We rarely cover pigs in our newsletter, but I figured I could continue with the Dr. Bustad theme and touch on a topic aligned with his interests and highlighted within his book’s chapter entitled “Pigs: From BC-2,000 AD—From Outhouse to Penthouse.” He and his co-author Glenn Horstman cover some interesting history surrounding ancient cultural and religious taboos forbidding the consumption of pork. Nonetheless, the domestication of the pig as a source of human food has obviously persisted, and the continued increases in numbers of swine throughout the world up to the present time provide evidence of the contribution of the pig to human nutrition through the ages.
I hadn’t looked into the literature recently to see where things stand regarding pig production. However, a quick search brought me to a paper, Modern Pig Production: Aspects of Animal Welfare, Sustainability and Circular Bioeconomy, (Sustainability 2025, 17(11), 5184) on modern pig production that covers aspects of animal welfare, sustainability and circular bioeconomy. Interestingly, this paper’s Introduction opens with the statement that “Pigs are similar to humans in many ways, resulting in some major advantages and some significant drawbacks in relation to the sustainability of pig farming.” That set the tone for a discussion about the advantages pigs gain from their similarity to humans. Anyone who has worked with pigs understands their complex behavior and high level of cognitive ability. It’s been noted that pigs often make direct eye contact with humans when evaluating their next action, and such abilities and actions may lead humans to have more empathy with pigs than with some other species, which can result in better welfare for pigs.
Unsurprisingly, given Dr. Bustad’s interest in the human-animal-bond he spent some time speaking to the voice and language of pigs. That led me down another rabbit hole to see where things stand currently with regard to deciphering pig vocalization. It turns out that a recent publication in Scientific Reports, A multi-stage ensemble framework for classifying pig vocalizations under noisy animal farm environments, (Sci Rep. 2025 Oct 6;15:34703) tackles the issue of classifying pig vocalization within noisy farm environments using precision technology. Among various indicators of animal welfare, pig vocalizations are widely recognized as key signals of health conditions, emotions, and behaviors. These vocalizations allow farmers to detect potential health issues or discomfort early, enabling timely interventions, a critical capability in intensive farming systems where the likelihood of disease transmission and stress-related disorders is markedly elevated. Automated monitoring systems for pig vocalizations offer a promising solution, enabling continuous health tracking, early issue detection, and optimization of the farming environment. By leveraging computer vision-based deep learning techniques, these systems enhance audio classification by converting audio signals into visual features, such as spectrogram images, for more accurate analysis.
That’s a lot of technical jargon but the take-home message from the Scientific Reports article is that their vocalization model accurately identified emotionally meaningful vocalization even under acoustically challenging conditions. Their findings suggest that AI-based acoustic monitoring holds significant potential as a real-time tool for assessing animal welfare which is in alignment with a previous study, Domestic pig sound classification based on TransformerCNN, that modeled pig sound classifications. However, the authors acknowledged that emotional categories such as Feeding, Frightened, and Anxious exhibited overlapping spectral and temporal patterns, resulting in high misclassification rates. Consequently, additional research is needed to capture a wide range of farming conditions, stress scenarios, breeds, age groups, and background noise profiles. A more diverse dataset would allow for finer-grained learning and better generalization across varied real-world situations.
Nonetheless, this research provides a reference for realistic behavioral and emotional analysis of domestic pigs. In effect, it touches on another key area of interest for Dr. Bustad: Listening. His chapter entitled “The Art and Importance of Listening” speaks to the benefits and challenges of listening effectively. Although he was referring to interpersonal communication, his final comment was that, “We must do more than hear; we must listen with our whole being.” It seems that the research highlighted above is helping us do that with respect to pigs. Dr. Bustad concludes in his chapter on pigs that during the long and often disturbing history of the pig, it has obviously spent more time in the ‘outhouse’ than in the ‘penthouse’, and suggests that we should appreciate that the pig belongs in the penthouse and should “help provide the care and attention dictated by one who inhabits this elevated station in life.” Perhaps expanding our understanding of what they are vocalizing will do exactly that!