Predicting the performance of beef cattle on diverse perennial forage mixtures using the cowbytes ration-balancing software program

The objective of this paper was to evaluate 29 perennial forage treatments consisting of five monoculture grasses as control, six simple mixtures, and 18 complex mixtures using the CowBytes® ration-balancing software and predict the performances of steers, dry gestating, and lactating beef cows over 3 years of forage harvest (2021, 2022, and 2023). Barley straw, a cheaper feed source was included in the model as supplement to standardize final ration quality when forage by treatment exceeded requirements. We found that the inclusion of straw reduced the daily ration cost. Predicted steer average daily gains was higher (0.80 kg day −1 ) on complex grass–legume mixtures in 2021 and 2023, whereas in 2022, simple mixture of Fleet meadow bromegrass (MB) + AC Yellowhead alfalfa (M1), and timothy grass (TG) monoculture treatments predicted higher gains. For dry gestating beef cows, a mixture of Fleet MB + AC Yellowhead alfalfa + AC Mountainview sainfoin + Veldt cicer milkvetch (M9), and orchardgrass (OG) monoculture predicted a gain of 0.10 kg day −1 in 2021, while in 2022 and 2023, simple mixture of Fleet MB + Spredor 5 alfalfa (M4), and complex grass–legume mixtures predicted a gain of 0.10 kg day −1 after supplementing with straws. For lactating beef cows, in 2021, complex grass–legume mixtures estimated a gain of 0.10 kg day −1 . In 2022 and 2023, monocultures of OG, Kirk crested wheatgrass, and TG met the predicted gain requirement of 0.10 kg day −1 . Over the 3 years, steers, gestating, and lactating cows performed well when fed with legume-dominated mixtures in the first year of forage production, but monoculture grasses and grass-only mixtures suffice nourishing them in the second and third years. Overall, our study highlighted differences in predicted animal performance across yearly harvested forages.