ADVANCED WHITE GENETICS

A Link Between Staple Length and Depth of Color

As part of our work using data from the AOA EPD database to examine whether fleece color affects the expression of fleece traits, we looked at the relationship between color and the EPDs for staple length for over 1300 males in the EPD database.  We found a pattern that suggests that faster fleece growth rates have a visible dilutive effect on the color we see in fawn, beige and white animals, by increasing the length of the hair relative to the amount of pigment produced to color it.    This means that two animals with identical genotypes for color (and similar environments, etc.) could have phenotypically different colors if their fleece growth rates were different:  The one with faster fleece growth would appear lighter than the one with slower growth. The implications for breeding decisions?  We discuss some of them in our library article on this topic.  Enjoy!…

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Does Depth of Color Affect the Expression of Other Fleece Traits?

We ask the question above as a short lead-in to an only slightly longer – but quite interesting – look at the possible connection between the depth of color of an animal’s fleece and the curvature of the fibers in that fleece, discussed in our library article on this topic.    Our curiosity about this was stimulated by analysis of the amount of pigment present in the fiber of different colored alpacas that was published in Kylie Munyard’s 2011 paper, “Inheritance of White Colour in Alpacas”, which, as we have noted before, has quite a bit to say about the likely genotypic characteristics of colored alpacas as well. Those of you who breed for dark browns and blacks, or who process dark-colored alpaca, will be well aware that these fleeces are quite different than otherwise similarly fine and uniform white and light fleeces in particular.  The yarns we make from fine dark fleeces are equally sumptuous but denser, silkier, and often notably bright.  They are suitable for different types of end products than those we produce with elite light fiber.  And, as the analysis in our library article suggests, it seems likely that these dark fleeces are different at least in part because the comparatively large amount of pigment in the hair affects how much curvature – a measure that correlates with crimp frequency, as well as memory in yarn or knitwear – is expressed in the fleece.   If true, this is more than a interesting bit of trivia. …

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No Such Thing as a Dominant White?

If any of the assertions below contradict what you believe about alpaca base coat color genetics, it’s definitely worth reading this blog post and continuing on to a very friendly, fun-loving statistical analysis that is available in our website’s library! 1. First, all white alpacas can produce color when they are bred to it. There is no such thing as a homozygous dominant white animal.  In fact, a pink-skinned white is in some ways as recessive a creature as a true black. 2. What’s more, many fawns are not just “dilute” but carry a white base coat color allele, which acts to dilute a brown allele in the production of the phenotypic coat color. You can actually breed two fawns together and get a homozygous white. 3. White breeders, no need to rely on those pure-white pedigrees to make sure you don’t produce fawns and browns. Turns out a brown allele can’t really hide itself well phenotypically. 4. Color breeders, to introduce white genetics into a color breeding program with lower odds of producing white offspring, breed that white animal to brown. The darker, the better. Now, if you are like me and lack an educational background in genetics, it may also be true that, like me, you find it hard to wade through genetic research on alpacas.  In my case, I can sometimes remember a conclusion from a genetics paper for only a few hours after I read it.  Sad, but true: Ask me a few days later and…

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Alpaca Temperatures and Fertility: We Checked Some Numbers

December 2016.  Those of you who are familiar with our alpaca breeding effort know that we are quantitatively oriented and research-focused.  We also like to share what we learn as broadly as possible.  Some of our research results – especially those from projects led by the human embryologist and fellow alpaca breeder Dr. Kim Gleason, of Dancing Horse Farm – find their way to formal publication.  Sometimes, though, there is incremental yield from our research and data collection that we can distribute more informally, and that is what we will be using this blog for going forward.  It was because of one of the preliminary results from participation in one of Kim’s long-term studies (in this case, on the effect of various husbandry choices on the sex ratios of crias produced,) that we began to collect temperatures on all of our sires and dams at the time we used them for breeding.  Previously, we had seen a close association between high ambient (i.e., environmental) temperatures and the production of a disproportionately large number of male crias relative to females.  We also understood that it was not the ambient temperature per se that was affecting the sex ratio, but rather the tendency of the animals’ temperatures to vary as a function of it.  In addition, we knew that looking at ambient temperature alone overlooked many important contributors to the animals’ response to heat and cold.  Accordingly, we begin to collect breeding-time animal temperatures in the summer of 2016.  In a…

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Micron-Adjusted Standard Deviation. Our “Secrets” Revealed, Part One

Our “Secrets” Revealed, Part One This is the first of a series of three blog posts where we will introduce and describe several proprietary analytical measures we calculate and use here at Little Creek to help assess our animals’ genetic propensity to produce specific, desirable fleece qualities in their offspring. We calculate these measures because we find they help us target specific genetic improvements more accurately with our breeding decisions.    If, as you read about these measures, you think they might be useful to you also, your next question might be “how can I calculate these measures for my own herd?”  The answer is simple – we will tell you how we do it.  And we will even do the analysis for your herd ourselves if you wish. The first measure we will introduce you here is the micron-adjusted standard deviation.  We use this measure to help us breed for animals that are exceptionally uniform without being exceptionally fine.  This is, in our opinion, the most important genetic step we can take as an industry to improve the prices we receive for our fleece.   We have written a detailed article on the calculation and validation of this measure that you can find in our library on this website if you wish.   Micron-Adjusted Standard Deviation (MASD) What is it?  MASD reveals the impact on micron uniformity of elements of animal’s genotype that are not linked to those that are associated with fineness.   A negative MASD is good because it implies…

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