Pressure load on specific body areas of gestating sows lying on rubber mats with different softness1

Abstract

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.

Do Rubber Floor Mats Prevent Lameness in Gestating Sows Housed in Large Groups? A Field Experiment on Three Commercial Farms in France

“…At the beginning of the study, the prevalence of lameness was similar within treatments: 23% ([ 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 ]) in treatment RM vs. 21% ([ 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 ]) in treatment C ( p = 0.33). No Treatment*Cycle interaction ( p < 0.05) was observed for any of the parameters under study, suggesting that the effect of rubber mat was constant over the two observed gestation periods.…”

“…These farms previously encountered lameness issues in sows. The prevalence of lameness in the three farms was 22% (confidence interval of 95% [ 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 ]) at the beginning of the study. Two of them (Farms A and B) had 250 sows and the third (Farm C) had 700 sows.…”

“…Therefore, rubber mats on slatted floors in the lying areas may be a solution to improve floor softness without impairing slurry evacuation by scraping. Mats increase the contact area between the animal’s body and the floor and limit push forces on body parts in contact with the floor [ 19 ], thereby improving the comfort of animals lying down on the floor. Using a preference test, Parsons et al [ 20 ] demonstrated that lame sows preferred rubber mats to concrete floors.…”