More than 40 percent of surveyed Icelandic competition horses were found in a study to have bit-related lesions in the leadup to two major events in the country.
Researchers found that 184 of the 424 horses examined before the preliminary rounds had bit-related lesions, representing 43 percent of the animals examined.
The lesions were classified as mild in 152 of the horses, representing 36 percent of the assessed horses. They were most often located in the corners of the lips and the nearby mucosa.
A further 32 horses, or 7 percent, had lesions that were classified as severe.
The researchers, Sigríður Björnsdóttir, Rebecka Frey, Thorvaldur Kristjansson and Torbjörn Lundström, reported their findings in the latest issue of Acta Veterinaria Scandinavica.
They concluded that bit-related mouth lesions were a general problem in Icelandic competition horses.
The type of bit influenced both the location and the severity of the lesions, they found.
“The use of curb bits with a port was found to be a decisive risk factor for lesions on the bars of the mandible, most of which were regarded as severe,” they wrote.
“The results also raised questions about the head and neck carriage demanded for the competition horses.
“From an animal welfare point of view, prevention of severe lesions in the bar region of the mouth should be given the highest priority.”
A team of eight veterinarians conducted field examinations of the mouths of the 424 five-gaited horses leading up to the two major events in Iceland in 2012.
Records from repeat examinations of 77 horses before the finals were used to assess potential risk factors.
Björnsdóttir and her colleagues found evidence that the presence of lesions on the bars of the mandible were strongly associated with the use of curb bits with a port. Many of these lesions were severe.
A strong association was also found between buccal lesions and the use of a snaffle bit.
“The results also raised questions about the head and neck carriage demanded for the competition horses,” they said.
They noted that six horses ridden with traditional Icelandic curb bits were all without oral lesions, which they described as a remarkable finding.
“It suggests the port plays a major role in the development of lesions in the bar region. However, the leverage effect of shanks and curb is likely to increase the effect of the port.”
Bit-related lesions in Icelandic competition horses.
Sigríður Björnsdóttir, Rebecka Frey, Thorvaldur Kristjansson and Torbjörn Lundström.
Acta Veterinaria Scandinavica 2014, 56:40 doi:10.1186/s13028-014-0040-8
The full study can be read here.