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Veterinary DNA
Bird Sexing, Surgical versus DNA
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Pairing is Tough if Sexes Look Alike
Aviculturists, from commercial to hobbyist, have been engaging in one of the oldest activities known to man besides raising birds: matchmaking! To successfully raise and eventually sell those cute, hand-fed babies, a compatible male and female have to be paired. Since most of our captive-bred birds are not sexually dimorphic, (without some degree of guessing), we have had to resort to other means to tell the sexes apart. By far the most common method until very recently, was surgical sexing, but with the advent of new and readily accessible technology, genetic sexing has become a safe, accurate and viable alternative.
Surgical Sexing
With the use of safer anesthetic agents, such as the inhalant isofluorane, better sterilization techniques and smaller instruments, surgical sexing is a relatively safe procedure in the hands of a skilled veterinarian. There are some avian doctors who have performed hundreds (or thousands) of these procedures and are probably confident in their technique. But surgical sexing requires the bird to be anesthetized for some period of time and probed through the body wall with an invasive laparoscope to see the internal sex organs (gonads). Surgical sexing does allow one to see any physical problems that may be apparent on the sex organs or any other organs that are viewed The organs are much more difficult to differentiate in an immature bird, although some of the larger birds can be done as early as eight to ten weeks old by an experienced doctor. The results are immediate and problems can sometimes be spotted right away that may not have been apparent. These "pros" are offset by the chances of a mistake due to the age of the bird or the seasonal changes of the gonads, the risk of anesthetic or surgically-related complications, and the chance for secondary infections from the surgery. These chances for complications are greatly increased when the surgery is done outside of a sanitary veterinary hospital.
DNA Sexing
Genetic or DNA sexing utilizes the fact that male and female birds have different genes or chromosomes, much like mammals. The difference is that the female bird (with ZW pair) determines the sex of the offspring since the male (with a ZZ pair) can only on tribute a 'Z' chromosome, just the opposite of us! VITA-TECH Canada Inc. utilizes recombinant DNA technology to look at a map or pattern created by the genetic material after a complicated preparation. We use red blood cells (birds have DNA in the nucleus, while mammal red blood cells do not hove a nucleus), so any bird large enough to provide a blood sample can theoretically be tested. Turn-around time is 7-21 days, depending on the load. These genetic "maps" are also unique to the individual bird and can be used to compare maps of other birds to establish parentage or degree of relatedness (DNA fingerprinting test). DNA fingerprinting can help breeders avoid line-breeding and possibly improve hybrid-vigor.
Accuracy 99+% Using DNA Sexing
Because of the degree of complexity and the delicacy of the cells being sampled, none of the laboratories mentioned above will guarantee their results with 100% accuracy, but they do boast over 99+% accuracy with virtually no risk to the patient. Sampling can also be done at any age, at any time of the year and in some instances, even hidden genetic abnormalities or the degree of relatedness can be seen.
As with any new technology, there are limitations and exceptions, so check with your veterinarian or contact VITA-TECH Canada Inc. directly before collecting samples. In the future, we will probably see the ability to check almost any species of bird and may even be able to identify and select desirable genes such as a specific color or increased egg production. |
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