Changes in Scratches and Skin Elasticity in Cull Sows after Transport to the Abattoir

Each year over 400,000 Danish sows are transported by road to abattoirs. Only very limited knowledge about these animals is available. In this study, the clinical condition of 522 sows was examined before and after transport to an abattoir. The effects of journey duration (max 8 hours), temperature in the vehicles, as well as the effect of sows’ pre-transport condition on their clinical condition at arrival were investigated.

The study included sows from 12 private farms sampled randomly, and stratified according to distance to a larger slaughterhouse. Selection of animals to slaughter was done by the farmers taking into account the EU Council Regulation (EC 1/2005), that excludes animals unable to move independently without pain; present open wounds, or prolapse; pregnant females in late gestation, or having given birth within a week. Transport duration ranged from 46-469 min (mean=236±114 min) and average temperatures from 3.4–26.1°C (mean=14.3±5.3°C). Clinical registrations were made on-farm before transport and immediately upon arrival at the abattoir, and we here present data on the number of scratches and skin elasticity (a measure of the degree of dehydration). Overall differences in these two variables were analyzed with Signed Rank Test (PROC NPAR1WAY), and the effects of journey and sow characteristics with PROC GLIMMIX, both analyses in SAS.

The Table shows the median and IQR (25% and 75%) of number of scratches and skin elasticity before and after transport.

Variable	Before transport	After transport	Signed Rank Test
Number of scratches	0 [0; 1]	6 [2; 12]	N=509; S=38134.5; P<0.001
Skin elasticity (sec)	3 [2; 3]	3 [3; 4]	N=492; S=5001.5; P<0.001

The risk of having more scratches was affected by an interaction between transport duration and average temperature (F_{3, 405}=8.44; P<0.001). The risk was generally high with temperatures above 18°C, but also increased with transport time with more moderate temperatures. At temperatures below 6.5°C the risk was highest on short transports. Among other findings, risk of more scratches was higher in dry sows compared to lactating sows (F_{1, 405}=7.96; P<0.01). Odds of getting more dehydrated were 2-6 times higher at temperatures above 18°C compared to lower temperatures (F_3,423=8.12; P<0.001).

These results show that the clinical condition of cull sows are worsened by the transport. Among the most important risk factors were transport duration and temperature. Future studies should examine whether, and to what extent cull sows can be transported without the welfare impact of the worsened clinical parameters.