Welfare of entire males and females in organic pig production when reared in single-sex groups

In the 25 EU countries more than 100 million male piglets are castrated each year. Castration is particularly problematic in organic pig production because it conflicts with the high welfare and other ethical standards associated with this system of animal production. The objective was to investigate possible welfare implications of producing organic entire male pigs. A total of 281 entire male pigs and 250 female pigs, raised in accordance with Danish organic standards in two commercial herds, were distributed into 15 male groups and 15 female groups. The pigs were observed at 40, 70 and 90 kg. Behaviour observations was made in two different periods, 'roughage provision' with observation of aggressive interactions lasting 30 min, and 'post-roughage provision' with observations of aggressive interactions, number of mountings and number of active animals in intervals of 15 min, lasting 90 min in total. Number of skin lesions and prevalence of lameness and general debility were assessed for each animal. The mean aggression levels were 4.3 interactions per animal per hour during 'roughage provision' and 1.9 during 'post-roughage provision', with no difference between genders in either period. Also no difference in severity of the aggressive behaviour between males and females was observed. Aggression decreased significantly with increasing pig weight during 'post-roughage provision' (P<0.001), and also during 'roughage provision' in herd B (P<0.05). No effect of pig weight on aggression level during 'roughage provision' was found in herd A. No significant difference in activity was found between males and females. The level of activity decreased with increasing weight of the animals (P<0.001). For skin lesions 10.4% of both males and females had ≥5 lesions, with a significant difference between sexes only at 70 kg in herd A (P<0.05) Most lesions were located on the front and chest/side of the pigs. Frequency of mounting was 0.3 per entire male per hour and 0.01 per female per hour, showing a difference between entires and females. Mounting was not affected by increasing weight of the animals. The prevalence of lameness was 1.6%, and a difference between males and females was found only at 70 kg on herd B (P<0.04). Poor general debility overall occurred in 3.5% of the pigs and no difference between sexes was found. The results indicate that it is possible to produce entire male pigs within the organic production system without compromising the welfare of the animals.