Simple Summary
Precision Livestock Farming (PLF) technologies enable the monitoring and acquisition of data relating to animal activities across various stages of farming. In a sheep farming system, the study of grazing sounds using recorders has allowed the clear recognition of activities such as herbage prehensions and rumination, thus characterizing grazing behavior. By employing point of view (POV) cameras, it was possible to recognize the aforementioned sounds and individual prehensions in two complex pastures (a grass-rich and a legume-rich swards). Different sound features have been highlighted between grass and legume prehensions. Significant linear regression for the number of herbage prehensions, eating and ruminating time was found between the values estimated solely from sound recordings and the actual values monitored via video analysis. Recording the number of bites is a key element for estimating herbage intake in grazing animals. Knowledge of this information provides valuable insights for improving both animal and pasture management, with positive consequences for production and environmental sustainability, even in extensive farming systems.
Abstract
The aims of the study were to evaluate the effectiveness of audio detection for identifying feeding sounds in free grazing sheep and to assess whether the recognition of these sounds could be influenced by pasture characteristics. Twelve Valle del Belice dry ewes were grazed on two mixed swards: on 10 May, grass-rich sward (G); on 13 May, legume-rich sward (L). Each ewe was fitted with a collar equipped with a point of view (POV) camera. All audio files (without viewing the videos) were listened to and sounds recognized as herbage prehension and rumination activity were highlighted. Time spent eating and ruminating was then calculated. To validate the audio file analysis, all video files were subjected to observation of the same behavioral aspects detected with audio. The regression between the prehensions number estimated using sound alone and the actual values recorded through video was significant (r2 0.743; p < 0.001). No differences were found in recognizing grazing behavior between data obtained by listening or watching the videos and between the two swards. The acoustic analysis of the single bites on grass and legume forages reveals significant differences between the two forage classes (p ≤ 0.001) particularly in terms of energy, temporal structure, and spectral features. Since sheep showed a strong selective activity towards legumes even in the grass-rich sward (selectivity index 3.1), this may have reduced acoustic differences between swards.