Development and evaluation of an animal health and welfare monitoring system for veterinary supervision of pullet farms

Regular welfare monitoring throughout rearing of pullets may help to identify problems early and take counteractions timely, which helps in guaranteeing good welfare. The aims of our observational study were (i) to establish and test a welfare monitoring system that can be used during (short) routine veterinary and technical staff visits for pullet flocks, (ii) to use the monitoring system to investigate variability between flocks and (iii) to analyse factors that potentially affect pullets' body weight, uniformity in body weight and mortality. The developed monitoring system tries to minimise the time required while not losing important information. Age-specific recording sheets comprise animal-based indicators of welfare and relevant environmental factors (housing, management, care) to allow for identifying causes of problems and targeted action. Finally, the system was implemented in a cross-sectional study and data collected in 100 flocks (67 organic, 33 conventional) on 28 rearing farms in Austria. Linear mixed models were used to identify factors influencing body weight, uniformity and mortality, both including all flocks (A) and only organic flocks (O) and a linear regression model with all flocks to investigate associations within animal-based indicators. High variability was found between flocks in animal-based indicators. Body weight was higher when the pre-rearing period was shorter (p ≤ 0.001, A&O), with higher intensities of light (p = 0.012, O), with only one compared to more stockpersons (p ≤ 0.007, A&O), with a higher number of flock visits per day (p ≤ 0.018, A&O), and a lower avoidance distance (p = 0.034, A). Body weight uniformity increased, with age and decreased with the duration of the light period (p = 0.046, A), and, amongst others, was higher on organic farms (farming type; p = 0.041). The latter may reflect a more uniform level of welfare due to a lower stocking density and lowered effects of social competition. Within organic flocks mortality was lower if pullets had access to a covered veranda (p = 0.025) resulting in an overall lower stocking density inside the barn, while in the model including all farms mortality was higher in cases where a disease had been diagnosed. We conclude that our monitoring system can easily be implemented in regular veterinary and technical staff visits, but could also be used by the farmers'. Several easy-to-record animal-based indicators of animal welfare could be analysed more frequently to increase early detection of problems. Implementation of such a routine-based monitoring system with easy-to-assess animal-based parameters and input measures can contribute to better animal health and welfare in pullets.

Exploring the Potential of Precision Livestock Farming Technologies to Help Address Farm Animal Welfare

The rise in the demand for animal products due to demographic and dietary changes has exacerbated difficulties in addressing societal concerns related to the environment, human health, and animal welfare. As a response to this challenge, Precision Livestock Farming (PLF) technologies are being developed to monitor animal health and welfare parameters in a continuous and automated way, offering the opportunity to improve productivity and detect health issues at an early stage. However, ethical concerns have been raised regarding their potential to facilitate the management of production systems that are potentially harmful to animal welfare, or to impact the human-animal relationship and farmers' duty of care. Using the Five Domains Model (FDM) as a framework, the aim is to explore the potential of PLF to help address animal welfare and to discuss potential welfare benefits and risks of using such technology. A variety of technologies are identified and classified according to their type [sensors, bolus, image or sound based, Radio Frequency Identification (RFID)], their development stage, the species they apply to, and their potential impact on welfare. While PLF technologies have promising potential to reduce the occurrence of diseases and injuries in livestock farming systems, their current ability to help promote positive welfare states remains limited, as technologies with such potential generally remain at earlier development stages. This is likely due to the lack of evidence related to the validity of positive welfare indicators as well as challenges in technology adoption and development. Finally, the extent to which welfare can be improved will also strongly depend on whether management practices will be adapted to minimize negative consequences and maximize benefits to welfare.

Human-animal interactions in agriculture and their impact on animal welfare and performance

Human-animal interactions are a common feature of modern intensive farming systems and these interactions may have marked consequences on animal productivity and welfare. Research in agriculture has shown interrelationships between the stockperson’s attitudes and behaviour and the behaviour, productivity and welfare of farm animals and the following model of human-animal interactions in agriculture has been proposed. Because a stockperson’s behaviour towards animals is largely under volitional control, this behaviour is strongly influenced by the attitudes that the stockperson holds about the animals. These attitudes and consequent behaviours predominantly affect the animal’s fear of humans which, in turn, affects the animal’s performance and welfare. The mechanism whereby fear affects performance and welfare appears to be through a chronic stress response. The risk to welfare also arises if the stockperson’s attitude and behaviour towards the animals are negative because the stockperson’s commitment to the surveillance of, and the attendance to, welfare issues is likely to be highly questionable.

Recent research in the pig industry has shown that a training programme targeting the key attitudes and behaviour of stockpersons produced improvements in stockperson attitudes and behaviour and animal behaviour and productivity. These results indicate the potential to improve animal productivity and welfare by targeting the stockperson’s attitudes and behaviour for improvement. Techniques which may be useful in this regard include staff selection and training procedures addressing these important human attributes.

The farmers’ influence on calves’ behaviour, health and production of a veal unit

Although veal production is a highly standardized system, there still remains considerable variability in productivity between units. This variability might be due to the farmers working on these units, through differences in stockmanship, work attitudes or behaviour, which in turn may affect animals’ fear responses, productivity and health. A survey was conducted on 50 commercial farms affiliated to the same veal company. All units had calves housed in individual crates, a similar number of crates, and the same diets and management advice. Data were collected on: building and general farm characteristics, farmers’ backgrounds and their attitudes towards their work and calves, farmers’ behaviour with the calves, calves’ reactivity to people, and disease level of the calves. Productivity results (growth rates, food efficiency and mortality) were used to classify veal units as ‘high producing’ (no. = 24) v. ‘moderate producing’ (no. = 26). Calves were less reactive to people in units where the farmer behaved sympathetically and where there were several stockpersons working. The disease level was lower in units where the farmer had a positive attitude towards the sensitivity of the calves to contact and towards the importance of cleaning. Productivity of the veal unit was associated with the health of the calves but not with their reactivity to people.

It is suggested that the farmer can have an influence on the success of the veal unit mainly through his/her ability to control the health of the calves and that a positive attitude towards animals and towards work (specifically cleaning actions) can improve the accuracy of surveillance and care of the animals. Moreover, through his/her behaviour with the calves and his/her ability to control their health, the farmer can play an important rôle in assuring calves’ welfare.

A Comparison of Zoo Animal Behavior in the Presence of Familiar and Unfamiliar People

As recorded in domestic nonhuman animals, regular interactions between animals in zoos and keepers and the resulting relationship formed (human-animal relationship [HAR]) are likely to influence the animals' behaviors with associated welfare consequences. HAR formation requires that zoo animals distinguish between familiar and unfamiliar people. This ability was tested by comparing zoo animal behavioral responses to familiar (routine) keepers and unfamiliar keepers (participants in the "Keeper for the Day" program). Study subjects included 1 African elephant (Loxodonta Africana), 3 Rothschild's giraffes (Giraffa camelopardalis rothschildi), 2 Brazilian tapir (Tapirus terrestris), and 2 slender-tailed meerkats (Suricata suricatta). Different behavior was evident and observed as decreased avoidance behavior toward familiar keepers (t7 = 6.00, p <  .001). This finding suggests the zoo animals have a lower level of fear toward familiar keepers. Keeper familiarity did not significantly affect any other behavioral measure. This finding suggests that in the current study, unfamiliar keeper presence did not appear to have detrimental effects. Furthermore, unfamiliar keeper-animal interactions could provide an increased number of positive human-animal interactions and potentially enhance animal welfare.

The integration of human-animal relations into animal welfare monitoring schemes

There are increasing local and international pressures for farm animal welfare monitoring schemes. Housing of farm animals is a contentious issue for many, although the impact of the housing system may be overestimated by some. In contrast, the topic of stockmanship has received relatively little attention, even though research has shown that animal carers or stockpeople have a major impact on the welfare of their livestock. While welfare monitoring schemes are likely to improve animal welfare, the impact of such schemes will only be realised by recognising the limitations of stockpeople, monitoring ‘stockmanship’ and providing specific stockperson training to target key aspects of stockmanship. Appropriate strategies to recruit and train stock-people in the livestock industries are integral to safeguarding the welfare of livestock. Monitoring the key job-related characteristics of the stockperson, attitudes to animals and to working with these animals, empathy, work motivation and technical knowledge and skills, provides the opportunity to detect deficits in stockmanship and the necessity for further targeted training. Due to the strong relationships between stockperson attitudes and behaviours and animal fear responses, as well as the relationships between attitudes and other job-related characteristics, we believe attitudes, together with empathy, work motivation and technical knowledge and skills, should be the principal focus of measuring stockmanship in on-farm welfare monitoring schemes.

Effects of social disruption on physical parameters, corticosterone concentrations, and immune system in two genetic lines of White Leghorn layers

Farm management practices such as increasing group size and mixing of unfamiliar chickens may cause social disruption and affect bird well-being. To examine genetic-associated physical and physiological differences in response to social disruption, 2 strains of White Leghorn hens were used in the study [i.e., HGPS (line selected for high group production and survivability) and DXL (DeKalb XL commercial line)]. Social disruption was created when hens were 50 wk of age by increasing group size from 4 hens (control) to 8 hens (experimental) per cage and providing an unstable social environment by moving 2 hens weekly between cages within the same line (experimental hens only). At 58 wk of age, hens were feather-scored. After euthanization, BW and the right adrenal gland weight were collected (n = 10 per treatment). Adrenal gland weight was adjusted for BW, and adjusted adrenal weight was used for analysis. Plasma corticosterone was quantified using RIA. The T-lymphocytes (CD4+ and CD8+) were measured using flow cytometry. Results showed that average feather cover score was greater for DXL hens than HGPS hens in both the unstressed (P < 0.05) and stressed treatment (P < 0.01). There was no difference in BW in DXL and HGPS hens between the control and the social disruption treatments. However, the relative adrenal weight of HGPS hens tended to be lower than control hens after social disruption (0.05 > P < 0.10). Plasma corticosterone was significantly lower in both strains following social disruption (P < 0.01). The T-lymphocyte ratio (CD4+:CD8+) was greater in HGPS hens than DXL hens post social disruption (P < 0.05). The data indicate that the 2 strains of hens reacted differently in terms of the adrenal system and immunity in response to social disruption. Hens selected for longevity with docile behaviors and high productivity, such as HGPS hens, provide a useful tool for improving animal well-being.

Chronic social stress differentially regulates neuroendocrine responses in laying hens: II. Genetic basis of adrenal responses under three different social conditions

Chicken lines were divergently selected for both high (HGPS) or low (LGPS) group productivity and survivability resulting from cannibalism and flightiness in colony cages. Each line has unique characteristics in physical indexes, domestic behavior, and physiological responsiveness to stress. The differences between the selected lines could be reflected in differing regulation of the neuroendocrine system such as the hypothalamic-pituitary-adrenal axis. Change of the adrenal function is a key initial event in response to stress in animals, which differs for this trait. Comparisons between the selected lines showed that adrenal function was stable in HGPS hens but not in LGPS hens in response to chronic social stress. Social stress-induced adrenal hypertrophy and its positive correlation with plasma corticosterone concentrations were found in the LGPS hens but not in the HGPS hens. The data demonstrated that chickens selected for variations in productivity and survivability variously altered the adrenal system in response to social stressors. The results suggest that these chicken lines could be valuable animal models for biomedical investigation of the effect of genetic-environmental interactions on the neuroendocrine function in controlling stress responses.

Effects of genetic selection for high or low antibody response on resistance to a variety of disease challenges and the relationship of resource allocation

Lines of white leghorn chickens were selectively bred for either a high (H) or low (L) antibody response to sheep erythrocytes. The parental lines, HH and LL, and reciprocal crosses, HL (sire line cited first and dam line second) and LH, were compared for their responses to various diseases. High antibody titers were associated with reduced body weight. Lines and their crosses were challenged with infectious diseases. The LL line was most resistant to Mycobacterium avium, whereas the HH line was most susceptible. The HH line was most resistant to Mycoplasma gallisepticum, whereas the LL line was most susceptible. These findings indicate that defense against infectious diseases are resource expensive. In order to save resources, it is possible that different parts of a population might genetically devote high levels of resources against different types of diseases so that the entire population is not susceptible to a single infection.

Effect of early handling of turkey poults on later responses to a dexamethasone-Escherichia coli challenge. 1. Production values and physiological response

The stress responses of mice and rats has been shown to be permanently altered by brief, gentle handling during the first 10 d of life, resulting in increased BW and resistance to stress-induced immunosuppression. The purpose of this study was to determine whether early handling of turkey poults could permanently affect production values and physiology of adult turkeys. Turkey poults were handled 0, 1 (1x), or 2 (2x) times daily for the first 10 d after hatch. Handling consisted of gently catching each poult and holding it for 10 s. On Day 11 after hatch, half of the birds from each handling treatment were treated with three injections of 2 mg dexamethasone (DEX)/kg BW on alternating days. On the day of the third DEX injection, duplicate pens of birds were also inoculated in the airsac with 0 or 50 cfu of Escherichia coli. The same birds were treated with a second series of DEX injections at 5 wk of age. Two weeks later, all birds were weighed, and 3 wk later four birds per pen were bled and 10 birds per pen were necropsied; relative organ weights were then determined. Surviving birds were treated with a third series of DEX injections at 10 wk of age; 2 wk later, all surviving turkeys were bled, weighed, and necropsied. Feed consumption was determined weekly. There were no differences due to handling treatment on the body weights or on the relative organ weights of birds that died after the first DEX treatment. Birds treated with a second DEX injection at 5 wk of age and handled 1x daily had decreased BW. Those handled 1x or 2x daily had higher feed conversion ratios. Surviving birds that were given a third DEX treatment had higher BW and no difference in feed conversion when handled 1x or 2x daily. Relative liver, heart, and spleen weights were affected by handling of DEX-E. coli-treated birds, as were serum chemistry values for calcium, iron, glucose, total protein, blood urea nitogen, uric acid, aspartate aminotransferase, alanine aminotransferase, lactate dehydrogenase, and gamma-glutamyltransferase. Handling also affected the numbers of white blood cells of DEX-treated birds. These results indicate that brief and gentle handling of turkey poults during the first 10 d after hatch has lasting effects on production values and physiology of adult turkeys and that these effects can be positive or negative. These results suggest a genetic divergence in the response to stress and its effect on production values and physiology of commercial turkey populations.

Effects of group selection for productivity and longevity on blood concentrations of serotonin, catecholamines, and corticosterone of laying hens

Selection of a line of White Leghorn chickens for high group productivity and longevity resulted in reducing cannibalism and flightiness in multiple-hen cages. Improvements in survival might have been due to changes of physiological homeostasis. The objective of the present study was to test the hypothesis that genetic selection for high (HGPS) and low (LGPS) group productivity and survivability also altered regulation of neuroendocrine homeostasis. Hens were randomly assigned to individual cages at 17 wk of age. At 21 wk of age, blood concentrations of dopamine, epinephrine, norepinephrine, and serotonin were measured using HPLC assay. Blood concentrations of corticosterone were measured using radioimmunoassay. The LGPS hens had greater blood concentrations of dopamine and epinephrine than the HGPS hens (P < 0.01). The blood concentration of norepinephrine was not significantly different between the lines, but the ratio of epinephrine to norepinephrine was greater in the LGPS hens (P < 0.01). The blood concentrations of serotonin were also higher in the LGPS hens compared to those in the HGPS hens (P < 0.01). Although the HGPS hens tended to have a higher level of blood corticosterone, the difference was not significant (1.87 +/- 0.19 vs. 1.49 +/- 0.21 ng/mL; P = 0.08). The results suggest that selection for group productivity and survivability alters the chickens' neuroendocrine homeostasis, and these changes may correlate with its line-unique coping ability to domestic environments and survivability.

Effect of early handling of turkey poults on later responses to multiple dexamethasone-Escherichia coli challenge. 2. Resistance to air sacculitis and turkey osteomyelitis complex

Dexamethasone (DEX)-induced immunosuppression facilitates Escherichia coli pathogenesis leading to lesions of air sacculitis and turkey osteomyelitis complex (TOC). The purpose of this study was to determine if early handling could affect resistance to disease in this model. Seven hundred twenty male turkey poults were handled 0, 1 (1x), or 2 (2x) times daily for the first 10 d after hatch. Handling consisted of gently catching each individual poult, holding it for 10 s, and placing it into a basket. Starting on Day 11 after hatch, half of the birds from each handling treatment were treated with three injections of 2 mg DEX/kg BW on alternating days. On the day of the third DEX treatment, duplicate pens of birds were also inoculated in the air sac with 0 or 50 cfu of E. coli. All DEX-treated birds were given a second series of DEX injections at 5 wk of age, and 10 birds per pen were necropsied 3 wk later. Surviving birds were treated with a third series of DEX injections at 10 wk of age. Two weeks later, all surviving turkeys were necropsied. All mortalities and necropsied birds were scored for air sacculitis and examined for TOC lesions. All livers, air sacs, and TOC lesions were cultured for bacteria. There was increased mortality after the first series of DEX treatments of birds handled 2x. After the second series of DEX treatments, birds handled 1x had increased mortality, incidence of air sacculitis, and recovery of E. coli from tissues, whereas 2x handled birds were identical to unhandled controls. After the third series of DEX treatments, handling 1x resulted in decreased air sacculitis scores and decreased incidence of mortality, green liver, TOC lesions, and recovery of E. coli from tissues. The effects of early handling of turkey poults were variable, depending on the number of DEX treatments and the age of the birds. These results suggest that early handling can affect the susceptibility of stressed turkeys to E. coli air sacculitis and TOC and that differences in susceptibility may be influenced by age and individual variability in the stress response.

Ease of capture in lines of Japanese quail (Coturnix japonica) subjected to contrasting selection for fear or sociability

Japanese quail (Coturnix japonica) of lines, which have been subjected to contrasting selection for duration of the tonic immobility (TI) reaction or social reinstatement (SR) behaviour over many generations show corresponding differences in underlying fearfulness and sociality. As fearfulness and sociality are particularly influential traits in domesticated species, the finding that such traits respond to artificial selection may have important implications for poultry welfare and performance. However, it is not known if or how such selection has influenced human-animal interactions. The present experiment investigated the influence of fearfulness and SR behaviour on the ease with which birds could be caught and handled. Birds of lines selected for duration of the TI response or SR behaviour were reared in mixed line groups (LTI and STI or HSR and LSR) of 491 and 346 birds, respectively, until 6 weeks of age. When the birds were 2, 4, and 6 weeks of age, they were caught one by one and their individual capture ranks noted. In the group of birds selected for duration of the TI response, birds selected of the line selected for short duration of TI were caught before those selected for long duration of the response. In the group of birds selected for SR motivation, birds of the high line were caught before their low lines counterparts. Coefficients of concordance between capture ranks were significant and capture ranks did not differ significantly across ages. These results imply that selection for low levels of fear or high levels of sociality produces animals that are less disturbed by human interventions than animals selected for the opposite traits. The greater ease of capture of low fear line birds than high fear line birds may be explained by reduced fear of humans. The fact that the birds selected for high levels of SR behaviour are easier to catch than birds selected for low levels of sociality is less readily explicable. One hypothesis is that HSR line chicks tend to be more strongly imprinted on each other and the human caretaker. However, SR behaviour is highly species specific in both lines, existing evidence for line differences in social discrimination is limited and birds of the two lines show similar duration of the TI response. Despite this, whatever their underlying causation, these results demonstrate that genetic selection can be used to reduce negative reactions to human beings and may be of value in the improvement of both animal welfare and productivity.

Human factors affecting the behaviour and productivity of commercial broiler chickens

1. The purpose of this study was to examine the relationship between stockperson attitude and behaviour; bird behaviour and productivity in the chicken meat industry. 2. No relationship between stockperson attitude and behaviour was observed, which is in contrast to studies in the pig and dairy industries. 3. Evidence is provided for the existence of sequential relationships between stockperson behaviour, bird fear levels and productivity in the broiler farms examined. 4. The mechanism(s) responsible for the negative relationships between fear levels and production is unclear. It is hypothesised that chronic stress or a series of acute stress responses may be the mechanism through which fear affects productivity. 5. The relationship between human behaviour, bird fear levels and productivity indicates the potential that exists to improve productivity and perhaps welfare of commercial broilers by reducing fear levels in broiler chickens.

Neonatal handling of Amazon parrots alters the stress response and immune function

The influence of neonatal handling on behavior and immune function was assessed in Orange-winged Amazon parrots (Amazona amazonica). Chicks (n=11) were gently handled daily from 25 days of age until 38 days post-fledging, while control chicks (n=9) were not handled. At 10 days post-fledging ( approximately 66 days of age), chicks were given tests to evaluate tameness (e.g., willingness to perch on an offered finger). They were then restrained for 10 min, either by being held while perching (handled group) or, because they would not perch, by being restrained in a towel (nonhandled group). Serum corticosterone levels were measured and immune status was assessed by: the delayed-type hypersensitivity (DTH) response to phytohemagglutinin-P (PH-P) injection; the humoral response to a killed Newcastle disease virus (NDV) challenge; and heterophil:lymphocyte ratio (H:L). Handled chicks were tamer by all measures of tameness. DTH was greater in nonhandled chicks (P</=0.002), as were serum corticosterone levels (Wilcoxon, P</=0.05), while NDV antibody titers were possibly reduced (P</=0.09). H:L ratios did not differ. We conclude that handling conditioned the birds to be held in a manner that appeared not to be stressful. The greater DTH response of nonhandled chicks suggests that either their DTH response was enhanced by the acute stress of being restrained in a towel, and/or the DTH response of handled chicks was suppressed as a result of the repeated physiologic stress from handling during the neonatal period. In either event, handling produced marked differences in response to types of restraint that would be typically encountered in the husbandry of Amazons in captivity.

Mechanical harvesting of broilers

At the end of the growout phase of broiler production essentially all broilers are caught and loaded into coops or cages entirely by hand. The catching of broilers remains one of the few aspects of broiler production not yet automated. Vacuum systems, permanent conveyors recessed in the floors of growout facilities, collecting mats, scoops, and self-propelled, combine-type devices have been tried with little success over the past 30 yr. Renewed efforts at developing mechanical broiler harvesters have been encouraging in recent years. Several equipment companies in North America and Europe have developed prototype mechanical harvesters that appear to have promise. The benefits of mechanical harvesting as compared to hand catching include lower costs and improved working conditions. In addition, studies conducted thus far indicate that mechanical harvesting will improve bird welfare both from a stress and injury standpoint.

Group selection for adaptation to multiple-hen cages: hematology and adrenal function

A selected line of White Leghorns that has shown improved survivability and productivity and reduced feather loss in multiple-hen cages was evaluated for hematological and adrenal responses under both stressed and unstressed conditions. It was hypothesized that hens selected for adaptation to multiple-bird cages would react less intensely to stressors. Three lines of chickens (selected, control, and commercial) were housed in either single-hen (1 hen) or multiple-hen cages (12 hens, social competition) at 16.7 or 17.1 wk of age. They were subsequently subjected to cold exposure at 33 wk of age and heat exposure at 44 wk of age. Genetic stock as a main effect, and the interaction of genetic stock with either a cold or heated environment or with cage size, had no effect on plasma levels of cholesterol and corticosterone. At the time of transfer to laying cages, the selected line of pullets, as indicated by a decrease in packed cell volume, appeared to adapt more quickly to the new waterer system of multiple-hen cages than did the control and commercial lines. At 33 wk of age, the control and commercial lines in multiple-hen cages experienced heterophilia and increased heterophil to lymphocyte ratios, whereas the selected line did not, when compared with these same lines in single-hen cages. This leucocytic response could be interpreted to mean that the selected line of chickens adapted better to social competition than either the control or commercial lines; however, a similar leucocytic response was not observed at 18 or 44 wk of age. In conclusion, the physiological characterization of the selected line of Leghorns showed evidence of improved adaptation to multiple-hen cages when compared to the other stocks. In some cases, the selected line responded less intensely to stress; however, trends were not always consistent.

Gordon Memorial Lecture. Stress, strains and resistance

1. Stress describes the bird's defence mechanisms and a stressor is the situation that elicits the defence response. 2. As the environment can be viewed as a composite of interacting stressors, the bird's success in coping with its environment depends on the severity of the stressors and the physiological ability to respond properly and thus maintain homeostasis. 3. The neural, endocrine and more recently immune systems are considered to be integrators of the stress response. Although stress responses may be necessary for survival in wild bird populations, they are often detrimental to efficient growth, skeletal integrity and disease resistance in domesticated fowl. 4. Stress responses are modified by the genetic components.

The Human-Animal Relationship in Agriculture and Its Consequences for the Animal

Although human factors are recognized as influential factors affecting the welfare and productivity of farm animals, only limited research has been conducted to identify these important human characteristics and to quantify their effects. During the last 13 years we have studied two apparently important human factors: the attitude and the behaviour of stockpersons towards farm animals.

We have proposed that in intensive animal production systems there are some important sequential relationships between the attitude and behaviour of the stockperson towards farm animals and the behaviour, performance and welfare of farm animals. Basically we have suggested that because a stockperson's behaviour towards animals is largely under volitional control it is strongly influenced by the attitudes and beliefs that the stockperson holds about the animals. Furthermore, the stockperson's behaviour towards animals affects the animals’ fear of humans which, in turn, affects the animals’ productivity and welfare. It is the occurrence of a stress response by animals which are highly fearful of humans which places their productivity and welfare at risk We have published data which strongly support these interrelationships between human attitude and behaviour and animal behaviour, productivity and welfare. This paper reviews this and other research on this subject. The results of research in the pig industry and to a lesser extent, the poultry industries indicate the excellent opportunity which exists to improve animal productivity and welfare by training and selecting stockpersons to have desirable attitudinal and behavioural profiles towards farm animals.

Fear of humans and its relationships with productivity in laying hens at commercial farms

1. The relationship between the behavioural responses of laying hens to humans and productivity was determined at 16 commercial sheds from 14 farms. 2. A number of behaviour variables were moderately to highly correlated with production variables; for example, the proportion of birds that moved away from an approaching experimenter in an unfamiliar environment ('shute test') was negatively correlated with peak hen day production, (PKHDP). 3. Behavioural responses to humans accounted for between 23 and 63% of the variation in a number of production variables, including PKHDP and the duration of a high level of production. 4. Inclusion of farm factor variables increased the amount of variation accounted for by the behaviour variables. For example, adding the variable 'time/day spent in the shed by stockpeople' to the behaviour variables 'the proportion of birds that moved away from an approaching human' in the shute test and 'the number of times birds in cages adopted an erect posture' in response to an approaching human increased the variation accounted for in PKHDP from 53 to 61%. 5. The results suggest that fear of humans may be a factor that limits the productivity of commercial laying hens.

Heat-stress influences on antibody production in chicken lines selected for high and low immune responsiveness

The effect of heat stress on antibody production to sheep red blood cells (SRBC) was investigated during three experiments using chicken lines selected over six generations for high (H) or low (L) plasma-antibody titer to SRBC after primary intramuscular immunization. The chickens were immunized 24 h after a heat-stress treatment (HS) of four periods of 30 min each at a temperature of 42 C with an intervening 30-min period at a temperature of 22 C. For the control treatment (CT), the chicks were handled the same, but at a temperature of 22 C. Antibody titers were measured on 3, 5, 7, 10, and 14 days postimmunization. The intramuscular immunizations, .25 mL of SRBC, were given in all three experiments; an additional intravenous immunization of .5 mL of 14% SRBC was given in Experiment 2 and of .5 mL of 5% SRBC in Experiment 3. A significant effect of the HS treatment on antibody titers (P less than .05 on Days 3, 5, 7, and 10 after immunization) was found only in Experiment 1. The titers decreased in the H line only. The differences between the H and L lines were significant (P less than .001) in all three experiments after both the intramuscular and the intravenous immunizations. Heat stress was found to have little or no effect on antibody production in the lines studied in the present experiments.

Human-animal interactions

The objective of this article is to discuss the human-animal relationship in animal production, emphasizing the importance of this relationship to the productivity and welfare of the animal, some of the factors that may regulate the relationship, and how to manipulate this relationship to improve the productivity and welfare of the animal.

Selective breeding of chickens for corticosterone response to social stress

Selection for either a high or low corticosterone response to social stress produced lines that differ for this trait. Comparisons between the selected lines and various crosses showed additive and nonadditive genetic variation but no maternal effects for response to social stressors as measured by heterophil/lymphocyte ratios. When the lines selected for divergent responses to social stressors were exposed to nonsocial stressors, they responded similarly.

Socialization, the sequencing of environmental factors, and their effects on weight gain and disease resistance of chickens

Weight gain following a 60-hr fast was influenced 1) by prior experiences of either a presence or an absence of a similar initial fast followed by either being moved to unfamiliar quarters or being fed corticosterone or 2) whether or not the chickens were socialized. Socialization, but not the environmental stresses, increased antibody response to erythrocyte antigens and increased resistance to Escherichia coli challenge. Although the experimental cockerels had increased heterophil/lymphocyte ratios following the feeding of corticosterone, their antibody response to erythrocyte antigen and their resistance to E. coli challenge were not altered. The presence or absence of water deprivation stress early in life failed to alter any results.

The effect of environmental temperature on immune response and metabolism of the young chicken. 1. Effect of intramuscular injection on heat production

The effect of intramuscular (IM) injection, per se, on heat (H) production was investigated in ad libitum- and restricted-fed pullets held at normal (21 C) and low (10 C) environmental temperatures. At 21 C IM injection, per se, decreased H-production of ad libitum- and restricted-fed pullets for 2 to 4 hr after injection. This effect was significant (P less than .01) in ad libitum-fed pullets, held at 21 C as well as at 10 C. Thus, when studying the effect of an immune response on the energy metabolism, an effect may be confounded with the effect of the IM injection per se when the measurements are made during the first 2 to 4 hr following injection.