| SeLECTIVELY BREEDING OUT A DROOPY EYE Copyright ©2006 Linda S. Rubin All Rights Reserved |
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Copyright 2006 Linda S. Rubin
| ORIGINAL BOOK REVIEW by Dr. Rainer R. Erhardt "Well, there is help on the horizon and anyone seriously interested in color genetics should take a look at Linda Rubin's book: COCKATIEL GENETICS MADE EASY! Though this book is primarily directed to breeders of cockatiel mutations, there is enough information in this volume to teach anyone the secrets of dealing with recessive, sex-linked, and dominant mutations..." ACBM, Vol. 65, No.12 CLICK TO READ THE REST OF THE REVIEW! 112 pages, 15 chapters, glossary & more! |
| SELECTIVELY BREEDING OUT A DROOPY EYE COPYRIGHT © 2006 LINDA S. RUBIN CF Genetics Consultant/Panel Judge From My Mailbox www.CockatielsPlusParrots.com Q. I have recently purchased a pair of cockatiels. The hen is a beautiful Whiteface Cinnamon Pied, but the problem is that she has droopy eyes. Can the trait for droopy eyes be bred out? If so, what should I look for in the male? Her current mate is a Whiteface Dominant Silver and I don't want to breed them together because of the Cinnamon mutation in the hen. A. I can understand why you wish to keep the Cinnamon and Dominant Silver mutations separate as far as color preferences, however, the droopy eye has little to do with the mutations you are breeding. However, you are astute to recognize the droopy eye problem and act on it, rather than ignore it. This is a credit to any aviculturist who confronts imperfection in his stock and we should all aspire to do the same, because everyone runs into difficulty at one time or another in their avicultural career. According to show standards, if a panel judge sees a cockatiel with a “droopy eye" on the show bench, it is typically disqualified and should be. In some instances, it could be contagious; in others, it is genetic and must be bred out of a line. To encourage that, as judges, we don’t reward genetic faults when we see them. However, the first step is to rule out possible medical issues. Do not go by what other breeders or sellers may tell you; confirm or eliminate any suspicions by taking any affected bird to an avian veterinary Diplomate for a trained opinion. Then, any genetic issues affecting the eyes may be addressed. Faults of this nature can be both a sensitive and ethical issue, because chances are that - unlike dealing with a minor show trait such as cheek patch size or wing bar clarity - you are tackling a fault that can be a real physical malady or disadvantage, both physically and aesthetically. Selective breeding is the technique used with any genetic trait we wish to preserve or eradicate from a bloodline. In the case of a "droopy eyed" bird, you would need to pair the bird to a mate that had no history of eye problems in its pedigree. Always remember: "Never breed a fault in one bird to the same fault in another bird" or quite simply, never breed a fault to a fault! The disadvantage with choosing selective breeding is that you'll be producing some chicks that will bear the same problem as a parent, but hopefully some will not. You can also produce splits, meaning some offspring may not show the fault visibly but may carry the gene in hidden form to pass down to their own young should the trait prove to be recessive. All traits are transferred through a particular mode of inheritance; usually through dominant, recessive, or sex-linked recessive inheritance. There is no way of knowing which form of inheritance will operate and affect a particular trait until you actually breed the birds. Meticulous record keeping is vital to the follow up of such a breeding plan. The question will be - if you do decide to breed the cockatiel with the droopy eyes - will you be prepared to produce some or possibly most of the chicks with the same inherited fault? You must have a plan to follow. Will you choose to handfeed the affected chicks and perhaps sell them (or give them away) as pets to prevent them from breeding? You must also consider that a novice might end up with an affected bird and breed it with another, not fully understanding the situation. You may have no control over a potential breeding once a bird has left your hands. If you can be happy with keeping your beautifully colored, but droopy-eyed cockatiel as a pet only and perhaps allow it the companionship of others but not allow it to breed (you can always replace viable eggs with fake or infertile ones) that is another option to consider. If you do decide to breed your hen, you may work a very difficult and undesirable fault into your lines that will take some generations to successfully eradicate. This is how faults are perpetuated and can end up in other aviculturists' aviaries. It's a tough situation; but you are not the first to face it. Whether it's the droopy eye, or some other genetic problem, it's a tough call. These are the difficult decisions we have to make. LSR. (Follow-up response: “Thanks Linda, I had a vet look at the droopy eye and she ruled out any disease and said it was most likely a genetic fault. I guess that rules out breeding and its too bad because she has good confirmation otherwise, well at least she is healthy. You brought up some points that I really didn't think about. I would hate to breed her and take the chance of carrying on the drooping eyelid. I guess the ethical thing to do is to let her hang out with everyone and have a happy life without reproducing. Thanks again).” |
