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The effects of simulated transport and handling on heart rate, blood pressure and renal arterial blood flow in the pig
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THE EFFECTS OF SIMULATED TRANSPORT AND HANDLING ON HEART RATE, BLOOD PRESSURE AND RENAL ARTERIAL BLOOD FLOW IN THE PIG
D.B. STEPHENS
and R.D. RADER
A.R.C. Institute of Animal Physiology, Babraham, Cambridge (Gt. Britain) and Human Centrifuge and Environmental Physiology Laboratories, University of Southern California, Los Angeles (U.S.A.)
ABSTRACT
The methods currently employed in pig husbandry usually involve transportation of animals at some stage of their productive cycle. In addition, pigs are aIso frequently handled for various purposes such as identification marking, minor surgery, weighing and vaccination. These events are usually novel to the animal and may produce an acute unconditioned emotional response. Events associated with transportation and handling induce a range of responses which are usually referred to as stress. If the various physiological responses are detectable, then measurements of parameters such as cardiovascular and renal blood-flow changes, which accompany the stress response, would be useful in studies designed to detect and evaluate the degree of the stress induced in pigs by novel stimuli. In the present study, ultrasonic techniques using chronically implanted flow sensors for measuring heart rate and changes in blood flow to the kidney in conscious, freestanding, and unanaesthetised pigs have been employed to detect cardiovascular responses to simulated transport and various handling procedures. In addition, blood pressure was measured via a transducer placed in the carotid artery. The weights of the pigs ranged between 40 and 50 kg at the time of surgery. During the first 30 min of exposure to the transport simulator, it was found that Heart Rate (HR) was elevated in all pigs. It rose to 150 beats/min from the resting control level of 110 beats/min. As the pigs became familiar with the experimental situation, as a result of repeated exposure, the increase in HR in response to transport simulation was reduced. There were no significant changes in blood pressure as a result of the experimental manipulation. After establishing the level of blood flow to the kidney in the resting pig whilst still in the home cage (as a base-line control value), the changes due to experimental manipulation were monitored. During the tests with the pig inside the transport simulator, renal blood flow, after a transient decrease at the start, increased to about 20% above the resting control value. Handling animals appeared to cause maximum disturbance. HR was elevated to more than double the level of the resting value. Similarly, there
410
was a two-fold increase in blood pressure, to 192 mm Hg compared to 96 mm Hg at rest. There was a concomitant marked decrease in renal blood flow. For example, in one pig the normal renal blood flow of 5 ml/s was reduced to nearly half during the handling procedure. However, within 4 min of release, normal flow levels had been re-established. It is not clear why renal flow increased for the greater proportion of the time when the animals were exposed to transport simulation. However, renal blood flow in many species is increased due to vasodilatation in response to several naturally-occurring substances, including dopamine and bradykinin. If, for example, dopamine is released in the pig along with adrenaline and noradrenaline from the adrenal gland, then the renal vasodilatation might be a direct effect of the dopamine. It is proposed to examine these possibilities in the future.
THE RELATIONSHIP BETWEEN SOCIAL FEEDING BEHAVIOUR IN PIGS
FACILITATION
AND
L.C. HSIA and D.G.M. WOOD-GUSH Edinburgh
School
of Agriculture,
West Mains Road,
Edinburgh
(Gt. Britain)
ABSTRACT
Sixteen young castrated boars and 4 sheep were used in this experiment, which had 4 replicates. Each of the 4 pigs in each replicate went through the following 4 treatments in a Latin square design: (A) a single pig with a sheep treatment in which the single pig and a sheep were kept in the same room but in different stalls. (B) Closed stall treatment in which the 4 pigs could see each other but were separated by bars. (C) Long trough treatment in which a trough long enough for 4 pigs to eat at the same time was provided. (D) Single trough-space treatment in which the trough provided only allowed one of the 4 pigs to eat at a time. The results show that total food consumption in Treatments C and D were significantly higher (P < 0.01) than in Treatment A. Total food intake in Treatment C was higher than in Treatment B (P < 0.05). Total eating time was greater in Treatments A and B than in Treatments C and D. The eating speed of pigs was significantly higher (P < 0.01) in Treatment C than in Treatments A and B. The speed of eating in the pigs was found to increase as body weight increased. The total amount of fighting, which included all types of aggressive behaviour, was significantly greater in the single trough-space treatment than in long trough treatment (P < 0.02). However, the amount of biting and butting did not differ between these two treatments.
THE EFFECTS OF SIMULATED TRANSPORT AND HANDLING ON HEART RATE, BLOOD PRESSURE AND RENAL ARTERIAL BLOOD FLOW IN THE PIG
D.B. STEPHENS
and R.D. RADER
A.R.C. Institute of Animal Physiology, Babraham, Cambridge (Gt. Britain) and Human Centrifuge and Environmental Physiology Laboratories, University of Southern California, Los Angeles (U.S.A.)
ABSTRACT
The methods currently employed in pig husbandry usually involve transportation of animals at some stage of their productive cycle. In addition, pigs are aIso frequently handled for various purposes such as identification marking, minor surgery, weighing and vaccination. These events are usually novel to the animal and may produce an acute unconditioned emotional response. Events associated with transportation and handling induce a range of responses which are usually referred to as stress. If the various physiological responses are detectable, then measurements of parameters such as cardiovascular and renal blood-flow changes, which accompany the stress response, would be useful in studies designed to detect and evaluate the degree of the stress induced in pigs by novel stimuli. In the present study, ultrasonic techniques using chronically implanted flow sensors for measuring heart rate and changes in blood flow to the kidney in conscious, freestanding, and unanaesthetised pigs have been employed to detect cardiovascular responses to simulated transport and various handling procedures. In addition, blood pressure was measured via a transducer placed in the carotid artery. The weights of the pigs ranged between 40 and 50 kg at the time of surgery. During the first 30 min of exposure to the transport simulator, it was found that Heart Rate (HR) was elevated in all pigs. It rose to 150 beats/min from the resting control level of 110 beats/min. As the pigs became familiar with the experimental situation, as a result of repeated exposure, the increase in HR in response to transport simulation was reduced. There were no significant changes in blood pressure as a result of the experimental manipulation. After establishing the level of blood flow to the kidney in the resting pig whilst still in the home cage (as a base-line control value), the changes due to experimental manipulation were monitored. During the tests with the pig inside the transport simulator, renal blood flow, after a transient decrease at the start, increased to about 20% above the resting control value. Handling animals appeared to cause maximum disturbance. HR was elevated to more than double the level of the resting value. Similarly, there
410
was a two-fold increase in blood pressure, to 192 mm Hg compared to 96 mm Hg at rest. There was a concomitant marked decrease in renal blood flow. For example, in one pig the normal renal blood flow of 5 ml/s was reduced to nearly half during the handling procedure. However, within 4 min of release, normal flow levels had been re-established. It is not clear why renal flow increased for the greater proportion of the time when the animals were exposed to transport simulation. However, renal blood flow in many species is increased due to vasodilatation in response to several naturally-occurring substances, including dopamine and bradykinin. If, for example, dopamine is released in the pig along with adrenaline and noradrenaline from the adrenal gland, then the renal vasodilatation might be a direct effect of the dopamine. It is proposed to examine these possibilities in the future.
THE RELATIONSHIP BETWEEN SOCIAL FEEDING BEHAVIOUR IN PIGS
FACILITATION
AND
L.C. HSIA and D.G.M. WOOD-GUSH Edinburgh
School
of Agriculture,
West Mains Road,
Edinburgh
(Gt. Britain)
ABSTRACT
Sixteen young castrated boars and 4 sheep were used in this experiment, which had 4 replicates. Each of the 4 pigs in each replicate went through the following 4 treatments in a Latin square design: (A) a single pig with a sheep treatment in which the single pig and a sheep were kept in the same room but in different stalls. (B) Closed stall treatment in which the 4 pigs could see each other but were separated by bars. (C) Long trough treatment in which a trough long enough for 4 pigs to eat at the same time was provided. (D) Single trough-space treatment in which the trough provided only allowed one of the 4 pigs to eat at a time. The results show that total food consumption in Treatments C and D were significantly higher (P < 0.01) than in Treatment A. Total food intake in Treatment C was higher than in Treatment B (P < 0.05). Total eating time was greater in Treatments A and B than in Treatments C and D. The eating speed of pigs was significantly higher (P < 0.01) in Treatment C than in Treatments A and B. The speed of eating in the pigs was found to increase as body weight increased. The total amount of fighting, which included all types of aggressive behaviour, was significantly greater in the single trough-space treatment than in long trough treatment (P < 0.02). However, the amount of biting and butting did not differ between these two treatments.