How to compare sweet potato feed analysis by form

Start with the form and the reporting basis

A sweet potato feed analysis is only useful when you know which material was tested. Roots, leafy vines, ensiled material and processing residues are not interchangeable: they differ in plant part, processing history and often moisture. First match the analysis to the form you intend to buy and use.

Next check whether results are reported as-fed or on a dry-matter basis. As-fed values include the product’s water; dry-matter values remove water from the comparison. To convert a dry-matter nutrient value to an as-fed value, multiply it by the fraction of the product that is dry matter. Without the moisture result and stated basis, two analyses can appear different simply because one product contains more water.

Roots: focus on carbohydrate and moisture

For sweet potato roots, moisture and dry matter are central comparison fields, particularly when comparing fresh roots with dried or otherwise processed material. They affect how much actual feed dry matter is delivered per unit purchased and how the product fits a ration on a consistent basis.

Starch and sugars help describe the roots’ carbohydrate contribution. Crude protein, fiber measures such as NDF or ADF, and ash can add context for ration formulation and comparison between lots. These measures do not establish a universal feed value: the analysis should identify the sample form and basis, and a nutritionist should interpret the results for the intended ration.

Vines and residues need their own context

Sweet potato vines are leafy plant material, so compare their moisture, dry matter, crude protein and fiber profile rather than assuming root analysis describes them. Fiber results, including NDF and ADF where available, help distinguish the plant material’s structural fiber characteristics. Ash can also help characterize the sample, but it should be read alongside the other results rather than treated as a stand-alone quality judgment.

Processing residues require a description of what the material contains and how it was produced. A residue may include different proportions of roots, peel, trimmings or other plant material depending on the process. Ask for the product identity and sample description before comparing its nutrient analysis with whole roots or vines. Protein, fiber, starch or sugars, moisture and ash are useful only when the tested material is clearly identified.

Silage analysis includes fermentation measures

For sweet potato silage, use the nutrient panel to understand the feed material and add fermentation measures to assess the ensiling result. Dry matter, crude protein, fiber, starch or sugars and ash can help characterize nutrient content. The relevant panel depends on whether the silage is made from vines, roots or a mixture.

Silage pH and fermentation-acid results, such as lactic, acetic and butyric acids, describe aspects of fermentation. Ammonia nitrogen can provide additional information about protein breakdown during ensiling. Interpret these results together and in context: pH alone does not describe the full fermentation profile, while fermentation measures do not replace nutrient analysis. The report should identify the sample and make clear whether results are on an as-fed or dry-matter basis.

Make a like-for-like comparison

Before comparing offers, line up the form, sample description, moisture or dry matter, reporting basis and analysis date or lot reference. Compare the same nutrient measures on the same basis. If one report is as-fed and another is dry-matter basis, convert before drawing conclusions; if the forms differ, treat that as a product difference, not a laboratory discrepancy.

Request the lot-specific analysis and its test documentation for the material being quoted, and check that the documentation identifies the sample and basis. The useful next step is to identify whether the intended purchase is roots, vines, silage or a named processing residue, then source that form through the [Sweet Potato ingredient page](/ingredients/sweet-potato).

Common questions.