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Significant increase in wintertime air temperature, especially the reduced cold extremes under climate change, might be beneficial to the winter survival of perennial crops. However, climate warming could result in less snowfall, reduced snow cover, as well as changes in climate conditions for fall hardening and winter thaws. How these changes might impact the risks of winter damages to overwintering crops, such as perennial forage crops requires a comprehensive assessment for proactively adapting to climate change in the agricultural sector, especially the beef and dairy industries. Based on the most up-to-date climate projections from a set of global climate models, we used a snow model and a suite of agroclimatic indices for perennial forage crops to assess potential changes in the risks of winter injury to perennial forage crops across Canada in the near-term (2030s), the mid-term (2050s), and the distant future (2070s). Our results show that the risk of exposure to extremely low temperatures (daily Tmin ≤ −15 °C) without snow protection is projected to decrease across Canada with improved conditions for fall hardening. However, winter thaws and rainfall are projected to increase, and this would increase the risk of winter injury due to loss of hardiness together with potential soil heaving and ice encasement. [ABSTRACT FROM AUTHOR]

Energy‐to‐protein ratios have been suggested as a potential forage attribute related to nitrogen (N) use efficiency in dairy cows but how these ratios vary with the cutting management of alfalfa‐based mixtures is poorly known. Our objective was to determine the effect of cutting schedules of alfalfa‐based mixtures and their species composition on two forage energy‐to‐protein ratios from a large number of samples from four field experiments with previously published results on forage dry matter yield and nutritive value. The two energy‐to‐protein ratios were (1) nonfiber carbohydrates (NFC) to crude protein (CP), NFC/CP, and (2) NFC to the sum of nonprotein N (NPN) and rapidly degradable protein fraction (PB1), NFC/(NPN + PB1). Cutting alfalfa‐based mixtures at the early bloom stage rather than at the early bud stage of alfalfa and taking a fall harvest increased mostly the NFC/CP ratio. Including at least one grass species with alfalfa had variable effects on the two ratios. Although several grass species were tested, we cannot conclude on the best grass species to use. Observed increases in the energy‐to‐protein ratios, however, were relatively small (<8%) and not always consistent in different experiments. Because the relative changes in the energy (NFC) and protein (CP or NPN + PB1) components of the ratios often varied in the same direction when induced by cutting schedules or the presence of grasses with alfalfa, opportunities to improve energy‐to‐protein ratios with those practices remain limited. Core Ideas: Cutting alfalfa‐based mixtures at early bloom of alfalfa increases forage energy‐to‐protein ratios.A fall cut of alfalfa‐based mixtures increases forage energy‐to‐protein ratios.Mixing one or two grass species with alfalfa has no consistent effect on forage energy‐to‐protein ratios. [ABSTRACT FROM AUTHOR]

In the continental cold and humid areas of northeastern North America, climate change by mid‐century may increase the yield potential of perennial forage species as a result of increased temperature and atmospheric CO2 concentration, and a longer growing season compared to the 1990−2000 period. More winter thaws and less snow cover along with more summer drought events, however, may reduce winter survival and summer regrowth, thus potentially reducing the persistence of perennial forages over time. Based on nearly two decades of research on the effects of climate change on forages in cold and humid areas of northeastern North America, through field experiments and modeling, we summarize in this review the expected effects of climate change on forage production in terms of yield, nutritive value, and winter survival. We also propose a set of 12 adaptation and resilience‐building strategies for forage systems that can be implemented at the field and farm levels. Research priorities for the future, including the improvement of species, forage management practices, and modeling tools, are also identified. Implementing strategies to alleviate or take advantage of the effects of a changing climate may improve productivity and resilience of well‐adapted forage systems in cold and humid areas. Core Ideas: Without adjusting the harvest schedule, perennial forage quality may be reduced by climate change by mid‐century.Winter thaws and reduced snow cover may increase the risk of winter damage to perennial forages in cold areas.Twelve adaptation and resilience‐building strategies are suggested for forage systems in cold and humid areas.Together, these strategies are expected to improve yield, nutritive value, and resilience of forage systems.Research priorities should target the improvement of species, forage management practices, and modeling tools. [ABSTRACT FROM AUTHOR]