Baled Silage Made From Surplus Annual Ryegrass Captures Higher Quality and Improves Replacement Heifer Gains.

The rapid growth of annual ryegrass (Lolium multiflorum Lam.) in late spring can result in forage surplus, even under well-managed grazing. The objective of this experiment was to compare the use of surplus annual ryegrass forage as a hay or baled silage crop to high-quality bermudagrass (Cynodon dactylon L. Pers.) hay in a replacement heifer (beef) development program.  This experiment was conducted at the Northwest Georgia Research and Education Center (near Calhoun, GA) where a field of annual ryegrass was sod-seeded into a bermudagrass pasture in September of 2008, grazed heavily in late winter 2009 (ending 15 March), and allowed to regrow to the early boot stage (18 April). The annual ryegrass was harvested and random swaths were either conserved as round bale silage (ARB) or dry hay (ARH). Bermudagrass hay (cv. Russell) was produced in early July and used as the control forage (BH). The 35-d feeding trial was a randomized complete block design with four blocks of beef heifers (250-300 kg) that had been stratified by weight. Each pen within the block was randomly assigned 10 heifers and one of the three treatments (ARB, ARH, or BH). Forage quality analysis performed prior to the feeding trial demonstrated that ARB was consistently higher in nutritive value than BH, which was generally superior to ARH. However, all treatments meet the nutritional requirements of beef replacement heifers (i.e., greater than 1.35 Mcal NE_m kg^-1, 0.77 Mcal NE_g kg^-1, and 98 g CP kg^-1) for appropriate gains (> 0.68 kg head^-1 d^-1), so the feeding trial was conducted without supplemental feed. Mean daily dry matter intake (DMI) was not significantly (P > 0.10) affected by treatment and averaged 2.2 kg d^-1 kg^-1 of bw across all treatments. However, average daily gain was highest (P = 0.06) for ARB (0.89 kg head^-1 d^-1), followed by BH (0.71 kg head^-1 d^-1), which was not significantly (P > 0.10) greater than ARH (0.57 kg head^-1 d^-1). These data indicate baled silage allows for the conservation of higher quality annual ryegrass forage and can result in superior animal performance relative to an annual ryegrass or bermudagrass hay production system.