Accurate assessment of forage mass in pastures is key to budgeting forage in grazing systems. Our objective was to determine the accuracy of an electronic capacitance meter, a rising plate meter, and a pasture ruler in measuring forage mass and to determine the cost of measurement inaccuracy. Forage mass was estimated in grazed pastures on farms in Pennsylvania, Maryland, and West Virginia in 1998 and 1999. Forage mass estimated by each method was compared with forage mass estimated by hand‐clipped samples. None of these indirect methods were accurate or precise, and error levels ranged from 26 to 33% of the mean forage mass measured on the pastures. The computer model DAFOSYM (Dairy Forage System Model) was used to simulate farm performance and the resulting effects of inaccuracies in estimating forage mass on pasture. A representative grazing dairy farm was developed, and the costs and returns from low‐input and conventional managements were calculated. Different scenarios were then simulated, including under‐ or overestimating forage yield on pastures by 10 or 20%. All scenarios simulated resulted in lower returns compared with the optimum farm, with decreases in net return ranging from $8 to $198 ha−1 yr−1. Underestimating forage mass resulted in less hay and silage being harvested, more pasture being consumed, and more forage purchased compared with the optimum scenario. The opposite occurred for overestimation of forage mass. Our results indicate that achieving greater accuracy (to within 10% of actual pasture yield) in estimating pasture yields will improve forage budgeting and increase net returns.

A variety of tools are used for measuring pasture height or capacitance. Cross calibrations between these tools would be helpful for extension staff and producers comparing measurements taken with one tool to those taken with an alternative tool. Rotationally and continuously stocked pastures in West Virginia, Pennsylvania, Maryland, and New York were sampled for forage height using a ruler, for compressed height using a falling plate meter and a rising plate meter, and for sward capacitance with a capacitance meter. Thirty to sixty measurements were made across each pasture with each device, with paddock means taken as the measurement for the device. Regressions were run using paired paddock means, testing each device as both the dependent and independent variable, with r2 ranging from 0.49 to 0.99. Residual analysis was conducted to evaluate biases due to location and stocking management using the falling plate meter means as the independent variable versus means of the other techniques. No bias in pasture measurements was found due to grazing management. There was a bias due to operator for ruler height and capacitance meter reading. These cross calibrations provide a mechanism for pasture managers to translate pasture heights or capacitance taken with one tool to those taken with another tool.

Brown marmorated stink bug (BMSB; Halyomorpha halys) is an emerging invasive species of grave concern to agriculture as a polyphagous plant pest with potential negative effects on the dairy industry. The purpose of this study was to determine the risk of including BMSB-contaminated silage in lactating dairy cow rations. First, 6 dairies, either highly infested (n=3; 30 to 100 bugs per stalk) or not infested (n=3), were sampled to assess the prevalence of bug secretion compounds tridecane (major component) and E-2-decenal (stink odor component) in silage and milk. Second, using wild BMSB, a mini-silo dose-response experiment (adding 100, 50, 25, 10, and 1 freshly crushed bugs/0.5kg of chopped corn) was conducted to assess the effect of ensiling on BMSB stink odor compounds. Finally, synthetic BMSB stink odor compounds (10g of tridecane and 5g of E-2-decenal) were ruminally infused twice daily over 3 d, and samples of milk, urine, and rumen fluid were collected to evaluate disposition. Bug stink odor compounds were sampled by solid-phase microextraction (SPME) and analyzed by gas chromatography-mass spectrometry (GC-MS). Milk production and feed composition were unaffected when BMSB-contaminated silage was fed. Moreover, no E-2-decenal was detected in silage or milk (detection threshold = 0.00125μg/mL). The dose-response of tridecane in mini-silo samples exhibited a linear relationship (R(2)=0.78) with the amount of BMSB added; however, E-2-decenal was completely decomposed and undetectable in spiked mini-silos after ensiling. Both synthetic secretion compounds infused into rumen were undetectable in all milk and urine samples. E-2-Decenal was not detectable in rumen fluid, whereas tridecane was detected only at 15 min postinfusion but not present thereafter. Feed intake was unaffected by infusion treatment and BMSB secretion compounds (E-2-decenal and tridecane) were not observed in milk. E-2-Decenal and tridecane from the metathoracic gland of BMSB are not able to contaminate milk either due to the ensiling process or because of metabolism within the rumen. Concern over BMSB stink odor compounds contaminating the fluid milk supply, even on highly infested farms, is not warranted.