PSVIII-26 Extending the grazing season for grass-fed beef production into the spring transition period

Abstract

Abstract In the Gulf Coast region, the spring transition period is a 45–60 d period between late April and mid-June. Red and white clovers’ growth pattern is delayed compared to winter grasses making them suitable for this transition period; however, an appropriate rest period allowing stockpiling is needed. Three treatments were evaluated on pastures planted in September of three consecutive years: 1) grazed until mid-February (MF); 2) grazed until first week of March (EM); and 3) grazed until last week of March (LM). Grazing re-started on May 1. Pasture was a mixed of annual ryegrass, red, white and berseem clover. Each year, 24 crossbred steers (330 ± 11 kg) were blocked by BW, allotted to 1 of 6 groups (2 replicates/treatment), and continuously stocked at 995 kg BW/ha. Forage mass at the beginning of the grazing period was greater (P < 0.05) in MF, followed by EM and LM. This represented a forage allowance of 2.0, 1.6, and 1.1 kg DM/kg BW. On d0, the proportion of annual ryegrass was greater (P < 0.05) in MF than in EM and the smallest in LM. Proportion of clovers was greater (P = 0.04) in EM in Year 2 while MF and LM were similar but greater for MF in Year 1. Berseem clover represented 59% of the clover biomass in MF while red clover was 72% of the clover biomass in LM. Proportion of clovers decreased with time while annual ryegrass became mature affecting its palatability. Steers that grazed on MF and EM had greater ADG (1.83 and 1.71 kg) than those on LM (1.41 kg). Grazing season was longer (P = 0.03) for MF (66 days) than for LM (39 days) while EM was intermediate (50 days). A rest period from early March to late April would allow grazing of high-quality pastures during the spring transition period.