Separation from the dam causes negative judgement bias in dairy calves.
Negative emotional states in humans are associated with a negative (pessimistic) response bias towards ambiguous cues in judgement tasks. Every mammalian young is eventually weaned; this period of increasing nutritional and social independence from the dam is associated with a pronounced behavioural response, especially when weaning is abrupt as commonly occurs in farm animals. The aim of the current study was to test the effect of separation from the cow on the responses of dairy calves in a judgement task. Thirteen Holstein calves were reared with their dams and trained to discriminate between red and white colours displayed on a computer monitor. These colours predicted reward or punishment outcomes using a go/no-go task. A reward was provided when calves approached the white screen and calves were punished with a timeout when they approached the red screen. Calves were then tested with non-reinforced ambiguous probes (screen colours intermediate to the two training colours). "GO" responses to these probes averaged (± SE) 72±3.6% before separation but declined to 62±3.6% after separation from the dam. This bias was similar to that shown by calves experiencing pain in the hours after hot-iron dehorning. These results provide the first evidence of a pessimistic judgement bias in animals following maternal separation and are indicative of low mood.
Animal Welfare Program, Faculty of Land and Food systems, University of British Columbia, Vancouver, Canada; Laboratório de Etologia Aplicada e Bem-Estar Animal, Departamento de Zootecnia e Desenvolvimento Rural, Universidade Federal de Santa Catarina, Florianópolis, Brazil.
Rolnei R
RR
Daros
Animal Welfare Program, Faculty of Land and Food systems, University of British Columbia, Vancouver, Canada.
João H C
JH
Costa
Animal Welfare Program, Faculty of Land and Food systems, University of British Columbia, Vancouver, Canada.
Marina A G
MA
von Keyserlingk
Laboratório de Etologia Aplicada e Bem-Estar Animal, Departamento de Zootecnia e Desenvolvimento Rural, Universidade Federal de Santa Catarina, Florianópolis, Brazil.
Maria J
MJ
Hötzel
Animal Welfare Program, Faculty of Land and Food systems, University of British Columbia, Vancouver, Canada.
Daniel M
DM
Weary
D000818:Animals; D002417:Cattle; D003118:Color Perception; D004192:Discrimination, Psychological; D004644:Emotions; D005260:Female; D006733:Horns / Q000294:innervation / Q000601:surgery*; D006358:Hot Temperature; D007600:Judgment; D008297:Male; D008426:Maternal Deprivation; D009035:Mothers; D010147:Pain Measurement; D010149:Postoperative Pain / Q000523:psychology*; D012201:Reward