Supplementation of Growing Beef Heifers With Starch or Highly Digestible Fiber Supplements

摘要

Producers are interested in cost-effective forage-based heifer development programs with supplemental feeding, if needed, of a single supplement (reducing the cost of mixed rations) so that it would meet their nutrient requirements.For three consecutive years, the effect of two levels of ground corn (GC) and soybean hulls pellets (SB), were evaluated on performance and grazing behavior of 90 replacement beef crossbred heifers (BW = 235±17 kg; average of 10.8 months of age) grazing annual ryegrass (Lolium multiflorum; cv.'Nelson') at low stocking rate.Treatments were: 1) no supplementation (CON); 2) 0.5% BW of ground corn (GC05); 3) 0.5% BW of soybean hull pellets (SB05); 4) 1% BW of ground corn (GC1); and 5) 1% BW of soybean hull pellets (SB1).Lower levels of supplements (0.5% BW) allowed for greater (P < 0.05) ADG (1.26 and 1.21 kg for GC05 and SB05, respectively), production per hectare and lower age and BW at puberty.Ground corn or SB at 1% BW negatively affected (P < 0.05) growth (0.88 and 0.95 kg, respectively), reproductive performance, number of steps, and grazing time (329 and 354 minutes, respectively) of heifers.Patch grazing time and bite rate were affected (P < 0.05) by grazing period due to changes in nutritive value of annual ryegrass and search for newly grown green leaves.Beef replacement heifers stocked at a low stocking rate with no supplementation may have a better development when compared to 1% BW supplementation using GC or SB and similar to a 0.5% BW supplementation level.