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Articles by Alpaca World Magazine:

Estimated Breeding Values (EBVs)

Steve Marshall



Introduction
Why is one alpaca worth more than another? How am I able to rank and differentiate between several alpacas of slightly varying characteristics? In the show ring Judges must make a decision and rank alpacas based solely on phenotype, that is, the observable, physical characteristics of alpacas presented on a particular day. While show results are significant in identifying elite alpacas, individual environmental conditions influence the presentation of each alpaca. In fact, a Judge may place five alpacas in a completely different order at two shows that are only a few weeks apart. The Judge should not be considered wrong at either show because the Judge makes a decision about their ranking as they appear on that particular day.

What are Estimated Breeding Values?
While ranking alpacas at shows has its place, calculating Estimated Breeding Values (EBVs) may be of far more use to a breeder interested in herd improvement. An Estimated Breeding Value is quite simply an estimation of the value of a particular alpaca in a particular breeding programme. With calculated EBVs a breeder may make more informed decisions about matings that should ultimately lead to greater herd improvement.

Within any alpaca herd there is significant variation and a variety of factors could have influenced the variation you see in the phenotype of each alpaca. The use of estimated breeding values can be an important tool to provide direction when making decisions about a breeding programme. EBVs may also be used to determine a monetary value ranking of animals in a herd. There are many different methods and criteria used for calculating EBVs.

Across-herd Genetic Evaluation (AGE)
Possibly the easiest method, and quite suitable for most breeding programs is the Australian Alpaca Association, AGE programme. The Across-herd Genetic Evaluation (AGE) programme involves supplying data for fleece and other traits and the Association manages the rest, providing the breeder with statistical data for further decision making. The AGE uses (BLUP) Best Linear Unbiased Prediction and is considered possibly the most accurate method of ranking any type of livestock. The AGE programme enables ranking of alpacas of different ages, on different properties to be compared and ranked taking into account different environmental and seasonal conditions.

What traits should be measured?
The alpaca industry is in its infancy and aside from the basic breed standard, people are still formulating ideas about what they consider important. How much should you value micron or body weight or fleece coverage? Some EBVs take into account only fleece data, while others have more of a whole alpaca approach. Using measurable data such as fleece statistics, body weight, etc, is very objective and helps to maintain accuracy and consistency. However, by using some more subjective information it is possible to take into account the total animal when calculating EBVs. I guess this is more like the problem faced by judges in the show ring. The more you have to make decisions about subjective traits the more likely you are to develop some inconsistency. It is possible to provide some examples, however, that what one breeder considers important may not be of such importance to another. The decision about which traits to measure and the weighting given to each should be based on the goals of your breeding plan.

Assessment Rubrics
In recent years there have been a number of very useful articles released detailing specific features to look for when identifying conformation faults. Some are in the form of ?breed standards? and have been published by various Alpaca Breeder Associations around the world and are available on web sites. Others are in the form of magazine articles, conference proceedings and scientific research papers. In most cases each document attempts to describe what the author considers the perfect alpaca. When measuring alpacas against these standards it becomes difficult to place a value on specific traits or characteristics according to how perfect the alpaca is because our judgment becomes rather subjective. For example, the Australian Alpaca Association breed standard for Huacaya alpaca states that an alpacas average height should be 90 ? 95 cm. When assessing the alpaca?s height for calculation of EBVs, what value should be given if it is within this range and what value outside this range? An even more difficult feature to assess due to its subjective nature is fleece coverage on head and legs. One breeder may highly value leg coverage while another considers fleece cover on legs insignificant. Assessment rubrics can be used to maintain objectivity and also maintain a focus on features that a particular breeder finds important. The example rubric below has been constructed for the purpose of this article and has limited detail to measure traits. However any breeder can construct a rubric with descriptors to help maintain consistency when assessing alpacas and applying values for particular traits. The rubric below specifically suits my purposes and each breeder should develop their own rubric assigning values to traits that are of importance to them.

Over 27.9 micron
0/20 27.9 ? 24 micron
4/20 23.9 ? 20 micron
8/20 19.9 ? 17 micron
12/20 16.9 ? 15 micron
16/20 Below 15 micron
20/20
Over 6.0 SD
0/10 5.0 ? 6.0 SD
2/10 4.0 ? 4.9 SD
4/10 3.5 ? 3.9 SD
6/10 3.4 ? 3.0 SD
8/10 Below 3.0 SD
10/10
Straight fibre not bundled


0/15 Wavy fibre with no obvious staple definition

3/15 Lose crimp and little staple definition

6/15 Crimp throughout fleece but presented in thick staples
9/15 Pencil thickness highly aligned staples with tight crimp
12/15 Small matchstick thickness highly aligned staples with tight crimp
15/15
Less than 2.0 kg total fleece weight
0/15 2.0 ? 2.9 kg total fleece weight
3/15 3.0 ? 3.9 kg total fleece weight
6/15 4.0 ? 4.9 kg total fleece weight
9/15 5.0 ? 5.9 kg total fleece weight
12/15 Over 6 kg total fleece weight
15/15
Runt alpaca, failed to grow out


0/10 Not showing correct propotions
Eg; short and long

2/10 20% above OR below average height OR weight for breed type
4/10 10% above OR below average height OR weight
for breed type
6/10 Average height and weight for breed type with shallow or small chest 8/10 Average height and weight for breed type with deep chest
10/10
Legs and head have minimal fleece coverage

0/5 Legs or head have some coverage but not both

1/5 Legs and head have some coverage but very different style to saddle fleece 2/5 Legs and head have good coverage but style not consistent with saddle 3/5 Full fleece coverage but lacking either style or length in places
4/5 Full fleece coverage with usable fleece across entire body and neck 0/5
Wry face


0/5 Overshot or undershot jaw

1/5 Long nose with banana ears

2/5 Long nose OR banana ears

3/5 Long nose OR banana ears with teeth not aligned
4/5 Short nose, short straight ears, teeth aligned
5/5
Significantly splayed or cow hocked legs 0/5 Stance lacks presence and alpaca doesn?t walk freely 1/5 Upright stance with cow hocked back legs
2/5 Upright stance but with slightly splayed front legs
3/5 Stance lacks upright presence but all legs are good 4/5 Upright stance with straight legs and walks freely
5/5
Multi colour fleece


0/3 Any colour but not solid. Eg: coloured with white on toes or head 0/3 Solid brown fleece


1/3 Grey fleece or Solid light medium or dark fawn fleece 2/3 Solid black fleece


3/3 Solid white fleece


3/3
Light blue eyes

0/2 Dark blue eyes

0/2 Black or Brown eyes with blue outer ring 1/2 One blue eye and one black eye
1/2 Two dark brown eyes
2/2 Two black eyes
2/2
Target ancestor not in pedigree OR inbreeding coefficient greater than 20 % 0/10 Target ancestor in pedigree once


2/10 Target ancestor in pedigree twice


4/10 Target ancestor in pedigree three times

6/10 Target ancestor in pedigree four times

8/10 Target ancestor in pedigree five times or more

10/10

In some cases a breeder is only interested in the EBV and could simply add the figures as they go to arrive at a sum total for the EBV. However, a breeder may elect to use a complete page for each alpaca recording the alpacas name and tag details at the top and totals down the right hand side. In this case a record of the value for each trait is retained for future reference. This could be particularly useful in identifying strengths and weaknesses of individual alpacas.

Example of EBV in practice
At Stansbury Alpacas we use EBVs for a variety of reasons. For us EBVs must take into account traits that are important to our particular breeding programme. Such traits or attributes include, fleece, conformation and inbreeding coefficients for our linebreeding programme. An example of criteria we use, traits that we assign values to, and how we calculate an EBV on an 18 month old alpaca.

Fleece Characteristics 60% Micron 20
Standard deviation 10
Style 15
Fleece weight 15

Animal Conformation 30% Size / height / weight 10
Fleece coverage ? head / legs 05
Head, muzzle, teeth and ear shape and size 05
Leg conformation and stance 05
Colour of fleece 03
Eye colour ? black / blue or gene carrier 02

Degree of inbreeding 10% Number of times line breeding target
animal appears in pedigree 10
__
Total 100

This method of assigning values to work out EBV?s is specifically tailored to meet the requirements of our own breeding plan. Some of the traits or characteristics that we assign numbers to are somewhat subjective and require the use of a descriptive rubric to maintain consistency.
There are some potential traps for users of EBV?s to be aware of. Firstly it is virtually impossible to compare EBVs from different herds due to the different environments. This is because environmental factors have a huge influence in the phenotype of an animal. Seasonal conditions also have an influence and for this reason it is prudent to calculate EBV?s in management groups that are of similar age. However the Australian Alpaca Association?s AGE programme is able to take into account these factors providing the breeder with accurate data despite environmental and seasonal variations.

Example of EBV with progeny value
If calculating EBV?s on older breeding females it would be wise to adjust the criteria for assigning values to include such factors as the consistency and quality of their offspring. An example of this is a ten year old female of sound conformation but poor fleece statistics giving her a low EBV, but that consistently produces female offspring that rank very highly. Below is a version of the previous EBV criteria that has been altered to take into account the new information available from a breeding female.

Fleece Characteristics 35% Micron 10
Standard deviation 10
Style 05
Fleece weight 10

Animal Conformation 25% Size / height / weight 10
Head, muzzle, teeth and ear shape and size 05
Leg conformation and stance 05
Colour of fleece 03
Eye colour ? black / blue or gene carrier 02

Progeny 30% Consistent trouble free breeder 05
EBV values of progeny 25

Degree of inbreeding 10% Number of times line breeding target
animal appears in pedigree 10
__
Total 100

Conclusions
Clearly, EBVs can be an important factor when looking at genetic improvement in a herd. However, it requires careful planning to ensure the EBVs accurately represent the traits that are of value in your breeding programme to be most useful. It is not much use using EBVs that take into consideration the effect of linebreeding if linebreeding is not part of your breeding plan. If considering the use of EBVs it is wise to fully recognize and articulate the specific goals for your own breeding plan first. In this way, when allocating weightings to particular traits the correct balance can be achieved to ensure the breeding goals are met.

Steve Marshall Stansbury Alpacas + 61 883 805 965 www.stansburyalpacas.com.au marshall@netyp.com.au