Effect of rearing system and mixing at loading on transport and lairage behaviour and meat quality: comparison of free range and conventionally raised pigs

Abstract

Free range pigs, born outdoors and reared after weaning in enriched indoor accommodation, were compared with conventionally raised pigs from a farm, matched for effects on meat quality, with respect to behaviour during transport and lairage, blood chemistry at slaughter and meat quality characteristics. Pigs were either kept in farm pen groups or were mixed at loading and kept in the groups, so formed, until slaughter. Free range pigs tended to settle faster during the 2 1 2 h transport and 2 h lairage than conventionally raised pigs and were more likely to lie as resting posture during transport. Mixing at loading had no effect on posture during transport or during lairage for free range pigs but mixed conventionally raised pigs showed a greater variability in posture during lairage compared to non-mixed conventionally raised pigs, presumably as a result of disturbance from fighting conspecifics. Conventionally raised and free range pigs showed similar levels of aggression during transport but conventionally raised pigs were more aggressive during the lairage (average for mixed groups 12 v. 2 fights, P , 0.001). Aggressive interactions, such as one-way bites, were almost exclusively confined to mixed groups and all fights with mutual biting in mixed groups occurred solely between unfamiliar animals. The frequency of unacceptable skin damage in the middle and shoulder was highest in conventionally raised pigs and in mixed groups. Cortisol concentration and creatine kinase (CK) activity in slaughter blood were not affected by the rearing system. Mixing did not affect cortisol concentrations but led to higher CK activities compared to non-mixing (957 v. 588 U/l, respectively, P , 0.05). The rate of pH fall after slaughter was not affected by the rearing system but muscle temperatures early post mortem were highest in free range pigs. Mixing did not affect pH or temperature early post mortem. Neither rearing system nor mixing at loading affected ultimate pH or internal reflectance (meat quality marbling values).

Caracterización de sistemas de producción de porcino y vacuno de engorde en Uruguay

“…No differences were found in blood cortisol concentration for pigs reared in outdoor and indoor systems (Rudine et al, 2007), or between both plasma and urine cortisol after transport and lairage for pigs reared in outdoor and indoor conventional system (Lebret et al, 2006). Similar results are reported by (Barton Gade, 2008) for free range and conventional raised pigs. However, the upholding of the differences showed at the farm between T1 and T2 after transport, as well as the higher level of aggression in T1 and the higher level of glucose, could be an evidence of distress in pigs under this treatment.…”

Do umbilical outpouchings affect the behaviour or clinical condition of pigs during 6h housing in a pre-transport pick-up facility?

“…However, when data were split according to the type of the UO, control pigs as well as non-hernia UO-pigs showed a higher frequency of aggression than the UO-pigs with umbilical hernia. For pigs, the normal post-mixing behaviour is fighting in order to re-establish the social hierarchy (Spoolder et al, 2000;Barton Gade, 2008), and so the lowered aggression level in UO-pigs as compared to control animals is a deviation from normal behaviour. This might be due to pain from the outpouchings or the animals attempting to avoid fighting-induced damage to their outpouchings.…”

“…fasting (Gispert et al, 2000), mixing with unknown conspecifics (Barton Gade, 2008) and high stocking density (Warriss et al, 1998), which all may compromise animal welfare (Lambooij, 2007). However, effects of typical pre-slaughter stressors on pigs with umbilical outpouchings (OUs) have not been examined.…”

The Effect of Mixing Entire Male Pigs Prior to Transport to Slaughter on Behaviour, Welfare and Carcass Lesions

“…Skin lesions are prevalent welfare outcomes of mixing [ 9 , 10 ] and skin lesions measured on the carcass are suggested as more sensitive indicators of aggressiveness than those measured on the live pig [ 11 ]. Barton Gade and colleagues [ 12 ] found that the carcasses of pigs from mixed groups had a higher skin lesion score than those kept in static groups. Fighting increases plasma cortisol levels [ 8 ] and higher skin lesion scores are associated with higher plasma cortisol [ 13 ].…”