES

Eye Muscle Scanners throughout New Zealand recently attended an Accreditation Scanning
Workshop at Lincoln University.

Six scanners were re-accredited and one new attendee was newly accredited.
INTRODUCTION – BACKGROUND TO THE PROJECT
Ultrasound measurements of sheep muscle and fat are widely used in New Zealand sheep
breeding programmes targeting genetic improvement of carcass lean tissue characteristics. An
increasing number of breeders are supplying ultrasound scan measurements (of muscle and fat)
to the Sheep Improvement Ltd recording scheme (SIL). In addition, commercial ultrasound
scanning services provide measurements on farm, at ram sales and shows, where the
measurements are often used to rank individual sheep, either formally or informally by breeders,
ram buyers and judges. In some cases ultrasound measurements taken at ram sales or shows have
differed from previous measurements giving rise to uncertainty about the reliability of the
ultrasound measurement technique. Repeatability of a measurement is used to describe how well
an initial measurement corresponds to subsequent measurements of the same characteristic, and
provides a useful measure of the accuracy of ultrasound measurement techniques applied to
sheep breeding programs.
The New Zealand Sheepbreeders' Association initiated eye muscle scanning accreditation
workshops for ultrasound operators in 2010. Each operator eye muscle scans 25 sheep twice and
their results have to meet an established set of criteria to gain accreditation. Only subject to all
their figures meeting the criteria established, was their accreditation approved. After two eye
muscle scanning workshops six scanners were accredited. At that stage it was proposed that the
workshop be held every four years in order to;

Act as a refresher course for scanners for them to interact and exchange ideas and concerns

Allow new entrants to the industry to be accredited
KEY AIMS – WHAT WAS THE PROJECT TRYING TO ACHIEVE?
The aims of this FITT project were to:

Have new scanners be accredited

Re-affirm standardisation techniques and reporting results to owners of animals

Allow sheep farmers to have confidence in their scanner

Provide a valuable forum where scanners will benefit collectively from this workshop
METHODOLOGY – WHAT WAS DONE IN THE TRIAL?
The workshop was held at the Johnstone Memorial Laboratory, woolshed, Lincoln University on
Thursday 15th May 2014. Seven operators attended. Twenty- five Coopworth ram hoggets provided
by Ashley Dene farm, Lincoln University were used in the workshop. These were approximately nine
months old with a live weight range was 37-61kg.

All operators measured the same sheep.

Repeat measurements by each operator were made on all animals.

Every effort was made to replicate normal working conditions.
Scanning measurements taken were width and depth of the eye muscle, and fat depth over the
eye muscle. A common reference point of the eye muscle was used for scanning, midway
between the last rib and pin bone.
Measurement guidelines
Root mean square deviation (RMSD) of repeated ultrasound scanning measurements is the
standard for accreditation. The criteria are as follows for eye muscle measurement (A) width, (B)
depth and eye muscle product (EMP) area;

RMSD value less than;
o
5mm for width (A).
o
2mm for depth (B).
o
1mm for fat (C)
o
2.1cm² for eye muscle product area (EMP)
Ranking of animals
The rank correlation between repeated measurements of EMP (runs 1 and 2) on a group of 25
animals is taken as an overall measure of the effectiveness of operators with a rank correlation of
greater than 0.50 between duplicate measurements of EMP on a group of 25 or more animals.
RESULTS
RMSD values, correlation coefficients and the average measurements are given for the width (A),
depth (B), fat (C) and EMP in tables 1, 2 and 3 below.
Table 1: RMSD of eye muscle width (A), depth (B), fat (C) and EMP measurements
Calculated between run 1 and run 2 Operator A B C D E F Width (A)(mm) 1.37 2.87 4.17 2.72 2.85 3.20 Depth (B)(mm) 1.09 1.17 1.74 1.77 1.33 0.94 Fat (C)(mm) 0.49 0.72 0.63 0.57 0.57 0.63 EMP(mm) 1.06 1.37 2.25 0.84 1.45 1.20 G 3.46 1.13 0.72 0.98 Table 2: Correlation of width, depth and EMP measurements by operators
Calculated between run 1 and run 2
Operator A B C D E Width (A)(mm) 0.96 0.85 0.76 0.81 0.88 Depth (B)(mm) 0.94 0.89 0.78 0.92 0.89 EMP(mm) 0.96 0.89 0.77 0.93 0.91 F 0.84 0.94 0.94 G 0.88 0.91 0.96 Table 3: Operators average measurement for width, depth, fat and EMP for run 1 and run 2
Width 1 Width 2 Depth 1 Depth 2 Fat 1 Fat 2 EMP 1 EMP 2 A 72.44 72.56 28.04 28.20 2.88 2.96 15.75 15.86 B 69.64 69.00 28.00 27.76 3.76 3.64 15.09 14.82 C 68.00 67.56 27.04 26.96 3.20 3.40 14.25 14.15 D 61.36 60.76 27.20 26.88 3.08 2.92 13.04 12.64 E 70.24 71.24 26.08 26.36 3.48 3.56 14.18 14.55 F 67.12 65.60 27.44 27.20 3.72 3.48 14.24 13.82 G 67.52 66.48 26.48 26.28 2.68 2.52 13.88 13.57 Average 68.05 67.60 27.23 27.09 3.26 3.21 14.35 14.20 All operators met the measurement guidelines for width (A), depth (B) and fat (C). Operator C was
outside the range set for EMP by 0.10, and their measurements in general showed a lower level of
accuracy.
Though Operator C meets the criteria for width (A) and depth (B) the RMSD values are near the
upper limit of the values required, they fail to meet the criteria set for EMP.
This is shown in Figure 1 below in the rank correlation between run 1 and run 2, with the combined
measurements of A and B = EMP. The lower level of accuracy of Operator C compared to
Operator A is shown in Figure 2 below.
Figure 1: Operator EMP ranking of animals between Run 1 and Run 2 for EMP 1 and EMP 2
1.10
0.97
0.95
0.91
0.89
Ranking
0.90
0.94
0.94
F
G
0.76
0.70
0.50
A
B
C
D
E
Operator
Figure 2: The difference in repeatability of Operator A and C in EMP measurement
20.00
Operator C 18.00
18.00
16.00
16.00
EMP 2
EMP 2
20.00
14.00
14.00
12.00
12.00
10.00
10.00
8.00
8.00
8.00
13.00
EMP 1
Operator A
8.00
18.00
13.00
EMP 1
18.00
Figure 2 clearly shows how lack of measurement accuracy between run 1 and run 2 affects the
distribution from the mid-line. Operator A plots are grouped close to the trendline. On the other
hand Operator C plots show a greater scatter from the trendline.
This scatter can be explained by looking at the measurements of several animals by Operator C in
table 4 below.
Table 4: Difference between EMP measurements for outlier readings as measured by Operator C
Tag
EMP 1
EMP 2
Difference (cm)
161
17.79
13.01
4.77
143
12.32
9.83
2.49
344
18.48
15.85
2.63
142
15.85
18.62
2.76
335
16.08
18.9
2.9
Operator C was subsequently given further training to improve the accuracy of the measurements
taken.
Operator D scanning technique also requires some examination. Table 3 shows operators average
measurement for width, depth, fat and EMP for Run 1 and Run 2. The average operator
measurements for width are 68.05 and 67.60; operator D measurements are 61.36 and 60.76. This is
a significantly lower value which is also reflected in the final measurement of EMP. The average
operator measurement for EMP is 14.35 and 14.20, for Operator D the corresponding
measurements are 13.04 and 12.64. The lower values by Operator D are not a problem if they are
the sole operator per mob of sheep. However, a problem could arise where the measurements
are required for competition and the lower values obtained by Operator D are compared to other
operator’s measurements, who, based on this evidence, would record higher measurement values.
Note: The data presented in this report were obtained from sample measurements from 25
animals. Consequently, the validity of this analysis and recommendations are dependent on the
patterns of variation and error observed in this sample being representative of the variation in
measurements from a larger group of animals.
HOW WILL THE GROUP APPLY THE PROJECT RESULTS TO THEIR
AGRI-BUSINESSES?
Following this workshop all sheep breeders will continue to have confidence and certainty in using
the below accredited scanners (see Appendix). It is also pleasing to welcome a new scanner, Mr
Murray Crossan, into the eye muscle scanning industry. The New Zealand Sheepbreeders’
Association has agreed that all eye muscle scanners are required to be reaccredited every four
years. The workshop continues to be a beneficial exercise with all the eye muscle scanners
together in the one shed, observing their techniques and offering advice and encouragement.
MORE INFORMATION
Further information on the measurement techniques and development of the measurement
guidelines for operators may be found in the report, Beef and Lamb NZ. FITT Final Report 08FT2007,
Accreditation of Ultrasound Operators. This may be requested by contacting Beef + Lamb New
Zealand.
To find out more about other FITT projects, freephone Beef + Lamb New Zealand on 0800
BEEFLAMB or visit www.beeflambnz.com/fitt.
This publication is made possible by sheep and beef farmer investment in the industry. Beef + Lamb New Zealand is
not liable for any damage suffered as a result of reliance on the information contained in this document. Any
reproduction is welcome as long as you acknowledge Beef + Lamb New Zealand as the source.
APPENDICIES – EXTRA INFORMATION
APPENDIX ONE: LIST OF ACCREDITED SCANNERS:
The accredited scanners based on the Eye Muscle Scanners Workshop 2014 are:

CLULEE, PETER
Outram

CROSSAN, MURRAY
Outram

FARMER, ROWAN
Dunedin

MCLELLAN, BARRY
Dunedin

SPARK, CHRIS
Foxton

SWEETMAN, MIKE
Dunedin

WHEELER, MELINDA
Hawke’s Bay