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”.
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