Auditory brainstem responses in weaning pigs and three ages of sows1

Abstract

Piglet crushing is a devastating welfare concern on swine farms; however, some sows appear unresponsive to a piglet’s call. Sow hearing ability is rarely considered despite the extensive body of research performed on crushing. In this study, pigs of four age groups (weaning, n = 7; gilts, n = 5; 2nd and 3rd parity, n = 5; 5th parity and up, n = 5) were anesthetized and auditory brainstem responses (ABRs) were performed to measure if pig hearing diminishes with age in a mechanically ventilated barn. Before testing, pigs were placed in a sound dampening box. ABRs were performed on animals using 1,000 clicks at two decibel (dB) levels: 90 and 127 dB sound pressure level. Latencies and amplitudes of waves I–V were measured and interpeak latencies for waves I–III, III–V, and I–V were calculated. Five pigs (three 2nd and 3rd parity, and two 5th parity and above) had no detectable waves at either decibel. Sows in 2nd and 3rd parities had very few distinguishable waves, with only wave I and II present in two sows. Amplitudes of waves I and V increased with increased dB (P < 0.001). Increasing dB decreased the latency of each of the recorded waves (P < 0.01). The vast majority of commercial swine are raised in noisy barn environments; it is possible that these environments directly affect the ability for pigs to hear and normal hearing development in this population of animals. Hearing has a significant effect on swine welfare as hearing is integral to successful animal handing and during moments of animal-to-animal communication. Hearing is a considerable welfare issue on farms and ways to decrease pig hearing loss should be considered.

Surgical procedure of intratympanic injection and inner ear pharmacokinetics simulation in domestic pigs

“…Overall, the waves evoked by bone-conduction ABR in standard pigs were clear, stable, reproducible, and well differentiated. In other studies, air-conduction ABR thresholds were between 40-and 50-dB sound pressure levels (SPL) for Rongchang pigs and unknown breed pigs, not reported in the paper (Hansen et al, 1992;Guo et al, 2010;Anderson et al, 2019). Here, we observed a slightly lower threshed of 38 dB SPL (n = 3).…”

“…In Figure 2A, we show comparisons between air-and bone-conduction responses (blue and orange, respectively). The figure shows three different cases and in the top panel the three main peaks typically seen in the porcine ABR are shown (Hansen et al, 1992;Guo et al, 2010;Anderson et al, 2019). These three peaks are labeled as waves I, III/ IV, and V with reference to human ABR waveforms.…”

Ontogeny of cellular organization and LGR5 expression in porcine cochlea revealed using tissue clearing and 3D imaging

“…For example, several recent reports used transgenic porcine models to study deafness and explore the applicability of gene therapy for rare genetic diseases that cause hearing loss—e.g., Waardenburg syndrome ( Guo and Yang, 2015 ; Hai et al., 2017 ; Xu et al., 2020 ). Measurements of behavior and physiological responses (i.e., auditory brainstem responses) to sounds have been established in wild-type pigs, thus providing a crucial step for creating a noise-induced hearing loss model ( Anderson et al., 2019 ; Heffner and Heffner, 1990 ; Kristensen and Gimsing, 1988 ). However, there is still a significant gap to connect these in-vivo measurements and rough anatomical and mechanical studies to molecular and cellular phenomena in the porcine cochlea.…”