A leaflet produced by the UK Health and Safety Executive warning of the dangers of squealing pigs has caught the attention of the British media.
Apparently a large group of pigs in intensive housing can create noise levels of 100 decibels or above, especially just before they are fed. Farmers are advised to either wear hearing protection or avoid the animals until they are fed and contented. (This is less of an issue for farmers with automated feeding systems that can be switched on from the outside).
I have to say I wasn't aware of quite how loud a big group of hungry sows could be (100 decibels is the same as a chainsaw), but it seems the risks from noisy pigs have been known about for some time. Searching the CAB Abstracts database, I found a paper from 1979 looking at noise deafness risk in three different types of livestock housing1. Noise exposure of stockmen [equivalent continuous noise levels] frequently exceeded the 'recommended limit of 90 decibels'. Levels were typically 93-97 decibels for pig housing, 79-82 decibels for dairy housing and 81-87 decibels for poultry housing. Another paper published in Occupation Health Review in 1992 highlights the case of one pig farmer with deteriorating hearing who had been exposed to the squealing of some 10,000 pigs 3 times a day at feeding time2.
Animal sounds are just one of the many loud noises that farmers are exposed to. An Australian study3 published in 2005 identified noise hazards from firearms, tractors without cabs, workshop tools, chainsaws, heavy machinery such as harvesters, and again those squealing pigs! So, are hearing problems common among farmers? According to a document from the U.S. National Agricultural Safety Database, entitled 'Protect Your Hearing'4, many farm workers have greater hearing loss than their non-farming contemporaries. And, although noise-induced hearing loss in farming was first documented in the late 1930s, only 20 to 30 percent of farmers report using hearing protection and many of them admit they rarely use it.
Back to the pigs…Are swine veterinarians also at risk? I came across a paper from 1996 looking at occupational hazards reported by swine veterinarians in the United States5. Of the members of the American Association of Swine Practitioners that responded to a questionnaire, 22% reported having a diagnosed hearing impairment. However, results of audiology testing at the 2002 annual meeting of the American Association of Swine Veterinarians found hearing loss to be more age related than occupational6. I would be interested to know if there have been any more studies.
- Noise deafness risk in livestock housing. Cermak, J. P.; Ross, P. A. Farm Building Progress (1979), No. 58, pp. 5-7.
- Dangerous Bacon. Owen, G. Occupational Health Review (1992), No. 38, pp.32
- Farm noise emissions during common agricultural activities. Depczynski, J.; Franklin, R. C.; Challinor, K.; Williams, W.; Fragar, L. J. Journal of Agricultural Safety and Health (2005), Vol. 11, No. 3, pp. 325-334.
- Protect Your Hearing. NASD Review: 04/2002. Extracted from MF-1085 'Health Concerns in Agriculture'. A tabloid published by Extension Agricultural Engineering, Kansas State University. Publication date: October 1993.
- Occupational hazards reported by swine veterinarians in the United States. Hafer, A. L.; Langley, R. L.; Morrow, W. E. M.; Tulis, J. J. Swine Health and Production (1996),Vol. 4, No. 3, pp. 128-141.
- Swine veterinarians and hearing loss: summary of results of audiology testing at the 2002 AASV annual meeting. Kattelmann, L.; Epperson, W.; Chase, C. Journal of Swine Health and Production (2005), Vol. 13, No. 1, pp. 34-37.