Three studies in northern Alberta, Canada, determined if white-tailed deer (WTD) exhibited seasonal compensatory growth and evaluated the effects of Spruce and Quebracho tannin (QT) supplemented diets on white-tailed deer (WTD) performance. Suitability of Alfalfa, Birdsfoot Trefoil, Chicory and Alsike Clover perennial forages and Berseem Clover, Canola, Pea, and Turnip annual forages was also evaluated. Alfalfa suitability was reaffirmed with preference (utilization and grazing time) and weight gains greater in chicory and trefoil. Establishment, productivity, and seasonal biomass and quality of all forages were good with winterkill severe in trefoil and chicory. Annual forages quality was excellent with WTD highly selective preferring peas and berseem with nutrient yield highest in turnips. WTD regulated intake of QT, selecting 3-3.4% QT in diets, causing reduced weight gain and feed intake and had no effect fecal parasite loads. QT diets (6-15%) reduced protein digestibility, feed intake, weight gain, and the urine urea:creatinine ratio.