The Alpaca Library Catalogue

Forty alpaca kids, comprising 20 huacaya and 20 suri, and 20 llama “chaku” (or woolly type), were chosen for a comparative investigation of the fiber and cuticular attributes based on fiber diameter, number of cuticular scales per 100 µm of fiber length, and scale height. Out of the three parameters investigated, the number of cuticular scales proved to be a valid diagnostic trait in distinguishing suri fleece from both huacaya and llama fleeces. A further characterization of the suri fleece was obtained by considering the frequency distribution of both fiber diameter and number of cuticular scale classes. The suri fleece was clearly different from both the huacaya and llama in that it possessed the highest percentage of fibers with less than eight scales, the lowest percentage of fibers with more than nine scales, along with the lowest percentage of fibers with a diameter of more than 35 µm. The validity of these classification criteria was fully supported by a classification discriminant analysis based on the jointed investigation of the data related to scale and diameter frequency classes, whose output was a 100% correct classification of the suri specimens along with an 85.7% and 71.4% of cases correctly classified in huacaya and llama, respectively. more »

We revisit the U.S. alpaca industry six years after having conducted a study suggesting the industry was in the midst of an unsustainable speculative bubble. We show that in the aftermath the bubble has largely burst. We also offer some lessons intended to prevent the recurrence of such bubbles in agriculture. more »

The theory of genomic selection is based on the prediction of the effects of genetic markers in linkage disequilibrium (LD) with quantitative trait loci (QTL). However, there is increasing evidence that genomic selection also relies on relationships between individuals or the patterns of LD associated with these relationships to accurately predict genetic value. This study aimed to examine the relative importance of information on essentially unrelated individuals on the estimation of breeding value when using gBLUP and BLUP. Analysis was undertaken using a simulated population of 2000 animals. Two reference populations were formed from 1750 animals and the accuracy of prediction was assessed for the remaining 250 animals that formed the test population. Two test populations were constructed such that one included 10 families that had no family members in the reference population and the other included 5 half siblings from 50 families. The gBLUP method more accurately predicted breeding value than BLUP in both test populations. The highest accuracy was achieved when gBLUP was used to predict the breeding value of closely related animals. However, gBLUP was still able to predict breeding value accurately even when animals were distantly related. more »

A preference-based approach, using the internet-based software 1000Minds, was used to derive part-worth utilities of farmers’ assessments with respect to traits in the definition of a breeding objective for sheep in Ireland and pasture plants in Australia. The most critical issue in developing such approaches is the clear definition of traits and the use of realistic ranges of variation in trait performance in order to define alternatives. Conversion of part-worth utilities (percentages) into economic values requires that the economic value is generated within the survey by providing respondents with options that relate to traits which can be defined in economic terms. In presenting alternatives, application of discounted gene-flow principles to breeding objectives in survey-based methods depends on the way questions are asked. It was apparent that respondents’ understanding of traits (attributes, levels), experience with the traits, and how alternatives are presented are very important in using preference-based approaches to define breeding objectives. Issues related to separation of true differences in preferences,confounding and double counting (in animal breeding objectives) are challenges in development of breeding objectives from such preference approaches. more »

Yearling fibre diameter profiles from the OFDA2000 instrument were used to derive records on mean and coefficient of variation (CV) of fibre diameter at multiple points in the post-weaning age window, from 20 to 90% of staple profile length. Genetic correlations were calculated between these traits and their yearling equivalents. Results showed that from 50% of the staple profile and higher, post-weaning fibre diameter is genetically the same trait as yearling fibre diameter. Although the derivation of CV of fibre diameter was less accurate, genetic correlations with the yearling expression were greater than 0.9 for all except one percentile point. The expected correlation between post-weaning and yearling fleece weight was also derived, and under simple assumptions it is not unreasonable to expect estimates of genetic correlations greater than 0.9. more »