ORCID Profile
0000-0002-3971-4161
Current Organisation
University of Tasmania
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Publisher: Elsevier BV
Date: 07-2017
Publisher: CSIRO Publishing
Date: 2017
Publisher: Elsevier BV
Date: 10-2016
Publisher: Elsevier BV
Date: 05-2019
Publisher: Frontiers Media SA
Date: 27-04-2021
DOI: 10.3389/FANIM.2021.663963
Abstract: Virtual fencing contains and controls grazing cattle using sensory cues rather than physical fences. The technology comprises a neckband-mounted device that delivers an audio cue when the animal nears a virtual boundary that has been set via global positioning system, followed by an electrical stimulus if it walks beyond the boundary. Virtual fencing has successfully been used to intensively graze cattle using a simple virtual front-fence, but a more complex intensive grazing system comprising moving virtual front and back-fences has not been assessed. We studied the effectiveness of virtual fencing technology to contain groups of Angus heifers within grazing cells defined by semi-permanent electric side-fences and virtual front and back-fences, compared to groups of heifers contained in cells defined only by electric fencing. Four groups of 10 Angus heifers were randomly allocated to a “control” (grazed with a conventional electric front and back-fence, n = 2 groups) or “virtual fence” treatment (grazed with a virtual front and back-fence, n = 2 groups). The groups of heifers grazed four adjacent experimental paddocks that were established using TechnoGrazing™ infrastructure. An estimated 9.5 kg pasture DM/heifer.day was offered in each of three 3 day allocations (9 day study period). Data collected include cues delivered by the neckbands, time beyond the virtual boundaries, pasture consumption for each allocation and heifer live weight changes over the study period. The virtual front and back-fences successfully contained one group of heifers in their grazing cell, but the second group of heifers spent an increasing amount of time in the exclusion zone during the second and third allocations and consequently received an increasing number of audio and electrical stimuli. There were no effects of electric or virtual-fence treatment on live weight change or pasture utilization. By grazing heifers in adjacent paddocks our experimental design may have produced a motivation for some heifers to cross the virtual boundary to regain close contact with familiar conspecifics. Despite this, valuable learnings were gained from this study. Most notably, virtual fencing should not be used to manage cattle that have close visual contact to other mobs. We conclude that the successful application of virtual fencing technology needs to accommodate the natural behaviors of cattle.
Publisher: CSIRO Publishing
Date: 2017
Publisher: MDPI AG
Date: 28-01-2020
DOI: 10.3390/ANI10020217
Abstract: This experiment examined whether pre-exposure to an electrical stimulus from electric fencing attenuates associative pairing of audio and electrical stimuli in dairy heifers. Two treatments were applied to 30 weaned heifers naive to electric fencing. Heifers in the ‘electric-fence’ treatment were exposed to an electrified perimeter fence and two periods of strip-grazing using electrified poly-wire. Control heifers remained naïve to electric fencing. The pairing of audio and electrical stimuli was assessed in a feed attractant trial using manually controlled training collars. Heifers received an audio stimulus (2 s 84 dB) when they breached a virtual fence after which a short electrical stimulus (0.5 s 120 mW) was administered if they continued to move forward. If the animal stopped moving forward no further stimuli were applied. By the third training session, electric-fence heifers received a lower proportion of electrical stimuli than control heifers (p = 0.03). The more exploratory interactions a heifer had with the electric fence, the lower the proportion of electrical stimuli she received during training (rs = −0.77, p = 0.002). We conclude that experience with electrical fencing enhanced the salience of the electrical stimulus delivered by manual collars used for virtual fence training.
Publisher: American Dairy Science Association
Date: 06-2021
Publisher: Elsevier BV
Date: 2017
Publisher: American Dairy Science Association
Date: 06-2021
Publisher: Oxford University Press (OUP)
Date: 05-2015
Abstract: Factors that have been shown to impact the welfare of group-housed sows are discussed in this review. Floor space allowance markedly affects sow welfare. In addition to quantity of floor space, the quality of space is important: spatial separation between sows can be provided with visual or physical barriers and stalls. Whereas 1.4 m/sow is insufficient, further research is required to examine space effects in the range of 1.8 to 2.4 m/sow in more detail. The period immediately after mixing has the most pronounced effects on aggression and stress, and therefore, well-designed mixing pens offer the opportunity to reduce aggression, injury, and stress while allowing the social hierarchy to quickly form. Because hunger is likely to lead to competition for feed or access to feeding areas, strategies to reduce hunger between meals through higher feeding levels, dietary fiber, or foraging substrate should be examined. However, feeding systems, such as full-body feeding stalls, can also affect aggression and stress by providing protection at feeding, but deriving conclusions on this topic is difficult because research directly comparing floor feeding, feeding stalls, and electronic sow feeder systems has not been conducted. Familiar sows engage in less aggression, so mixing sows that have been housed together in the previous gestation may reduce aggression. Although there is evidence in other species that early experience may affect social skills later in life, there are few studies on the effects of early "socialization" on aggressive behavior of adult sows. Genetic selection has the potential to reduce aggression, and therefore, continued research on the opportunity to genetically select against aggressiveness and its broader implications is required. Most research to date has examined mixing sows after insemination and knowledge on grouping after weaning is limited.
Publisher: Elsevier BV
Date: 07-2017
Publisher: Elsevier BV
Date: 2019
Publisher: Frontiers Media SA
Date: 21-12-2020
DOI: 10.3389/FANIM.2020.618070
Abstract: A better understanding of factors that influence learning of cattle with respect to new virtual fencing technology is required to inform the development of best practice training protocols and guide the introduction of the technology to naïve dairy cattle. This experiment examined the effect of age on (1) the efficiency of associative pairing of audio and electrical stimuli in dairy heifers and (2) the retention of this associative pairing over a long period of time without use. Fifty-nine Holstein dairy heifers were used in feed attractant trials where audio cues and electrical stimuli were delivered through manually controlled training collars. Heifers were allocated to four treatments that differed in the age at which naïve animals underwent training these were 6-months (“6M” n = 15), 9-months (“9M” n = 15), 12-months (“12M” n = 15), or 22-months of age (“22M” n = 14). Animals in the 6, 9, and 12M treatments underwent a second round of training at 22-months of age (i.e., at the same time as naïve 22M heifers). Heifers received an audio stimulus (2 s 84 dB) when they breached a virtual fence after which a short electrical stimulus (0.5 s 3 V, 120 mW) was administered if they continued to move forward. If the animal stopped moving forward no further stimuli were applied. There were no effects of age treatment on the total number of interactions with the virtual fence ( P & 0.05). During initial training, 22M heifers received a lower proportion of electrical stimuli (i.e., responded to audio without requiring the electrical stimulus P & 0.001) and more frequently stopped walking ( P = 0.01) and turned back ( P = 0.008) following administration of the audio cue compared to younger heifers. Previous training at an early age did not improve the responsiveness of heifers to virtual fencing when re-trained at 22-months of age ( P & 0.05). We conclude that dairy heifers should be trained to virtual fencing technology close to calving age rather than earlier in their ontogeny and that stock be re-trained following an extended period without virtual fencing technology.
Publisher: Brill | Wageningen Academic
Date: 2015
Publisher: CSIRO Publishing
Date: 2015
Publisher: MDPI AG
Date: 21-06-2023
DOI: 10.3390/ANI13132049
Abstract: This study aimed to determine the effects of early-life physical and social enrichment on the ability of dairy heifers to integrate into a herd of mature cows. Fifty heifer calves were reared from the ages of 2–13 weeks in one of three treatments: (1) Hand-reared and group-housed in sheds (CC) (2) Hand-reared and group-housed at pasture (−S) or (3) Hand-reared and group-housed at pasture, with 3 non-familial dry cows per group (+S). At 23 months of age, these heifers were introduced in groups to small herds of cows (Cows) at pasture. Social interactions were recorded continuously for two 1-h periods. Feeding, ruminating and resting behaviours of all animals and walking, standing and lying behaviours of 36 heifers only (+S = 14, −S = 13, CC = 9) were recorded for 48 h after mixing. Heifers that were managed as calves according to the CC treatment delivered less agonistic behaviour to other heifers after mixing than those reared in the +S or −S treatments (p = 0.002 and p = 0.041, respectively). On Day 2, +S heifers and cows spent the lowest proportion of time feeding (p = 0.961), with −S heifers spending significantly more time feeding than cows (p = 0.046), while CC heifers spent more time feeding than both +S heifers and cows (p = 0.027 and p 0.002, respectively). Increasing the complexity of the early-life environment, particularly socially, may aid heifers in integrating into groups of multiparous cows later in life and shape their lifelong social experiences with same-age conspecifics.
Publisher: MDPI AG
Date: 09-08-2023
DOI: 10.3390/ANI13162571
Abstract: This study investigated cow-calf productivity in a 10-week, pasture-based, extended suckling system featuring part-time cow-calf contact and once-a-day milking. A total of 30 dairy cows and their calves were assigned to two treatments: (1) cow and calf managed in an extended suckling system or (2) cow and calf separated at birth and managed as usual. Cow-calf pairs grazed together during the day and spent the night separated by fence-line contact. The dams were reunited with the calves after once-a-day milking every morning. The commercial treatment pairs were separated after birth, and cows were milked twice a day and managed within the farm herd. Commercial calves were reared and managed as per commercial Australian practices. Cow-calf dams yielded 9 L/cow/day less saleable milk (p 0.001), and their milk had lower fat (p = 0.04) but a higher protein percentage (p 0.001) than commercial cows during pre-weaning. However, milk yield and composition were comparable post-weaning. Dam-suckled calves gained weight faster and were therefore weaned 2 weeks earlier than commercial calves, which were offered 8 L/day milk. This study has demonstrated a novel system of extended cow-calf suckling that could be practical to implement in pasture-based dairies. The long-term effects and scalability of the extended suckling system described here require further validation.
Publisher: Oxford University Press (OUP)
Date: 02-2020
DOI: 10.1093/JAS/SKAA037
Abstract: Transferring sows and their litters to group lactation (GL) after an initial period of farrowing crate (FC) housing could enhance the viability of GL for commercial production. Group lactation from 7 d postpartum would reduce the time sows spend in confinement, but the effects of early mixing on animal welfare and productivity require examination. Two experiments were conducted on sows and piglets kept in GL from 7, 10, or 14 d postpartum, compared with FC. Experiment 1 utilized 180 sows and 1,887 piglets over five time replicates (n = 60 sow and litter units per treatment) comparing GL from 7 or 14 d postpartum to FC. In experiment 2, 108 sows and 1,179 piglets were studied over three time replicates (n = 36 sow and litter units per treatment) comparing GL from 10 or 14 d postpartum to FC. All sows farrowed in FC. Group lactation sows were transferred to pens (one pen of five sows at 8.4 m2/sow and one pen of seven sows at 8.1 m2/sow, per GL treatment and replicate) with their litters at 7 (GL7), 10 (GL10), or 14 (GL14) d postpartum. Farrowing crate sows and their litters remained in their FC. Data were collected on sow feed intake and reproduction, piglet mortality (from day 6 postpartum), and sow and piglet weight changes, plasma cortisol concentrations, and injuries. Piglet mortality was greater in the GL7 (17 ± 1.8%) and GL10 treatments (12 ± 0.9%) compared with GL14 (8.3 ± 1.8% P ≤ 0.001 and 8.1 ± 0.9% P ≤ 0.001 in experiments 1 and 2), and greater in GL overall compared with FC (2.7 ± 1.5% and 1.8 ± 0.9% in FC in experiments 1 and 2 P ≤ 0.001). Piglets from GL7 were also lighter at weaning than GL14 piglets (P & 0.001), whereas GL10 and GL14 did not differ (P & 0.05). Overall, piglets in GL were lighter at weaning than piglets in FC (P ≤ 0.01). Sows from GL7 were heavier at weaning (P = 0.001), and GL10 sows tended to be heavier at weaning (P = 0.08), than GL14 and FC sows. Post-mixing, sow cortisol (P ≤ 0.01) and sow and piglet injuries (P ≤ 0.02) were greater in GL than FC. Treatment had no effect on sow feed intake or reproductive performance (P & 0.05). Under the conditions of this research, the known benefits of two-stage GL housing were achieved at a cost particularly to piglets in terms of increased piglet mortality and injuries after mixing, and reduced piglet growth. The risk of piglet mortality decreased with older age at mixing.
Publisher: CSIRO Publishing
Date: 30-01-2023
DOI: 10.1071/AN22248
Abstract: The pasture-based replacement dairy heifer is typically housed and managed intensively from birth until weaning, but post-weaning is housed outdoors in paddocks under less intensive management. Little is published about the welfare of the weaned dairy heifer in pasture-based systems. The aim of this review is to consolidate the scientific literature and provide an overview of factors affecting the welfare of weaned heifers on pastoral dairies. Heifer welfare during transition to the milking herd can be optimised through calving support and by pre-exposing heifers to some of the stressful conditions associated with the milking herd. For the former, heifers should be well grown at calving (≥85% mature bodyweight) and could be mated to bulls that will produce a smaller calf (e.g. Jersey bulls, sexed semen to produce a female calf). Sires should be selected for high ease of calving predicted transmitting ability, and farms should develop and implement a calving intervention and assistance policy. Mixing heifers with milking cows prior to calving, exposing them to competitive grazing conditions and training them to the milking parlour may reduce overall stress burden and enhance adaptability, but research is needed to quantify the welfare and productive merit of this sort of program in seasonal pasture-based dairy systems. This review highlights a lack of recent data relating to the management of the replacement heifer between weaning and their first calving. Research needs to document and disseminate modern dairy heifer management practices in pasture-based systems, as these will affect heifer welfare. The following data need to be collected as a priority: (1) frequency that heifers are weighed or receive health assessments, (2) heifer grazing management, (3) frequency and age of surgical removal of supernumerary teats, (4) mortality rate from weaning until the first lactation, and (5) typical procedures to transition heifers to the milking herd, including management of the first calving. There is also a need to document the management and housing conditions of exported dairy heifers living in other countries.
Publisher: CSIRO Publishing
Date: 16-11-2022
DOI: 10.1071/AN21139
Abstract: Current research on factors affecting the welfare of dairy calves is predominantly based on indoor, year-round calving systems. Calf rearing in these systems differs from that in more seasonal, pasture-based dairy production, meaning that risks to the welfare of dairy calves may not always be comparable between the two systems. The aim of this review was to consolidate the scientific literature relating to calf welfare in pasture-based dairy systems from birth until weaning, allowing for (1) the identification of current and emerging risks to calf welfare and (2) the formation of recommendations to mitigate these risks. Many of the risks to calf welfare discussed in this review are not exclusive to pasture-based dairies. This includes a global trend for increasing perinatal mortalities, a significant number of calves failing to achieve effective passive transfer of immunity, the low uptake of best practice pain relief when calves are disbudded, and the feeding of restricted milk volumes. In addition to these persisting welfare risks, two factors discussed in this review pose an immediate threat to the social license of dairy farming the separation of cow and calf soon after birth and the management of surplus calves (i.e. calves not needed by the dairy industry). Several recommendations are made to improve the uptake of best-practice calf rearing and progress the development of alternative pasture-based rearing systems that accommodate changing community expectations. These include communication strategies that strengthen farmer beliefs regarding the welfare and productivity benefits achieved by best practice calf rearing and challenge beliefs regarding the associated costs. Farmers should also be encouraged to benchmark their rearing practices through improved record keeping of key rearing inputs and outcomes. Biological research is needed to advise the development of new calf rearing recommendations and the evolution of existing recommendations. Research priorities identified by this review include the effects of dystocia on the neonate and strategies to mitigate these effects, relationships between features of pen design and calf health and welfare, feasibility of dam rearing in large pasture-based dairy systems, and strategies that increase the value of the surplus calf.
Publisher: Elsevier
Date: 2024
Publisher: MDPI AG
Date: 05-06-2018
DOI: 10.3390/ANI8060086
Publisher: Cambridge University Press (CUP)
Date: 2023
DOI: 10.1017/AWF.2023.5
Abstract: Substrates and objects are provided to farm animals on the assumption that they improve animal welfare by enriching the environment, but these often fail to consider the extent to which an environmental enrichment (EE) improves animal welfare, if at all. Furthermore, there are numerous definitions of EE, each with a unique expectation. If expectations of animal welfare improvement are set too high, industry uptake may be thwarted, but if thresholds are set too low it will not result in meaningful improvements to animal welfare. We propose an EE framework based on revised definitions of EE that reflect improvements to various components of animal welfare: (i) pseudo-enrichment (ii) EE for meeting basic needs (iii) EE for pleasure and (iv) EE for positive welfare balance. This framework requires short- and long-term assessments to determine the impact of the EE, although many are lacking in the production animal literature. Redefining EE with a focus on specific animal welfare outcomes will assist producers in identifying the optimal EE for their enterprise. Subsequently, we encourage dialogue between farmers, researchers and industry stakeholders when designing environmental enrichment programmes. This framework is a science-based tool that can be used to inform the development of clear EE assessment protocols and requirements for animal welfare legislation, assurance programmes and industry. This evidence-based framework ensures that the focus is on the outcome of EE programmes rather than the intent. Importantly, this framework has the flexibility to adapt even as baseline environments evolve, ensuring the continual improvement to production animal welfare.
Publisher: Elsevier
Date: 2017
Publisher: Elsevier BV
Date: 05-2018
DOI: 10.1016/J.BEPROC.2018.02.016
Abstract: This experiment examined the effects of group composition on sow aggressive behaviour and welfare. Over 6 time replicates, 360 sows (parity 1-6) were mixed into groups (10 sows per pen, 1.8 m
Publisher: CSIRO Publishing
Date: 2015
Publisher: Cambridge University Press (CUP)
Date: 2023
DOI: 10.1017/AWF.2023.23
Publisher: CSIRO Publishing
Date: 13-02-2023
DOI: 10.1071/AN22271
Abstract: Context Dairy calves are often separated from their dams following birth, despite the beneficial effects of early life adult contact on behavioural development across species. Cow–calf contact systems are rare and often difficult to implement in the modern dairy industry. The development of alternative systems offering some of the benefits of adult social contact during early life, such as contact with non-maternal adults, has been limited. Aims This study explored the behavioural patterns of grouped pre-weaned calves reared with or without non-maternal adult contact, and is the first in a series of studies following the social and behavioural development of experimental calves from the age of 2 weeks to 2 years. Methods Four groups of 10 calves housed at pasture were studied from 2 to 12 weeks of age. Two groups were housed with three non-maternal dry cows each (+S). Calf behaviour in these groups was compared with that of calves in the remaining two groups, housed without adult contact (−S). Observations were conducted on behaviours including grazing, locomotion and lying, using 5-min scan s ling between morning (0930 hours) and afternoon (1600 hours) milk-feeding on 1 day every second week of the experiment (AN22271_IE1.gif = 5.9 h of data ± 0.4 h/group.day). Key results Few behavioural differences were found between groups. All groups performed mostly lying behaviour in the middle of the day and spent the most time grazing in the afternoon before the evening milk feed. Conclusions Our results indicated that calves housed at pasture behave according to innate diurnal patterns previously observed in studies of calves housed with the dam, and choose to spend the majority of daylight hours lying or grazing. Being housed with non-maternal adults has few effects on these observed behavioural patterns. Implications Our study suggests that non-maternal adult contact does not affect the immediate behavioural development of calves housed at pasture. Future research needs to explore longitudinal effects of this contact.
Publisher: Oxford University Press (OUP)
Date: 03-2016
Abstract: This study examined the relationships between in idual sow aggressive behavior and sow welfare, based on aggression, skin injuries, and stress, in a total of 275 pregnant domestic sows. Over 4 time replicates, sows were randomly mixed into groups of 10 (floor space of 1.8 m/sow) within 7 d of insemination in both their first and second gestations (200 sows per gestation with 126 sows observed in both gestations). Measurements were taken on aggression (both delivered and received) at feeding, skin injuries, and plasma cortisol concentrations at d 2, 9, and 51 after mixing. Live weight gain, nonreproductive removals, litter size (born alive, total born, and stillborn piglets), and farrowing rate were also recorded. In both the first and the second gestations, sows were classified at d 2 after mixing as "submissive" (delivered little or no aggression at feeding relative to aggression received), "subdominant" (received more aggression at feeding than delivered), and "dominant" (delivered more aggression at feeding than received). In both gestations, sows classified as dominant at d 2 subsequently delivered more (gestation 1, < 0.01 gestation 2, < 0.01) and received less (gestation 1, < 0.01 gestation 2, < 0.01) aggression and gained the most weight (gestation 1, < 0.01 gestation 2, < 0.01). Dominant sows had the least skin injuries throughout gestation 1 ( = 0.04), and although submissive sows sustained the most skin injuries at d 9 and 51 of gestation 2, at d 2 the classifications did not differ in skin injuries ( 0.05 gestation 2, = 0.02). There were no significant relationships between aggression classification and reproduction and nonreproductive removals ( > 0.05). In conclusion, sows classified as dominant at feeding at d 2 subsequently received less aggression at feeding, sustained fewer skin injuries, and had higher live weight gain. Submissive and subdominant sows in groups are likely to benefit from the provision of increased resources such as space and access to feed.
Publisher: Brill | Wageningen Academic
Date: 29-05-2013
No related grants have been discovered for Megan Verdon.