A Systematic Review on Validated Precision Livestock Farming Technologies for Pig Production and Its Potential to Assess Animal Welfare.

Several precision livestock farming (PLF) technologies, conceived for optimizing farming processes, are developed to detect the physical and behavioral changes of animals continuously and in real-time. The aim of this review was to explore the capacity of existing PLF technologies to contribute to the assessment of pig welfare. In a web search for commercially available PLF for pigs, 83 technologies were identified. A literature search was conducted, following systematic review guidelines (PRISMA), to identify studies on the validation of sensor technologies for assessing animal-based welfare indicators. Two validation levels were defined: internal (evaluation during system building within the same population that were used for system building) and external (evaluation on a different population than during system building). From 2,463 articles found, 111 were selected, which validated some PLF that could be applied to the assessment of animal-based welfare indicators of pigs (7% classified as external, and 93% as internal validation). From our list of commercially available PLF technologies, only 5% had been externally validated. The more often validated technologies were vision-based solutions (n = 45), followed by load-cells (n = 28; feeders and drinkers, force plates and scales), accelerometers (n = 14) and microphones (n = 14), thermal cameras (n = 10), photoelectric sensors (n = 5), radio-frequency identification (RFID) for tracking (n = 2), infrared thermometers (n = 1), and pyrometer (n = 1). Externally validated technologies were photoelectric sensors (n = 2), thermal cameras (n = 2), microphone (n = 1), load-cells (n = 1), RFID (n = 1), and pyrometer (n = 1). Measured traits included activity and posture-related behavior, feeding and drinking, other behavior, physical condition, and health. In conclusion, existing PLF technologies are potential tools for on-farm animal welfare assessment in pig production. However, validation studies are lacking for an important percentage of market available tools, and in particular research and development need to focus on identifying the feature candidates of the measures (e.g., deviations from diurnal pattern, threshold levels) that are valid signals of either negative or positive animal welfare. An important gap identified are the lack of technologies to assess affective states (both positive and negative states).

The dose-response relationship between the amount of straw provided on the floor and gastric ulceration of pars oesophagea in growing pigs.

The aim of the present study was (1) to determine the dose-response relationship between the amount of straw provided on the floor and oesophageal ulceration in pigs kept under typical Danish production conditions (18 pigs/pen, 0.7m2/pig, partly slatted floor, ad libitum access to feed), (2) to reveal whether straw ingestion explains the effect of straw provision on the stomach health and (3) to elucidate the effect of straw ingestion on the stomach conditions. Data were collected at slaughter (approximately 100kg body weight) on pigs provided with straw amounts in the range 10g to 500g wheat straw/pig/day from 30kg body weight and fed a wheat-based pelleted feed added 15% non-heated and non-pelleted rolled barley. Aims (1) and (2) included 712 pigs kept in 42 pens, whereas (3) was studied on a subset of 37 pigs with either none or obvious amounts of straw in the stomach. The amount of straw provided affected stomach health in a curvilinear manner. Provision of up to approximately 300gstraw/pig/day progressively decreased the risk of oesophageal ulceration and scarring. At larger amounts of straw the ulceroprotective effect of straw was reduced which requires further investigation. Straw ingestion appeared to be an essential intermediary factor for the improvement of stomach health. The number of pigs without straw in the stomach decreased linearly with the logarithm of the amount of straw provided, which explained the effect of straw provision on stomach health. The structure of the stomach contents increased as revealed by the increased weight and dry matter content and decreased sedimentation of the digesta. Provision of approximately 300gstraw/pig/day on the floor may be a potential strategy to reduce, but not inevitably eliminate, oesophageal ulceration in pigs in commercial pig production.

Impact of the amount of straw provided to pigs kept in intensive production conditions on the occurrence and severity of gastric ulceration at slaughter.

This study examined effects of the amount of straw offered on occurrence and severity of gastric lesions in pigs kept in pens (18 pigs, 0.7 m(2)/pig) with partly slatted flooring and 10, 500 or 1000 g straw/pig/day from 30 kg live weight. The pigs had ad libitum access to dry feed. Forty-five pigs were used, three from each of 15 pens. After euthanization, the dimension of the non-glandular region of the stomach was measured. Lesions were characterized and scored. Irrespective of straw provided, 67% of the pigs showed signs of gastric pathology. Pigs provided with 500 or 1000 g straw were pooled as 'permanent access'. The proportion of pigs with ulcerations was reduced by permanent access to straw (7 vs. 33%; P<0.05), suggesting that permanent access to straw may improve animal health, and be considered as one possible strategy to limit gastric ulceration in pigs.