This study was conducted to determine the fatty acid (FA) content in pasture grasses, legumes, and non-leguminous forbs in northeast West Virginia. Grass, legume, and forb plant material were collected from rotationally stocked pastures and analyzed for crude protein (CP), linoleic acid (C18:2), α-linolenic acid (C18:3), and total FA content. Species within botanical classes varied in FA content. Forbs had the highest linoleic acid (C18:2) content followed by legume and grass species. Grasses and forbs had the highest α-linolenic acid (C18:3) content. Forbs had the highest total FA content. These field data were combined with FA data from the research literature to evaluate the correlation of CP concentration with fatty acid concentration. Likewise, after accounting for CP, the summer months caused a decrease while forbs caused an increase in α-linolenic acid (C18:3) content. Vegetative growth and leafiness are the major determinants of FA content in pasture forage. Grazing management to benefit vegetative growth and the presence of desirable forbs in tune with seasonal changes are valuable tools to increase desirable FA profiles in milk and meat products that may be of benefit to human health.

Core Ideas: Forage density has a linear relation to pasture height. The regression of forage density to pasture height is a measure of plant morphology within the sward. Forage mass is the product of forage density and pasture height resulting in a second‐order relation with zero intercept. The form of the second‐order relation of forage mass to pasture height can be diminishing return, linear, or exponential, depending on the distribution of forage density within the pasture.

Pasture-based livestock production is impacted by management and weather. In pastures, there is conflict between leaf retention for plant growth and leaf harvest for animal nutrition. Defoliated pastures with low light interception (LI) may have a low forage growth rate (FGR), while excessive growth shades leaves, reducing FGR and resulting in an S-shaped regrowth curve. To optimize production, it is best to keep FGR linear. Three studies were conducted to evaluate the impact of management and weather on FGR. Replicated pastures were used to measure FGR when grazed from 25 to 10 cm and allowed to regrow. The impact of alternative defoliation timings and intensities on FGR were studied using clipped treatments at three recovery intervals and two stubble heights. Variability in FGR was studied using a field validated plant growth model. Of the 24 growth periods studied, two displayed exponential, 12 linear and 10 linear-plateau growth. There was no effect of FM on growth curve form. In May and June, LI increased with canopy height, up to 0.93. Stubble height and days of growth impacted FGR with an interaction. There was no treatment impact on root density. Weather caused variation in FGR. A low FGR risk occurs at high elevations; greater risk occurs east of the plateau.