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Physiological and behavioural aspects of assessing stress and welfare in the pig
579 The stress-induced changes in the function of the endocrine system very often result in unsatisfactory reproductive performance. Preliminary results of dealing with previous reproductive disorders in intensive piggeries are reported.
PHYSIOLOGICAL AND BEHAVIOURAL STRESS AND WELFARE IN THE PIG
ASPECTS
OF ASSESSING
J.L. BARNETT Animal Research Institute,
Werribee, Vie., 3030
(Australia)
ABSTRACT Background information is given on adrenal function in pigs and the implications this has for the design of experiments to examine acute stressors and to obtain a representative measure of plasma corticosteroids. Two experiments using corticosteroids to measure stress responses in pigs are described. First, individual and group penning of pigs is compared. Moving pigs to a new environment results in an acute stress response which is more severe when social interactions are involved. The effects of the penning treatment resulted in a chronic stress response in individually penned (no visual or tactile contact) pigs; the a.m.-p.m. rhythm of corticosteroids was abolished, afternoon values were higher (P < O.Ol), and mean corticosteroid binding capacity was lower (P < O.Ol), with a consequent elevation (P < 0.05) of free (biologically active) corticosteroids. In the second experiment, the effects of man-animal interactions were examined in growing pigs. Two treatments were imposed from 8 to 24 weeks of age, which resulted in either an avoidance or approach behaviour by the pigs to humans. In the group that showed avoidance, a 2-min exposure to humans resulted in an acute stress response (P < 0.05) with a I-fold increase in hormone levels, that returned to pre-exposure levels within 30 min. In the absence of humans, this group also had elevated (P < 0.005) corticosteroid levels throughout the day. One consequence of this chronic stress response was a significant reduction in growth rate (P < 0.05) and a lower food conversion rate.
THE SOCIAL ENVIRONMENT FEMALE PIG
AND REPRODUCTION
OF THE
P.H. HEMSWORTH Animal Research Institute,
Werribee,
Vie., 3030 (Australia)
ABSTRACT The objective of this paper is to discuss briefly two recent studies that demonstrate the important role of the social environment on reproduction of the gilt and sow. The influence of the social environment during rearing was studied by rearing four
PHYSIOLOGICAL AND BEHAVIOURAL STRESS AND WELFARE IN THE PIG
ASPECTS
OF ASSESSING
J.L. BARNETT Animal Research Institute,
Werribee, Vie., 3030
(Australia)
ABSTRACT Background information is given on adrenal function in pigs and the implications this has for the design of experiments to examine acute stressors and to obtain a representative measure of plasma corticosteroids. Two experiments using corticosteroids to measure stress responses in pigs are described. First, individual and group penning of pigs is compared. Moving pigs to a new environment results in an acute stress response which is more severe when social interactions are involved. The effects of the penning treatment resulted in a chronic stress response in individually penned (no visual or tactile contact) pigs; the a.m.-p.m. rhythm of corticosteroids was abolished, afternoon values were higher (P < O.Ol), and mean corticosteroid binding capacity was lower (P < O.Ol), with a consequent elevation (P < 0.05) of free (biologically active) corticosteroids. In the second experiment, the effects of man-animal interactions were examined in growing pigs. Two treatments were imposed from 8 to 24 weeks of age, which resulted in either an avoidance or approach behaviour by the pigs to humans. In the group that showed avoidance, a 2-min exposure to humans resulted in an acute stress response (P < 0.05) with a I-fold increase in hormone levels, that returned to pre-exposure levels within 30 min. In the absence of humans, this group also had elevated (P < 0.005) corticosteroid levels throughout the day. One consequence of this chronic stress response was a significant reduction in growth rate (P < 0.05) and a lower food conversion rate.
THE SOCIAL ENVIRONMENT FEMALE PIG
AND REPRODUCTION
OF THE
P.H. HEMSWORTH Animal Research Institute,
Werribee,
Vie., 3030 (Australia)
ABSTRACT The objective of this paper is to discuss briefly two recent studies that demonstrate the important role of the social environment on reproduction of the gilt and sow. The influence of the social environment during rearing was studied by rearing four