Introduction
Feeding hay to livestock, including small ruminants and horses, is a common management practice in northeast Florida. Hay production is a large part of the agriculture economy and winters are cold enough to stop the growth of most perennial grasses. Unless owners have access to equipment to plant winter annuals, feeding hay is usually the easier option from a management standpoint.
The challenge comes with the diversity of hay quality. Not all hay is equal, and this is impacted by fertilization, harvest, maturity, storage, and grass or legume variety. To help balance diets and ensure your animals are getting what they need, send samples to labs and have the samples analyzed for nutritional information. The results can be disorienting, and the purpose of this article is to help producers and owners understand those results to increase the efficiency of their feeding management.
Components of Report
Dry Matter (DM)– The portion of forage left after water is removed via air drying. This is important for conserved forage, such as hay, and should be approximately 85%-92%.
Acid Detergent Fiber (ADF)– The least digestible plant carbohydrates (cellulose and lignin). ADF is negatively correlated with digestibility, so low ADF indicates high digestibility. Increases as forages mature.
Neutral Detergent Fiber (NDF)– All cell wall contents plus ADF. Represents the total fiber component of the hay, and is indicative of intake. As NDF increase, intake decreases. Increases as forage matures.
Crude Protein (CP)– The amount of nitrogen in the forage. Decreases as forage matures.
Total Digestible Nutrients (TDN)– Estimate of energy content. The greater the value, the more energy dense.
Relative Feed Value (RFV)– Expected animal intake and its energy value. It ranks hay against full bloom alfalfa using ADF and NDF, and includes digestible dry matter (DDM) and dry matter intake (DMI). H Higher RFV indicates higher quality hay.
RFV = DDM x DMI / 100
Relative Forage Quality (RFQ)- Similar to RFV but uses TDN in place of DDM. Higher RFQ indicates higher quality hay.
RFQ = TDN x DMI / 100
Forage Quality Standards by Forage Type
| Hay | Quality | TDN | CP |
|
Grass Hay |
Great | >58% | >12% |
| Good | 55-57% | 10-11% | |
| Fair | 52-54% | 8-9% | |
| Poor | <52% | <8% | |
|
Legume Hay |
Great | >64% | >18% |
| Good | 60-63% | 16-17% | |
| Fair | 57-59% | 14-15% | |
| Poor | <57% | <14% |
RFQ Forage Quality Category
| Quality | RFQ | Uses |
| Premium | ≥ 140 | Lactating Dairy, Heifers |
| Good | 110-139 | Brood mares, working horses, Lactating Beef, Nursing mares |
| Fair | 90-109 | Dry cows, non-working horses |
| Utility | < 90 | N/A |
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