Stocking Rate and Energy Supplementation Effects on Replacement Beef Heifers Grazing Annual Ryegrass

The development of breeding heifers is a critical point in the beef cattle enterprise. The effect of stocking rate and supplementation strategy at high stocking rate were evaluated on Brahman influenced heifers (BW = 250±3.6 kg) continuously stocked on annual ryegrass (Lolium multiflorum Lam. cv. ‘Nelson’) with the following treatments in a completely randomized design with 3 replicates: 1) LOW stocking rate (2.5 heifers/ha); 2) MED stocking rate (5.0 heifers/ha); 3) HIGH stocking rate (7.5 heifers/ha); 4) High stocking rate + 1% BW of ground corn (HIGH+C); and 5) High stocking rate + 1% BW of soybean hulls (HIGH+SBH). Dry matter intake was greater (P = 0.03) for heifers in LOW and MED, while those in HIGH, regardless receiving supplement or not, were the lowest. Heifers grazing LOW and MED did not differ (P = 0.06) in ADG. Supplemented heifers and those in MED produced the most beef per unit of land; however MED and HIGH were not significantly different. Grazing days was greater for LOW and supplemented heifers. There was a year effect for ADG, beef production, and grazing days which were smaller in year 1; however years 2 and 3 were not different (P > 0.05) between them except in production per hectare. Lower stocking rates allowed for appropriate BW gains. Level of supplementation affected DMI from ryegrass, replacing it and affecting animal performance. Weather conditions had an impact on forage production, hence affecting animal performance. Supplementation programs must consider level and type of energy supplement used.