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Early-weaned Angus x Simmental heifers were used to evaluate the effects of postweaning nutritional management on feedlot performance, carcass merit, and the relationship of intramuscular and subcutaneous fat deposition to the feed efficiency among heifers fed for a high-quality market. Sixteen heifers were weaned at 73 [+ or -] 5.5 d of age and grazed on endophyte-infected tall fescue for 18 mo before entering the feedlot (early-weaned-P). Eighty heifers from the following year's calf crop were weaned at 71 [+ or -] 5.5 d of age and allowed either ad libitum access to a 25% concentrate diet (early-weaned-25C) or limit-fed a 90% concentrate diet (early-weaned-90C) to achieve a similar ADG. Following a 119-d growing period, 16 early-weaned-90C and 16 early-weaned-25C calves were paired based on BW and growth rate and individually fed during the finishing period along with the early-weaned-P heifers. Ultrasound measurements of s.c. and i.m. fat were recorded at approximately 60-d intervals throughout the finishing period. Feed efficiency was regressed against s.c. and i.m. fat, and i.m. fat was regressed on s.c. fat. Despite a similar ADG, early-weaned-90C calves gained more efficiently (P [is less than or equal to] 0.05) in the feedlot than early-weaned-25C calves. Heifers finished as yearlings tended (P [is less than or equal to] 0.10) to gain faster but gained less efficiently (P [is less than or equal to] 0.01) than early-weaned-90C heifers finished as calves. The rate of s.c. and i.m. fat deposition was similar between early-weaned-90C and early-weaned-25C heifer calves. The calves were grouped together for comparison to yearlings. Feed efficiency decreased quadratically (P [is less than or equal to] 0.01) as s.c. fat cover increased. The rate at which feed efficiency decreased relative to increasing s.c. fat cover was similar regardless of age at feedlot entry. However, heifers finished as calves gained more efficiently (P [is less than or equal to] 0.01) than yearlings at any given fat thickness. Feed efficiency decreased linearly (P [is less than or equal to] 0.01) as i.m. fat increased among heifers finished as calves. Additionally, heifers finished as calves deposited i.m. fat at a faster rate relative to s.c. fat (P [is less than or equal to] 0.01) than yearlings. These data suggest that heifers finished as calves produce high-quality carcasses with less s.c. fat cover while gaining more efficiently than heifers finished as yearlings. Key Words: Feed Efficiency, Heifers, Ultrasound, Weaning

Two trials were conducted to evaluate intake restriction, energy, and protein source on the performance and carcass merit of heifers limit-fed corn gluten feed. Trial 1 crossbred heifers (n = 140) were allotted to ad libitum wet corn gluten feed (WCGF)hay, ad libitum WCGF-corn, WCGF-corn continuously limit-fed to achieve a gain of 1.1 kg/d or WCGF-corn fed in the following sequence: 70% of ad libitum for 20 d, ad libitum for 20 d, and 2 d common intake during the 84-d growing period. One-half of these restricted-refed heifers received a rumen-undegraded protein supplement, and the other half received a rumen degraded protein supplement. Heifers were fed a common finishing diet ad libitum subsequent to the growing period. Heifers offered ad libitum WCGF-hay and WCGF-corn were slaughtered at a common compositional fat end point. Heifers limit-fed WCGF-corn were slaughtered at the same time as heifers offered ad libitum WCGF-corn, regardless of subcutaneous fat cover. Limit-feeding WCGF-corn diets to growing heifers reduced ADG (P [is less than or equal to] 0.01) but did not compromise feed efficiency. Method of intake restriction, continuous or ad libitum-interrupted, and supplemental protein source did not affect combined growing-finishing performance. However, when fed for a common length of time, the average of the limit-fed heifers had lighter carcass weights (P [is less than or equal to] 0.01) and lower (P = 0.04) marbling scores. Heifers offered ad libitum WCGF-hay gained slower (P [is less than or equal to] 0.01) and less efficiently (P [is less than or equal to] 0.01) than heifers offered WCGF-corn. Trial 2 crossbred heifers (n = 222) were allotted to dry corn gluten feed (DCGF)-corn ad libitum or restricted to 80% of ad libitum for 42, 84, or 126 d; or ad libitum corn silage or DCGF-corn silage at 80% of ad libitum for 84 d. Feed efficiency (P = 0.07) and ADG (P = 0.08) tended to behave quadratically, being poorer for heifers limit-fed for 126 d during the growing period. Heifers limit-fed DCGF-corn gained more efficiently (P = 0.05) than heifers grown on ad libitum corn silage. Limit-feeding CGF-corn to growing beef heifers can be used to achieve moderate rates of gain without compromising feed efficiency. However, limit-feeding during the growing period may result in lighter weight carcasses with lower quality grades if not fed to the same fat end point as heifers grown with free access to concentrate. Key Words: Cattle, Gluten, Maize, Plane of Nutrition

Efficient utilization of the non-grain portion of corn plant and distiller's grains for ruminants and the grain for ethanol will allow optimization of both food and fuel production. Corn stover can be effectively used as animal feed if it is collected before in-field dry-down. This study determined the yield and nutritive value of corn stover, distiller's dried grains with solubles (DDGS), and feed value enhanced stover (FVES) (a mixture of corn stover and DDGS) on different corn harvest dates, and determined the harvest time that maximizes whole-plant utilization. Corn and corn stover were harvested at different dates from 21 August to 23 November in 2009, and DDGS samples were produced from the corn samples collected at different harvest dates by dry grind fermentation. From 21 August to 23 November, dry matter yield of the stalk and leaf fraction and the cob decreased by 37.4% and 9.8%, respectively. During the same time period, neutral detergent fiber, acid detergent fiber, and lignin concentrations in the stalk and leaf fraction increased by 16.8, 12.7, and 1.0 percentage points', respectively, while crude protein concentrations decreased by 4.1 percentage points. For FVES, both the highest dry matter yield and the highest total digestible nutrient concentration were reached when corn just reached physiological maturity. Corn and corn stover can be harvested at the corn physiological maturity stage for maximum dry matter yield and optimum nutrient quality of FVES for ruminants, leaving more corn for ethanol production. [ABSTRACT FROM AUTHOR]

Harvest date greatly affects the biomass yield, moisture, and quality of corn and stover. Traditionally, corn and stover have been harvested at lower moisture levels. However, corn stover and grain can be more effectively utilized as animal feed and biomass-ethanol feedstock if they are collected before in-field dry down. This study determined dry matter yield, moisture content, and quality of corn and stover before, during, and after grain maturity in central Illinois. The two-year average kernel moisture was 37.4% (w.b.) when reaching physiological maturity. At the same time, the average stover moisture was 67.7% (w.b.). The dry matter yield of grain increased rapidly until reaching grain maturity and remained relatively stable after grain maturity, with an average yield of 11.2 t ha-1 over the two-year study. For corn stover, the two-year average dry matter yield was 14.7 t ha-1 at the beginning of the study (filling stage), and it decreased to 13.2 t ha-1 at grain physiological maturity and further decreased to 11.0 t ha-1 throughout grain dry down. During grain dry down, the moldy kernel percentage increased from 2.1% to 4.1% and the stalk lodging percentage increased from 1.2% to 3.6%. The results of this study showed that early harvest of corn and stover at grain maturity has several advantages: higher dry matter yield of stover, lower moldy kernel percentage, and fewer plant lodgings. [ABSTRACT FROM AUTHOR]