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A 72-d trial was conducted to estimate the combined effect of forage allowance and a fiber-based energy supplement in stocker cattle grazing wheat. Eight pastures (2.7 to 5.1 ha) each contained seven test steers (initial BW = 210 ± 36 kg). Weekly, additional steers were stocked in each pasture in a put and take method to achieve forage allowance of either 2.5 or 5.5 kg forage DM / kg steer BW (4 pastures each). Two pastures in each forage allowance were fed daily with a supplement containing 50% wheat midds and 50% soybean hulls at the rate of 1.5 kg per steer. Forage mass was measured twice weekly using a calibrated rising plate meter. Cattle were weighed weekly on calibrated scales. Data were analyzed using linear regression with pasture as the experimental unit. Mean ADG was 1.36 kg/d. One pasture in the high forage allowance, non-supplemented treatment was removed because we were unable to maintain the designed forage allowance. The interaction of forage allowance and supplement was not significant (P = 0.37) for ADG, and supplementation did not affect ADG (P = 0.20), however increased forage allowance tended to improve ADG (P = 0.06, 0.21 kg ADG per kg forage allowance). To further investigate forage DMI, a 14-d trial began on day 36. Three of the seven test steers in each pasture were randomly chosen and administered 7 ± 0.1 g of TiO2 daily at 0700 as an external marker to estimate fecal output. Forage DMI (at an assumed 72% DM digestibility) averaged 2.1% of midpoint BW, below our expectation. Additional forage allowance tended to improve estimated forage DMI (P= 0.06), but supplement had minimal effect (P = 0.30). [ABSTRACT FROM AUTHOR]

A 72-d trial was conducted to estimate the combined effect of forage allowance and a fiber-based energy supplement in stocker cattle grazing wheat. Eight pastures (2.7 to 5.1 ha) each contained seven test steers (initial BW = 210 ± 36 kg). Weekly, additional steers were stocked in each pasture in a put and take method to achieve forage allowance of either 2.5 or 5.5 kg forage DM / kg steer BW (4 pastures each). Two pastures in each forage allowance were fed daily with a supplement containing 50% wheat midds and 50% soybean hulls at the rate of 1.5 kg per steer. Forage mass was measured twice weekly using a calibrated rising plate meter. Cattle were weighed weekly on calibrated scales. Data were analyzed using linear regression with pasture as the experimental unit. Mean ADG was 1.36 kg/d. One pasture in the high forage allowance, non-supplemented treatment was removed because we were unable to maintain the designed forage allowance. The interaction of forage allowance and supplement was not significant (P = 0.37) for ADG, and supplementation did not affect ADG (P = 0.20), however increased forage allowance tended to improve ADG (P = 0.06, 0.21 kg ADG per kg forage allowance). To further investigate forage DMI, a 14-d trial began on day 36. Three of the seven test steers in each pasture were randomly chosen and administered 7 ± 0.1 g of TiO2 daily at 0700 as an external marker to estimate fecal output. Forage DMI (at an assumed 72% DM digestibility) averaged 2.1% of midpoint BW, below our expectation. Additional forage allowance tended to improve estimated forage DMI (P= 0.06), but supplement had minimal effect (P = 0.30). [ABSTRACT FROM AUTHOR]

Simple Summary: Nutrient losses from grazing systems are a source of water and air pollution and a cost to producers, as these nutrients must be replaced. Improved management systems are needed in order to reduce nutrient losses. Feeding cattle directly and allowing manure to fertilize the grass improved nutrient use efficiency, but was not always more economical compared to fertilizing the grass directly. Replacing fertilizer with feed supplements is a viable management system to reduce nutrient losses from grazing systems. The objective was to examine the effects of dried distillers' grains supplementation and fertilization strategies on the cattle performance and resource use efficiency of stocker cattle grazing on Plains Old World bluestem. Over 4 consecutive years, heifers and steers (average n = 239) were randomly assigned to 1 of 4 treatments: (1) low input, low stocking density, and no fertilizer or distillers grains supplementation (LOW); (2) high stocking density and no fertilizer with distillers grains supplementation (DDGS); (3) high stocking density and 90 kg of nitrogen/ha with no distillers grains supplementation (NFERT); (4) high stocking density, 90 kg of nitrogen/ha, and 39 kg of phosphorus/ha with no distillers grains supplementation (NPFERT). Cattle grazed in the pastures from mid-May to mid-September each year, except for 2011, when the experiment ended in July due to lack of forage. Data were analyzed using a linear model with fixed effects of treatment, year, and treatment × year (R software). Nitrogen use efficiency (retained/inputs) was affected by a treatment × year interaction, where LOW had the greatest efficiency in all years and DDGS was greater than NFERT and NPFERT in all years except 2012, with NFERT and NPFERT being not different in all years. The estimated total carbon equivalent emissions were greater for DDGS, NFERT, and NPFERT than LOW, but the carbon footprint (kg CO2eq/kg weight gain) was lesser for LOW and DDGS, which were not different, than NFERT and NPFERT, which were also not different. Replacing nitrogen fertilizer with dried distiller's grains improved the cattle performance and the efficiency of resource use, and could be a viable economic alternative to traditional systems. [ABSTRACT FROM AUTHOR]

Spring (SPRING) and fall (FALL) born steers (n = 211) were used in a mixed effects model to evaluate calving season and conception method [artificial insemination (AI) or natural service (NS)] on finishing performance and carcass traits. SPRING were weaned in October, grazed dormant range for 90 days and grazed wheat pasture for 90 days before shipping to finish. FALL were weaned in May, and grazed tallgrass prairie for 120 days before shipping to finish. Initial and final BW, days on feed, ADG, DMI, and gain to feed efficiency were evaluated as performance measures. Dry matter intake and gain:feed were analyzed on pen basis. Hot carcass weight, yield grade, fat thickness, ribeye area, and marbling score were collected at harvest. Bodyweight of SPRING and AI steers were heavier (P ≤ 0.05) entering and leaving the feedlot than FALL and NS steers, respectively. Compared to FALL steers, ADG (P < 0.01) and DMI (P = 0.03) were greater for SPRING and required less days on feed (P ≤ 0.05). Calving season and conception method (P ≥ 0.2) did not affect gain:feed. Conception method (P = 0.5) did not affect ADG, DMI, and days on feed. SPRING had higher yield grades (P < 0.01) and increased in fat thickness (P = 0.01) compared to FALL steers. There were no differences (P = 0.2) in hot carcass weight, ribeye area, and marbling score due to season of birth. Steers born from AI mating had greater hot carcass weight (P = 0.01) and marbling score (P = 0.02), but conception method did not affect yield grade, fat thickness, and ribeye area (P > 0.2). These results demonstrate SPRING steers are heavier entering and leaving the feedlot, have higher ADG and DMI, and require less days on feed; however, gain:feed, hot carcass weight, ribeye area, and marbling score did not differ from FALL steers. An economic analysis is needed to validate an AI program based on calving season in north-central Oklahoma. [ABSTRACT FROM AUTHOR]