Is it time to prescribe Mozart? According to veterinary neurologist Susan O. Wagner, DVM, MS, DACVIM, an adjunct faculty member at The Ohio State University College of Veterinary Medicine in Columbus and coauthor of Through a Dog’s Ear: Using Sound to Improve the Health & Behavior of Your Canine Companion, the answer is a resounding yes. At the Fetch dvm360® virtual conference this week, Wagner presented evidence that suggests sound affects animals on a psychological level. She encouraged attendees to utilize particular genres of music to create a more relaxed experience for their patients.
Before delving into the specific benefits of music therapy, Wagner provided a brief overview of some basic tenets of sound measurements, noise toxicity, and the study of bioacoustics versus psychoacoustics.
At the most elementary level, sound is waves of energy that affect the nervous system. The 2 terms used to categorize sound are frequency, which is measured in Hertz (Hz), and intensity, which is measured in decibels (dB). Humans hear frequencies of 20 to 20,000 Hz, whereas dogs can hear frequencies between 40 and 45,000 Hz and cats up to 64,000 Hz.
Part of understanding how sound can positively impact a species involves recognizing its adverse effects, Wagner said. For reference, a normal conversation occurs at 50 dB and a lawnmower generally operates at 90 dB. Animal laboratories routinely reach noise levels of 80 dB, with human activity transiently increasing intensity by as much as 40 dB. Hearing damage occurs instantly at 100 dB (think standing next to a jet engine) or when exposed to 80 dB for longer than 15 minutes, which happens more often than one might think, she said.
Although noise levels in a typical veterinary clinic could become detrimental to staff working lots of overtime hours, it is the patients Wagner called attention to. “Researchers have examined the effects of noise toxicity in animals, which expands beyond hearing damage,” she said.
For instance, a study published in Applied Animal Behaviour Science found that dogs exposed to sound blasts of 85 dB experienced increased heart rates and salivary cortisol levels.1 The noise also elicited postural signs of anxiety. Birth defects have been documented in mice and rats when the mother was exposed to noise pollution during pregnancy.2 Behavioral changes were also detected in their offspring.3
While there is decades-old research on the effect of noise on animals, Wagner said the study of sound in animals historically was categorized through bioacoustics. This places an emphasis on how animals communicate and the positive and negative effects of their environments, but it does not account for psychoacoustics. Typically applied only to humans, psychoacoustics examines the perception of sound, psychological responses, and its impact on the nervous system.
Examining the physiologic effects of sound and music opens the door to understanding how certain melodies can be used to calm anxious pets.
Music and animal welfare
“Music therapy and sound enrichment are low-cost, easy modalities to enrich the lives of captive animals,” Wagner said. “Whether it be a short-term stay in a veterinary clinic or shelter, or long-term captivity in a sanctuary or zoo, sound can play a key role in enhancing the welfare of these animals.”
Sound therapy research has illustrated music’s influence on a variety of species. In 1 study, cows were more likely to come into the milking parlor if signaled by music.4 “Behaviorists might say that is classical conditioning, and some of it can be, but it has to start with a pleasant stimulus,” Wagner said. “You play pleasant music to the cows and then they are adapting to it. It is a combination of classical conditioning and sensory…