EEG changes in 4-week-old lambs in response to castration, tail docking and mulesing.
OBJECTIVE
To interpret changes in EEG in relation to perceived pain of castration, mulesing and docking in lambs.


METHODS
Analysis of covariance (randomised block design) to determine the effects of treatment on eight bandwidths of the EEG frequency spectrum.


METHODS
Ninety-eight, 3- to 4-week-old lambs were subjected to one of seven treatments: castration, tail docking, mulesing, ear tagging, sham shearing, formalin injection (to induce lameness) and handling. EEG was recorded for 15 min before treatment, during treatment, and for 15 min after treatment.


RESULTS
Consistently lower mean power values across all bandwidths of the EEG were found at the time of mulesing and docking than at handling and shearing (P < 0.01). Formalin injection resulted in lower power values than handling and shearing (P < 0.01). Castration had lower power values than handling and shearing. Similarly, for 15 min after treatment, mulesing and formalin injection had significantly lower power values than handling, shearing, ear tagging and castration (P < 0.05).


CONCLUSIONS
The consistent effects associated with mulesing, docking and castration compared to handling, shearing and ear tagging suggest that mulesing at both the time of treatment and during 15 min after treatment results in a response that is similar to that of induced lameness. Docking and castration result in a response at the time of treatment that is similar to induced lameness and mulesing, but during 15 min after treatment is similar to the non-noxious control treatments. However, the depressing effects on the mean power values are the reverse of that anticipated from a previously developed pain model, highlighting the need for further research to develop this technology to evaluate pain associated with husbandry procedures.
Jongman
E C
EC
Animal Welfare Centre, Victorian Institute of Animal Science, Werribee, Victoria.
Morris
J P
JP
Barnett
J L
JL
Hemsworth
P H
PH
D000822:Animal Husbandry / Q000379:methods; D000823:Animal Identification Systems / Q000662:veterinary; D000827:Animal Welfare; D000818:Animals; D000831:Animals, Newborn; D004569:Electroencephalography / Q000662:veterinary*; D005260:Female; D007267:Injections / Q000662:veterinary; D008297:Male; D009919:Orchiectomy / Q000009:adverse effects / Q000662:veterinary; D010146:Pain / Q000175:diagnosis / Q000209:etiology / Q000662:veterinary*; D010147:Pain Measurement / Q000662:veterinary; D010502:Perineum / Q000601:surgery; D012756:Sheep / Q000502:physiology* / Q000601:surgery*; D013312:Stress, Physiological / Q000209:etiology / Q000503:physiopathology / Q000662:veterinary*; D013623:Tail / Q000601:surgery