Breeding Without Mendelism: Theory and Practice of Dairy Cattle Breeding in the Netherlands 1900–1950

In the 1940s and 1950s, Dutch scientists became increasingly critical of the practices of commercial dairy cattle breeders. Milk yields had hardly increased for decades, and the scientists believed this to be due to the fact that breeders still judged the hereditary potential of their animals on the basis of outward characteristics. An objective verdict on the qualities of breeding stock could only be obtained by progeny testing, the scientists contended: the best animals were those that produced the most productive offspring.