182

This sec t ion of the s tudy focusses on the individual animals and the re la t ionsh ips be- t w e e n various pa rame te r s of the i r behav iour and p roduc t ion . Thus, a measure of correla- t ion (r) be tween each of the m e a s u r e m e n t s r ecorded was de t e rmined . For behavioura l measu remen t s , on ly the cor re la t ion be t w een the f r equency of in i t ia t ing aggression and mi lk ing t e m p e r a m e n t (r = 0 .58) was s ignif icant at the P < 0.05 leveL. However , the cor- re la t ion coeff ic ients for the re la t ionsh ips b e t w e e n p r o p o r t i o n of t ime spen t passively as a calf and f r equency of in i t ia t ing aggression (r = 0.43), f r equency of in i t ia t ing social l icking and p r o p o r t i o n of t imes pushed in to the par lour (r = - 0 . 5 3 ) , and p r o p o r t i o n of t imes pushed in to the par lour and milking t e m p e r a m e n t score (R = 0 .52) all t e n d e d to- wards s ignif icance (P < 0.10). When behavioura l and p r o d u c t i o n m e a s u r e m e n t s ~,,ere cons idered , on ly the coef f ic ien t of cor re la t ion b e t w e e n the f r equency to in i t ia te social l icking and m e a n daily milk yield was s ignif icant (r = 0.63).

Overall, t he s tudy showed tha t calves reared in res t r ic ted individual pens develop t ime- budge t s in which the p r o p o r t i o n of t ime spen t passively varies be tween calves. It is hypo- thesised (Denn i son , 1985) t ha t this inf luences the i r response to social e n c o u n t e r s ex- pe r ienced w h e n calves are g rouped toge the r a f te r weaning. Successful o u t c o m e s of en- coun te r s are posi t ively re in forced and may b e c o m e associated wi th greater f r eedom of m o v e m e n t or pr ior i ty of access to resources, one of wh ich is appa ren t ly the mi lk ing par lour . They en te r easily and exh ib i t a good mi lk ing t e m p e r a m e n t . However , this does no t necessari ly m e a n t ha t they are general ly easier to handle . This hypo thes i s can t h e n be t es ted w i th several repl icates in d i f fe ren t e n v i r o n m e n t s to examine its general val idi ty as a scheme for the d e v e l o p m e n t of behav iour pa t t e rns in dairy catt le.

R E F E R E N C E S

Denn i son , S.G.C., 1985. The d e v e l o p m e n t of behav iour pa t t e rn s in dairy heifers w i th an assessment of the i r t e m p e r a m e n t . Ph.D. Thesis, Univers i ty of Ed inburgh .

Dickson, D.P., Barr, G.R., J o h n s o n , L.P. and Wieckert , D.A., 1970. Social d o m i n a n c e and t e m p e r a m e n t of Hols te in cows. J. Dairy Sci., 53: 904- -907 .

TONIC IMMOBILITY IN THE DOMESTIC FOWL: A DESCRIPTIVE PROFILE

R.B. JONES

A.F.R.C. Poultry Research Centre, Roslin, Midlothian EH25 9PS (Gt. Britain)

ABSTRACT

Fear is widely regarded as an undes i rab le s ta te in t e rms of b o t h welfare and pe r fo rm- ance, and it is o f t en e s t ima ted using the ton ic i m m o b i l i t y reac t ion . Ton ic i m m o b i l i t y (TI) is an un l ea rned s ta te of m o t o r i nh ib i t i on and reduced responsiveness induced by physical res t ra in t . The behavioura l and physiological charac ter i s t ics of the response in ch ickens are descr ibed, and various theor ies wh ich have been advanced to a c c o u n t for the TI p h e n o m e n o n are discussed. The available evidence indica tes t h a t ton ic i m m o b i l i t y is posi t ively re la ted to fear, and m a y rep resen t the t e rmina l r eac t ion in a sequence of ant i - p r e d a t o r responses. Some o f the n u m e r o u s t echn iques wh ich have been used to induce the TI response are descr ibed, b u t a U-shaped w o o d e n cradle is r e c o m m e n d e d as the mos t rel iable m e t h o d for adu l t birds. The ton ic i m m o b i l i t y r eac t ion is sensi t ive to a var ie ty of social, genet ic and e n v i r o n m e n t a l fac tors and, appl ied in c o n j u n c t i o n w i th o t h e r tests , it is cons ide red to be a useful behav ioura l m e t h o d for assessing fearfulness .