Experimental design and results of cohabitation trial. Sixteen female adult cattle (O) and one breeding bull (□) of the breeds Limousin (─) and German Simmental (−−−) were enrolled in the 12-week cohabitation trial. Pink, yellow, green, and blue indicate animals in the acute, subacute, chronic, and subclinical stage of bovine besnoitiosis, respectively. A) Five healthy, non-pregnant Simmental heifers (Study animals [SA] 3, 4, 6, 8, and 9), and a healthy Simmental bull (SA 1) were kept together with three chronically Besnoitia besnoiti infected, non-pregnant Limousin cows (SA 13, 15, and 16) on a 2,500 m2 pasture. A control group of six healthy, non-pregnant Simmental heifers (SA 2, 5, 7, 10, 11, and 12) were confined at a minimal distance of 20 m in a 200 m2 paddock area. On trial day [td] 3, the acutely B. besnoiti infected, pregnant Limousin cow SA 20 was introduced into the pasture group. B) The acutely B. besnoiti infected, pregnant Limousin cow SA 22 was introduced on td 51. By this time SA 20 had entered the chronic stage, and SA 4 and 6 were in the subacute stage of disease. C) In the final week of the trial, SA 4, 6, and 22 had reached the chronic stage of bovine besnoitiosis and SA 8 was identified as subclinically infected.