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According to the results of a study presented at the 4th European Symposium of Porcine Health Management, immunological castration decreases aggression in males co-penned with females.
During the experiment, a total of 144 pigs were distributed in 18 pens (each of 4 entire males and 4 females). In half of the pens males were vaccinated against GnRF (36 animals) at 74 days of age and about 6 weeks before slaughter (152 days of age). Aggression was assessed from 1 wk before the second dose of vaccine by direct observation of aggressive interactions in 4 pens per treatment, 3 days per week for 20 min. Interaction types were classified (in order of severity) as mount, threat, lift, thrust (head knock), bite, chase and chase plus bite (7 categories). Injuries were assessed on individuals twice per week in 4 pens per treatment. Injuries were rated 0 to 3, depending on number of scratches in specific parts of the body (3 parts per side; total score per pig 0 to 18).
Pens with entire males showed more frequent (P=0.013) aggression with a tendency to higher intensity (P=0.085). Additionally, entire males were mainly initiators of aggression, while in immunologically castrated pens aggression was initiated equally by males and females. Furthermore, after the second dose of vaccine, pigs penned with entire males had more injuries than pigs in immunologically castrated pens (P<0.01).
Morales J., Piñeiro C., Wilson S., Manzanilla E.G., Nanjiani I., Wuyts N. Immunological castration decreases aggression in male pigs co-penned with females in the late a fattening period. 4th European Symposium of Porcine Health Management. 2012.
