This experiment compared the performance response of supplementing corn gluten feed (CGF) or corn to calves grazing stockpiled tall fescue pastures over a 70-d period. Forty-four Angus x Simmental calves (238 ± 4 kg) were stratified across 6 treatments by BW and sex in a 2 x 3 factorial arrangement. Calves were supplemented cracked corn (n = 16) or CGF (n = 18). Calves were housed in 2 pastures and supplemented individually using the SmartFeed Pro feeding system, with all treatments represented in each pasture. Supplement DMI was programmed at 0.59, 0.87, or 1.13% BW. Calves which failed to train to the feeding system (n = 10) were treated as an un-supplemented control. Weight and flesh condition score (FCS) were recorded every 14-d, and ultrasound 12th rib fat thickness (FT) was measured on d 0 and 70. Data were analyzed with PROC GLM in SAS with supplement type as a main effect, sex as a fixed effect, and group as a random effect. Individual supplement DMI was included in the model as a covariate rather than a main effect due to high variation. Significance was defined at P ≤ 0.05 and means were separated using LSD. Initial BW, FCS, and FT were similar (P ≥ 0.12) among treatments. No differences (P ≥ 0.25) were observed in supplement DMI throughout the experiment. No differences (P ≥ 0.64) were observed in ADG and supplement G:F through 14 d. Through d 28 to 70, CGF-fed calves had greater (P ≤ 0.03) ADG and supplement G:F relative to corn-fed calves. Final FCS was greater (P < 0.01) for CGF-supplemented calves relative to those supplemented corn, though FT was not different (P = 0.87). These data indicate that supplementing CGF rather than corn yields a greater performance response in beef calves grazing stockpiled tall fescue.
This 2-year experiment evaluated productivity of wild-type endophyte-infected tall fescue (KY-31) and novel endophyte-infected tall fescue (MaxQ) summer stockpiled (SS) pastures and the performance of fall-calving beef cow/calf pairs grazed on each cultivar. Pregnant Simmental x Angus cows (128 total, 64 each year) were stratified by BW, BCS, and expected calving date, then allotted to 1 of 10 groups. Forage growth was stockpiled from April to initiation of strip-grazing on 31 August of 2017 and 2018. Cows grazed treatment pastures for 52 d from 23 ± 14 d prepartum to 29 ± 14 d postpartum, and calved on treatment pastures. Forage quadrats were clipped from the grazed and ungrazed portions of each pasture to determine weekly forage mass (FM). Total ergot alkaloid (TEA) concentrations were analyzed for all pastures at the beginning of the experiment and every subsequent 2 weeks for KY-31. Cow BW was recorded on 2 consecutive d and BCS determined at the start and end of the experiment. In year 2, ultrasound 12th rib fat thickness (BF) was measured at the beginning and end of the treatment period Milk production was estimated using the weigh-suckle-weigh technique at 29 ± 14 postpartum. In year 1, TEA concentrations for KY-31 pastures did not differ (P < 0.48) over time. Fescue cultivars were not different (P ≥ 0.15) in forage CP, TDN, and grazed or ungrazed FM. Cow BW, BCS, and BF at the beginning and end of grazing were not different (P ≥ 0.41) by treatment. Milk production was higher (P < 0.01) for KY-31 grazed cows. Calving date, calf BW, calf ADG were not different (P ≥ 0.65) by treatment. Neither AI nor overall conception rates differed (P ≥ 0.23) between cultivars. Performance of fall-calving cows pre-exposed to KY-31 was not improved when grazed on MaxQ in a SS system.
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