Field material for assessing the diet of grazed domestic animals was collected in the summer season of 2020 on the territory of the Black Lands (the southern part of the Caspian lowland within the borders of the Republic of Kalmykia). The research area belongs to the northern subzone of the desert zone (Zones and Zones…, 1999). Data on the composition of forage plants in the diet of jointly grazed sheep, cows and horses were obtained using the method of microhistological cuticular analysis of excrement. This method is used for the first time to assess the diet of sheep, cows and horses in the study area. 25 plant species were identified in the summer diet of grazed animals, of which 21 species were noted when describing vegetation in the key area. It was revealed that the diet of grazed domestic animal species differs in the ratio of the main forage groups of plants in it: cereals, sedges and various grasses. The share of cereals is the highest in the diet of horses (92%), and the share of various grasses prevails in the diet of sheep (35%).

Materials on the composition of forage plants in the bison diet were obtained within the enclosure of nonconsumptive use at the Rostov Nature Reserve in the summer and autumn seasons of 2018. The described area is located in the sod-forming cereal-grass steppes in the Western Manych River valley. Data on the seasonal dynamics of the composition of forage plants in the bison diet were produced via cuticular microscopic analysis of fecal samples. An electronic database was created for the plant cuticle structures typical of the species providing the floristic richness of grassland for bisons in order to identify the species of the botanical fragments in the fecal samples. Thus, the proportion of cereals in the summer and autumn diets comprised 64% and 84%, respectively. The selectivity indices of cereal species were measured as 2.1 in the summer and 4.3 in the autumn seasons. For motley grasses, it was 0.5 in the summer season and decreased to 0.2 in the autumn. The index value depends on the animals' taste preferences, the species richness in the aboveground phytomass of grassland, and the plant growth stage.

The fodder resources, nutrition, and food supply of free-ranging Bactrian camels, Przewalski horses, and saigas on a fenced forb-grass steppe pasture are studied. The species composition of consumed plants, food selectivity, digestibility, and amount of consumed forage are estimated seasonally. All three species differ in all diet parameters.

Abstract—This paper reports the results of investigation on the food of free-grazing Bactrian camels in a forb–grass steppe pasture, including anthropogenically disturbed areas with dominance of ruderal annuals. We identified the composition of consumed plants using a microhistological analysis of the feces; the digestibility coefficient based on inert (indigestible) silicon contained both in the diet and feces; the quantity of the forage consumed based on the mass of the feces and the digestibility coefficient; and the energy balance based on interrelations between the actual consumption and the existing requirement norms of camels and wild ungulates in energy. In spring, camels mainly consume graminoids (Stipa sp. and Festuca valesiaca), switching to forbs, largely ruderal annuals, in summer and autumn. The forage digestibility is low in spring (56%), increasing to 69–70% in summer and autumn. Low daily consumption rates of dry forage mass in winter and spring (8–9 kg) are changed to high in summer and autumn (20–26 kg), this reflecting the animals’ winter hypophagy. The amount of energy received during the warm season (1.2–1.8 MJ/kg W 0.75) considerably exceeds the requirements, thus explaining the ability of camels to accumulate a safety store of fat in the humps.