Technical Abstract: Reproductive performance in young beef cows is often compromised due to a mismatch of physiological demands and suboptimal environmental conditions. Studies conducted at the Corona Range and Livestock Research Center from 2000 to 2007 evaluated 3 postpartum supplement strategies that varied in the amount of glucogenic precursors (GP) supplied. Reproductive variables, milk production, and serum metabolites were used to assess supplement effectiveness and economics associated with 2- and 3-yr-old beef cows (n = 379) grazing native range. Supplements were individually fed twice/wk at 1135 g/d (2003-2004) or 908 g/d (all other yr) and provided: 1) 327 g CP, 109 to 118 g RUP, 44 to 47 g GP (CON); 2) 327 to 341 g CP, 142 to 157 g RUP, 57 to 70 g GP (BP); 3) 327 g CP, 151 to 173 g RUP + 40 to 100 g of propionate salt (NutroCal, Kemin Industries, Inc.), 93-141 g GP (P). Blood samples were collected once/wk (2000) or twice/wk (2001-2007) for progesterone analysis to estimate days to resumption of estrus. Cows were exposed to bulls for 60 d or less and pregnancy was confirmed by rectal palpation at weaning. Days to resumption of estrus after calving decreased linearly (P = 0.02), resulting in an increased pregnancy rate (P = 0.01) with increasing supplemental GP. Milk production exhibited a quadratic (P = 0.04) response to increasing GP, with cows fed BP producing the most amount of milk. However, a linear decrease (P = 0.07) in days from BW nadir to estrus was found with increasing consumption of GP. Total kg of calf weaned per cow exposed for the supplemental year and subsequent year was greater (P = 0.07) for cows fed P than the other supplements. The improvement in pregnancy rate by supplementing P resulting in an increase in total revenue of 15.3% compared to CON-fed cows and 7.2% compared to BP-fed cows in the subsequent year after supplementation. These data suggest feeding young cows additional GP in the form of propionate salts allows for partitioning of nutrients away from milk production and towards reproduction, allowing for increased profitability by increasing pregnancy rates and decreasing days to resumption of estrus. Key words: Beef Cow, Glucogenic Precursors, Supplementation, Reproduction.