Portrait | SA’s most famous animal geneticist


Portrait | SA’s most famous animal geneticist

In the cattle world, Prof Jan Cornelius Bonsma is revered as one of the great scientists. ANNELIESE BURGESS tells us more about the father of SA's Bonsmara breed, who continues to influence farmers and ranchers worldwide.

MY FATHER studied under Prof Jan Bonsma. I remember him speaking with great reverence about the animal scientist who created the Bonsmara breed of cattle uniquely adapted to South African conditions. My father became a Bonsmara farmer because of Bonsma.

Bonsma was head of the Department of Animal Husbandry at the University of Pretoria and published more than 180 articles during his career. He earned his master’s in animal science in 1936 and did postgraduate work at Iowa State University with world-renowned animal geneticist Jay Lush.

In 1937, he returned to South Africa and embarked on the most comprehensive climatological and ecological experimentation on bovines in the world. His work was conducted at the Mara Research Station near Musina in the dry-tropical Limpopo basin. He headed the station for 23 years.

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Bonsma’s objective was to solve South Africa’s cattle industry problem. The native breed, Afrikaner, was well-suited to the climate but commercial production trailed breeds from other countries. In contrast, imported European cattle performed poorly in the harsh tropical and sub-tropical parts of South Africa. Bonsma's goal was to develop a breed of high-yielding and environmentally adapted cattle.

His methodology — centred on “selection for functional efficiency” — remains the cornerstone of the Bonsma doctrine. He went about selecting the best male and female specimens for breeding by measuring, assessing and comparing their physical attributes. 

The cattle in South Africa in the 1930s were mainly Bos indicus (Brahman type) of the Sanga and Afrikaner breeds.

Bonsma’s research at Mara revealed much of what we know today about the environmental adaption of cattle to different climatic regions. He measured and compared the differences between animals' weight gain, body temperature, rates of respiration and pulse, tick counts, hide thickness, hair count per square centimetre, fertility, milk production, mortality and longevity.

He performed 14 body measurements on more than 1,000 animals every three months throughout their lives. He developed an unrivalled ability to judge livestock.

Bonsma found that the British cattle breeds performed poorly, not because of their inability to digest the very low protein grass, as initially thought, but because of chronic malnutrition caused by hyperthermia (the opposite of hypothermia) because they animals did not have a way of processing excessive metabolic heat. Cattle that couldn’t cool their bodies would spend their days panting in the shade or wading in the water instead of grazing. 

He found animals, even from the same breed, did not respond to heat similarly. Those with thicker hides and shorter hair were better able to adapt. He also developed a better understanding of the influence of the endocrine system on bovine physiology. He discovered that animals with hormonally balanced endocrine systems dealt with environmental challenges best. And, most critically, he found these hormonally balanced animals all had the same phenotype — what is referred to as the “Bonsma type”.


Bonsma spent many years improving the performance of the Afrikaner, South Africa’s native cattle breed, before applying his genetic principles to develop a new breed. After many cross matings and back-crosses, the Bonsmara was born, a hardy new composite breed using Afrikaner cows and Hereford and Shorthorn bulls. 

The University of Pretoria gave Bonsma an honorary doctorate. He authored more than 200 works, including seven books, and spoke around the world about his knowledge of beef cattle. His list of accolades is long, with many from American universities and international cattle breed associations. They include Texas A&M University awarding him the position of distinguished guest professor. He was the first foreigner to earn this honour. He was also inducted into the International Stockmen’s Educational Foundation hall of fame.

Today, Bonsmara cattle are found not only in South Africa but in Zimbabwe, Namibia, Zambia, Eswatini, Botswana, Angola, Mozambique, Rwanda, Australia, Argentina, Paraguay, Congo, Argentina and the US.

♦ VWB ♦

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