Eleven calves from the European bison breeding centres of Białowieża National Park (Poland) were observed during the first 3 months of life to investigate their integration patterns into a group. Spatial relations of the calf with other bison in a group were reflected in the distance to group members of various categories and in the extent to which individuals synchronized their behaviour. Data on changes in the calf’s activity pattern provided information on the transformation in feeding habits. Three main phases were identified in the early period of European bison’s life: (1) establishment of mother-infant bond, (2) incorporation of a calf into a calf subgroup, and (3) integration of the calf into the whole group. Incorporation of the calf into a herd started in week 2. The pattern of calf’s integration was determined by transformation of its activity pattern. At first similarity of activity patterns among calves resulted in synchronization of their behaviour and proximate company. In the next phase, the change in the primary source of nutrition from nursing to grazing and gradual alteration of activity pattern towards an adult’s one led to non-specific spatial relations with group members and integration of the calf into the herd.
Sarcocysts were found in muscle tissue of a wisent (Bison bonasus) which was born and kept in Germany. Light microscopic and ТЕМ examination revealed all the Ihrcc named species known from cattle: Sarcocystis cruzi („thin-walled“, with longer hairlike villar protrusions of the primary cyst wall); S. hirsuta („thick-walled“, with tongue-like protrusions of the cyst wall arising with very short and narrow stalklets from the surface of the cyst and containing rows of electron-dense granules in the core); and S. hominis („thick-walled“, with fmger-like protrusions of the cyst wall not constricted at their base and containing few or no electron-dense granules). So far, only S. cruzi was known to occur in Bison bison in North America. The findings in the wisent strikingly support a modified conception of the intermediate host specificity in Bovinae. In this connection the identity of S. cruzi and S. poephagicanis is suggested as well as that of S. hirsuta and S. poepliagi.