Systems development of new techniques

Summary Sheep systems and the effect upon them of incorporating new techniques need to be evaluated in terms of overall economic efficiency and of ease of management. The efficiency of the system and the effect of new techniques are shown to vary according to circumstances; some techniques are useful in some and not in others. Lamb production per ewe bears a curvilinear relationship to litter size at birth and to ovulation rate and the optimum value varies markedly according to husbandry conditions. Relatively little information is available on ewe intake, an important component of system efficiency. Some data is presented which illustrates the important effect of this factor in the evaluation of new sheep genotypes. The fact that sheep are part of mixed systems involving other species and other crop enterprises on the same land makes evaluation of new techniques more complex. The evaluation of new silvopastoral systems is an interesting development in this field.