Nutritive Value, Protein Fractionation and In Vitro Rumen Fermentation Characteristics of Pulse-Processing Screenings as Alternative Feedstuffs for Ruminants

Pulse-processing plants generate large volumes of screenings, that is, undersized, broken and foreign-matter-contaminated grain that is removed before the material enters the human food chain. Their feeding value for ruminants is still poorly documented. This study characterised the chemical composition, Cornell Net Carbohydrate and Protein System (CNCPS) nitrogen fractions, in vitro ruminal dry matter degradability (IVDMD) and rumen fermentation behaviour of screenings from five pulse species: soybean, dry bean, chickpea, green lentil and red lentil. Six independent batches per species (n = 30) were obtained from processing plants in different regions of Türkiye. Total digestible nutrients (TDNs) and energy values were estimated with NRC (2001) equations, gas production was recorded for 48 h in a semi-automatic modular system and fitted to a logistic model, IVDMD was measured in a DaisyII incubator and volatile fatty acids (VFAs), pH and NH3-N were determined after 24 h of incubation. Differences were declared at p < 0.05 throughout. Soybean screenings had the highest crude protein (35.99%), recalculated TDNs (75.26%) and 48 h gas production (65.16 mL per 460 mg of incubated sample), a ranking that largely disappears once gas is expressed per gram of incubated organic matter; chickpea screenings combined the highest starch (50.67%), IVDMD (71.27%) and fractional degradation rate. Dry bean screenings fermented most slowly, with a lag time of 10.46 h. Acetate, propionate and total VFAs did not differ among species. No parent grain was analysed alongside the screenings, so any comparison with clean pulse grain rests on published values for other samples and cultivars. Within that limit, the screenings carry enough protein, calculated energy and rumen-undegradable protein to warrant testing as partial replacements for conventional concentrates in feeding trials.