Are Cows More Picky Than Goats? Answers From Large-Scale Innovative Feeding Experiments Conducted 275 Years Ago

For his 18th century thesis, Carl Linnaeus collected 643 different plant species which were then fed to horses, cows, pigs, sheep and goats. The results were carefully compiled but were not analyzed until today, 275 years later, when they were also published in the journal Biological Journal of the Linnean Society.

“This was perhaps the first experiment in what would become the subject of ecology in the late 19th century. By today’s standards, it was a large-scale experiment involving an impressive number of plants,” notes Håkan Rydin, professor of plant ecology at Uppsala University and one of the researchers who conducted the analysis.

Linnaeus’s thesis, Pan Svecicus, describes 2,325 experiments involving 643 different plant species. It was published in 1749 and defended by his student, Nils Hesselgren. Previously, Linnaeus and his disciples had traveled throughout Sweden to gather information from farmers about the best pastures for their animals.

Although the thesis was translated into German and English and was known to contemporary botanists in Europe, the results were never analyzed. Rydin, however, collaborated with other researchers to compile and analyze the data.

The results show that pigs are the most selective, consuming 32% of the 204 plant species tested on all animals. They are followed by horses (59%), cows (66%), sheep (82%) and goats (85%). The animals generally prefer legumes and grasses.

“Pigs were probably the pickiest eaters, because they are omnivores and don’t eat only plants. Surprisingly enough, the animals weren’t very good at avoiding toxic plants. Cows and horses were the best at this,” Rydin says.

The thesis contains numbers and references to Flora Svecica, Linnaeus’ list of the Swedish flora. According to the researchers, this is one of the first times Linnaeus used the now common naming convention, which also allowed them to identify the species involved in the experiments.

“Carl von Linné laid the foundation for future scientists to be able to analyze this field. It took about 200 years before biologists started using statistics. What is also absolutely fascinating is that all the data is documented. If this had been done more recently, researchers probably would not have kept the raw data,” adds Rydin.