Darbo tikslas: įvertinti paršavedžių reprodukcinių savybių indekso (R) kitimą didėjant paršavedžių amžiui. Darbo uždaviniai: 1. įvertinti tiriamųjų paršavedžių reprodukcinių savybių rodiklių kitimą nuo pirmo iki paskutinio apsiparšiavimo; 2. paskaičiuoti reprodukcinių savybių indeksus (R) kiekvienai paršavedei, atskirai kiekvienam apsiparšiavimui; 3. įvertinti reprodukcinių savybių indekso (R) kitimą didėjant apsiparšiavimų skaičiui. / Work goal: the analysis of change of an index of reproductive characteristics of a sow depending on age. For achievement of this goal, raise the following objektives: 1) to estimate change of reproductive characteristics of investigated sows from the first to the last farrows; 2) to calculate indexes (R) reproductive characteristics for each sow, separately on everyone farrow; 3) to estimate index change (R) reproductive characteristics at number increase farrow. The work has been executed in 2008 in the enterprise of pigs of the Kaunas area. It was made 14 groups of sows of breed landrace. Test sows were from first to seventh farrows. The analysis of a reproduction and calculations of an index of a reproduction are executed on everyone farrow (from 1 to 7). For an estimation of efficiency and a reproduction index were analyzed the following indicators: 1. Fertility of sows, in units; 2. Quantity of piglets 21 days old, in units; 3. Weight of nest of piglets 21 days old, in kilo; 4. Quantity of piglets at weaning, in units; 5. Weight of nest of piglets at weaning, in kilo. The analysis of the sow's fertility changes, depending on the quantity of farrows, found that the fertility increased from the first farrow. The lowest fertility was at first pigs sow – 9.93 piglets, the highest fertility was found during the fourth farrow – 10.63 units or 0.70 piglets more that the first farrow. From the fourth farrow was found the tendency of reduction of fertility, i.e. fertility of the... [to full text]