[Evaluation of environmental factors on the fertility of heifers].

The investigations had the aim to find out the environmental influences upon the fertility performance of 8100 heifers in a big heifers farm. The different reproductive parameters were evaluated by the help of biostatistical methods. The evaluation of the different influences showed no effect in the relation of fertility and nutrition and fertility and seasonality.

[Planned control of reproduction processes in industrialized cattle production].

Reference is made to the authors' own experience and to evaluated literature in an account of possibilities which so far have been explored for planned control of reproduction processes in industrialised cattle production. Synchronisation of oestrus in heifer has been found to be suitable for reproduction control even under conditions of industrialised production. The method has been in use on several farms.