A Review on the Influence of Noise on the Welfare of Dogs.

Dissecting the science

Raghy, R., Jacob, N. and Tamizhkumaran, J., 2023. A Review on the Influence of Noise on the Welfare of Dogs.

​A Summary​

We know that dogs are capable of processing sound in a more sophisticated way than humans. We also know that the result of this is that many dogs become fearful of loud or unpredictable noises. Approximately 1/3 of the dog population is fearful of noises of this type with fireworks, thunderstorms and gunshots being the most reported and the most examined in regards to this.

In people noises sitting around 2000-4000Hz will cause highest "annoyance" whereas for dogs, this number is around 8000Hz. In kennelled dogs, such as those in rescue, were found to have a decline in hearing ability when exposed to sounds between 100-108dB over the course of six months (Scheifele 2012).

The responses seen by dogs when exposed to these loud noises were typically fearful (panting, pacing, hiding etc.) or freezing and not moving - exhibiting what can be considered both active and passive stress.

Ear Anatomy and breed difference in hearing capacity

The ear consists of the pinna, external ear canal, middle ear and inner ear. The pinna can either be upright or pendulous and collects sound waves to send to the tympanic membrane. Because the ear canal is deeper than in people, dogs are better at collecting sound, they do approximately four times better than people. Dogs such as Newfoundlands and St Bernards have been found to be the best at hearing subsonic sounds, due to head size and size of ears, while simultaneously it has been reported that prick ears, such as that belonging to German Shepherds or Husky's are better at orienting towards sound. The paper goes on to discuss breed predisposition to deafness in Dalmatians, and mentions that the Poodle, Dachshund, St Bernard and Chihuahua are most well known for their great ability to hear high frequency sounds.

Canine response to noise

Noise is well documented as one of the most frequent catalysts for sudden onset fear responses with domestic dogs reared in kennels for over 6 months with exposure to over 100-108dB of noise meaning a decline in hearing capability. While demonstrating a fearful response is normal, the response to sound sensitivity can have a detrimental impact on welfare. A dog that is noise sensitive and repeatedly exposed to the fearful stimulus over time can experience physical, emotional and social impact (Mills et al., 2014). 

Stress and fear

When exposed to intermittent, unpredictable and loud noises over prolonged periods of time, dogs can experience a severe fear response either behaviourally, physiologically or both (Coppola et al., 2006). Interestingly only respiratory rate was noted as increasing when dogs were exposed to normal levels of background noise under the dB threshold and not unpredictably (Stellato et al., 2007).

Dogs are in danger of severe hearing impairment when exposed to loud noise levels throughout the day (Well 2009).

Unexpected noises caused quick reactions such as tachycardia, hypertension and increased epinephrine and norepinephrine secretion (Engeland et al., 1990). Dreschel and Granger (2005) reported a significant rise (207%) in salivary cortisol which lasts for 40 m due to exposure to acute, irregular noises.

The effect of music on canine welfare

Auditory enrichment has been show to decrease high arousal behaviours and is used in kennels as a way to improve welfare. Use of music in kennels has also shown positive impacts on metabolism and immune system. Heavy metal was shown to have a negative impact, with classical having most positive (Lori et al., 2012).

Conclusions

Research is needed into preference testing of noises in kennelled dogs. More thought should go into kennel building strategies due to the impact noisy doors, fans, cleaning equipment can have on dogs. Behavioural medication had help noise sensitive dogs and is often used by owners and veterinary professionals as a way of managing noise phobia in dogs.