Potential climate change effects on warm-season production of livestock in the United States

摘要

Both earlier and current global climate models (GCMs) suggest increased air temperatures in the biosphere, which may impact the economic viability of livestock production systems in the United States. Increased ambient temperatures lead to depressedvoluntary feed intake (VFI), in turn reducing weight gains or milk production. Animals are somewhat able to adapt to higher temperatures with prolonged exposure but production losses will occur in response to higher temperature events. Climate-change scenarios of two current global climate models (Canadian Climate Centre [CGCMI]; Hadley Centre for Climate Prediction and Research [Hadley]) suggest significant impacts on livestock production systems. The primary focus of this report is on VFI models thatcan be used in assessing the potential impacts of climate change on the productive performance of dairy cattle (daily milk production), swine, and beef cattle (daily weight gain) during warm seasons. The VFI algorithms were based on current National Research Council publications providing nutrient requirements for the three livestock categories. Example impact assessments are presented and discussed based on linking the VFI algorithms to dimatological data for current impacts (1975-95) and to the CGCMIand Hadley models for estimating the potential impacts of climate change (2020-2040 and 2080-2100) on productive performance during the June-October period in the United States. While the estimations of production losses are not fully consistent betweenthe two climate models (CGCMI projects higher losses than Hadley), both indicate marked reductions (weight gains or daily milk production) from current levels in some areas for animals fully-exposed to the effects of climate warming. Quantifying these potential impacts of climate change provides producers a basis for proactive adjustments in management strategies (e.g., breeding to modify responses or environmental modification to buffer the impact) in areas projected to have substantial economic losse