engleski

Effect of litter standardization and equalization in hyperprolific sow line on piglet survival at one week of farrowing: preliminary results

Selection procedure to increase sow prolificacy has resulted in litters with a large number of physically immature piglets at birth. Farrowing with large litters in hyperprolific pig lines is related to high variability in Piglet Birth Weight (PBW) in the litter. In large litters (>14 born alive piglets), there is a great number of piglets lighter than 800 g at birth, so called Poor Viable Piglets (PVP). Variability in piglet size within a litter results in different piglet ability to establish ownership of a functional teat and a high percentage of deaths in the first week of life. The aim of the breeding procedure called Standardization of Litter (SL) is transfer of healthy PVP under the second or third parity sows with good maternal abilities, i.e. lactation, to enable their proper growth during the nursing period as compared to large and inhomogeneous litters. Equalization (EQ) of litters aims to equalize normal body mass piglets according to sow capacity. The aim of the study was to analyse the effect of SL and EQ on the Number of Piglets on day 7 post partum (NP7) and to estimate the significance of these effects in the model of calculation according to farrowing data. The study was conducted in commercial conditions and included 386 farrowings in hyperprolific sow lines Landrace x Large White cross (Topigs 20). On day 3 post partum, i.e. upon completion of the colostrums period, 12% of the overall number of litters were equalized (EQ) and 6% underwent SL. Milk replacement was additionally used in SL and EQ litters. Data analysis was performed using GLM model with effects included in the model of calculation: interaction (*) of Parity Order (PO) with the average Number of Weaned Piglets per litter (PO*NWP) in second or third parity ; NBA piglets per parity (NBAp) ; interaction of Gender (G) (Male or Female in the litter group defined as M*F) in SL and EQ litters ; Average Number of Piglets Alive per farrowing Group (ANPAG) ; and effects of Management Procedure (MP) defined as SL or EQ in the litter. Results were expressed as LSM±SE. The Number of Piglets alive on day 3 (NP3) post partum in SL litters was 12.37±0.21 versus 12.82±0.14 in EQ litter. NP7 was significantly (P<0.05) higher in EQ (11.79±0.29) as compared with SL (10.71±0.42) litters. The PVP survival rate on day 7 of farrowing was 86.5% and 91% in SL and EQ litters, respectively. Significant effects (P<0.01) were recorded for G, NBAp and ANPAG, with significant difference for PO*NWP and MP at the level of P<0.05. Although the number of survived piglets was higher in EQ litters, SL was found to be an efficient management procedure in reducing the number of piglets died in the first 7 days post partum and increasing economic production of piglets per sow. Therefore, attention should be focused on piglet equalization in litters, as well as on PVP and within-litter variability in piglet birth weight.

litter size, standardization, piglet survival

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