Again: And concerning this copulation of causes it is said: The Spirit comes to the assistance of our infirmity.
"Historical Introductions to the Symbolical Books of the Evangelical Lutheran Church"
Friedrich Bente
The contagion, the nature of which remains still unknown, is transmitted mainly during copulation.
"Special Report on Diseases of Cattle"
U.S. Department of Agriculture J.R. Mohler
The bull may have the disease and convey it to all the cows with which he comes in contact, or he may become infected by one cow, and, although not showing the disease, he may, during copulation, transmit it for several days after to all other cows.
"Special Report on Diseases of Cattle"
U.S. Department of Agriculture J.R. Mohler