Jim Lea

Jim Lea

orcid

Research Focus & Metrics

Academic Career Length

19Years (2008-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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18 September 2017 in Animals
Verified
Journal Article
Open access
PDF file
DCDana Campbell
Dana Campbell
JLJim Lea
Jim Lea
WFWilliam J. Farrer
William J. Farrer
SHSally J. Haynes
Sally J. Haynes
CLCaroline Lee
Caroline Lee
Global Positioning System (GPS)-based virtual fences offer the potential to improve the management of grazing animals. Prototype collar devices utilising patented virtual fencing algorithms were placed on six Angus heifers in a 6.15 hectare paddock. After a “no fence” period, sequential, shifting virtual fences restricted the animals to 40%, 60%, and 80% of the paddock area widthways and 50% lengthways across 22 days. Audio cues signaled the virtual boundary, and were paired with electrical stimuli if the animals continued forward into the boundary. Within approximately 48 h, the cattle learned the 40% fence and were henceforth restricted to the subsequent inclusion zones a minimum of 96.70% (±standard error 0.01%) of the time. Over time, the animals increasingly stayed within the inclusion zones using audio cues alone, and on average, approached the new fence within 4.25 h. The animals were thus attentive to the audio cue, not the fence location. The time spent standing and lying and the number of steps were similar between inclusion zones (all p ≥ 0.42). More lying bouts occurred at the 80% and lengthways inclusion zones relative to “no fence” (p = 0.04). Further research should test different cattle groups in variable paddock settings and measure physiological welfare responses to the virtual fencing stimuli.

20 June 2020 in Animals
Verified
Journal Article
Open access
PDF file
DCDana Campbell
Dana Campbell
JOJackie Ouzman
Jackie Ouzman
DMDamian Mowat
Damian Mowat
JLJim Lea
Jim Lea
CLCaroline Lee
Caroline Lee
RLRick Llewellyn
Rick Llewellyn
The eShepherd® virtual fencing system being commercialized for cattle has the potential to exclude cattle from environmentally sensitive areas. Animals are given audio cues to indicate a fence line via a neckband device. An electrical pulse is administered if the animal continues moving forward following an audio cue. A commercial trial was conducted in South Australia to assess whether virtual fencing technology could exclude 20 cattle from an area of regenerating saplings; across 44 days; using a contoured fence line. The results showed that the cattle were able to rapidly learn the virtual fencing cues; responding appropriately to the audio cue for 74.5% of 4378 audio signals; and were excluded from the regenerating area for 99.8% of the trial period with the more complex fence line (contoured; not straight) in place. IceQube R’s® measuring lying time and bouts showed no consistent increasing or decreasing pattern of change. At the trial conclusion; the feed available in the protected zone was double the quantity and quality of the grazed zone. Technical issues occurred with some of the pre-commercial prototype devices; but those versions are now obsolete. This study observed a single group of cattle in one paddock; further testing of the virtual technology is warranted.

22 December 2018 in Animals
Verified
Journal Article
Open access
PDF file
DCDana Campbell
Dana Campbell
SHSally J. Haynes
Sally J. Haynes
JLJim Lea
Jim Lea
WFWilliam J. Farrer
William J. Farrer
CLCaroline Lee
Caroline Lee
Grazing cattle can both negatively and positively impact riparian zones, dependent on controlled grazing management. Virtual fencing technology, using collar devices that operate via GPS can provide audio cues and electrical stimuli to temporarily exclude cattle from specified areas as desired. An early experimental prototype automated virtual fencing system was tested in excluding ten cattle from a riparian zone in Australia. Animals were given free access to an 11.33-hectare area for three weeks, excluded from river access by a virtual fence for ten days (2.86-hectare inclusion zone), followed by free access again for six days. Animals were almost exclusively contained by the virtual fence. All animals received audio cues and electrical stimuli with daily fence interactions, but there was high individual variation with some animals first approaching the fence more often than others. Overall, there was an approximately 25% probability that animals would receive an electrical stimulus following an audio cue. Individual associative learning may have been socially-facilitated by the group’s behaviour. Following fence deactivation, all animals re-entered the previously excluded area. Further research with more groups and longer periods of exclusion using updated collar devices would determine the scope of virtual fencing technology for cattle grazing control.

20 June 2008 in Australian Journal of Experimental Agriculture
Verified
Journal Article
Closed access
PDF file
JLJim Lea
Jim Lea
DND. D. O. Niemeyer
D. D. O. Niemeyer
MRM. T. Reed
M. T. Reed
AFA. D. Fisher
A. D. Fisher
DFD. M. Ferguson
D. M. Ferguson
This series of experiments was undertaken to develop a low animal impact, inexpensive and simple method of continuous logging of body temperature in free-ranging adult cattle for periods up to 7 days. Two different types of logger (iButton and Vemco minilogger) and three different methods of attachment (surgical implant, anal girth strap and anal tail attachment) for the iButton were investigated. The technique based on the iButton temperature logger, secured to the tail head was the most effective. This technique required minimal animal handling and provided reliable and accurate measurement of temperature in freely behaving cattle.

18 September 2018 in Animals
Verified
Journal Article
Open access
PDF file
Angela LeesAngela Lees
Angela Lees
JLJim Lea
Jim Lea
HSHannah Salvin
Hannah Salvin
LCLinda Cafe
Linda Cafe
ICIan Colditz
Ian Colditz
CLCaroline Lee
Caroline Lee
This study evaluated the relationship between rectal temperature (TREC, °C) and vaginal temperature (TVAG, °C) in grazing Bos taurus heifers, to develop an understanding of the reliability of these measures as estimates of core body temperature. Nineteen Angus heifers (BW = 232.2 ± 6.91 kg) were implanted with intra-rectal and intra-vaginal data loggers. Rectal temperature and TVAG were simultaneously recorded at 20 s intervals over 18.5 h. Heifers were housed as a singular cohort on grazing pastures for the duration of the study. A strong linear relationship (R2 = 0.72, p < 0.0001) between the measurement sites was identified. The mean difference between TREC and TVAG was small, in which TVAG was on average 0.22 ± 0.01 °C lower than TREC. Individual twenty second TREC and TVAG data were used to determine the pooled mean TREC and TVAG and then to highlight the within measure variation over time. The coefficient of variation was, on average, lower (p < 0.001) for TVAG (0.38%) than TREC (0.44%), indicating that TVAG exhibited less variation. Overall, the results from the current study suggest that a strong relationship exists between TREC and TVAG, and that TVAG may be a more reliable estimate of core body temperature than TREC in grazing Bos taurus heifers.

18 September 2020 in Sensors
Verified
Journal Article
Open access
PDF file
HXHaocheng Xu
Haocheng Xu
SLShenghong Li
Shenghong Li
CLCaroline Lee
Caroline Lee
WNWei Ni
Wei Ni
DADavid Abbott
David Abbott
DCDana Campbell
Dana Campbell
Understanding social interactions in livestock groups could improve management practices, but this can be difficult and time-consuming using traditional methods of live observations and video recordings. Sensor technologies and machine learning techniques could provide insight not previously possible. In this study, based on the animals’ location information acquired by a new cooperative wireless localisation system, unsupervised machine learning approaches were performed to identify the social structure of a small group of cattle yearlings (n=10) and the social behaviour of an individual. The paper first defined the affinity between an animal pair based on the ranks of their distance. Unsupervised clustering algorithms were then performed, including K-means clustering and agglomerative hierarchical clustering. In particular, K-means clustering was applied based on logical and physical distance. By comparing the clustering result based on logical distance and physical distance, the leader animals and the influence of an individual in a herd of cattle were identified, which provides valuable information for studying the behaviour of animal herds. Improvements in device robustness and replication of this work would confirm the practical application of this technology and analysis methodologies.