History of the NWRC herd
Deliberate and organised captive breeding of the Arabian oryx began in Saudi Arabia in April 1986, when 57 animals were transported from the farm of the late King Khalid bin Abdulaziz in Thumamah (now the King Khalid Wildlife Research Center or KKWRC) to the National Wildlife Research Center (NWRC) in Taif [Asmodé & Khoja, 1988, Greth & Schwede, 1993].
Veterinary and sanitary management
Shortly after their arrival, an outbreak of bovine tuberculosis forced managers to undertake a heavy antibiotic treatment of the original herd [Flamand et al., 1994; Greth et al., 1994]. In addition, it was decided to produce a buffer generation to prevent the reintroduction of tuberculosis-infected oryx. Up to now on, calves produced by the founder herd (A-generation) are removed from their dam immediately after birth, and hand-reared in order to reduce the risk of horizontal transmission of pathogenic agents. These oryx (B-generation) are regularly tested for tuberculosis as well as a variety of other pathogenic agents. They join the breeding nucleus when tests are consecutively negative. After breeding, they produce the third generation of oryx (C-generation), which are tuberculosis free and mother-reared. More than 80% of the C-generation oryx produced are reintroduced into the wild.
An additive sanitary measure was to confine A-generation oryx into an area of about 60 enclosures separated from the 75 larger enclosures that host B and C-generation oryx. In each enclosure, there is a smaller pen of about ten square meters to allow the capture and handling of each oryx at any time.
Food and water are provided inside the capture pen. The captive oryx receive dry forage and water ad libitum. About 100 tons of Rhodes grass hay are supplied each year to 250 individuals. Depending on their nutritional requirements (pregnant female, growing calf, ageing animal), some oryx may also be provided with lucerne hay and/or 14% protein-pellets.
Genetic management of the herd is of particular importance and is designed towards maintenance of the initial genetic diversity and the limitation of the inbreeding level.
The degree of relatedness within the original oryx herd of the NWRC is unknown, and the Arabian oryx microsatellite loci discovered up to now are not sufficiently polymorphic to carry out a large-scale parentage inference analysis [Marshall et al., 1999]. Consequently, we considered original animals with unknown parents as "founders" [Greth et al., 1992].
The policy implemented is to balance the putative "founder" representations within each captive generation. Ultimately, we built-up a captive oryx population recognized as the most polymorphic of all captive herds with evidences that no recent management-related bottleneck had occurred [Marshall et al., 1999]. This outcome is explained by the fact that all genetic lineages existing on earth have been included in the captive herd ("World Herd", original Saudi, Qatari and Abu Dhabi lineages) [Marshall, 1998].
A stock suitable for reintroduction
The certified disease-free condition of animals, through annual prophylaxis, serosurveillance and testing (including chromosomic abnormality as 18-19 Robertsonian translocation [Kumamoto et al., 1999]), ensures that this stock has achieved a healthy status superior to that of many other collections of oryx, most of which lack a testing history designed to exclude specific diseases. Nowadays, the NWRC oryx captive-breeding programme is capable of providing suitable animals for large-scale reintroduction throughout the Arabian Peninsula. Since 1994, the NWRC oryx herd has numbered about 250 individuals.
Captive herd management
By the end of 2005, the number of captive Arabian oryx at the NWRC numbered 127 (61 males and 66 females). This represents a decrease of about 34% when compared to 2004. This decrease is attributed to the low breeding rate, an increased mortality rate and the re-introduction of eight oryx into the Mahazat as-Sayd Protected Area and a further 27 oryx to Rawdat Al-Kharim. In addition, NWRC donated 16 oryx to various private collections in Saudi Arabia (Anajariyya & Muhammed 2005). By the end of 2006, this number reached to 113 (59 males and 54 females), a decrease of 11% compared to 2005. This decrease resulted from the controlled breeding of nucleus group. We also donated five animals to Prince Mish’al bin Saud bin Abdulaziz, the Governor of Najran (Anajariyya & Muhammed 2006).
Temporal distribution of the A-, B-, C- and D-generation Arabian oryx in the NWRC captive population from 1986 to 2006.
Herd demography since 1986
This section gives information about 20 years of Arabian oryx production at the NWRC.
Since the first arrival of 57 oryx in 1986, 33 new oryx were added to the founder generation. The last founder immigration occurred in 1996. Since that time, all new ‘arrivals’ resulted from births or rehabilitation of animals from the Mahazat as-Sayd and 'Uruq Bani Ma'arid protected areas.
Herd productivity (births minus deaths) was maximal between 1992 and 1995 (65 births in 1995). Since that time, breeding has been significantly reduced to the benefit of re-introductions, which resulted in the reduction of the captive herd size (Anajariyya & Muhammed 2006).
Oldest living Arabian oryx at NWRC
The oldest living Arabian oryx at the NWRC is a female that reached in its 21st years of age (21 years, 9 months, 15 days) by the end of 2007. Born on 15 March 1986 and came with the first group of animals from KKWRC, Thumamah, on launching of the captive breeding program at the NWRC, where she became a founder of the herd. She left ten offspring (8 male, 2 female) in the herd and some of them are released in the wild ((Anajariyya & Muhammed 2006).
The oldest living Arabian oryx in the world known to us was the male at the NWRC, which was died on 14 December 2003 at the astonishing age of 23 years and 10 months (Anajariyya & Muhammed 2006).