[Selection of laboratory rats for fertility components in synchronized estrus using Suisynchron-Praemix. 2. Results...

The following results were obtained from experimental studies into selection of laboratory rats for fertility and random mating with oestrus being synchronised by means of Suisynchron-Prämix, through eight generations: --Success of selection without synchronised oestrus was higher than that with synchronised oestrus by selection according to the basic index and with one and the same selection intensity. --Litter size and weight were higher in the selected variants, as a result of increased potential fertility (rate of ovulation). --In the population with selection and synchronised oestrus a negative relationship was found to exist between the directly correlated selection results regarding fertility parameters, on the one hand, and the effect of synchronisation, on the other. --Both the rates of ovulation and litter parameters were lower in the population with selection and synchronised oestrus, as a result of synchronisation. --The effect of synchronised oestrus on the population with selection and synchronised oestrus was partially eliminated owing to selection for fertility.