School of Agriculture, Food and Ecosystem Sciences - Theses
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ItemRelationships between ranging behaviour and welfare of commercial free-range broiler chickens( 2017)Free-range chicken meat consumption has increased, partly driven by consumer perception that free-range housing is better for welfare. However, there have been few scientific investigations into the implications of ranging on broiler chicken welfare. Furthermore, how and why chickens access an outdoor range is largely unknown. Previous research has monitored broiler chicken ranging and welfare at the flock level. However, not all chickens access the range when the opportunity is provided. Subsequently, measures at the flock level may not be an accurate assessment of the implications of range use. With the advancement of technology, tracking individual chicken ranging behaviour is now possible. The research presented throughout this thesis was designed to obtain a greater understanding of the relationships between individual ranging behaviour of free-range broiler chickens on commercial farms and the relationships with welfare. Chapters Three and Four provide descriptive analysis of the environmental factors associated with ranging behaviour. Tracking individual chicken ranging behaviour showed that the proportion of the flock that accessed the range was greater than previously estimated with alternate methodologies. Range use was season dependent with fewer chickens and range visits observed in winter flocks. Heterogeneous flock ranging behaviour was considerable, including chickens that only accessed the range once (8 to 12% of tracked chickens) and high frequency ranging chickens (3 to 9% of tracked chickens) that accounted for more than one third to a half of all range visits within the flock. Chapters Five and Six investigated relationships between ranging behaviour, individual chicken characteristics and welfare. Few relationships were identified in winter flocks, which may be reflective of minimal range use. In summer flocks, lower weight, better gait scores, increased plumage cover and lower physiological stress responses prior to range access were predictive of subsequent ranging behaviour. These results suggest that individual characteristics and/or early life experience may be partially responsible for heterogeneous flock ranging behaviour. Furthermore, accessing the range was related to welfare in summer flocks after range access; including reduced fear responses and improved gait scores and cardiovascular function. The study presented in Chapter Seven, investigated relationships between distance ranged from the shed and chicken welfare. Bi-directional relationships between ranging distance and body weight were observed. Frequently ranging further from the shed was associated with improved gait scores, less hock burn, and reduced acute physiological fear responses to confinement after range access was provided. Increased foot pad dermatitis was associated with increased range visits, but not ranging distance. These results suggest that ranging further from the shed had subsequent implications for welfare. This thesis provides evidence that accessing an outdoor range has bi-directional relationships with chicken welfare. Due to the nature of the research presented in this thesis causation could not be identified. However, the research contributes to the limited knowledge of free-range broiler chicken welfare. As such, the broader understanding of ranging and welfare on commercial farms obtained through this thesis provides industry relevant, hypothesis generating evidence to aid optimal ranging behaviour on commercial farms that promotes good welfare.
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ItemThe effects of floor space allowance and nest box access on the welfare of caged laying hens (Gallus gallus domesticus)( 2015)One of the welfare issues attracting the most attention in the egg industry is the use of conventional cages in production, specifically the behavioural restrictions associated with housing laying hens in cages. This issue has increased the push for use of alternative housing; cage free, free range, and furnished cages. The major experiment, which consisted of several parts, in this PhD program examined the effects of floor space allowance during rearing, as well as, floor space allowance and access to a nest box during production on the welfare of caged laying hens. Birds were reared from 7 weeks of age at 315 or 945 cm2/bird. At 16 weeks of age, birds were allocated to production cages with 542 or 1648 cm2/bird, with or without access to a nest box. At 26 weeks of age, 4 weeks of intensive measurements on behaviour and physiology were conducted. During this time physiological stress was measured using corticosterone concentrations, both basal and after an ACTH challenge, in plasma, eggs, and faeces. Haemotology was studied using heterophil to lymphocyte ratio. Video recordings during this time were used to assess the effects of the treatments on behavioural time budgets and pre-laying behaviour. At 30 weeks of age, 4 weeks of preference testing for the preference of either space or a nest box over feed commenced. Each of the four replicates was complete when the birds were 34 weeks of age. There were no main effects of treatment on physiological measurements. There was a significant (P = 0.048) effect of rearing space allowance on the percentage of time the birds spent drinking, with the birds reared in the smaller space allowance drinking more often. There were a number of significant (P < 0.05) effects of production space allowance on the behavioural time budgets that indicated restriction in performance of behaviours for hens housed in the smaller production space allowance: birds with less space spent less time mobile (64%), inedible pecking (36%), drinking (29%) and preening (17%). However, these birds spent more time resting (42%) and feed pecking (27%) and sitting (33%). Hens with access to a nest box spent significantly (P = 0.046) more time resting and significantly (P = 0.044) less time sham dust bathing than hens without access to a nest box. There were no effects of rearing or production space allowances on pre-laying behaviour or choice behaviour for space or a nest box verses food in the Y-maze test, however, hens with access to a nest box exhibited significantly (P = 0.023) longer individual sitting bouts prior to oviposition and chose the nest box over food significantly (P = 0.0053) more than hens without access to a nest box. Egg weight was significantly (P = 0.028) lower at 29 weeks of age in hens that had been reared at the larger space allowance. Feather condition was poorer in hens both in the smaller production space allowance (P = 0.011) and given access to a nest box (P = 0.037). There were no further main effects on measures of productivity, extra-cuticular calcium or feather condition. The results suggest that being housed at the smaller space allowance (315 and 542 cm2/bird during rearing and production) did not result in chronic (long-term) physiological stress for these laying hens. However, the results suggest that being housed at the smaller space allowance did result in some behavioural restriction. The effect of the nest box appears to be one of experience for the birds rather than necessity as hens without access to a nest box showed no biological disruption when compared to birds with access to a nest box and were less likely to choose a nest box over feed than hens that had access to a nest box.
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ItemThe Indicators of stockmanship and their relationships with behavioural observations and supervisor assessments of stockpeople( 2015)The welfare of Australian farm animals has become an increasingly important issue; this is evident by consumer pressure, as well as national and international pressure to improve animal welfare and on-farm animal welfare monitoring schemes. Furthermore, the general public‟s interest in farm animal welfare has increased substantially in recent years. This interest is encouraged by the media and it is usually the stockperson‟s actions that attract such media attention. According to the Theory of Planned Behaviour (TPB), the stockperson‟s attitudes towards pigs are likely to influence their behaviour in terms of the implementation of husbandry and management practices. Subsequently, these husbandry and management behaviours can affect the welfare of the pig. There are a number of different animal welfare assessment indicators, each with varying reliability. However, despite the recognised importance of stockpeople, in regard to animal welfare, very few animal welfare audits include assessing stockmanship. This study investigated the indicators of stockmanship using a series of questionnaires and direct observations of stockmanship. Subsequently, these indicators were used to establish a metrics in which stockmanship could be measured over time. Following data collection, the questionnaires were refined using Principal Component Analysis (PCA) to identify the underlying commonalities of the questions. This process produced twelve individual stockmanship subscales (i.e. Recognition and relationships, Job satisfaction, Responsibility and independence, Positive interaction beliefs, Physical effort beliefs, Husbandry beliefs, Negative attitudes towards pigs, Positive attitudes towards pigs, Empathy – Attribution, Empathy – Affect, Citizenship and Knowledge). In addition to the stockperson self-reported questionnaire, four supervisor subscales were identified to provide a cross-validation with the relevant stockperson subscales. The four supervisor subscales were: Conscientiousness, Reliable, Proactive and Dutiful. All questions within each questionnaire subscale were intercorrelated at a significance level of at least 0.01. Cronbach‟s alpha coefficients ranged from 0.69 to 0.90; moderate to high reliability. The supervisor survey subscales also attained moderate to strong reliabilities with Cronbach‟s alpha coefficients ranging from 0.71 to 0.95. Both empathy subscales (i.e. Affect and Attribution) significantly correlated with mild and/or positive stockperson behaviours. Empathy – Affect significantly, negatively correlated with negative stockperson behaviour. In addition, both empathy subscales significantly correlated with both negative and positive attitudes towards pigs. Both empathy subscales negatively correlated with negative attitudes towards pigs and positively correlated with positive attitudes towards pigs. Negative attitudes towards pigs were significantly correlated with negative stockperson behaviours. Positive attitudes towards pigs were significantly correlated with mild/positive behaviours towards pigs. Furthermore, behaviours of a negative nature were negatively correlated with other self-report questionnaire subscales including: Citizenship and Husbandry beliefs. The stockperson questionnaire subscale, Knowledge correlated with a number of other stockperson subscales including: Citizenship, Empathy – Attribution, Positive attitudes towards pigs, Positive interaction beliefs, and Responsibility and Independence. These results suggest that knowledge about pig health and welfare is related to citizenship, empathy, positive beliefs and attitudes towards pigs and handling pigs as well as being responsible and independent at work. Test-retest methodology was carried out to further assess the reliability of the stockperson questionnaire and supervisor survey as stockmanship measurement tools. Inter-item reliability remained strong with most subscales, achieving Cronbach‟s alphas above 0.70. The correlations between the test and retest data showed significant correlations, ranging from r = 0.35 – r = 0.76. Following reliability and validity tests, the questionnaires were incorporated into a software program entitled, Prohand Benchmark. A field-trial and subsequent focus group discussions were carried out in order to assess the utility and practicality of using the program on-farm. The majority of participants found the program to be user-friendly, clear, relevant and a potential asset to the Australian Pig Industry. The results reported in this thesis indicate that improving empathy, knowledge, citizenship and attitudes towards pigs in stockpeople will reduce inappropriate and negative behaviours towards pigs during handling and improve pig welfare outcomes in Australian piggeries. Given that a number of stockperson attributes have been found to be relevant to good farm animal welfare outcomes, it seems appropriate to use these attributes to benchmark stockmanship, so that the results can be used both to monitor changes in stockmanship over time and to identify areas where training of stockpeople is indicated.
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ItemFire, resources and behavioural responses of ground-dwelling mammals( 2015)Planned fire is commonly used to reduce adverse effects of bushfire to human life and property, but may also be used to conserve biodiversity. However, there is a dearth of information regarding the effect of these fires on fauna. I investigated the response of ground-dwelling mammals to a planned fire event in the Otway Ranges, south-eastern Australia. Bush rats (Rattus fuscipes) and swamp wallabies (Wallabia bicolor) were chosen as study species given that they are expected to be affected by a change in vegetation resources due to fire. The differences in body size of the two species provided the scenario to study fire effects at two different spatial scales. At a small scale, I studied changes in abundance of bush rats as a consequence of fire, plus the role of unburnt areas as refuges. I used microsatellite markers to study movement of individuals between slopes and gullies. At a larger scale, I used GPS technology to track swamp wallabies before, during and after fire, to study changes in home range and habitat selection, as well as behaviour during fire. The studies included different temporal levels as well, the study on abundance and movement of bush rats, and on habitat selection of swamp wallabies, compared data from two months before with two months after fire. Home range data of swamp wallabies compared data two months before fire with data from up to eight months after the fire. Finally, the study on movement of wallabies during the fire, included data from 36 hours when the fire was burning compared to pre-fire data. The study on bush rats corresponded to a Before-After Control-Impact (BACI) design using a paired catchment approach, while the study on wallabies corresponded to an Impact Analysis (IA) design, comparing responses not only before and after, but also during fire. There was no strong relationship between the different responses that were quantified and the amount of area that was burnt within transects and home ranges, possibly because there were enough unburnt areas available in the post-fire landscape, emphasizing the importance of keeping areas of unburnt vegetation when applying planned fires. Yet, the impact of fire was presumably larger on bush rats; this was reflected in the reduction of abundance of individuals, while all swamp wallabies survived. The impact of fire varied between the two study species, reflecting the importance of investigating the effect of planned burns at different spatial and temporal scales. The strategy used in the fire event that I studied, i.e. of low intensity, progressively and in patches across the targeted area did not have major effects on the study species. The information provided in this thesis intends to improve the capacity for land managers to consider the ecological effects of planned fire by adding to current knowledge linking fire, resources and behavioural responses. Further assessment involving more intense fire would be necessary to assess the response of bush rats and swamp wallabies, and to predict the possible consequences that a wildfire could have on these species.