RESUMO
Following the use of sugar beet pulp that was retrospectively found to be predominantly contaminated with zearalenone (ZEN) in diets of reproducing sows largely exceeding the EU-guidance value for critical ZEN concentration of 0.25 mg/kg, farmers did not report any changes in the reproductive performance of sows. Thus, the aim of the study was to verify this guidance value in a dose-response setup by using sugar beet pulp as a ZEN source hitherto not considered a risky feedstuff additionally characterized by comparatively low levels of deoxynivalenol. A total of 90 sows was equally allocated to one of the three feed groups during experimental lactation 1 and up to 40 days after insemination: CON with a minimal ZEN concentration, ZEN1 with a target concentration of 250 µg ZEN/kg feed, and ZEN2 with a target concentration of 500 µg ZEN/kg feed. Thereafter, all sows received the same feed without ZEN for the rest of gestation, and the following lactation for testing of putative carry-over effects resulting from previous ZEN exposure. Exposure of sows to ZEN with blood serum as an indicator was linearly related to dietary ZEN concentrations. Reproductive and zootechnical performances of sows were only affected by ZEN exposure at weaning weight. Clinical-chemical parameters indicated no clear effect of ZEN exposure. An influence of ZEN on the occurrence of tail and ear injuries (not necrosis) in piglets and lesions on the mammary complexes in sows is possible. The influence of a ZEN concentration above the EU guidance value on the study farm can therefore not be neglected.
RESUMO
Rubber mats offer a possibility to increase lying comfort for sows with positive effects on sow lying behavior and health. However, until now, no information has been reported about the relationship between the softness of rubber mats and the pressure load on certain body areas of sows. We used a total of 68 (40 multiparous, 28 primiparous) German Landrace × German Landrace sows with a BW within the range of 90 to 330 kg (divided in 3 weight classes) to measure peak force and distribution of pressure during lying in the sternal and half recumbent position. Measures were done in an experimental pen that was equipped with a pressure sensor map system (5400 NTL; Tekscan Inc., Boston, MA). Three rubber mats differing in softness (penetration depth: hard mat, 4.0 mm [HM]; soft mat, 14.6 mm [SM]; very soft mat, 43.0 mm [VSM]) were tested and compared to concrete floor (CF) as a reference. Pressure load was analyzed in the sternal position for the sternum, belly, and ham body regions and also in the half recumbent position for the shoulder. For each lying position we determined the body region with the highest pressure load and analyzed the peak force (PF) and the contact area (CA) using a mixed model ANOVA (MIXED procedure of SAS Enterprise, version 4.3., SAS Inst. Inc., Cary, NC) with floor type, weight class of sows, and their interaction as fixed factors. Overall, the highest values for PF in the sternal position were found on the sternum (median: 1.62 N/cm(2)) and in the half recumbent position on the shoulder (median: 2.72 N/cm(2)). In the sternal position PF on the sternum was lower on VSM compared to CF (P = 0.001). In the half-recumbent position PF on the shoulder was lower on VSM compared to CF (P = 0.013) and compared to HM (P = 0.011). The weight of the sows affected PF on the sternum in the sternal position, with lower values in weight class 1 compared to weight class 2 (P = 0.001) and weight class 3 (P = 0.002). Contact area under the sternum was larger on SM (P = 0.016) and VSM (P = 0.008) compared to CF in the sternal position, and this was affected by weight class (P = 0.0002). In the half-recumbent position floor type did not affect CA under the shoulder, but CA was larger in weight classes 2 and 3 compared to weight class 1 (all P < 0.05). Assuming that a reduced PF in combination with pressure distributed over a larger area will increase lying comfort, hard rubber mats do not seem to offer a high lying comfort with regard to pressure load on debited body regions such as the sternum or shoulder.