Conser­va­tion Assess­ment and Manage­ment Plan (CAMP)

Back­ground

The Arabian horse orig­i­nated with migrating Bedouin tribes in the greater Arabia Deserta, an area roughly encom­passing today’s coun­tries of Iraq, Jordan, Syria, Saudi Arabia, Bahrain, the Arab Emirates, Oman, and Yemen. Western accounts from the 1700s onward attest to the Bedouin prac­tice of breeding within a closed gene pool of horses whose prove­nance was known to the tribes. Horses so bred were called “asil.” While the first Arabians taken to the West were used prin­ci­pally to develop other breeds, a few studs main­tained lines trace­able entirely to Bedouin sources. Such studs in most of Western Europe and Russia were deci­mated by war in the 19^th and early 20^th centuries.
Two major programs that devel­oped outside the coun­tries of origin during the 1800s survived into the 1900s: that in Egypt and the Blunt program at Crabbet stud in the UK. The Egyptian program evolved with the changes in polit­ical struc­ture as described below and continues today. Studs in Egypt and the U.K. provided horses for other breeders around the world, supple­mented by a few direct desert exports such as those obtained by the Daven­port expe­di­tion of 1906 and gifts of horses from Saudi Arabia to West­erners involved in oil devel­op­ment efforts in the early and mid-​​1900s.

Heritage programs and the asil horse

Begin­ning in the 1950s and ’60s, a few breeders in the U.S. became concerned with the poten­tial loss of this presump­tive asil gene pool, as evidence devel­oped that most of the horses being bred in the West and regis­tered as “Arabians” included non-​​Arabian ances­tors. Mrs. John E. Ott and her daughter Jane created The Blue Arabian Horse Catalog to docu­ment the horses then in the U.S. that descended entirely from Bedouin stock. Their efforts were expanded by the forma­tion of Al Khamsa, Inc. in 1974. In parallel with these efforts, the Asil Club (based in Germany) began to docu­ment extant horses of entirely Bedouin origin, prin­ci­pally those remaining in Europe. In Egypt, the breeding programs that had orig­i­nated with the Pashas in the 1800s continued through the founding of the Royal Agri­cul­tural Society’s pure­bred Arabian program in 1914, its renaming as the Egyptian Agri­cul­tural Orga­ni­za­tion, and later incor­po­ra­tion of the Inshass horses of Kings Faoud and Farouk. The closed gene pool of “Egyptian” Arabian horses popu­lated programs around the world; it continues in Egypt where it consti­tutes the longest-​​documented closed herd of presumed asil horses outside of the coun­tries of origin.  In 1969 The Pyramid Society (based in the U.S.) took on the role of perpet­u­ating horses from this herd.
For the past 35–40 years, breeders who adhered to the concept of breeding with this presump­tive asil gene pool pursued a type of conser­va­tion breeding by limiting matings to those between horses who fit the asil defi­n­i­tion. Over time, breeders collab­o­rated infor­mally and devel­oped sub-​​populations based on defined founder groups. What began in the U.S. as “Blue List” breeding (matings among horses cata­logued by the Otts) has trans­formed into distinct heritage groups. The largest of these, iden­ti­fied by their heritage names (in ascending order of extant popu­la­tion size, with average annual foal produc­tion shown) are:

• Blue Star (a subset of the horses iden­ti­fied by the Otts); 10 foals
• Daven­port (trace­able to the 1906 impor­ta­tion, with the poten­tial addi­tion of two horses from the same geographic area that were imported to the U.S. for the 1893 World’s Fair); 35 foals
• Heir­loom (horses from the Egyptian programs prior to the forma­tion of the RAS Arabian horse breeding section in 1914); 40 foals
• Sheykh Obeyd (horses from the Egyptian programs including the RAS and EAO programs but gener­ally prior to the incor­po­ra­tion of horses from the Inshass stud); 40 foals (in addi­tion to most of the Heir­loom foals)
• Straight Egyptian (defined by The Pyramid Society and gener­ally including most, but not every foun­da­tion animal from the Heir­loom and Sheykh Obeyd groups, with addi­tional founders from the Inshass stud); 500 foals (in addi­tion to most of the Heir­loom and Sheykh Obeyd foals)

Each of these heritage groups has sub-​​populations that include/​exclude specific founder horses, with the under­standing by some breeders that main­taining sub-​​populations within the group is bene­fi­cial to long-​​term conser­va­tion (the late Dr. Ann Bowling and Michael Bowling have had a profound impact in this regard). There are a small number of other founder horses that have been inter­bred with horses from the groups described above, but their annual foal produc­tion numbers are small and declining (fewer than 50 per year).

Current status

During the first 75 years of the 20^th century, most asil horses were bred from a wide range of avail­able asil stock, with matings constrained by logis­tics of distance and lack of infor­ma­tion on avail­able horses. The heritage groups had not devel­oped. During the past 30 years, this trend has completely reversed. Most horses are bred within defined heritage groups, while the popu­la­tion of asil horses that incor­po­rate a broader group of founders has become quite small. Of the recent (since 2000) average annual foal crop of 700, fewer than 50 repre­sent crosses among these heritage groups. Unlike most popu­la­tions where broad cross-​​breeding is prac­ticed, with the trend toward theo­ret­ical uniform heterozy­gosity, the reverse is currently true for the asil popu­la­tion.
Contem­po­rary breeders who hew to a concept of conser­va­tion breeding within the historic asil defi­n­i­tion have no frame­work based on the science of popu­la­tion genetics within which to make breeding deci­sions. Most seek to produce a desir­able animal (by their own defi­n­i­tion of quality and adher­ence to Bedouin type) by breeding a stal­lion of heritage group A to a mare of heritage group A. There has been no systemic docu­men­ta­tion of the extant herd in total and no deter­mi­na­tion of genetic diver­sity within or across groups that could lead to a conser­va­tion plan based on the devel­oping prin­ci­ples of popu­la­tion genetics as applied to closed-​​herd breeding. The heritage groups have never been eval­u­ated, using contem­po­rary genetic tools, to deter­mine their viability or effi­cacy for future cross-​​breeding. It is unknown whether some groups are already so inbred that further exten­sion of the group will actu­ally contribute to lost diver­sity (the reverse of the intent for main­taining such groups), or whether the sub-​​population struc­ture of a given heritage group will allow that group to continue for some time.
Some heritage groups are absolutely unique in their founders; other share some founder animals. No work has been done to eval­uate the shared-​​founder groups to deter­mine if, de facto, addi­tional sub-​​groups have arisen but are not recog­nized because they do not corre­spond to the histor­ical events that framed the defined heritage groups. Deter­mining the genetic diver­sity of sub-​​groups, both those of unique founders and shared founders, would likely be crit­ical to a conser­va­tion plan.
The Arabian horse popu­la­tion expe­ri­enced a huge increase in breeding during the 1970s-’80s and a precip­i­tous decline during the past 15 years. Such a decline is expected to continue, or even accel­erate, given current economic condi­tions. This argues for imme­diate action on the project described below, as the asil popu­la­tion is likely expe­ri­encing a genetic bottle­neck that may substan­tially reduce the number of retained founder genes.
The Insti­tute for the Desert Arabian Horse was formed, in part, to support research with the goal of conserving the asil horse inter­na­tion­ally based on collab­o­ra­tive efforts. The Institute’s Board of Direc­tors are breeders from various heritage tradi­tions concerned about the popu­la­tion trends and the lack of a scien­tific basis for the nominal conser­va­tion programs that have evolved. There are other breeders who are suffi­ciently far-​​sighted that they support scien­tific assess­ment of the diver­sity of the herd and devel­op­ment of a conser­va­tion plan. It will be the Institute’s role to engage these breeders in imple­menting a conser­va­tion plan.

Project concept

The Insti­tute for the Desert Arabian Horse wishes to under­take a research project leading to devel­op­ment of a conser­va­tion plan for the asil horse outside of its coun­tries of origin. While species survival plans have become the norm for endan­gered wildlife, conser­va­tion plans for rare breeds of domestic live­stock are only recently being devel­oped. Because the Arabian horse is a domestic animal with some historic landrace char­ac­ter­is­tics, the Board of Direc­tors of the Insti­tute is seeking acad­emic research part­ners with rele­vant exper­tise and interest in conducting such a project and devel­oping such a plan. The initial efforts would be limited to eval­u­ating the extant herd and offering breeding schemes for stock within North America (this herd is well-​​documented). Subse­quent efforts could incor­po­rate inter­na­tional stock, much of which derives from Egyptian and/​or North Amer­ican inter­me­diate ances­tors (the Insti­tute is engaged in a sepa­rate census project to  iden­tify and docu­ment the asil horses outside of North America).
The goal is similar to that found in wildlife species survival plans: to retain 90–95% of the gene diver­sity for the next 100 years.
There would be two major phases: first, to char­ac­terize and analyze the struc­ture and diver­sity of the extant popu­la­tion; and, second to develop conser­va­tion breeding plans/​models. The first phase is intended to answer these funda­mental questions:

• What are the relatedness/​diversity char­ac­ter­is­tics of the extant herd?
• What are the trends and likely outcome if there is no inter­ven­tion or new knowl­edge applied to breeding schemes?
• Are the heritage groups and sub-​​populations useful for future breeding schemes? If not, what sub-​​population struc­ture would be useful?
• Would the popu­la­tion benefit from specific breeding schemes to achieve the goal of retaining 90–95%% of gene diver­sity for the next 100 years?

Based on a layman’s under­standing, the Insti­tute Board of Direc­tors can imagine the following possible elements. These are intended only as the basis upon which to have further discus­sion with researchers.

Phase I – Char­ac­terize and analyze the struc­ture and diver­sity of the extant popu­la­tion
1.  Iden­ti­fi­ca­tion of unique dam lines
During the 1990s, the late Dr. Ann Bowling, Univer­sity of Cali­fornia Davis, conducted pioneering research to iden­tify discrete dam lines using the D-​​loop hyper­vari­able region of mito­chon­drial DNA. Through her work, 16 histor­ical lines, iden­ti­fied to 13 different haplo­type sequences, have already been char­ac­ter­ized. Dr. Cecilia Torres-​​Penedo has continued this work. The Insti­tute has provided samples to Dr. Torres-​​Penedo that iden­ti­fied an addi­tional histor­ical line as sharing one of the 13 sequences found by Dr. Bowling. We are working with Dr. Torres-​​Penedo to char­ac­terize the remaining 25 dam lines in the U.S., and further work on samples from unique lines found in other coun­tries is antic­i­pated.
2.  General char­ac­ter­i­za­tion of diver­sity in the extant popu­la­tion, based on pedi­gree
The intent is to char­ac­terize the asil group broadly — to iden­tify the current gene diver­sity, effec­tive popu­la­tion size, founder contri­bu­tion, and founder repre­sen­ta­tion. One of the issues in such analysis is deter­mining whether it is neces­sary to work from foun­da­tion horses or whether later-​​generation animals can be used to simplify the analysis, without losing the gran­u­larity needed to eval­uate diver­sity.
3.  Deter­mi­na­tion of sub-​​populations, diver­sity within and between sub-​​populations, and their useful­ness for future breeding
This includes consid­er­a­tion of unique sub-​​populations and eval­u­a­tion of sub-​​populations that share some founders. For the latter, it may lead to iden­ti­fi­ca­tion of sub-​​populations not previ­ously iden­ti­fied as heritage groups. It will be impor­tant to eval­uate gene diver­sity within iden­ti­fied heritage groups and their sub-​​populations to deter­mine whether or how such diver­sity can be retained so the sub-​​population can continue to be a reser­voir of genetic mate­rial for the future. This element might also involve deter­mining the loss or gain of diver­sity resulting from removal of one or several sub-​​populations.
4.  Projec­tion of future popu­la­tion diver­sity based on recent prac­tice
Deter­mine the trend in diver­sity, perhaps by calcu­lating Founder Genome Equiv­a­lents and Effec­tive Popu­la­tion Size at some interval over the past 50–60 years. (The largest heritage group last added founder animals in 1945; other, unre­lated heritage groups added horses as late as 1961). The purpose is to iden­tify whether and to what extent diver­sity is being lost by past and on-​​going breeding prac­tices. This may include extinc­tion prob­a­bil­i­ties as well.
5. Compar­ison of quan­ti­ta­tively deter­mined expected diver­sity, using pedi­gree information, with diver­sity deter­mined by using mole­c­ular markers
Microsatel­lite and PCR research is allowing for compar­ison of expected allelic diver­sity with that deter­mined in the lab. It would be useful to test some of the calcu­lated relat­ed­ness values deter­mined in the above-​​described elements against data from microsatel­lite and/​or PCR, as that could influ­ence the construc­tion of future breeding plans that are premised on calcu­lated values of heterozy­gosity.
The best applic­able math­e­mat­ical model(s) will need to be iden­ti­fied. The sub-​​population struc­ture may influ­ence the weighting of within– versus between-​​group diver­sity. Relat­ed­ness deter­mi­na­tions will need to take into account that some of the sub-​​populations are highly inbred and there­fore stan­dard inbreeding calcu­la­tions may not reveal suffi­cient differ­en­ti­a­tion because the common­ality of most-​​frequent ancestor is more than 5 gener­a­tions back in the pedi­gree. For example, 6 sons and 11 daugh­ters from a domi­nant 1934 sire were imported to the U.S. The true domi­nance of that sire is not discerned only by looking at imported animals as founders, or by calcu­la­tion of inbreeding in less than 6–8 generations.

Phase II – Devel­op­ment of conser­va­tion breeding plans/​models
This phase will likely not be under­taken until elements 1–4 in Phase I are substan­tially complete. Researchers involved in Phase I may be expected to offer recom­men­da­tions as to the construct of Phase II.
Insti­tute resources
The Insti­tute for the Desert Arabian Horse can provide data­base pedi­gree infor­ma­tion and some infor­ma­tion tech­nology assis­tance to convert data from the Insti­tute data­base to a form usable by researchers. It also will form an Advi­sory Group for the project, composed of breeders who have substan­tial knowl­edge of the struc­ture of the heritage groups. The purpose of the Advi­sory Group is to assist researchers in under­standing the foun­da­tion, historic changes/​development, struc­ture, and anom­alies of each of the heritage groups and their sub-​​group struc­ture. The members also can serve as infor­ma­tion bridges to the breeder popu­la­tion that will be encour­aged to under­stand the results of Phase I and engage in conser­va­tion prac­tices consis­tent with the recom­men­da­tions from Phase II.