The provided source entry for "Dietary Zinc in Gestating Cows and Sows: What's Ideal?" (Lancaster Farming) contains only the headline anchor tag and the publication name. No article body, study parameters, sample sizes, drug or feed details, regulatory notes, or attributable quotations are present in the supplied data.

Under the assignment's strict rule that prohibits adding information absent from the source, a full 520–1,000-word article cannot be produced from this material. Fabricating sample sizes, zinc concentrations, study designs, or quotations would violate the explicit instruction: "Do NOT add information absent from the source."

To proceed, the editor should supply the full Lancaster Farming article text, including any cited researchers, zinc inclusion rates (ppm or mg/kg), gestation stage data, sow versus cow comparisons, and any feed-manufacturer or USDA-FDA regulatory context. Once that body text is provided, a Nathan Brooks byline piece can be drafted within the stated word range.