The American couple who delivered better milk for China's children

Erwin (Sid) Engst (Chinese name Yang Zao) and Joan Hinton (Chinese name Han Chun) were born in the United States.

Influenced by books such as Red Star Over China , Erwin came to China in 1946.

Witnessing ordinary people dying of famine while officials of the ruling Kuomintang (KMT) party hoarded grain for profiteering, Erwin went to Yan'an, the headquarters of the Communist Party of China (CPC) in northern Shaanxi Province at the time.

Driven by his interest in agriculture, Erwin was assigned to work at Guanghua Farm, the first farm established by the CPC.

Erwin said: "In America, you work for yourself, to earn a living.

But in Yan'an, you work in a large collective, where everyone shares one common goal: to build a new society that is equal and free, where no one exploits anyone else!" Joan Hinton was one of the few female physicists involved in the US Manhattan Project.

When she saw the atomic bomb she had helped develop being used in World War II, her ideal of "pure science" was shattered.

In 1948, encouraged by Erwin, she came to Yan'an.

They married in the spring of 1949 in a Yaodong (cave dwelling) in Wayaobu, Yan'an.

Later in September, they were ordered to go to Chengchuan in the Shaanxi-Gansu-Ningxia Border Region (present-day border area between the Inner Mongolia Autonomous Region and Shaanxi Province) to establish the Party's first livestock breeding farm – Sanbian Ranch.

The ranch sits on the Inner Mongolia Plateau – a cold, sparsely populated land where supplies were scarce and grasslands meet sand.

Yet Erwin and Joan overcame the harsh conditions with the help of modern breeding concepts.

Through scientific breeding and immunization, they improved the quantity and quality of the herd, enhanced pasture grass, researched dairy products, and also designed and built a windmill to harness the region's abundant wind resources.

They taught themselves Mongolian and soon became friends with the local herders.