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Development of a predictive model to identify the day of lambing in extensive sheep systems using autonomous Global Navigation Satellite System (GNSS)

conference contribution
posted on 2022-03-30, 02:31 authored by Eloise FogartyEloise Fogarty, G Cronin, David SwainDavid Swain, L Moraes, Mark TrotterMark Trotter
The aim of this project was to develop a model capable of predicting day of lambing from GNSS data. A field trial was conducted in New Zealand over a two-week period from September to October 2017. Forty ewes were fitted with GNSS tracking collars, recording at three-minute intervals. Animals were visually observed to record birth events. Of the 40 ewes, 25 lambed during the experimental period. A heuristic model was developed to predict the day of lambing by classifying ewes as either 'non-lambing' or 'lambing' on each day of the study based on her speed of movement, mean distance to peers and extent of spatial landscape. Predictions were based on the series moving over or under a given threshold, determined through estimated least-square means from the linear mixed-effects statistical analysis. The overall accuracy of the model was 83.0%, with a sensitivity of 63.6% and specificity of 84.1%. The results of this project highlight the potential for GNSS tracking for post-hoc detection of lambing events. This could be used to inform graziers on the status of individual animals and their flock as a whole, particularly in extensive farming systems where close observation may be limited. Further work should be conducted on larger datasets to improve reliability of results.


Category 3 - Industry and Other Research Income



O'Brien B; Henessy D; Shalloo L

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Cork, Ireland


The Organising Committee of the 9th European Conference on Precision Livestock Farming (ECPLF)

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Peer Reviewed

  • Yes

Open Access

  • No

External Author Affiliations

Ohio State University, USA; University of Sydney

Author Research Institute

  • Institute for Future Farming Systems

Era Eligible

  • Yes

Name of Conference

9th European Conference on Precision Livestock Farming

Parent Title

Precision Livestock Farming '19: Papers Presented at the 9th European Conference on Precision Livestock Farming