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Dec. 16, 2011
Quest for double ewes
DNA identifies sheep prone to multiple births.
ARIEH O’SULLIVAN THE MEDIA LINE
An advanced DNA test developed in Israel is now helping Bedouin shepherds identify which of their sheep carry the gene for twins so they can produce more lambs with smaller herds.
“The Bedouins who traditionally grow sheep anyway whether or not it makes money, now realize the potential here,” said Aviv Kahana, a molecular biologists who heads the department that developed the DNA testing kit at Bactochem Labs in Israel. “This can make a revolution in the Bedouin herds because it makes sense economically.”
For centuries, the Bedouin in the Negev Desert in southern Israel have traditionally raised the indigenous, fat-tailed Awassi sheep because they are so adapted to the harsh desert conditions. But about four years ago, the Israeli Volcani Centre, an agriculture research institute, started introducing the new Afec into their herds to reduce the mortality rate and increase the incidence of twins among the Awassi. The Afec breed is the Israeli name for the Boorola sheep from New Zealand, which is known to carry the multiple birth gene mutation.
“Now this mutation has entered into the Awassi, which is very hardy and will stand up in the desert climate, but instead of having 1.1 offspring per birth, we will have something like 1.7,” Kahana told this reporter.
Scientists have sought for years to find the double ewe – the sheep with the gene that makes it more likely they will produce twin lambs and give shepherds two animals for the birth of one.
Bactochem Labs is located adjacent to the Weizmann Institute of Science in Ness Tsiona, less than an hour’s drive from the Negev. In a meeting of Israeli high technology and traditional herding, Bactochem’s DNA test can be done in the field at a cost of about 60 shekels ($16 US) for each animal. The test, called Real Time PCR, identifies the ewes with the special gene. Bedouin shepherds say it’s worth it since they can sell the sheep for hundreds of shekels more to other breeders, Kahana explained.
The new test allows a shepherd to raise flocks of sheep who will be able to reproduce more efficiently since fewer ewes will be required for getting the same number of lambs. This will mean a saving in feed and water.
About half the flocks tested have been found to have the twin gene. While called the twin gene, those that carry it actually have multiple births, often three or four lambs. But as good as it is for the sheepherder, the DNA test is bad news for some ewes. Those found not to have the twinning gene have their future mapped out for them as mutton on someone’s table. Only the ones with the twin gene get to keep on breeding.
“The price of feed for animals is rising and you want to pay less for feed and sell more meat…. They want to produce the maximum amount of meat from the smallest number of animals that they have to feed. They feed the mothers and they get from a smaller number of mothers the same amount of meat, or they have the same number of mothers that give now birth to 30 percent more offspring, meaning a 30 percent increase in meat,” Kahana said.
He said that about 50 percent of the offspring of the sheep in every generation with the twin gene will be carriers, meaning that the next generations will have to be checked as well. He added that it was difficult to get the use of high-tech developments into the mindset of the Bedouin.
“It is not easy because, for most of the Bedouin, words like ‘genetics’ or ‘mutations’ are new for them and the tradition is still very strong to grow traditionally in the remote areas,” Kahana said.
This could prove to be suitable for the Bedouin as they become more sedentary and less nomadic. Many Bedouin are starting to raise their herds in pens near their homes and Kahana said this was necessary since ewes giving multiple births tended to need help.
“These kinds of animals should be grown next to the manager of the herd. There should be an eye on them, not on the traditional way, where you don’t see your animals very much. So it is a shift they have to make to manage their herds much more carefully,” he continued.
While the testing is being offered to Bedouin and Jewish shepherds, it is also suitable for sheep farmers in Palestinian areas and in Jordan, who also have started to crossbreed their flocks with the Afec breed. “I think the potential is very high,” Kahana said.
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