Dairy farmer's son John Willett, who has died aged 92, helped revolutionise East Anglia's cattle breeding industry over more than five decades.

As manager of the new Wymondham artificial insemination centre, which was set up by the Milk Marketing Board in the late 1940s, his five-strong team introduced the latest genetics with semen from top bulls.

After he retired in December 1983, he used his skill as an AI technician helping many dairy farmers with their herds. And, he enjoyed his 15 minutes of fame when he was invited to appear on the national TV programme, 'I've Got A Secret,' as the AI man, who had 'sired' hundreds of thousands of calves.

The concept of AI had been pioneered by North Norfolk's Sir John Hammond a decade earlier at Cambridge University. It led to the formation of the Beccles Cattle Breeding Centre, headed by the MMB's chief veterinary officer, Geoffrey Smith, who taught Mr Willett the AI technique in 1947 at nearby Hedenham.

'I'll never forget my first morning on the job. I knew nothing about AI. I went out with Geoffrey Smith from the Beccles Centre which was just being built. He rolled back his sleeves – in those days we had no gloves – and suddenly his hand was shoved up the cow's backside.'

When his elder brothers took on the family farm, he later joined the 4th battalion Cheshire Regiment and was sent to France with the British Expeditionary Force. As machine gunners, they were ordered to defend the beachhead at Dunkirk in late May 1940 to enable the evacuation to continue. Mr Willett was in one of the last groups to be rescued.

He served for the duration, mainly as an instructor. He met his wife, Brenda, a Norfolk girl living at Geldeston, and they were married in 1943. After he was demobbed in 1946, he went on to join the MMB.

In the late 1940s and 1950s, Norfolk was not considered a big dairy county although there were some larger herds. The impact of foot-and-mouth disease outbreaks after the second world war encouraged a shift of dairy farming to the eastern counties.

When he started at Wymondham as senior inseminator, the average workload was 15 to 20 cows a day although it quickly rose to more than 50. Ironically, his two brothers also later become AI inseminators, based in their native Cheshire.

In retirement, he was a keen bowls player and gardener at his home in Attleborough. He leaves a widow, Brenda, four children, five grandchildren and three great-grandchildren.

A celebration of his life will be held at Colney Wood Burial Park on Friday, November 11 at 1pm.

Michael Pollitt