Performance of Proximity Loggers in Recording Intra- and Inter-Species Interactions: A Laboratory and Field-Based Validation Study

Knowledge of the way in which animals interact through social networks can help to address questions surrounding the ecological and evolutionary consequences of social organisation, and to understand and manage the spread of infectious diseases. Automated proximity loggers are increasingly being used to record interactions between animals, but the accuracy and reliability of the collected data remain largely un-assessed. Here we use laboratory and observational field data to assess the performance of these devices fitted to a herd of 32 beef cattle (Bos taurus) and nine groups of badgers (Meles meles, n  = 77) living in the surrounding woods. The distances at which loggers detected each other were found to decrease over time, potentially related to diminishing battery power that may be a function of temperature. Loggers were highly accurate in recording the identification of contacted conspecifics, but less reliable at determining contact duration. There was a tendency for extended interactions to be recorded as a series of shorter contacts. We show how data can be manipulated to correct this discrepancy and accurately reflect observed interaction patterns by combining records between any two loggers that occur within a 1 to 2 minute amalgamation window, and then removing any remaining 1 second records. We make universally applicable recommendations for the effective use of proximity loggers, to improve the validity of data arising from future studies

Using temporal associations to determine maternal parentage in extensive beef herds

The assignment of maternal parentage, although time-consuming and expensive using traditional methods, is essential for genetic improvement. Within the sheep industry the recording of time-based (temporal) associations without human intervention has been routinely used to derive maternal parentage, however it has not been researched in extensive beef production systems. To determine whether temporal associations could be used to assign maternal parentage, cows and calves had their identity recorded as they walked to water over a 27-day trial. Two methods of association were investigated, being the half-weight index and the time difference between a cow and calf having their identity recorded. The half-weight index, which is a measure of the number of times two individuals are recorded together, correctly assigned greater than 90% of maternal pairs. When investigating the duration of data recording it was shown that 85% of maternal parentage could be achieved within only 21 days. Further work is required to determine the effect of calf age, herd and paddock size; however, the results showed that the half-weight index method of determining maternal associations is a labour-saving and accurate alternative to traditional methods used to identify maternal parentage.Associated Grant:Telstra; Meat & Livestock Australi

Using temporal associations to determine postpartum oestrus in tropical beef cows

Corbet, NJ ORCiD: 0000-0002-7468-2177The radio frequency identification (RFID) technology introduced with the National Livestock Identification System has increased the precision of livestock management. Tag readers incorporated in walk-over-weighing systems have enabled automated collection of daily RFID sequential data as cattle access water. The temporal sequence of individuals accessing a watering point in a rangeland grazing system could potentially provide knowledge of key aspects of animal behaviour. The current study investigated the use of the shortest daily average interval of time from cow to bull (TTB) coming to water over a 29-day period to predict postpartum oestrus events. Fifteen Brahman and 15 Belmont Red cows mated to bulls of the same breed in separate paddocks were fitted with proximity loggers, heat-mount detectors and were ovarian-scanned with ultrasonics to determine the timing of postpartum oestrus. The data collected from these devices were compared with RFID sequence data of the bulls following cows to water to evaluate whether TTB alone could predict oestrus activity. At the start of the experimental period, mean (±s.d.) weight and days postpartum of the Brahman cows were 527 (±43.4) kg and 89 (±18.4) days respectively, and of the Belmont Red cows 513 (±54.1) kg and averaged 66 (±19.6) days postpartum. Six of the 15 Brahman cows and 9 of the 15 Belmont Red cows displayed oestrus activity, as indicated by increased contact with the bull, an activated heat-mount detector and the presence of an ovarian corpus luteum. The sensitivity and specificity of TTB as an indicator of oestrus events across the groups were 0.65 and 0.60 respectively. Temporal sequence data have the potential to contribute to the determination of oestrus and date of conception. © 2018 CSIRO

A scoping study to assess the precision of an automated radiolocation animal tracking system

The spatial precision of a new automated radiolocation animal tracking system (ARATS) was studied in a small-scale (5 ha) trial site. Twelve static tags, in a four by three grid, transmitted for 28 days. The 12 tags recorded 36,452 transmissions with a mean transmission per tag of 3037. Each transmission included the tag number, date and time and the calculated longitude and latitude. The mean location and then the Euclidean distance from the mean location for each tag were calculated in order to derive location precision per tag. The overall precision for the 12 tags was ±22 m with a SD of 49 m with the most and least precise tags having precisions of ±8 m and ±51 m, respectively. As with other geolocation technologies, it would appear that structures in the environment cause signal propagation effects including multipath and non-line-of-sight, which result in errors in the derived locations. The distance from the mean data was log transformed (log10) and summarised in order to present all data over a 24-h period. There was a statistically significant decrease in precision between 11:00 and 17:00 h. These data were correlated with meteorological parameters for the period of the trial, again summarised over 24 h, with temperature, humidity, wind speed and pressure all having significant correlations with the precision data. The variance between individual tag transmissions were compared to see whether the distance between derived locations increased as time between transmissions increased. The means for each tag showed the same variance as the mean precision values, that is the more precise tags had lower means and the less precise tags had higher means. However, no tags showed a trend towards an increase in the distance between locations as the time between transmissions increased. In order to assess whether there was any spatial variability in the derived locations, the variability in distance between tags was compared for all tag combinations. Tags that were proximal to each other had shorter distances between the mean derived locations and less variance, whereas tags farther apart had large distances and large variance in the mean derived locations. The ARATS assessed in this static evaluation showed a lower level of spatial precision than commercially available global positioning systems. However the system could still have application when used to derive proximal associations between animals in low stocking-rate, extensive grazing situations such as are present in northern Australia.Associated Grant:PHD researc

Validation of accelerometer use to measure suckling behaviour in northern Australian beef calves

Corbet, NJ ORCiD: 0000-0002-7468-2177Knowledge of suckling behaviour in beef calves is important for understanding the health and wellbeing of both cows and calves. The present study was conducted to explore the use of tri-axial accelerometers to identify suckling bouts and suckling duration per bout in beef calves under free-range conditions. Three experiments were conducted: Experiment 1 was conducted to develop a model to characterise suckling in calves; Experiments 2 and 3 were conducted to apply the model when cattle were managed in pastoral paddock conditions. One Holstein Friesian and one Droughtmaster cow-calf pair were used in Experiment 1 for 2 days. The tri-axial accelerometer was fitted to a neck collar of the Droughtmaster calf and at the bottom and the right side of a halter on a Holstein Friesian calf on consecutive days. The initial model was developed using data collected from one calf for one day only to classify accelerometer data into suckling and non-suckling periods. In Experiment 2, 24 Belmont Red calves with accelerometers attached on the right side of the halters were visually observed for 10 days. The model was applied to raw data obtained through use of the accelerometers and the model could be used to successfully identify 98.8% of suckling bouts when compared with visually recorded behavioural data. The average suckling duration per bout recorded by accelerometers was 9.72 ± 0.20 min, whereas visually it was 9.32 ± 0.19 min. In Experiment 3, 20 Brahman calves fitted with accelerometers were visually observed for 6 h for 3 consecutive days. The model could be used to identify 95% of suckling bouts from the accelerometer data, corresponding to total number of suckling bouts observed visually. The average suckling duration per bout recorded by accelerometers was 13.69 ± 1.82 min, while with visual observations was 12.23 ± 1.77 min. The results indicate that accelerometers are a very effective tool to record suckling behaviour in beef calves in pastoral paddock conditions. © 2018 Elsevier B.V