Submitted to: Biosystems Engineering
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/18/2024
Publication Date: 9/24/2024
Citation: Bery, S., Brown-Brandl, T.M., Rohrer, G.A., Sharma, S., Leonard, S.M. 2024. Impact of crate design, number of heat lamps, and lying posture on the occurrence of shoulder lesions in sows. Biosystems Engineering. 247:249-256. https://doi.org/10.1016/j.biosystemseng.2024.09.017.
DOI: https://doi.org/10.1016/j.biosystemseng.2024.09.017

Interpretive Summary: This study aimed to investigate the effects the number of heat lamps, crate size, sow weights, sow posture and body conditioning score on the incidence of shoulder lesions in sows. The results indicated a significant interaction between the number of heat lamps and crate size regarding the occurrence of shoulder lesions. Specifically, the mean occurrence of shoulder lesions in the smallest crate size, with two heat lamps was much greater than when crate size was expanded or only 1 heat lamp was used. The smaller creep area brought the heat lamps closer to the sow, resulting in increased temperature around the shoulder and making it more susceptible to lesion development. Additionally, crates with smaller sow area may have potentially affected the sow's natural movement, causing her to spend more time on one side, which contributed to the development of lesions. Therefore, to reduce the occurrence of shoulder lesions producers should consider increasing the crate size of farrowing pens and only use one heat lamp.

Technical Abstract: This study investigated the interaction of sow and engineering factors on shoulder lesion formation. Sows were randomly assigned to three farrowing crate designs: Traditional Stall Layout, Expanded Creep Stall Layout, and Expanded Sow & Creep Stall Layout. Each crate configuration was further differentiated by the inclusion of either one (1HL) or two (2HL) heat lamps. Digital and depth images were collected from an overhead time of flight depth camera (Kinect V2) every 5 s. Computer vision techniques were employed to analyze top-down digital images from the 21st to the 24th day of farrowing to detect and estimate lesion size. Additionally, the study incorporated an analysis of sow lying behaviors on the occurrence and size of lesions using depth images. Sow’s environmental and phenotypic data - weight, parity, body condition score, total lying time and number of lying transitions in a day were investigated for impact on shoulder lesion. The results indicated that the interaction of smaller crate sizes and increased heat lamp usage significantly impacted lesion occurrence (p < 0.05). Also, higher parity and lighter weight sows showed higher lesion occurrence (p < 0.05). However, other factors, such as the number of heat lamps alone and detailed metrics of lying postures, did not show a significant impact on lesion occurrence. In contrast, none of the studied factors showed a significant impact on the size of shoulder lesions. This highlights the importance of allocating crate space with respect to heat lamp placement to the sows. Science4Impact Statement (S4IS): This manuscript evaluates shoulder lesions’ presence and size in lactating sows housed within farrowing stalls. Shoulder lesions are one of the main causes of premature culling in sows and are a major concern for animal well-being. Understanding the impact of crate design and the number of heat lamps is important for the engineering design of the farrowing environment.