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The effects of fasting and transportation on beef cattle. 1. Acid-base-electrolyte balance and infrared heat loss of beef cattle
Livestock Production Science, 20 (1988) 15-24
15
Elsevier Science Publishers B.V., Amsterdam - - Printed in The Netherlands
T h e E f f e c t s of F a s t i n g and T r a n s p o r t a t i o n on B e e f Cattle. 1. A c i d - B a s e - E l e c t r o l y t e B a l a n c e a n d I n f r a r e d H e a t Loss of B e e f Cattle 1 A.L. SCHAEFER, S.D.M. JONES, A.K.W. TONG and B.C. VINCENT
Agriculture Canada, Research Station, Lacombe, Alberta TOC 1S0 (Canada) (Accepted 22 January 1988)
ABSTRACT Schaefer, A.L., Jones, S.D.M., Tong, A.K.W. and Vincent, B.C., 1988. The effects of fasting and transportation on beef cattle. 1. Acid-base-electrolyte balance and infrared heat loss of beef cattle. Livest. Prod. Sci., 20: 15-24. The purpose of the present study was to examine acid-base-electrolyte and thermal adaptation in beef cattle subjected to marketing stress. Fifty yearling, market-weight Hereford steers and heifers were allocated to one of 3 treatments. Treatment 1 (T1, n = 17 ) animals were transported 3 km and slaughtered following a 24-h fast. Treatment 2 animals (T2, n -- 17 ) were mixed by sex, transported 320 km and slaughtered after a 48-h fast. Treatment 3 animals (T3, n= 16) were transported as per T2 with an additional 320 km transport on Day 2 (total fasting = 72 h) prior to slaughter. Compared to pretreatment measurements, blood bicarbonate, base excess, carbon dioxide and hydrogen-ion concentration were reduced (P < 0.01 ) for all animals when measured again immediately preslaughter. In contrast, blood lactate was seen to increase ( P < 0.04) compared with preslaughter values. Among treatments, T2 animals displayed higher (P < 0.05 ) bicarbonate, base excess and standard bicarbonate values than animals in T1 or T3. The mean infrared body heat loss was reduced (P ~<0.01 ) with increased fasting and transportation which, interestingly, coincided with progressively darker meat colour. These data suggest marketing stress can induce changes in the acid-base and thermodynamic status of an animal.
INTRODUCTION
The transportation, mixing and handling conditions to which cattle are subjected during marketing represent significant physical (Stephens, 1980) and psychological (Kilgour and Dalton, 1984; Lefcourt, 1986; Warriss, 1986; Kenny and Tarrant, 1987) stressors. Much can and has been done to alleviate marketing stress by reducing stress owing to the mixing of unfamiliar animals ~Scientific Paper No. 572, Agriculture Canada, Research Station, Lacombe, Alberta T0C 1S0, Canada.
0301-6226/88/$03.50
© 1988 Elsevier Science Publishers B.V.
16
(Price and Tennessen, 1981; Morisse et al., 1985), as well as improving preslaughter and lairage nutrition (Morisse et al., 1985; Wythes et al., 1985; Hutcheson and Cole, 1986) and even by the use of tranquilizers ( Romanyuck, 1982). However, in spite of these changes there will probably continue to be animals that are particularly susceptible to marketing stress and also certain undesirable marketing conditions which are not easily changed. This is exemplified by the incidence of dark cutting often observed with the marketing of bulls (Price and Tennessen, 1981; Morisse et al., 1985; Lacourt and Tarrant, 1985) and to a lesser extent, cattle in general (Warriss, 1986). Collectively, these factors continue to create an economically costly situation and present a challenge to the animal industry in terms of improving both animal welfare and meat quality. The intention in the present study, therefore, was to improve our understanding of the physiological adaptation or changes an animal experiences as a result of transportation, time off feed and mixing prior to slaughter. In this respect, the in vivo acid-base stability of intra- and inter-cellular compartments is known to be directly related to and influenced by the acid-base stability of the extracellular space (Martin, 1985). Particularly important in this regard are the CO~ transport kinetics and blood acid-base buffering resulting from the conversion of C02 to carbonic acid (Pearson, 1976; Stewart, 1983). It is conceivable, therefore, that preslaughter shifts in acid-base stability may predispose the animal to changes in post-slaughter meat biochemistry such as dark cutting. Understanding when and how extracellular acid-base shifts may occur in marketed cattle is therefore fundamental to designing prophylactic treatments in an attempt to prevent factors contributing to poor meat quality and to improve animal welfare. In addition, it was the intention of this study to test the usefulness of infrared thermography for identifying animals and conditions most influential in terms of marketing stress and in terms of thermoregulatory stability. Changing physical environments, such as would occur in the transport and marketing of cattle, are known to result in changes in skin temperature (Houdas and Guieu, 1975) which in turn, can lead to changes in thermoregulation (Frens, 1975 ). These changes should be sensitive to analysis by infrared thermography. M A T E R I A L S AND M E T H O D S
Animals and management
Fifty Hereford cattle approximately 1 to 1.5 years of age and composed of 30 steers and 21 heifers were used. Steers and heifers were penned separately. The animals received a balanced silage and cereal grain ration. Water and iodized salt were also freely available throughout the study, except during transportation. Animals were randomly selected from the steer and heifer groups ac-
17
cording to initial body weight and assigned to one of 3 treatments. T r e a t m e n t Group 1 (control) consisted of 7 heifers and 10 steers. These animals were not subjected to mixing by sex. Handling and transportation were minimized to only that required to truck the animals to the meat research center (approximately 3 km). Time off feed, including lairage at the beef unit, was approximately 24 h for T r e a t m e n t Group 1 animals. T r e a t m e n t Group 2 consisted of 7 heifers and 10 steers. These animals were taken off feed at the same time as Group 1 animals. Group 2 cattle were mixed by sex and transported in a commercial cattle truck for 320 km (6 h) prior to being unloaded and left in lairage for an additional 24 h. These animals were fasted for a total of 48 h prior to slaughter. T r e a t m e n t Group 3 animals consisted of 6 heifers and 10 steers. These animals were treated as Group 2 cattle with an additional 320 km (6 h) transport on the second day. Prior to slaughter, time off feed for T r e a t m e n t 3 cattle was approximately 72 h.
Infrared thermography Scans were collected on all animals in the holding area of the meat research center just prior to stunning. Infrared scans were collected on an 'Agema' model 782 camera (AGA Lidingo, Sweden) and analysis of the image data for average surface temperature and pixel counts was completed on an I B M enhanced AT computer using viewsoft software (Viewscan Ltd., 66 Drumlin circle, Unit 5, Concord, Ontario K4K 2T9). An infrared image of an animal is composed of an array of pixels. A pixel is the smallest addressable area on the infrared image which represents a temperature reading.
Blood sampling and metabolite analysis Blood samples from all animals were collected on two occasions. The first blood sample was collected 10 days prior to conducting handling, transportation and mixing treatments. Twenty ml of whole blood were collected into chilled vacutainers (Becton Dickinson Canada, Inc., Missisauga, Ontario) using a venous-puncture procedure while restraining the animals in a head gate. Samples were centrifuged immediately and 5 ml of plasma and 5 ml of serum were dispensed and deep frozen ( - 80 °C) for later analysis. A second blood sample was collected following the infrared thermograph scans while the animals were in the holding area of the abattoir. Animals were held in the abattoir for less than 6 h prior to stunning. The samples were again collected by venous puncture into chilled vacutainers while restraining the animals in a head gate. On both blood sampling occasions, an additional 2 ml of whole blood was collected, I ml of which was used for lactate determination and I ml collected into a chilled heparinized tuberculin syringe, capped and analysed for PO2, PCO,~ and p H within 0.5 h of sampling. Blood lactate was determined by an enzy-
18 matic method (Sigma diagnostic kit 826, Sigma Chemical Comp. St. Louis, Missouri ). Blood gas and pH were determined on a micro 13 blood gas analyser (Instrument Labs Inc. Lexington, MA). Instrument calibration for blood pH was accomplished by using two buffered standards for pH and two medical grade gas standards to calibrate for P02 and P C Q . Calibration was done prior to and between samples. Each blood sample was analysed in triplicate for pH, PO2 and PC02. Hematology analysis for hemoglobin, hematocrit, red blood cell and white blood cell count was conducted on a cell Dyn 700 analyser (Sequoia-Turner Corp. Mountain View, CA). Blood bicarbonate, total CO2, standard bicarbonate and base excess values were calculated according to procedures described for the operation of the IL micro 13 blood gas analyser (Instrumentation Laboratory Inc., 113 Hartwell Ave., Lexington, MA).
Statistical analysis A split-plot linear model which included the main plot effects of sex, treatment and interactions, subsampling on two occasions within each animal and all interactions, was used to analyze the physiological measurement data. The thermogram and meat color data were analyzed by a model with sex, treatment and 2-way interactions. Mean separation of significant main effects was by single degree of freedom linear contrast. All analyses were performed by S.A.S. (1985). RESULTS
Pretreatment values The pretreatment physiological data taken for blood gas, hydrogen-ion concentration and blood lactate collected prior to the stress of transportation, mixing, lairage and fasting were similar for all animals.
General effects of marketing stress Marketing stress as imposed in the present study caused changes in basic physiological parameters irrespective of the treatment. With the exception of POe, statistically-significant reductions were seen in blood bicarbonate, base excess, PCO2, standard bicarbonate and hydrogen-ion concentration. Blood lactate concentration increased compared with pretreatment control values (Table 1 ).
19 TABLE 1 Least squares means and standard errors of blood acid-base values and lactate for market-weight steers and heifers subjected to marketing Measurement
Control pretreatment value
Post-treatment value at slaughter
Probability*
Bicarbonate (mequiv. l- 1) Base excess (mequiv. l- 1) PCO~ (mm Hg) PO2 (mm Hg) Standard bicarbonate (mequiv. 1-1 } Hydrogen-ion concentration ( X lO-Smoles 1 1) Lactate (mmol 1-1 )
32.27 +_0.67 6.68_+0.67 34.0 +_0.7 39.7 _+1.3 30.21 +_0.52
27.27 _+0.67 3.46_+0.67 28.6 _+0.7 43.1 _+1.3 27.70 _+0.52
0.001 0.001 0.001 0.05 0.001
4.19 _+0.07
3.90 _+0.07
0.005
5.53 _+0.33
6.50 + 0.33
0.04
*Probability of F-test of the main effect.
Effect of treatment A m o n g the p o s t - t r e a t m e n t c o m p a r i s o n s , no statistically-significant changes in h e m a t o l o g y values n o r in blood lactate or h y d r o g e n - i o n c o n c e n t r a t i o n were evident. O f interest, however, was the o b s e r v a t i o n t h a t blood b i c a r b o n a t e , base excess, P C 0 2 a n d s t a n d a r d b i c a r b o n a t e all showed similar p a t t e r n s of change owing to t r e a t m e n t effects. Specifically, the G r o u p 2 animals all displayed an increase (P~< 0.05) in these p a r a m e t e r s (30.94 +- 1.14 mequiv. 1-1, 6.80 +- 1.14 mequiv. 1-1, 32.38 + 1.17 m m Hg, 3 0 . 3 0 _ 0.89 mequiv. 1-1) c o m p a r e d with G r o u p 1 ( 2 5 . 7 6 + 1 . 1 4 , 1 . 4 3 + 1 . 1 4 , 2 7 . 1 1 + 1 . 1 7 , 2 6 . 1 1 + 0 . 8 9 ) or G r o u p 3 ( 2 5 . 1 1 + 1 . 2 0 , 2 . 1 6 + 1 . 1 9 , 2 6 . 2 8 + 1 . 2 3 , 26.68+_0.93) animals. T h e single par a m e t e r deviating f r o m this p a t t e r n was the PO2 which s h o w e d a c o m p a r a t i v e r e d u c t i o n in G r o u p 3 animals. N o s e x - t r e a t m e n t i n t e r a c t i o n s were observed.
Infrared thermography On the basis of i n f r a r e d t h e r m o g r a p h y scans, t r a n s p o r t t r e a t m e n t s caused a r e d u c e d m e a n skin t e m p e r a t u r e ( T a b l e 2 ). Of i n t e r e s t also, were the observed changes in t h e p a t t e r n of i n f r a r e d t e m p e r a t u r e s illustrated by the 5 t e m p e r a ture zones in Fig. 1. I n c r e a s i n g t h e d u r a t i o n of mixing, t i m e off feed d u r i n g lairage, t r u c k i n g a n d h a n d l i n g caused a r e d u c t i o n in t h e areas of skin t e m p e r a t u r e b e t w e e n 23 a n d 26°C, 26 a n d 29°C a n d over 30°C. In c o n t r a s t , an increase in the areas of skin t e m p e r a t u r e b e t w e e n 20 a n d 23 ° C a n d 0 a n d 20 ° C was observed. T h e m a g n i t u d e of t h e s e changes was m o s t p r o n o u n c e d in the T r e a t m e n t 3 animals.
21 these are depleted muscle glycogen (Morisse et al., 1985), particularly owing to time off feed (Ozutsumi, 1984), an increased plasma cortisol concentration (Stephens, 1980; Kent and Ewbank, 1986; Kenny and Tarrant, 1987) as well as adrenocorticotropic hormone, lactate and catecholamine levels (Hattingh et al., 1985 ), in addition to an increase in blood leucocyte and neutrophil counts (Kent and Ewbank, 1986). Collectively, these changes, along with the normally-imposed limited access to water during transport, present a considerable challenge to the animal, including the need to maintain acid-base, electrolyte and fluid stability. In the present study some of these changes were seen, such as the approximately 15% increase in blood lactate in post-treatment compared with normal or control blood values. In addition, specific changes in blood acid-base parameters were seen, the most important of which in terms of acid-base chemistry was probably the roughly 10% reduction in hydrogen-ion concentration (higher pH). The causes of these physiological changes are often difficult to establish. However, as discussed by Lacourt and Tarrant {1985 ), stress can arise in cattle both through physical events and by adrenaline-mediated factors. In the present study, the physical transport, handling and lairage imposed on the cattle with the ensuing environmental temperature changes, limited water, feed deprivation and exercise were probably major physical stressors. In comparison, adrenaline-mediated stress experienced by the cattle was probably due to handling and/or the mixing of unfamiliar individuals. Of particular interest was the observation that Treatment Group 2 appeared to experience the greatest change in acid-base values. This is depicted by the 15% increase in blood bicarbonate, 300-500% increase in base excess, 15-20% increase in PCO2 and a 10-12% increase in standard bicarbonate. The additional physical stress resulting from handling and transportation imposed on Group 3 did not appear to exacerbate the blood-value changes observed in Group 2 cattle. In fact, the blood parameters measured in Group 3 cattle were closer to those observed in cattle subjected to a minimal amount of stress. This may be partly due to the re-establishment of group bonds and hierarchy within Group 3 animals owing to a longer time in lairage compared with Group 2 cattle. This would suggest that the psychological and sociological factors associated with marketing and mixing cattle are significant physical stressors, as has been suggested by Kilgour and Dalton (1984) as well as Kenny and Tarrant (1987). A full understanding of the effects of marketing stress on cattle in terms of acid-base physiology is incomplete without an accompanying knowledge of major caution and anion concentrations (including anion gap calculations ) in both the plasma and urine. The present study nevertheless demonstrates that marketing stress can cause significant shifts in physiological parameters important in the control of acid-base stability in cattle. These changes, particularly when involving electrolyte transport in muscle tissue and the ensuing
23 REFERENCES Frens, J., 1975. The influence of skin temperature on thermoregulation. In: N.J.M.A. Tilburg, M.G. Strasbourg and E.F.J.R. Bath (Editors), Thermography. S. Karger, Basel, pp. 218-223. Hattingh, J., Wright, P.G., Mitchell, G., Maria, F., Ganhao, S., Riekert, S. and Ritchie, A., 1985. Effects of blood sampling and slaughter on certain blood variables of cattle. S. Afr. J. Anim. Sci., 81: 280-281. Houdas, Y. and Guieu, J.D., 1975. Environmental factors affecting skin temperatures. In: N.J.M.A. Tilburg, M. Strasbourg and E.F.J.R. Bath (Editors), Thermography. S. Karger, Basel, pp. 157-165. Hutcheson, D.P. and Cole, N.A., 1986. Management of transit-stress syndrome in cattle: Nutritional and environmental effects. J. Anim. Sci., 62: 555-560. Jones, S.D.M., Schaefer, A.L., Tong, A.K.W. and Vincent, B.C., 1988. The effects of fasting and transportation on beef cattle. 2. Body component changes, carcass composition and meat quality. Livest. Prod. Sci., 00: 00-00. Kilgour, R. and Dalton, C., 1984. Livestock Behavior. Methuen Publishers Ltd. Auckland, New Zealand, pp. 7-53. Kent, J.E. and Ewbank, R., 1986. The effect of road transportation on the blood constituents and behaviour of calves. III. Three months old. Br. Vet. J., 142: 326-335. Kenny, F.J. and Tarrant, P.V., 1987. The physiological and behavioural responses of crossbred Friesian Steers to short-haul transport by road. Livest. Prod. Sci., 17: 63-75. Lacourt, A. and Tarrant, P.V., 1985. Glycogen depletion patterns in myofibres of cattle during stress. Meat Sci., 15: 85-100. Lefcourt, A.M., 1986. Usage of the term stress as it applies to cattle. Vlaams Diergeneeskd. Tijdschr.. 55: 258-265. Martin, D.W., 1985. The chemistry of respiration. In: D.W. Martin, Jr., P.A. Mayes, V.W. Rodwell and D.K. Granner (Editors), Harpers Review of Biochemistry. 20th edn. Lang Medical Publishers, Los Angeles, California, pp. 610-620. Morisse, J.P., Cotte, J.P. and Huonnic, D., 1985. High pH bullock meat. High sugar preslaughter regime. RTVA, 211: 27-31. Ozutsumi, K., Ito, K., Kawanishi, T., Yamazaki, T. and Karia, Y., 1984. Physiological changes in body weight and blood characteristics of fattened cattle during fasting from finishing to slaughter. Jpn. J. Zootech. Sci., 55: 735-740. Pearson, J.F., 1976. Maternal and fetal acid-base balance. In: R.W. Beard and P.W. Nathanielsz (Editors), Fetal Physiology and Medicine. W.B. Saunders Comp. Ltd., London, pp. 429-509. Price, M.A. and Tennessen, T., 1981. Preslaughter management and dark-cutting in the carcasses of young bulls. Can. J. Anim. Sci., 61: 205-208. Romanyuck, B.P. and Stoyanovskii, S.V., 1982. Stress during transportation and the quality of meat. Veterinariya (Moscow), 6: 60-61. S.A.S., 1985. S.A.S. User's Guide: Basics and Statistics. Version 5 edition, S.A.S. Institute Inc., Box 8000, Cary, NC. Stephens, D.B., 1980. Stress and its management in domestic animals: A review of behavioral and physiological studies under field and laboratory situations. Adv. Vet. Sci. Comp. Med., 24:179210. Stewart, P.A., 1983. Modern quantitative acid-base chemistry. Can. J. Physiol. Pharmacol., GI: 1444-1461. Warriss, P.D., 1986. Live animal marketing effects on carcass and meat quality. Proceedings, Agriculture Canada Work Planning Meeting on Meat Quality. Research Program Service, Minister of Supply and Services Canada 1987, Ottawa, Manitoba, October 1986, pp. 7-41. Wythes, J.R., Johnston, G.N., Beaman, N. and O'Rourke, P.K., 1985. Preslaughter handling of cattle: The availability of water during the lairage period. Aust. Vet. J., 62:163-165.
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RESUME Schaefer, A.L., Jones, S.D.M., Tong, A.K.W. et Vincent, B.C., 1988. Les effets du jefine et du transport chez les bovins de boucherie. 1. Equilibre acido-basique, dlectrolytes et d~tection de la perte de chaleur par thermographie. Livest. Prod. Sci., 20:15-24 (en anglais). Nous avons examin~ les effets de l'adaptation thermique, de l'~quilibre acido-basique et des ~lectrolytes sanguins sur la couleur de la viande de bovins de boucherie soumis au stress caus~ par la mise en march~. Cinquante bouvillons et g~nisses Hereford d'un an, et de poids commercial ont ~t~ r~partis en trois groupes. Les animaux du premier groupe (T1, n = 17 ), ont ~t~ transport~s sur une distance de 3 km, et abattus apr~s avoir ~t~ priv~s de nourriture durant 24 heures. Le deuxi~me groupe (T2, n = 17) dtait compos~ d'animaux m~lang~s ~ des animaux ~trangers, transport~s sur une distance de 320 km puis abattus apr~s un jefine de 48 heures. Le troisi~me groupe (T3, n = 16) requt un traitement semblable au deuxieme groupe mais ffit transport~ sur une distance suppl~mentaire de 320 km pour atteindre un jefine d'une dur~e de 72 heures. Pour tousles animaux, les niveaux sanguins de bicarbonate, de gaz carbonique et d'ion hydrog~ne mesur~s juste avant l'abattage furent significativementplus faibles que ceux mesur~s avant le traitement (P < 0.01 ). Par contre, le niveau initial de lactate ~tait plus ~lev~ ( P < 0.04) que celui pr~c~dant l'abattage. Le deuxi~me groupe, a cependant d~montr~ des niveaux de bicarbonate, exc~s de base et bicarbonate ~talon plus ~lev~sque les animaux des Groupes 1 et 3. La d~perdition de chaleur moyenne mesur~e par thermographe ffit r~duite (P < 0.01 ) proportionnellement ~ l'augmentation de la longueur du jefine et du transport coincidant; avec une couleur plus fonc~e de la viande. Ces rdsultats sugg~rent que la tension caus~e par la mise en march~ des animaux peut provoquer un changement du statut thermodynamique et acido-basique de l'animal. KURZFASSUNG Schaefer, A.L., Jones, S.D.M., Tong, A.K.W. und Vincent, B.C., 1988. Die Auswirkungen der N[ichterung und des Transports auf Fleischringer. 1. S~iure-Basen-Elektrolyt-Bilanzund mit Infrarot gemessener W~meverlust von Fleischrindern. Livest. Prod. Sci.., 20:15-24 (auf englisch). Zweck des Versuches war die Feststellung der S~iure-Basen-Elektrolyte und der thermischen Anpassung von Fleischrindern, die dem Vermarktungsstress unterworfen sind. 50 einj~hrige, auf das Vermarktungsgewicht gebrachte Ochsen und F~sen der Hereford-Rasse wurden zuf~illigauf eine von drei Behandlungsgruppen verteilt. In Behandlung 1 (T1, n = 17) wurden die Tiere 3 km transportiert und nach 24stfindiger Nfichterung geschlachtet. Die Tiere der Behandlung 2 (T2, n = 17) wurden beziiglich Geschlecht gemischt, 320 km transportiert und nach 48stfindiger Nilchterung geschlachtet. In Behandlung 3 (T3, n = 16) wurden die Tiere wie in Behandlung 2 transportiert, wozu am 2. Tag ein zus~itzlicher Transport von 320 km kam, bevor sie nach 72 Stunden Nfichterung geschlachtet wurden. Verglichen mit den Me£ergebnissen vor der Behandlung zeigten das Bicarbonat des Blutes, der Basenfiberschut~, das Kohlendioxyd und die Wasserstoff-Ionen-Konzentrationbei allen Tieren direkt vor der Schlachtung signifikant niedrigere Werte ( P < 0.01 ). Im Gegensatz dazu zeigte das Blut-Laktat einen Anstieg im Vergleich zu den Werten vor der Behandlung (P < 0.04). Zwischen den Behandlungen zeigten Tiere der Gruppe T2 hShere Were fiir Bicarbonat (P < 0.05 ), Basenfiberschu£ und Kohlendioxyd als die Tiere der Gruppen T1 und T3. Der mittlere, mit Infrarot gemessene Wiirmeverlust reduziert sich mit zunehmender N~ichterungsdauer und Transportl~inge (P < 0.01 ), welches interessanterweise mit steigender dunkler Farbe des Fleisches einherging. Diese Ergebnisse deuten an, da~ der Stre£ der Vermarktung Ver~nderungen im S~ure-Basen-Haushalt und im thermodynamischen Zustand eines Tieres verursachen kann.
15
Elsevier Science Publishers B.V., Amsterdam - - Printed in The Netherlands
T h e E f f e c t s of F a s t i n g and T r a n s p o r t a t i o n on B e e f Cattle. 1. A c i d - B a s e - E l e c t r o l y t e B a l a n c e a n d I n f r a r e d H e a t Loss of B e e f Cattle 1 A.L. SCHAEFER, S.D.M. JONES, A.K.W. TONG and B.C. VINCENT
Agriculture Canada, Research Station, Lacombe, Alberta TOC 1S0 (Canada) (Accepted 22 January 1988)
ABSTRACT Schaefer, A.L., Jones, S.D.M., Tong, A.K.W. and Vincent, B.C., 1988. The effects of fasting and transportation on beef cattle. 1. Acid-base-electrolyte balance and infrared heat loss of beef cattle. Livest. Prod. Sci., 20: 15-24. The purpose of the present study was to examine acid-base-electrolyte and thermal adaptation in beef cattle subjected to marketing stress. Fifty yearling, market-weight Hereford steers and heifers were allocated to one of 3 treatments. Treatment 1 (T1, n = 17 ) animals were transported 3 km and slaughtered following a 24-h fast. Treatment 2 animals (T2, n -- 17 ) were mixed by sex, transported 320 km and slaughtered after a 48-h fast. Treatment 3 animals (T3, n= 16) were transported as per T2 with an additional 320 km transport on Day 2 (total fasting = 72 h) prior to slaughter. Compared to pretreatment measurements, blood bicarbonate, base excess, carbon dioxide and hydrogen-ion concentration were reduced (P < 0.01 ) for all animals when measured again immediately preslaughter. In contrast, blood lactate was seen to increase ( P < 0.04) compared with preslaughter values. Among treatments, T2 animals displayed higher (P < 0.05 ) bicarbonate, base excess and standard bicarbonate values than animals in T1 or T3. The mean infrared body heat loss was reduced (P ~<0.01 ) with increased fasting and transportation which, interestingly, coincided with progressively darker meat colour. These data suggest marketing stress can induce changes in the acid-base and thermodynamic status of an animal.
INTRODUCTION
The transportation, mixing and handling conditions to which cattle are subjected during marketing represent significant physical (Stephens, 1980) and psychological (Kilgour and Dalton, 1984; Lefcourt, 1986; Warriss, 1986; Kenny and Tarrant, 1987) stressors. Much can and has been done to alleviate marketing stress by reducing stress owing to the mixing of unfamiliar animals ~Scientific Paper No. 572, Agriculture Canada, Research Station, Lacombe, Alberta T0C 1S0, Canada.
0301-6226/88/$03.50
© 1988 Elsevier Science Publishers B.V.
16
(Price and Tennessen, 1981; Morisse et al., 1985), as well as improving preslaughter and lairage nutrition (Morisse et al., 1985; Wythes et al., 1985; Hutcheson and Cole, 1986) and even by the use of tranquilizers ( Romanyuck, 1982). However, in spite of these changes there will probably continue to be animals that are particularly susceptible to marketing stress and also certain undesirable marketing conditions which are not easily changed. This is exemplified by the incidence of dark cutting often observed with the marketing of bulls (Price and Tennessen, 1981; Morisse et al., 1985; Lacourt and Tarrant, 1985) and to a lesser extent, cattle in general (Warriss, 1986). Collectively, these factors continue to create an economically costly situation and present a challenge to the animal industry in terms of improving both animal welfare and meat quality. The intention in the present study, therefore, was to improve our understanding of the physiological adaptation or changes an animal experiences as a result of transportation, time off feed and mixing prior to slaughter. In this respect, the in vivo acid-base stability of intra- and inter-cellular compartments is known to be directly related to and influenced by the acid-base stability of the extracellular space (Martin, 1985). Particularly important in this regard are the CO~ transport kinetics and blood acid-base buffering resulting from the conversion of C02 to carbonic acid (Pearson, 1976; Stewart, 1983). It is conceivable, therefore, that preslaughter shifts in acid-base stability may predispose the animal to changes in post-slaughter meat biochemistry such as dark cutting. Understanding when and how extracellular acid-base shifts may occur in marketed cattle is therefore fundamental to designing prophylactic treatments in an attempt to prevent factors contributing to poor meat quality and to improve animal welfare. In addition, it was the intention of this study to test the usefulness of infrared thermography for identifying animals and conditions most influential in terms of marketing stress and in terms of thermoregulatory stability. Changing physical environments, such as would occur in the transport and marketing of cattle, are known to result in changes in skin temperature (Houdas and Guieu, 1975) which in turn, can lead to changes in thermoregulation (Frens, 1975 ). These changes should be sensitive to analysis by infrared thermography. M A T E R I A L S AND M E T H O D S
Animals and management
Fifty Hereford cattle approximately 1 to 1.5 years of age and composed of 30 steers and 21 heifers were used. Steers and heifers were penned separately. The animals received a balanced silage and cereal grain ration. Water and iodized salt were also freely available throughout the study, except during transportation. Animals were randomly selected from the steer and heifer groups ac-
17
cording to initial body weight and assigned to one of 3 treatments. T r e a t m e n t Group 1 (control) consisted of 7 heifers and 10 steers. These animals were not subjected to mixing by sex. Handling and transportation were minimized to only that required to truck the animals to the meat research center (approximately 3 km). Time off feed, including lairage at the beef unit, was approximately 24 h for T r e a t m e n t Group 1 animals. T r e a t m e n t Group 2 consisted of 7 heifers and 10 steers. These animals were taken off feed at the same time as Group 1 animals. Group 2 cattle were mixed by sex and transported in a commercial cattle truck for 320 km (6 h) prior to being unloaded and left in lairage for an additional 24 h. These animals were fasted for a total of 48 h prior to slaughter. T r e a t m e n t Group 3 animals consisted of 6 heifers and 10 steers. These animals were treated as Group 2 cattle with an additional 320 km (6 h) transport on the second day. Prior to slaughter, time off feed for T r e a t m e n t 3 cattle was approximately 72 h.
Infrared thermography Scans were collected on all animals in the holding area of the meat research center just prior to stunning. Infrared scans were collected on an 'Agema' model 782 camera (AGA Lidingo, Sweden) and analysis of the image data for average surface temperature and pixel counts was completed on an I B M enhanced AT computer using viewsoft software (Viewscan Ltd., 66 Drumlin circle, Unit 5, Concord, Ontario K4K 2T9). An infrared image of an animal is composed of an array of pixels. A pixel is the smallest addressable area on the infrared image which represents a temperature reading.
Blood sampling and metabolite analysis Blood samples from all animals were collected on two occasions. The first blood sample was collected 10 days prior to conducting handling, transportation and mixing treatments. Twenty ml of whole blood were collected into chilled vacutainers (Becton Dickinson Canada, Inc., Missisauga, Ontario) using a venous-puncture procedure while restraining the animals in a head gate. Samples were centrifuged immediately and 5 ml of plasma and 5 ml of serum were dispensed and deep frozen ( - 80 °C) for later analysis. A second blood sample was collected following the infrared thermograph scans while the animals were in the holding area of the abattoir. Animals were held in the abattoir for less than 6 h prior to stunning. The samples were again collected by venous puncture into chilled vacutainers while restraining the animals in a head gate. On both blood sampling occasions, an additional 2 ml of whole blood was collected, I ml of which was used for lactate determination and I ml collected into a chilled heparinized tuberculin syringe, capped and analysed for PO2, PCO,~ and p H within 0.5 h of sampling. Blood lactate was determined by an enzy-
18 matic method (Sigma diagnostic kit 826, Sigma Chemical Comp. St. Louis, Missouri ). Blood gas and pH were determined on a micro 13 blood gas analyser (Instrument Labs Inc. Lexington, MA). Instrument calibration for blood pH was accomplished by using two buffered standards for pH and two medical grade gas standards to calibrate for P02 and P C Q . Calibration was done prior to and between samples. Each blood sample was analysed in triplicate for pH, PO2 and PC02. Hematology analysis for hemoglobin, hematocrit, red blood cell and white blood cell count was conducted on a cell Dyn 700 analyser (Sequoia-Turner Corp. Mountain View, CA). Blood bicarbonate, total CO2, standard bicarbonate and base excess values were calculated according to procedures described for the operation of the IL micro 13 blood gas analyser (Instrumentation Laboratory Inc., 113 Hartwell Ave., Lexington, MA).
Statistical analysis A split-plot linear model which included the main plot effects of sex, treatment and interactions, subsampling on two occasions within each animal and all interactions, was used to analyze the physiological measurement data. The thermogram and meat color data were analyzed by a model with sex, treatment and 2-way interactions. Mean separation of significant main effects was by single degree of freedom linear contrast. All analyses were performed by S.A.S. (1985). RESULTS
Pretreatment values The pretreatment physiological data taken for blood gas, hydrogen-ion concentration and blood lactate collected prior to the stress of transportation, mixing, lairage and fasting were similar for all animals.
General effects of marketing stress Marketing stress as imposed in the present study caused changes in basic physiological parameters irrespective of the treatment. With the exception of POe, statistically-significant reductions were seen in blood bicarbonate, base excess, PCO2, standard bicarbonate and hydrogen-ion concentration. Blood lactate concentration increased compared with pretreatment control values (Table 1 ).
19 TABLE 1 Least squares means and standard errors of blood acid-base values and lactate for market-weight steers and heifers subjected to marketing Measurement
Control pretreatment value
Post-treatment value at slaughter
Probability*
Bicarbonate (mequiv. l- 1) Base excess (mequiv. l- 1) PCO~ (mm Hg) PO2 (mm Hg) Standard bicarbonate (mequiv. 1-1 } Hydrogen-ion concentration ( X lO-Smoles 1 1) Lactate (mmol 1-1 )
32.27 +_0.67 6.68_+0.67 34.0 +_0.7 39.7 _+1.3 30.21 +_0.52
27.27 _+0.67 3.46_+0.67 28.6 _+0.7 43.1 _+1.3 27.70 _+0.52
0.001 0.001 0.001 0.05 0.001
4.19 _+0.07
3.90 _+0.07
0.005
5.53 _+0.33
6.50 + 0.33
0.04
*Probability of F-test of the main effect.
Effect of treatment A m o n g the p o s t - t r e a t m e n t c o m p a r i s o n s , no statistically-significant changes in h e m a t o l o g y values n o r in blood lactate or h y d r o g e n - i o n c o n c e n t r a t i o n were evident. O f interest, however, was the o b s e r v a t i o n t h a t blood b i c a r b o n a t e , base excess, P C 0 2 a n d s t a n d a r d b i c a r b o n a t e all showed similar p a t t e r n s of change owing to t r e a t m e n t effects. Specifically, the G r o u p 2 animals all displayed an increase (P~< 0.05) in these p a r a m e t e r s (30.94 +- 1.14 mequiv. 1-1, 6.80 +- 1.14 mequiv. 1-1, 32.38 + 1.17 m m Hg, 3 0 . 3 0 _ 0.89 mequiv. 1-1) c o m p a r e d with G r o u p 1 ( 2 5 . 7 6 + 1 . 1 4 , 1 . 4 3 + 1 . 1 4 , 2 7 . 1 1 + 1 . 1 7 , 2 6 . 1 1 + 0 . 8 9 ) or G r o u p 3 ( 2 5 . 1 1 + 1 . 2 0 , 2 . 1 6 + 1 . 1 9 , 2 6 . 2 8 + 1 . 2 3 , 26.68+_0.93) animals. T h e single par a m e t e r deviating f r o m this p a t t e r n was the PO2 which s h o w e d a c o m p a r a t i v e r e d u c t i o n in G r o u p 3 animals. N o s e x - t r e a t m e n t i n t e r a c t i o n s were observed.
Infrared thermography On the basis of i n f r a r e d t h e r m o g r a p h y scans, t r a n s p o r t t r e a t m e n t s caused a r e d u c e d m e a n skin t e m p e r a t u r e ( T a b l e 2 ). Of i n t e r e s t also, were the observed changes in t h e p a t t e r n of i n f r a r e d t e m p e r a t u r e s illustrated by the 5 t e m p e r a ture zones in Fig. 1. I n c r e a s i n g t h e d u r a t i o n of mixing, t i m e off feed d u r i n g lairage, t r u c k i n g a n d h a n d l i n g caused a r e d u c t i o n in t h e areas of skin t e m p e r a t u r e b e t w e e n 23 a n d 26°C, 26 a n d 29°C a n d over 30°C. In c o n t r a s t , an increase in the areas of skin t e m p e r a t u r e b e t w e e n 20 a n d 23 ° C a n d 0 a n d 20 ° C was observed. T h e m a g n i t u d e of t h e s e changes was m o s t p r o n o u n c e d in the T r e a t m e n t 3 animals.
21 these are depleted muscle glycogen (Morisse et al., 1985), particularly owing to time off feed (Ozutsumi, 1984), an increased plasma cortisol concentration (Stephens, 1980; Kent and Ewbank, 1986; Kenny and Tarrant, 1987) as well as adrenocorticotropic hormone, lactate and catecholamine levels (Hattingh et al., 1985 ), in addition to an increase in blood leucocyte and neutrophil counts (Kent and Ewbank, 1986). Collectively, these changes, along with the normally-imposed limited access to water during transport, present a considerable challenge to the animal, including the need to maintain acid-base, electrolyte and fluid stability. In the present study some of these changes were seen, such as the approximately 15% increase in blood lactate in post-treatment compared with normal or control blood values. In addition, specific changes in blood acid-base parameters were seen, the most important of which in terms of acid-base chemistry was probably the roughly 10% reduction in hydrogen-ion concentration (higher pH). The causes of these physiological changes are often difficult to establish. However, as discussed by Lacourt and Tarrant {1985 ), stress can arise in cattle both through physical events and by adrenaline-mediated factors. In the present study, the physical transport, handling and lairage imposed on the cattle with the ensuing environmental temperature changes, limited water, feed deprivation and exercise were probably major physical stressors. In comparison, adrenaline-mediated stress experienced by the cattle was probably due to handling and/or the mixing of unfamiliar individuals. Of particular interest was the observation that Treatment Group 2 appeared to experience the greatest change in acid-base values. This is depicted by the 15% increase in blood bicarbonate, 300-500% increase in base excess, 15-20% increase in PCO2 and a 10-12% increase in standard bicarbonate. The additional physical stress resulting from handling and transportation imposed on Group 3 did not appear to exacerbate the blood-value changes observed in Group 2 cattle. In fact, the blood parameters measured in Group 3 cattle were closer to those observed in cattle subjected to a minimal amount of stress. This may be partly due to the re-establishment of group bonds and hierarchy within Group 3 animals owing to a longer time in lairage compared with Group 2 cattle. This would suggest that the psychological and sociological factors associated with marketing and mixing cattle are significant physical stressors, as has been suggested by Kilgour and Dalton (1984) as well as Kenny and Tarrant (1987). A full understanding of the effects of marketing stress on cattle in terms of acid-base physiology is incomplete without an accompanying knowledge of major caution and anion concentrations (including anion gap calculations ) in both the plasma and urine. The present study nevertheless demonstrates that marketing stress can cause significant shifts in physiological parameters important in the control of acid-base stability in cattle. These changes, particularly when involving electrolyte transport in muscle tissue and the ensuing
23 REFERENCES Frens, J., 1975. The influence of skin temperature on thermoregulation. In: N.J.M.A. Tilburg, M.G. Strasbourg and E.F.J.R. Bath (Editors), Thermography. S. Karger, Basel, pp. 218-223. Hattingh, J., Wright, P.G., Mitchell, G., Maria, F., Ganhao, S., Riekert, S. and Ritchie, A., 1985. Effects of blood sampling and slaughter on certain blood variables of cattle. S. Afr. J. Anim. Sci., 81: 280-281. Houdas, Y. and Guieu, J.D., 1975. Environmental factors affecting skin temperatures. In: N.J.M.A. Tilburg, M. Strasbourg and E.F.J.R. Bath (Editors), Thermography. S. Karger, Basel, pp. 157-165. Hutcheson, D.P. and Cole, N.A., 1986. Management of transit-stress syndrome in cattle: Nutritional and environmental effects. J. Anim. Sci., 62: 555-560. Jones, S.D.M., Schaefer, A.L., Tong, A.K.W. and Vincent, B.C., 1988. The effects of fasting and transportation on beef cattle. 2. Body component changes, carcass composition and meat quality. Livest. Prod. Sci., 00: 00-00. Kilgour, R. and Dalton, C., 1984. Livestock Behavior. Methuen Publishers Ltd. Auckland, New Zealand, pp. 7-53. Kent, J.E. and Ewbank, R., 1986. The effect of road transportation on the blood constituents and behaviour of calves. III. Three months old. Br. Vet. J., 142: 326-335. Kenny, F.J. and Tarrant, P.V., 1987. The physiological and behavioural responses of crossbred Friesian Steers to short-haul transport by road. Livest. Prod. Sci., 17: 63-75. Lacourt, A. and Tarrant, P.V., 1985. Glycogen depletion patterns in myofibres of cattle during stress. Meat Sci., 15: 85-100. Lefcourt, A.M., 1986. Usage of the term stress as it applies to cattle. Vlaams Diergeneeskd. Tijdschr.. 55: 258-265. Martin, D.W., 1985. The chemistry of respiration. In: D.W. Martin, Jr., P.A. Mayes, V.W. Rodwell and D.K. Granner (Editors), Harpers Review of Biochemistry. 20th edn. Lang Medical Publishers, Los Angeles, California, pp. 610-620. Morisse, J.P., Cotte, J.P. and Huonnic, D., 1985. High pH bullock meat. High sugar preslaughter regime. RTVA, 211: 27-31. Ozutsumi, K., Ito, K., Kawanishi, T., Yamazaki, T. and Karia, Y., 1984. Physiological changes in body weight and blood characteristics of fattened cattle during fasting from finishing to slaughter. Jpn. J. Zootech. Sci., 55: 735-740. Pearson, J.F., 1976. Maternal and fetal acid-base balance. In: R.W. Beard and P.W. Nathanielsz (Editors), Fetal Physiology and Medicine. W.B. Saunders Comp. Ltd., London, pp. 429-509. Price, M.A. and Tennessen, T., 1981. Preslaughter management and dark-cutting in the carcasses of young bulls. Can. J. Anim. Sci., 61: 205-208. Romanyuck, B.P. and Stoyanovskii, S.V., 1982. Stress during transportation and the quality of meat. Veterinariya (Moscow), 6: 60-61. S.A.S., 1985. S.A.S. User's Guide: Basics and Statistics. Version 5 edition, S.A.S. Institute Inc., Box 8000, Cary, NC. Stephens, D.B., 1980. Stress and its management in domestic animals: A review of behavioral and physiological studies under field and laboratory situations. Adv. Vet. Sci. Comp. Med., 24:179210. Stewart, P.A., 1983. Modern quantitative acid-base chemistry. Can. J. Physiol. Pharmacol., GI: 1444-1461. Warriss, P.D., 1986. Live animal marketing effects on carcass and meat quality. Proceedings, Agriculture Canada Work Planning Meeting on Meat Quality. Research Program Service, Minister of Supply and Services Canada 1987, Ottawa, Manitoba, October 1986, pp. 7-41. Wythes, J.R., Johnston, G.N., Beaman, N. and O'Rourke, P.K., 1985. Preslaughter handling of cattle: The availability of water during the lairage period. Aust. Vet. J., 62:163-165.
24
RESUME Schaefer, A.L., Jones, S.D.M., Tong, A.K.W. et Vincent, B.C., 1988. Les effets du jefine et du transport chez les bovins de boucherie. 1. Equilibre acido-basique, dlectrolytes et d~tection de la perte de chaleur par thermographie. Livest. Prod. Sci., 20:15-24 (en anglais). Nous avons examin~ les effets de l'adaptation thermique, de l'~quilibre acido-basique et des ~lectrolytes sanguins sur la couleur de la viande de bovins de boucherie soumis au stress caus~ par la mise en march~. Cinquante bouvillons et g~nisses Hereford d'un an, et de poids commercial ont ~t~ r~partis en trois groupes. Les animaux du premier groupe (T1, n = 17 ), ont ~t~ transport~s sur une distance de 3 km, et abattus apr~s avoir ~t~ priv~s de nourriture durant 24 heures. Le deuxi~me groupe (T2, n = 17) dtait compos~ d'animaux m~lang~s ~ des animaux ~trangers, transport~s sur une distance de 320 km puis abattus apr~s un jefine de 48 heures. Le troisi~me groupe (T3, n = 16) requt un traitement semblable au deuxieme groupe mais ffit transport~ sur une distance suppl~mentaire de 320 km pour atteindre un jefine d'une dur~e de 72 heures. Pour tousles animaux, les niveaux sanguins de bicarbonate, de gaz carbonique et d'ion hydrog~ne mesur~s juste avant l'abattage furent significativementplus faibles que ceux mesur~s avant le traitement (P < 0.01 ). Par contre, le niveau initial de lactate ~tait plus ~lev~ ( P < 0.04) que celui pr~c~dant l'abattage. Le deuxi~me groupe, a cependant d~montr~ des niveaux de bicarbonate, exc~s de base et bicarbonate ~talon plus ~lev~sque les animaux des Groupes 1 et 3. La d~perdition de chaleur moyenne mesur~e par thermographe ffit r~duite (P < 0.01 ) proportionnellement ~ l'augmentation de la longueur du jefine et du transport coincidant; avec une couleur plus fonc~e de la viande. Ces rdsultats sugg~rent que la tension caus~e par la mise en march~ des animaux peut provoquer un changement du statut thermodynamique et acido-basique de l'animal. KURZFASSUNG Schaefer, A.L., Jones, S.D.M., Tong, A.K.W. und Vincent, B.C., 1988. Die Auswirkungen der N[ichterung und des Transports auf Fleischringer. 1. S~iure-Basen-Elektrolyt-Bilanzund mit Infrarot gemessener W~meverlust von Fleischrindern. Livest. Prod. Sci.., 20:15-24 (auf englisch). Zweck des Versuches war die Feststellung der S~iure-Basen-Elektrolyte und der thermischen Anpassung von Fleischrindern, die dem Vermarktungsstress unterworfen sind. 50 einj~hrige, auf das Vermarktungsgewicht gebrachte Ochsen und F~sen der Hereford-Rasse wurden zuf~illigauf eine von drei Behandlungsgruppen verteilt. In Behandlung 1 (T1, n = 17) wurden die Tiere 3 km transportiert und nach 24stfindiger Nfichterung geschlachtet. Die Tiere der Behandlung 2 (T2, n = 17) wurden beziiglich Geschlecht gemischt, 320 km transportiert und nach 48stfindiger Nilchterung geschlachtet. In Behandlung 3 (T3, n = 16) wurden die Tiere wie in Behandlung 2 transportiert, wozu am 2. Tag ein zus~itzlicher Transport von 320 km kam, bevor sie nach 72 Stunden Nfichterung geschlachtet wurden. Verglichen mit den Me£ergebnissen vor der Behandlung zeigten das Bicarbonat des Blutes, der Basenfiberschut~, das Kohlendioxyd und die Wasserstoff-Ionen-Konzentrationbei allen Tieren direkt vor der Schlachtung signifikant niedrigere Werte ( P < 0.01 ). Im Gegensatz dazu zeigte das Blut-Laktat einen Anstieg im Vergleich zu den Werten vor der Behandlung (P < 0.04). Zwischen den Behandlungen zeigten Tiere der Gruppe T2 hShere Were fiir Bicarbonat (P < 0.05 ), Basenfiberschu£ und Kohlendioxyd als die Tiere der Gruppen T1 und T3. Der mittlere, mit Infrarot gemessene Wiirmeverlust reduziert sich mit zunehmender N~ichterungsdauer und Transportl~inge (P < 0.01 ), welches interessanterweise mit steigender dunkler Farbe des Fleisches einherging. Diese Ergebnisse deuten an, da~ der Stre£ der Vermarktung Ver~nderungen im S~ure-Basen-Haushalt und im thermodynamischen Zustand eines Tieres verursachen kann.