Sensory Evaluation of Hay Mylen Bohle Area Extension Agronomist Oregon State University Extension Service Crook County
Hay Quality Sensory Evaluation Guidelines Acknowledgement(Utah State University Pub: AG/Forage & Pasture/2007-01) Authors • Tom Griggs, Extension Forage Specialist, West Virginia University, formerly with Utah State University • Steve Fransen, Extension Forage Specialist, Washington State University • Mylen Bohle, Area Extension Agronomist, Oregon State University
Hay QualitySensory Evaluation Guidelines • Hay can vary widely in nutritional value for livestock • Assessment of quality depends on end-use application • Requirements for specific nutrient levels and sensory properties vary widely with livestock class and performance targets.
Hay QualitySensory Evaluation Guidelines Laboratory analyses of hay for comparison purposes has been based on: + Fiber + Crude Protein + Minerals More recent approaches include determinations of digestibility of dry matter (DM) and fiber Energy is the most important nutrient in DM followed by protein, and then minerals.
Hay QualitySensory Evaluation Guidelines • Fiber is a large component (35-70%) of hay DM and is only partially digestible to ruminants and horses • Fiber and digestibility are central to lab tests and ration formulation approaches because: • Ruminants and horses have fiber requirements for normal digestive functions and health • Knowledge of fiber digestibility (varies widely) improves predictions of forage energy availability
Laboratory Testing is Essential for Matching Up Forage / Livestock Needs • But it does not reveal important characteristics such as: • Bale Handling • Transport and Stacking • Anti-quality • Odor • Dust, weeds, weed seeds, impurities or injurious substances • Extent of leaf capture, attachment or pulverization • Texture, color and taste • Presence and dimensions of flower buds and seed heads
Package Functionality • How well can the hay be handled, transported, and stacked - which is a function of: • Bale shape • Bale density • Structural integrity
Odor • Odor can signal: • Heat damage (tobacco-like odors) • Mold from spoilage • Soil contamination • Excessive wetness
Maturity Stage • Maturity stage is directly related to: • Fiber • Digestible Energy • Crude Protein Levels • Fiber increases while digestible energy and protein decrease with advancing maturity
Foreign Material • Dusts, mold, soil and rocks • Weed seeds and plant parts (invasive noxious and poisonous weeds) • Old alfalfa crowns • Stubble • Non-crop species and materials such as barbed, sharp, abrasive, or other features that could harm animals or feed machinery
Texture and Condition • Ease of consumption by animals with discomfort or injury to mouth, face and eyes • Respiratory or other health disorders • Waste dues to sorting in feed bunks or losses onto soil • Leafiness describes leaf concentration in bale • Retention describes degree to which leaves remain attached to stems or flakes as bales are opened and fed • Shatter describes the extent of pulverization of baled leaves
Texture and Condition • Texture and condition can vary widely due to pre-baling differences in: • Crop canopy • Conditioning • Tractor wheel traffic • Mechanical handling operations • Baling at differing moisture levels
Color • Largely an appearance factor that is Not related to feeding value, although it can indicate: • Presence of pre-harvest diseases • Post harvest molds from excessively wet hay • Leaching of soluble sugars from rained on hay • High levels of leaf loss from raking, turning, and baling excessively dry material • Bleaching from the sun