PSXI-30 The effects of hybrid and maturity on the nutritive value of snaplage

Abstract

Abstract The aim of this study was to assess the nutritive value of snaplage as affected by hybrid and maturity. Five corn hybrids were grown at 70,000 plants/ha on three replicate plots (5 x 5 m) in each of three blocks (21°14′ S, 44°58′ W). Hybrids were harvested at target maturity stage of 40, 35, and 30% of moisture (M1, M2, and M3, respectively) by removing ears from two rows in each plot. Ears were weighed and split into two subsamples. One was split into kernels, husk and shank, and cob, weighed and oven-dried. The second subsample was processed and ensiled in 5-L jars for 90 d. Measurements included dry matter (DM) yield, nutrient analysis and in vitro digestion of neutral detergent fiber (NDF-D, 48h). The experimental design was randomized complete blocks using a mixed repeated-measures model. Data were analyzed using MIXED procedure of SAS, followed by a Tukey test at P ≤ 0.05. Mean moisture at harvest were 42.9, 36.8, and 31.3% for M1, M2, and M3, respectively. The DM yield was unaffected by hybrid and maturity (on average = 19 t/ha). The NDF concentration of husk increased at each maturity (81.5, 83.4, and 83.7% DM, respectively) and NDF-D decreased (45.5, 43.4, and 41.4%, respectively). The NDF concentration of cob increased at each maturity (76.0, 79.5, and 81.6% DM, respectively) and NDF-D decreased (47.3, 43.7, and 38.4%, respectively). Among hybrids, NDF concentration of snaplage varied from 20.9 to 24.5% DM (P = 0.014). The NDF-D of snaplage decreased at each maturity (Figure 1; P = 0.001). The starch concentration of snaplage increased from M1 to M2, but no difference between M2 and M3 (P = 0.009). Snaplage has a wide harvest window; however, changes in the nutritive value of snaplage as affected by maturity should be considered when formulating diets.