It has been a long time. I wanted to note work done by Judy Sponaugle, Laurence Gilley and others on history of their respective breeds, but I want to post something timely that I think is important for the future of breeds. I want to talk about breeding plans and the place of AI and ET in expanding numbers. I'll get back to other works on history later...
I am not against ET or AI. I believe the tools have their place. I repect the Milking Devon Association for their conservative stance on ET until the impact of their current rules and the consequences of ET could be studied. I am just a firm believer in a breeding plan and careful consideration of the impact of individuals on the population as a whole...
I want to give you a cut and paste "points concerning embryo transfer" that the AMDCA president Drew Conroy had regarding the ET policies for their organization. I think this is one of the most respectable heritage breed individuals with more integrity and love for the development of the devon (be it milking or otherwise)...
American Milking Devon Cattle Association's BackgroundInformation in conjunction with a member survey on EmbryoTransfer (ET) policies and procedures.
By Drew Conroy, AMDCA PresidentJune 29, 2007
Many breed associations similar in size to our have struggled with this very issue. My comments below are not meant to be persuasive, but rather provide some background information on theuse of Embryo Transfer and both positive attributes and areas of concern. Personally, I would like to see us allow EmbryoTransfer, but do it in a way that ensures the embryos are what they are supposed to be. For a more comprehensive overview of thetechnology, I would recommend reading Training Manual for EmbryoTransfer in Cattle, by George E. Seidel, Jr. and Sarah MooreSeidel, of the Animal Reproduction Laboratory, Colorado StateUniversity, Fort Collins, CO 80523, USA. Published by the Foodand Agriculture Organization of the United Nations, as FAO ANIMALPRODUCTION AND HEALTH PAPER 77, which can be viewed at
http://www.fao.org/docrep/004/t0117e/t0117e00.htm Thoughts from:Don Bixby, of the American Livestock Breeds Conservancy would notrecommend that we disallow this practice. In fact, he stated, "Ifwe are allowing Artificial Insemination, there is a much greaterchance of concentrating the gene pool, through the fact that wehave not drawn many bulls, and the semen is readily accessible tomany members due to its low cost. Phil Sponenberg explained, "Embryo transfer is 'value neutral 'really, but can have a VERY bad downside in rare breeds ofnarrowing genetic variation on the female side of the equation.So, it is best if recipients are not purebred cows. And, likelyit is best to limit the numbers produced by an individual cow inany one year. Id do the same on the bull side, too, though. " Don Bixby has nothing against strong policies restricting itsuse, but he warned that this is not easy to do or get consensuson a policy within a breed association. The North American Devon Cattle Association has alreadyinterpreted our one year moratorium as a ban on ET, and perceivedour survey of the membership to be in some way construed to be"small in our thinking". Interesting reading and the author'smisinformation and opinions are quite malicious for anassociation trying to lure AMDCA members to join theirassociation. see:
http://www.northamericandevon.com/info.html#AMDA. It is one ofthe highlighted items, on June 14", the fourth item down from thetop. Advantages of Embryo Transfer Technology for a breed such as theAmerican Milking Devon: There is little doubt that with small numbers of animals, as wehave in this breed, if you are trying to expand animal numbers,this can allow more rapid expansion. Our goal is to expand animalnumbers. Hopefully we can work so our breed is moved fromcritical to at least threatened, and maybe Watch or Recoveringstatus. We have not had a lot of growth. in animal numbers, andengaging technology will provide one tool to grow animal numbers.Also on the positive side the sale of embryos could allowbreeders in remote areas to have easier and cheaper access toAmerican Milking Devon Cattle, particularly the female side ofthe gene pool. The end result could be that people in areas wherethere are few of our cattle, could more easily access thegenetics and start their own herd. Embryo's can be shipped and moved much easier than live cattle.Embryos can be shipped as easily as straws of semen. More purebred cows and bulls on the ground would allow for moreselection based on traits individual breeders desire, and mightallow culling of genetically inferior animals, which I do notbelieve is happening at all, with the current high prices. Concerns in using Embryo Transfer include:If a few cows are used, and those cows generate a large number ofembryos you can create a genetic bottleneck. However, the samething is true for the use of semen, and even more so, as it is alot less costly than embryo transfer, which means more peoplewill likely adopt (or have already adopted) ArtificialInsemination versus Embryo Transfer. In the last few years we have had a few people buying up a numberof animals, which resulted in higher average prices for MilkingDevon Cattle than we have seen in the past. This rise in priceshas been welcomed by many, including myself. However, this is aclear example, of how a few people can affect a breed with smallnumbers of animals, in a short period of time. There maybe some need for disclosure that the cows were flushed.For genetic reasons, we would want buyers to know that a cowpurchased after flushing may have a greater than normal number ofoffspring in the population. There are also some concerns about the reproductive status of theanimals after being used as flush cows. I could find no datasaying that cows that are flushed are routinely less fertile, butin the process of flushing, there is the chance of damage to thereproductive tract, and the flush cows becoming overweight (asdry donor cows), which often leads to difficulty breeding. Thishappens in cattle left open for long periods that have not beenflushed. Recommendations, if members decide to support Embryo Transfer. There is a real need for documentation, that the embryos instraws are what they are supposed to be. The American EmbryoTransfer Association has clear rules for documenting thecollection of embryos, as well as protocols for theidentification and sale of embryos: view their website on theInternet at
http://www.aeta.org/ for more information. They deferto breed associations about individual rules on genetic testingand so forth. Genetic testing of the sire and dam are required by manyassociations and the Dexter Cattle Association and other DairyBreed Associations require the DNA testing of offspring resultingfrom ET. If the embryos are not going to be immediately implanted intorecipient cows that the owner of the flushed cow controls, theinformation necessary for documentation on the embryo for laterregistration should also include: On the container of frozen embryos: identification of the organization that processed the embryos breed of embryo identification of the dam (sire optional) date on which the embryos were frozen identification number for the container number and stages of embryos in the containerOn the goblets and canes: cane and goblet numbers identification of the organization that processed the embryos date of cryopreservation identification of dam and sire breed number of embryos kind of packaging/indication of repackaging*The above recommendations come from Seidel and Seidel, Food andAgriculture Organization of the United Nations, FAO ANIMALPRODUCTION AND HEALTH PAPER 77, Chapter 16, Records. as cited inthe references. Given the above information, it would seem that at a minimum theassociation should likely require an embryo recovery certificate,which may also include: a) an embryo evaluation b) the date of cryopreservation or freezing of embryos, particularly if the resulting embryos are for sale. c) There may also be a need for embryo transfer documentation, if recipient cows are sold carrying embryos. There is also a need for similar testing for embryos as requiredby bulls for diseases prior to drawing semen, there is a similarneed for health testing of cows used as donors, according toNational Association of Animal Breeder standards. This willensure that the embryos meet the requirements ents forinternational sale and shipping, plus provide an assurance ofhealth of the embryos to the buyers. SummaryIn the case of small populations every animal counts and therecan be a benefit realized from Embryo Transfer, but it is not thecure fora small population, as genetic diversity is important aswell as animal numbers. There is the possibility of imposingrestrictions on the number of calves from each cow that could beregistered, as a way to minimize the possible effect that one cowhas on the population, but again, this limitation would besimilar to limiting the number of offspring allowed from a bullwho has been drawn and used for artificial insemination, whichthe association has not ever addressed. One of the problems with selection of traits such as for milkproduction within a breed, is that the real value of the breedmay lie in other characteristics that might be lost if there isincreased specialty selection. At this time we have no verifiableproduction information on milk production or progeny tests onbulls, so selection will not likely be as intensive as it mightbe in other breeds. In any case, embryo transfer would allowpossible inferior animals (for certain traits) to be propagatedat a rapid pace, possibly displacing other more geneticallysuperior animals for the same traits. Finally, the other challenge is that breeders with the bestintentions may not get a cow that flushes well, despite the costand efforts to do so. References:Phone Interview with Don Bixby, DVM, Technical Program Manager,American Livestock Breeds Conservancy (ALBC), Pittsboro, NorthCarolina, Monday June 11, 2007 Phone Interview with Marjorie Bender, Research and TechnicalDirector, American Livestock Breeds Conservancy (ALBC),Pittsboro, North Carolina, Monday, June 11, 2007 Phone Interview with Jeannette Beranger, ALBC Research andTechnical Program Manager American Livestock Breeds Conservancy(ALBC), Pittsboro, North Carolina, Monday, June 11, 2007Email Message from D. Phillip Sponenberg, DVM, PhD, Professor ofPathology and Genetics Department of Biomedical Sciences,Virginia-Maryland Regional College of Veterinary Medicine,Virginia Tech, Blacksburg, VA., June 20, 2007. George E. Seidel, Jr. and Sarah Moore Seidel, of the AnimalReproduction Laboratory, Colorado State University, Fort Collins,CO 80523, USA. Training Manual for Embryo Transfer in Cattle. FAOANIMAL PRODUCTION AND HEALTH PAPER 77, Viewed on the InternetJune 13 2007 at:
http://www.fao.org/docrep/004/t0117e/t0117e00.htm
