Air-dried solids from primary sewage sludge were gamma-irradiated (1 megarad) and used as 50% or more of d.m. in experimental range supplements (RS, 20-22% crude protein) fed to beef cows in late gestation-early lactation during 92 ± 10 days each year for 5 years when forage lacked protein. Other cows in the same herd received no supplement (NONE) or cottonseed meal (CSM) at the same times. Intakes of RS or CSM were about .45 kg/hd in the first 3 years; .9 kg/hd for RS and CSM in the fourth year, and .45 kg/hd for CSM and .9 kg/hd for RS in the fifth year. Calf weights at weaning did not differ (P>.25) in the first 3 years (NONE, 171; CSM, 179; and RS, 176 kg) but were increased (P<.05) by CSM (192 kg) over RS (180 kg) or NONE (177 kg) in the last two years. Calf crops were increased 10 to 12% over NONE by CSM during all 5 years and increased 11% over NONE by RS during the first 3 years; but in the last 2 years (when RS intakes were .9 kg/hd) RS decreased calf crop 8% below NONE. No evidence of toxicity was found in terms of symptoms: blood clinica profiles; heavy metals in blood, milk, or livers sampled yearly; liver mixed-function oxidase activity; or, histopathology of organs and tissues of cows at slaughter after 5 years. But RS diminished liver vitamin A when fed as sole diet to sheep and, apparently, RS exacerbated vitamin A deficiency in the cow herd during the two final breeding seasons.