GA Wright's letter about dairy cows was based on personal experience of a small herd some years ago – hardly a reflection of current trends. ("Cows' suffering exaggerated", July 23).

According to UK Agriculture, there are about two million dairy cows in the UK.

Thirty per cent of them are affected by mastitis at any one time and one million cases of clinical mastitis occur in the UK every year. GA Wright said that in his herd of 40, he had four cases of mastitis in a year; his herd obviously didn't follow the current trend. Concerning mastitis, GA Wright said, "The secret is to spot trouble straight away and treat at once".

While clinical mastitis produces obvious symptoms, it can occur in subclinical form with no visible changes to the udder or milk, "making the number of these cases impossible to calculate".

GA Wright disagreed that 50 per cent of dairy cows suffer leg and foot disorders saying "We didn't have any of Ms Allison's cows' trouble".

According to Defra, "The level of lameness in dairy cattle in the UK is unacceptably high. It is a major cause of pain and discomfort to the animals".

Professor John Webster, of Bristol University's Veterinary Science Dept, said: "There is an annual incidence of lameness of 50 per cent and a prevalence of 20 per cent – meaning that half the cows in Britain go lame each year and 20 per cent are lame at any one time".

He also says that, "A depressing number are culled after only two or three lactations because they are worn out either through complete loss of body tissue (emaciation), or breakdown of the udder tissue, or chronic lameness".

Will Professor Webster be accused of exaggeration?

GA Wright said that I should "stick to the facts now and again". I can assure him that I do check my facts. I suggest he does likewise and looks at the current "bigger picture" rather than relying on outdated experience.

Mrs Elizabeth Allison, Aylestone.