BIRGIT ZUMBACH, KURT-JOHANNES PETERS
Humboldt-Universität zu Berlin, Department for Animal Breeding in the Tropics and Subtropics, Germany
To satisfy the increasing demand for milk and milk products in tropical countries sustainable measures have to be taken to improve the local milk production. Sustainable improvement could be attained by the association of farmers to set up a communal genetic improvement programme which also implies awareness raising and management improvement. Such a breeding programme should be simple, practical and at low costs. Therefore, a virtual nucleus rather than a station nucleus should be considered. The objective of this study is to identify and quantify the impact of different factors like management, recording quality and breeding scheme on the efficiency of a breeding programme. The efficiency of a breeding programme depends on the one hand on the genetic gain attained per year which is a function of selection intensity, accuracy, genetic variation, and generation interval taking into account inbreeding. On the other hand there are the costs. The following calculations are based on a population of 1000 cows with natural mating (mating relation 1:40; useful life of bulls: 3 years; pre-selection factor: 2). Management is represented in survival rate of calves and calving interval. Given good management with a survival rate of 80% and a calving interval of 18 months, 83 bull dams are required for the provision of breeding bulls while under bad management conditions (survival rate 50%, calving interval of 30 months) 222 are needed. Theoretically, accuracy of selection is calculated based on the amount of information considering genetic relationships and the population parameters. This accuracy assumes an optimal breeding structure, pedigree recording and accurate recording of environmental effects. Breeding efforts may be nullified if environmental effects cannot be corrected for. The breeding scheme suggested for tropical cattle breeding is a young sire programme where the generation interval (about 4 years) is substantially lower than in a progeny testing programme (>10 years). Additionally, it is much simpler and cheaper to organise. Thus, it is evident that breeding efforts under unfavourable conditions only promise good success if the farmers understand the breeding procedures and co-operate with regard to management and recording.
Keywords: Breeding, communal, dairy, smallholder, tropics