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The livestock industries are a major contributor to the economy of the northeastern United States. Climate models predict increased average maximum temperatures, days with temperatures exceeding 25 °C, and higher annual precipitation in the Northeast. These environmental changes combined with increased atmospheric CO2 concentration are expected to either increase or decrease forage productivity depending on the crop, and may decrease protein content and forage digestibility. Winter damage to sensitive forage species may also increase. Predicted temperature increases are expected to reduce fertility in dairy cattle and heat stress-induced inflammation may limit energy available for productive functions. Additional loss in milk production due to decreased feed intake is estimated to be up to 1% of the projected annual milk production through 2100. The effects of climate change on the beef industry in the Northeast are expected to be minimal. Broiler production in the region may benefit from warmer winter and summer temperatures, but future housing will require greater insulation and ventilation fan capacity. Providing adequate housing and ventilation to offset climate changes will also be important for the layer industry and will likely increase the price of eggs. Climate change is expected to have an economic impact on the horse industry in the region through additional management of land and forage resources, building of shelters, and heat abatement at equine events. Increased temperatures and more intense storms will increase nutrient losses and gaseous emissions from animal manure. Uncertainties about how host animals, pathogens, and disease vectors will respond to climate change highlight the need for continued animal health monitoring. [ABSTRACT FROM AUTHOR]

Interest in native plant species for conservation and production has increased because of new federal policies. We evaluated accessions of the native cool-season grass Virginia wildrye (Elymus virginicus L.) from the northeastern USA for nutritive value and its association with plant morphological traits. Thirteen accessions, one cultivar (Omaha), and one commercial ecotype of Elymus were transplanted into single-row field plots in late summer of 2000 at Beltsville, MD, Rock Springs, PA, and Big Flats, NY. Two orchardgrass (Dactylis glomerata L.) cultivars were included. Primary growth was harvested in April (Beltsville) or May (Rock Springs and Big Flats) of 2001 and 2002 and analyzed for neutral detergent fiber (NDF), crude protein (CP), and digestible NDF (dNDF). Nutritive value measures were related to plant morphological attributes [leaf width, length, area, and leaf-to-stem mass ratio (LSR)]. Virginia wildrye accessions differed (P < 0.01) in nutritive value and often had lower NDF and higher CP and dNDF than the commercial ecotype, Omaha cultivar, and orchardgrass. The LSR accounted for most of the variation in nutritive value. Orchardgrass was more mature at harvest than Elymus entries and thus lower in nutritive value. Neutral detergent fiber was negatively correlated with LSR (r = -0.26 to -0.74, P < 0.05), whereas CP and dNDF were positively correlated (r = 0.36 to 0.80 for CP and 0.44 to 0.74 for dNDF, P < 0.05). Neutral detergent fiber was also positively correlated (r = 0.27 to 0.86, P < 0.05) with leaf length. Virginia wildrye is comparable to other cool-season grasses in nutritive value. [ABSTRACT FROM AUTHOR]

Pasture productivity under harsh environments can be increased by planting more drought-resistant species or by increasing species diversity. This research was conducted under two large (10.2 × 26.8 m) rainout shelters combined with a drip irrigation system to provide deficit, normal, and excessive moisture conditions. A two-species mixture containing the relatively drought-tolerant species, orchardgrass (Dactylis glomerata L.) and red clover (Trifolium pretense L.) and two five-species mixtures were compared with a mixture containing the drought-sensitive species, white clover (Trifolium repens L.) and Kentucky bluegrass (Poa pratensis L.), which are the predominant species in northeastern USA pastures. Plots were clipped from midMay to early October in 2000 and 2001 on a schedule that mimicked management-intensive grazing practices. The five-species mixture containing chicory (Cichorium intybus L.), orchardgrass, Kentucky bluegrass, perennial ryegrass (Lolium perenne L.), and white clover had the greatest dry matter yield at all moisture levels. Yield in that mixture increased 89% in the dry, 61% in the normal, and 43% (by weight) in the wet treatments compared with the white clover/ Kentucky bluegrass mixture. Increased yield was primarily due to the robust growth of chicory which dominated the mixture, accounting for 71% of harvested biomass by the fall of 2001. In addition, white clover growing in the mixture with chicory had improved leaf water relations and greater relative growth rates than white clover growing in the two-species mixture. Including the functional attribute of a deep-rooted forb appeared to be more important than species richness, per se, in improving forage yield. [ABSTRACT FROM AUTHOR]

Most forage grasses grown in the northeastern USA are introduced species. Interest in native plant species for conservation and production has increased because of new federal policies. We evaluated northeastern accessions of the native cool-season grass Virginia wildrye (Elymus virginicus L.) for yield, persistence, and plant morphological traits. Thirteen accessions, one cultivar (Omaha), and one commercial ecotype of Elymus were transplanted into single-row field plots in late summer of 2000 at Beltsville, MD, Rock Springs, PA, and Big Flats, NY. Two orchardgrass (Dactylis glomerata L.) cultivars were the checks. Yield and morphology (leaf width, length, mass, area, and tillers per plant) data were collected during 2001 and 2002. The Elymus accessions produced as much dry matter (28-57 g per plant) as the cultivar and commercial ecotype. Orchardgrass yielded more than twice as much dry matter than the mean of all Elymus entries (94 vs. 34 g per plant averaged for years and locations). The difference in productivity was related to reduced tillering in Elymus especially during regrowth. Yield per plant was strongly correlated (r = 0.62-0.81, P < 0.01) with the number of tillers per plant. Differences in productivity were also reflected in leaf blade traits, with Elymus having a lower leaf area and mass than orchardgrass. Leaf traits were positively correlated (r = 0.35-0.56, P < 0.05) with plant yield. Some northeastern Elymus accessions would probably perform as well as the commercial sources of Elymus in conservation plantings. [ABSTRACT FROM AUTHOR]