Expected Progeny Differences (EPDs) are calculated for ten traits—nine fleece traits plus birth weight. Fleece data is collected from standardized fiber analysis. Growth and maternal trait data is also collected for the EPD program for birth weight, weaning weight, and birthing ease.
EPDs provide an estimate of the average difference in an individual’s progeny performance as compared to the national herd OR as compared to another individual animal. EPDs cannot predict the outcome of a single breeding, but rather predict the progeny performance on average over a number of progeny. Utilization of EPDs for traits of interest in breeding plans which include selection for desired traits will, over time, move the herd’s performance in the desired direction.
EPDs are ONE tool in a breeder’s toolbox for making informed breeding decisions. Conformation is not yet addressed by the EPD program. Other traits such as maternal characteristics are also not yet addressed by the program. AOA will continue to evaluate and add traits as necessary over time.
In order to make the best use of EPDs it is most helpful to have breeding plan goals for your overall herd as well as for specific animals within your herd. Use EPDs to help you select for a group of potential herdsires or animals to purchase and then evaluate those animals on their other merits — type, conformation, color, maternal qualities, general robustness of health, and temperament are additional traits that may have significant impact on the success of your breeding plans.
An accuracy is given to each trait on each alpaca that an EPD is calculated for. Accuracy is based on the amount of performance information available on the animal and its connected relatives — particularly the number of progeny analyzed. Accuracy is also based on the heritability of the trait and the genetic correlations with other recorded traits. Hence accuracy is a relative indicator of the confidence you can place in that particular EPD.
An accuracy value is represented by a number between 0 and 1. Accuracy is a relative indicator of the confidence you can place in that particular EPD. The closer an accuracy is to one, the more reliable the EPD value is.
Trait data is collected on nine fleece traits along with birth weight, weaning weight, and birthing ease. Birth weight, weaning weight, birthing ease, and fleece weights are entered by the owner on the "Trait Data" tab of the alpaca's page. To learn more about these traits read User Entered Trait Data. All other trait data must be submitted directly to AOA from an approved fiber testing lab.
For inclusion in the AOA EPD Program, fleece samples should be taken from the mid-side of the alpaca and cut at the base of the staple near the skin. This needs to be a 4"x4" sample. Please note that this is larger than the 2"x2" sample required for simple fleece testing. The sample will then be mailed to an approved testing lab, along with the computer-generated order form provided by AOA's automated Shear Report Tool. Read the Shear Report Guide for instructions on using AOA's online shear report tool.
Once your fleece sample has been tested, you will receive the histogram results for each animal directly from the lab. An electronic copy of the results are forwarded to AOA for inclusion in the EPD program.
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EVERY alpaca's data is important. Your alpaca's trait data affects the EPD results of ALL related alpacas. By participating you learn valuable information on your alpaca while increasing the accuracy of EPDs within the alpaca’s pedigree. Accurate EPDs help you make informed breeding decisions that further your herd's genetics, which should be the goal of any alpaca breeder. Also, this helps improve the overall characteristics of the national herd, which benefits the industry as a whole. This information will ultimately be used to help move the North American herd towards the most desirable alpacas for both breeding and commercial production.
Alpaca's primary function is fleece production. As a result, EPDs have a huge focus on fleece characteristics and EVERY alpaca's data is important even if they are not being bred. Your alpaca's fleece data affects the EPD results of ALL related alpacas ultimately leading to more accurate EPDs. This helps improve the fleece characteristics of the North American herd which benefits you as someone who is focused on fiber. By participating, you are helping to provide better and more accurate EPD data on alpacas within that pedigree while at the same time learning valuable information about that alpaca's fleece. EPDs will ultimately be used to help achieve alpacas with the most desirable fleece characteristics for commercial production. That information will help you to make decisions on how best the fiber should be used and will also help you make decisions on future fiber alpaca purchases that will give you a better fleece for your fiber business.
The intrinsic value of the alpaca is predicated on the fineness and quantity of the fiber it produces. EPDs enable breeders to make larger gains and faster progress in the overall quality and quantity of their alpacas’ fiber. By precise selection of breeding partners, individual farms can now achieve their own specific genetic improvement goals. EPDs allow breeders to select breedings based on the alpaca’s “Genotype” (their genetic merit) and not “Phenotype” (how they look) which tells the breeder little about the animal’s true breeding value. The use of EPDs has proven effective in every commercial livestock industry. EPDs provide an additional indicator of an alpaca’s value and are useful when purchasing or marketing alpacas.
Expected Progeny Differences (EPDs) are a key piece of all large livestock industries. Having the production data to backup what alpaca breeders have been saying for years will help the alpaca industry become more recognized by other livestock industries. EPDs help alpaca breeders make more informed breeding decisions which improves the quality of their alpacas over time and in turn improves the national herd. This leads to even more desirable alpacas with highly sought after fleece characteristics and genetics. The North American alpaca industry has long been seen as a worldwide leader in the alpaca industry in the areas of science and technology. Expected Progeny Differences are the next step in the evolution of the industry's innovation and growth.
EPDs are based on a set of characteristics that are tracked on your alpacas and reported to AOA for inclusion in the EPD calculation. The EPD calculation will only be done once per year since new fleece data is only available each year after shearing. While many of the characteristics are based off of fleece characteristics, not all of them are and additional traits will be added over time as they become more desired by the membership. The calculation itself is a well developed process used in all major livestock industries and is based on Best Linear Unbiased Prediction (BLUP). The BLUP calculation takes many things into account when calculating the EPD for each trait.
Heritability is a measure of the strength of the relationship between performance (phenotypic values) and breeding values (genetic makeup) for a trait in a population. Heritability is a measure of the degree to which a trait such as fiber production or fiber diameter is genetically determined. Heritability is an important factor among the several factors determining how much genetic improvement can be made in any characteristic.
OFDA stands for Optical Fibre Diameter Analysis. It refers to instruments used to make precise measurements on alpaca fiber. The measurements provide the data to create histograms. Measurements made with OFDA equipment comply with standards set by the American Society for Testing and Materials (ASTM). The ASTM standard (D2252) defines procedures for measuring fineness in alpaca fiber.
Starting with this webpage is a great beginning. Please use the resources and links available on this page to learn more about EPDs. If you have questions that aren't addressed by the resources listed here, contact the AOA office and we will be happy to direct you to the right person for your question.