Last update: March 23, 2012 10:24:40 AM E-mail Print

 

Identification of Sheep at the Carnarvon Experimental Station

JAN Cloete & JJ Olivier

ALL sheep at the experimental farm are involved in a facet of research requiring more conscientious record keeping than normally required in practice. Records include inter alia, weekly masses, parent identification and birth masses. Parent identification at the Carnarvon experimental farm is described briefly in this article.

The sire number, dam number, birth mass and date of birth are required of the 500 to 800 lambs which are annually born on the experimental farm. A newborn lamb must be identified within 24 hours of birth, as it is known that lambs can be switched among ewes. The data gained is used for the framing of genetic parameters. It is thus essential to have the animal identified as soon and accurately as possible.

Parent identification already starts at mating. The duration of the mating season is six weeks and manual service is practised. The unserved ewes are penned in the morning. Small flocks of approximately 30 - 40 ewes are let loose among the teasers for five minutes. All ewes standing still whilst being served by teasers are seen as being in season. Those ewes are taken to a separate pen. They are served once and the ram number is recorded. Should a ewe be on heat again within 14 days, she will be mated to the same ram. All ewes, which were served in a specific week of mating, are assembled in the same camp. After 14 days the served ewes are brought to the teasers for a re-test. The ewes served again within the 4th to 6th week, are not re-tested for heat. Normally, between 80% and 90% of the ewes are served within the first three weeks of the mating period.

In the lambing season, all gravid ewes are placed in a separate camp. In the camp small temporary catching kraals are erected, using gates. The camps are inspected each morning and all ewes which have lambed the previous night, are taken to the smaller camps. The ewe and her lamb are marked uniformly with a temporary mark as soon as possible. Later in the morning, when all ewe lambs are in the kraals, the lambs are marked permanently with an ear tag and the lamb's number is noted next to the dam's number. After the lambs have been marked permanently, they are usually left in a bordering camp. As the ewes are lambing in a relatively big camp, the chances of switching lambs are limited. Young ewes sometimes cause trouble by running away when being driven after lambing. Such a ewe is left overnight with her lamb in the catching kraals and such ewes rarely reject their lambs again. Hand reared lambs are limited to an absolute minimum. After another week the stronger ewe lambs are transferred to a bigger camp.

There are many different methods by which parent identification can be done.

The method used depends on the facilities available and the degree of accuracy required.

 

 

Published

Afrino Manual 3