This article presents the results of a study of the energy and protein value of perennial forage crops (Galega orientalis Lam. and Silphium perfoliatum L.) cultivated on reclaimed lands in the central Non-Chernozem Zone of the Russian Federation. A zootechnical assessment of the efficiency of using the resulting forage in livestock diets was conducted. A three-year experiment revealed that, under favorable weather conditions, the green forage yield structure of the studied crops is characterized by the dominance of the first cutting, which accounts for an average of 85 to 90 % of the total yield. The contribution of the second cutting to overall productivity ranges from 9.91 % to 20.22 %. The dry matter content of freshly mown plants during this period ranged from 21.60 % to 24.83 %, crude protein from 12.44 % to 21.44 %, crude ash from 5.56 % to 7.43 %, and nitrogen-free extractive substances from 44.96 % to 51.50 %. It was established that hay from plants harvested in the budding-early flowering phase has high nutritional value, meeting first-class requirements, and has average nutritional value (0.56–0.59 feed units) and a low crude protein content (13.02–16.05 %). The energy value of finished hay from a mixture of red clover and timothy grass, as well as a mixture of eastern galega and silphium, was high — 9.01 and 9.21 MJ/kg of dry matter, respectively. Replacing a mixture of red clover and timothy grass hay with a mixture of eastern galega and silphium hay in the goats' diet increased protein digestibility by 14.04 % (83.99 % versus 82.95 %) and nitrogen-free extractive substances by 2.72 % (82.13 % versus 79.41 %). No significant difference was found.
Kapsamun et al. (Thu,) studied this question.