Ácth response to transport stres

8/12/2019 CTh Response to Transport Stres

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ADRENOCORTICAL RESPONSE OF CALVES TO TRANSPORT STRESS ASMEASURED BY SALIVARY CORTISOLL. R. FELL and D. A. SHUTT

Department of Agriculture, Hawkesbury AgriculturalResearchUnit, P.O. Bor217,Richmond, N.S.W. 2753, Australia. Received 14 Nov. 1985, accepted 27 Mar.t 986.

Fell, L. R. and Ssurr, D. A. 1986. Adrenocortical response of calves to trans-port stress as measured by salivary cortisol. Can. J. Anim. Sci. 66:631-641 .A new approach utilizing a nonstressful technique of saliva collection and de-termination of salivary cortisol by radioimmunoassay was used to monitor the ad-renocortical response of calves to repeated transport stress. Four standardized truck-ing and sampling procedures were used with l9 calves previously trained to beingmustered into a race (chute) and having saliva collected. Basal mean salivary cor-tisol levels in the 19 calves ranged from 0.3 -r 0.4 nmol L-\ to 3.4 -r 0.6 nmolL ', and after 30 min of trucking manoeuvres (starting, turning, reversing and stop-ping), significant increases (P


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638 cANADTAN JOURNAL oF ANIMAL scrENCEont eu tendance i connaitre une 16action corticosurr6nale inf6rieure d celle des veauxde croisement du m6me Age. Rien ne laisse croire que 1a r6action corticosurr6nalesubit des modifications par suite de l'adaptation des veaux au transport.Mots cl6s: R6action corticosurr6nale, veaux, stress li6 au transport, cortisol salivaire

A method of assessing adrenocortical re-sponse to stress, based on measurement ofthe concentration of cortisol in saliva, wasdeveloped (Fell et al. 1985) as partof a needfor re-evaluation of stress in farm animals(see Dantzer and Mormdde (1983)). It alsoavoids the adrenocortical effects of stressassociated with frequent blood sampling(Bassett and Hinks 1969). This method al-lows the monitoring of changes in biolog-ically active free cortisol in plasma, butnot protein-bound cortisol as it does not en-ter the saliva.Calves are often exposed to stress whenthey are transported from their home farm(Kilgour and Mullord 1973; Carson andWood-Gush 1984), and plasma corticoste-roids have been used as one index of stressto evaluate some of the effects of transport(Stephens and Toner 1975; Johnston andBuckland 1976; Crookshank et al. l9'79).The present investigation was carried out toextend the above observations by examin-ing group and individual responses ofcalves to repeated transport stress. Thisstudy involved nonstressful saliva col-lection and determination of changes in sal-ivary cortisol to monitor stress.MATERIALS AND METHODS

Twenty-eight calves were used in this experi-ment, 14 Friesians and 14 mixed beef breeds(predominantly Hereford, Aberdeen Angus), ofwhich 20 were male and eight female. The calveswere purchased locally and were reared fromabout 1 wk old. The experimental design com-prised four replicates of a standardized truckingprocedure (i.e. four trips), carried out with 19of the calves (designated T1-Tl9), over a periodof 2 wk. Of these calves T4, T7, T11 and Tl9were females and the other 15 were males. Atthe mid-point of this period the age of the calvesranged from 16 d (T19) to 60 d (Tl), and theirweights ranged from 40 to 80 kg.

The truck used had a floor space of 2.5 x 4.3m which was totally enclosed by a slatted steelcrate with spaces (5 cm) between the slats. Thetrucking procedure included moving the calvesfrom a paddock to a race for pretreatment sam-pling of saliva (experimental period 1). Thecalves were previously accustomed to this pro-cedure. Nineteen of the calves were then drivenup a ramp for loading, from the rear, onto thetruck for 30 min of trucking manoeuvres, whichincluded reversing, turns to left and right, andstopping and starting (experimental period 2). Asecond salivary sample was then coilected on thetruck. The calves were then exposed to an ad-ditional 2 h of normal road transport before re-turning to the presampling area (experimentalperiod 3). After unloading down the ramp, thecalves were sampled for a third time in the race,then released into their home paddock, and sam-pled in the race 2h later (experimental period 4)and24h later. Trips I and2 were carried out inthe same truck, but trips 3 and 4, unavoidably,had to be carried out in another truck which wasthe same size, but a different model. The secondtruck appeared to have better suspension andgave a smoother ride. Nine control calves weresampled in the race with the calves that had beentransported (after experimental period 3).Saliva samples from the calves were aspiratedfrom the side of the mouth with minimum re-straint, and cortisol was determined by specificradioimmunoassay as described by Fell et al.( r 985).Salivary cortisol was found by Fell et al.(1985) to give an accurate measurement ofplasma''free'' cortisol in the sheep, and this wasconfirmed in five of these calves. When the fivecalves were sampled after20 min transportation,the mean salivary and plasma free cortisollevels increased from 1.9 + 0.5 nmol L ' and0.8 + 0.1 nmol L 'to 9.0 -t- 1.3 nmol L 'and9 .6 + 1.2 nmol L ' , respectively. Total cortisollevels in blood plasma of the calves increasedfrom 11 + 2 nmol L-'to 100 + ll nmol L 'during the same period. There is normally anincrease in salivary flow rate during transport,but cortisol concentration has been shown to be

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FELL AND SHUTT - TRANSPORT STRESS AND SALIVARY CORTISOL IN CALVESindependent of salivary flow rate (see Vining etal. (1983), Fell et al. (1985)). Differences be-tween mean values in these exoeriments weredetermined by Student's unpaired r-test. and re-sults are expressed as the mean + SE.

RESULTS AND DISCUSSIONThe space provided for the calves in thetruck (approximately 0.5 m,/calf) allowedroom for them to move about, but on eachtrip the calves huddled together, particu-larly during highway travelling at a steadyspeed. Most faced towards the rear of thetruck. During the trucking manoeuvres(turning, stopping etc.), some calves losttheir footing temporarily, but, with one ex-ception, all calves remained standingthroughout most of the treatment so nonewas noticeably trampled. One calf (T5) waslying down for most of the first trucking andhis salivary cortisol was in the middle of therange for this trip.With each successive trip, the calveswere noticeably easier to drive up the rampand onto the truck and seemed to be moresure-footed during transport, indicating thatsome degree of behavioral adaptation wasoccurring. However, this was not reflectedin salivary cortisol. The mean salivary cor-tisol levels for the 19 calves in resoonse tofour separate trips are shown in Fig. l. Onall four occasions after 30 min of truckingmanoeuvres, mean salivary cortisol levelsincreased significantly from pretreatmentvalues of 0.3 -r 0.4 nmol L-'to 3.4 -r 0.6nmol L I to values ranging from 10.5 -r1.4 nmol L I to 16.0 -i- 2.3 nmol L-'(P


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CANADIAN JOURNAL OF ANIMAL SCIENCEfour transport treatments. Salivary cortisoldeterminations in samples collected fromthese two groups of calves, before trans-port, at the end of 30-min transport to thenew farm, or 24 h after arrival at the newfarm, showed no significant differences.Mean cortisol values before transport were

2.6 -r 0.8 nmolL-1(n:6)and3.2 + 0.7nmol L 1 (n : 14). After 30 min transport,significantly higher (P


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Ácth response to transport stres

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