Alpaca World Magazine Summer 2005 - Classical MileEnd Alpacas

Blue-EyedWhitesAustralian biologist and alpaca breederElizabeth Paul considers the infl uence ofcolour genetics in the occurrence of thiscommon problem.Within the Australian nationalherd, there are a signifi cantnumber of blue-eyed white(bew) alpacas. There has been aconsiderable amount of discussionbetween breeders as to whether or notblue-eyed whites should be used forbreeding, or whether their deafnessprecludes them from living a normalalpaca life. On the other hand, therehas been more than one AustralianSupreme Champion blue-eyed whitemale, which has gone on to a stud career.It is my belief that the gene responsiblefor producing grey coloured fl eece onalpacas is merle, or something extremelysimilar, possibly in combination with awhite-marking gene, like tuxedo. Thesegenes can have an additive effect whencombined in a genotype, and mayproduce what is called a blue-eyedwhite animal. The material that I havecollected indicates that there is a strongconnection between grey alpacas andblue-eyed white ones.Summary of theMerle ConditionThe merle pattern in dogs is particularlyassociated with dogs such as BorderCollies, Australian Shepherd Dogs,Shetland Sheepdogs, and CardiganCorgis; but it is also well established insome hound breeds such as Dachshundsand Great Danes. The word merle is acorruption of marl, which in turn is acontraction of marble. The merle genehas a distinctive effect on black or liverpigment in dogs, and the coat of a‘blue’ merle dog appears as a silveryor blue-grey background, marbled withsplashes or blotches of black. In fact, thedog is genetically black. The eyes may bepartially or fully blue, or the dog may haveone of each colour. The effect of merleon a red or tan colour base produces asable merle, which is far less striking inappearance than a blue merle, althoughthey may still have blue eyes (matingsbetween blue merles and sables arefrowned on in most dog breeds). Themerle causes clumping of pigment withinthe fi bre, like the recessive diluting geneabove, and the fi bre appears silvery grey.There may be more white in the coat of amerle dog than would be normal for thebreed, and the amount of merling canvary considerably between individuals.Merle M cannot completely mask thenon-merle condition, mm, and so an Mmanimal appears as an intermediate form,showing characteristics of both alleles, inits coat. For this reason merle is called anincomplete dominant gene.Merle also has an additive effect whencombined with the genes controlling whitemarks. This effect is more pronounced inthose breeds which already have whitemarkings.Lethality of MerleMatings between two merle dogs areusually prohibited in most breeds, ashomozygous merle, MM, is known to bean in utero lethal, like RR roan in horses,However, in dogs, not all MM progenydie before birth. Some are born alive,although they may be born with moderateto severe defects of eyes, hearing andreproductive organs. MM merles are alsomore likely to be white or nearly white,and to have two blue eyes.An MM merle, mated to a solidnon-merle mm, would produce all Mm(heterozygous) merle progeny. ShetlandSheepdog breeders, among others,apparently used to keep the occasionalall-white (presumably homozygous) merlepup for breeding back to non-merle dogs,so they could then produce all merlelitters, with very even grey colour.In my opinion, blue-eyed white alpacasare equivalent to blue-eyed white merledogs. That is, they are coloured alpacas,overwhelmed by either homozygous merleor the combined action of merle pluswhite-marking genes.BEW ChecklistFrom my own observations, blue-eyedwhite alpacas are likely to exhibit most ofthe following characteristics:❍ Two blue eyes, or one blue and oneblack eye, or parti-coloured blue/blackeyes; very occasionally two black eyes.This may be due to the fact that someblue eyes darken over time.❍ Almost certain to be permanently deaffrom birth on full blue-eyed side.❍ Patches of pigmented skin particularlyon points, ie nose, toes with blackpads (toenails may be stripey), spotsof black skin down spine, near tail.(Some blue-eyed whites have pink skinand feet). Pigment spots may growover time.❍ May have very white fl eece but withsome coloured fi bres growing out ofpigmented spots particularly alongspine, near root of tail and aroundankles. Coloured fi bre or spots may notbe evident in young cria but becomemore noticeable with age.❍ Often large framed, heavy boned.❍ Both sexes may have fertility problems,or be sterile.❍ Mated to solid coloured mates, theyproduce a range of coloured criaincluding greys and/or multi/pinto.❍ Usually have lots of white and/or greyin the pedigree, occasionally alsomulti/pinto.❍ May have very good fl eececharacteristics.❍ Usually called Snowfl ake or Crystal!Problems DeafnessDr David Andersen, of Ohio StateUniversity has clearly shown in his studythat most blue-eyed white alpacasare stone deaf. However, this is morelikely to be a perceived problem for itsowner than an actual problem for thealpaca itself. Alpacas are extremely alertanimals with superb eyesight, and arevery quick to pick up visual cues fromtheir herd mates. They probably rely farmore on their eyesight to alert them todanger, than on their hearing. It shouldbe noted that homozygous merle dogsare generally more severely affected intheir sight, with reduction of eye sizeand actual blindness being common.Blue-eyed white alpacas appear to havenormal size eyes and see normally, atleast in daytime.FertilityThe bigger issue is that some bewalpacas may have reduced fertility oreven be completely sterile. This maybe due to various abnormalities of thereproductive system, as noted by DrGeorge Jackson of Western Australia,in a post to the AAA message board inJune 2002. However, most appear to befertile and can breed normally, despitetheir deafness. They are not mute, andmake the same sounds as hearingalpacas. I have four bew femalesmyself~ three of which are certainly deafThey are all fertile, and are all excellentmothers.Mating ResultsTable I shows the results of matingswhich had both parents’ and progeny’scolours listed in the Australian AlpacaAssociation Herd Books, Vol5 2-11inclusive. Mating white x white gave a2% chance, and mating colour x colourTABLE 1 Results of Matings using AAA Herd Books 2–11 inclusiveMating Grey Progeny White Progeny TotalWH x WH 173 6069 8626% of Total 2 70WH x BLK 88 143 1227% of Total 7 12GREY x GREY 700 22 1108% of Total 63 2COL x COL 285 817 18,188% of Total 1.6 4.520 | Alpaca World Magazine Summer 2005