The experiment aimed to determine the effect of the oestrus induction by Serodin and Dinolityc preparations in gilts. The research were conducted on the farm of industrial pigs fattening on 188 crossbreed gilts (Polish Large White x Polish Landrace) with body weight of 100-110 kg and aged 5.5-6 months. The animals were divided onto 3 groups: one control and two experimental. The preparations mentioned above were the factors differentiating experimental groups and were given to gilts in form of injection once in group II (Serodin) and twice in group III (Dinolityc+Serodin). After gilts introduction to the basic herd the estimation of their reproductive use and rearing to the second farrowing was conducted. Obtained results proved that the oestrus induction in gilts in a big farm simplifies the technological groups formation in the stage of mating and pregnancy and causes that more sows with the oestrus induced stay in a basic herd to the third reproductive cycle. However, the highest value of economic fertility was stated for sows without the induction of oestrus.

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