Review/Oorsig Volume 22, Issue 01 - Page 16

Oorsig/Review Selection for Optimal Production Dr Ariena Shepherd Optimal production has various definitions de- pending on individual viewpoints. In small stock breeding many confuse it with breeding indica- tors for example high weaning percentages or high growth rates. These parameters are impor- tant but they are just tools in developing a selec- tion system for optimal production. Optimal production is achieving increasing yields using cost-effective measures over long periods. To achieve this precise breeding objectives must be defined and the economic impact and costs evaluated as well as possible impact on other traits considered. The breeding objectives must then be implemented and progress tracked. Precision livestock farming technologies have made it possible to evaluate individuals rather than averages which has made higher selection pressure possible. Basics Before any selection program can be implemented basic structures must be in place. All animals must be individually identified. Progeny must be linked to dams and preferably to sires as well. Recording data must be done at least once a year. Records must be kept so that comparisons can be done over years. 16 Selection Selection has to be aimed at the big picture. A flock evaluation can identify the major causes of losses and which breeding objectives can have the biggest economic impact. Disease and health are often the best place to start as factors are usually easy to identify and progress is quick. In emerging flocks or small holding flocks this can sometimes be a problem as culling large numbers of animals may not be possible. Also, it may be difficult to convince a farmer that culling 30% of his flock will improve his profitability. If this is the case culling can be done over more than one year but this will delay progress. Guidelines for Production Parameters This is dependent on area, nutrition and type of farming system. An extensive farmer which lambs several thousand ewes compared to an intensive farmer lambing 500 ewes will have different production parameters. The objective is to set guidelines for each farm individually once the flock evaluation is done. The best time is 6 weeks before breeding. First cull all chronically sick animals – mastitis, claws, abscesses. If possible cull all ewes which have not produced a live lamb during the last 12 months. This may be done at weaning the following season if there are no current records. Start identifying parasite taxis. Many farmers are resistant to less antiparasitic use as they think it will decrease their production but reducing antiparasitic use in the dry season