Septoria musiva causes leaf spot and canker diseases of trees in the genus Populus, and is one of the most damaging fungal pathogens of hybrid poplar in eastern North America. The effect of host water stress on Septoria canker development was studied in two separate greenhouse experiments. Hybrid poplar clones NM6, NC11396, and NE308 were stressed by withholding water until predawn water potential fell below -1.0 MPa. Stems were treated by removing a leaf and applying agar plugs that were either colonized by S. musiva (inoculated) or sterile (control) to the wound. Cankers on inoculated water-stressed trees were significantly larger than those on nonstressed trees. A leaf disk assay also was conducted three times with the NM6 and NE308 trees. We cut two disks from each of 120 stressed and 120 well-watered trees, placing them on water agar in 24-well tissue culture plates. A conidial suspension was applied to one disk in each pair and sterile water to the other. Inoculated disks from water-stressed trees developed less necrosis than those from well-watered trees. These results demonstrate that environmental influences on host condition must be considered in evaluating resistance of clones proposed for widespread culture of hybrid poplar.
The objective was to document a bedded hoop barn for feeding market beef cattle. A comparison between a bedded hoop barn (15.2 × 36.6 m) and an open-front feedlot building (11.0 × 61.0 m) was conducted in southwest Iowa. The hoop barn was oriented north-south on a ridge with no windbreak. In summer, temperature was relatively consistent between the structures and ambient conditions, although the north end of the hoop barn had a slightly elevated dew point temperature. A summer temperature-humidity index showed that the hoop barn had fewer hours in "alert" category than either open front or ambient conditions. In winter, a cold stress index showed that the open-front barn provided the most shelter for the cattle with 92% of the hours classified as "no impact," compared with the hoop barn at 77% and ambient at 51%. Both ends of the hoop barn were open, except for piled big round bales for a windbreak during winter. Growth, feed-to-gain, and dry matter intake for the cattle were similar between housing systems. Quality and yield grades were similar. Mud scores may be less for cattle from the bedded hoop barn compared with the openfront feedlot where mud was possible. Labor usage was similar for the hoop barn and the open-front feedlot. Labor occurred throughout the feeding period for the hoop barn because manure cleaning occurred weekly. Bedded hoop barns offer a viable alternative for feeding beef cattle and may reduce feedlot runoff.
IntroductionPasture productivity in Iowa often is limited by low productivity of cool-season grasses during summer. This uneven seasonal distribution of forage production could be improved by including species in pasture systems that perform better under higher temperatures. Warm-season grasses produce most of their growth during summer when cool-season grasses are semi-dormant. By using cool-season and warm-season pastures in a sequential system, it should be possible to improve seasonal productivity.The overall objective of this project was to evaluate the productivity of sequential grazing systems for beef cattle production in southern Iowa. Specific objectives were to: (1) evaluate the impact of legumes on the productivity of coolseason pastures grazed in the spring and fall, (2) evaluate warm-season grasses for summer grazing, and (3) determine the effects of pasture sequence on the productivity of season-long grazing systems. Materials and MethodsEight sequential and four continuous grazing systems were evaluated to determine the impacts of legumes and warm-season grasses on seasonlong productivity of grazing systems. Pastures were established at the McNay Research Farm near Chariton, Iowa on a Grundy-Haig soil. Smooth bromegrass (Bromus inermis Leyss. cv. Bounty) was planted into twelve 3-acre pastures in early spring 1996. At the same time, birdsfoot trefoil (Lotus corniculatus L. cv. Norcen), alfalfa (Medicago sativa L. cv. Alfagraze), and kura clover (Trifolium ambiguum Bieb. cv. Rhizo) each were planted into three of the pastures. All seeding was done into dead sod using a no-till drill. Seeding rates were 12 lb/acre for smooth bromegrass, 5 lb/acre for birdsfoot trefoil, and 8 lb/acre for alfalfa and kura clover. Pastures were blocked by soil characteristics such that each legume treatment and a control (N-fertilized) pasture occurred in each of three blocks. Big bluestem (Andropogon gerardii Vitman cv. Roundtree) and switchgrass (Panicum virgatum L. cv. Cave-in-Rock) were established into an adjacent set of six 4.5-acre pastures during the summer of 1994, using corn as a companion crop. Big bluestem was seeded at 8.0 lb/acre, and switchgrass was seeded at 5.5 lb/acre-both with corn at a population of 15,000 plants/acre.The grazing systems were designed on the basis of a fixed seasonal carrying capacity, and pastures were stocked with growing cattle throughout the 1997, 1998, 1999, 2000, and 2001 grazing seasons. Stocking densities for cool-season pastures were 2 animals/acre during spring and fall grazing seasons, and 0.7 animals/acre during the summer. Warm-season pastures were stocked with 1.8 animals/acre. Animals were weighed at approximately 4-week intervals during the grazing period to determine performance for each component of the system. Grazing of cool-season pastures began in May each year, and cattle were rotated to summer pastures based on grazing readiness of warm-season grasses. Two steers remained on cool-season pasture throughout the summer grazing period to serve as a control and ...
The use of bedded hoop barns in finishing systems for beef cattle has not been widely researched. In this management system, beef cattle are confined to hoop barns throughout finishing, and bedding is used to absorb animal waste, which results in minimal effluent. The objective of this study was to compare the performance and carcass characteristics of finishing beef steers (n = 1,428) managed in a bedded hoop-barn management system vs. an open-feedlot system with shelter. Six feeding trials were conducted over a 3-yr period. Three trials were conducted during summer-fall and 3 trials were conducted during winter-spring. Crossbred steers were allotted to 3 pens in the hoop-barn system and to 3 pens in the open-lot system (approximately 40 steers per pen in both facility systems). Stocking densities for the steers were 4.65 m 2 per steer in the hoop-barn system and 14.7 m 2 per steer in the open-lot system. The steers were begun on trial weighing 410 and 411 kg (SD = 21), were fed for 102.3 and 103.0 d (SD = 3.8), and were weighed off test at 595 and 602 kg (SD = 21) for the hoop-barn and open-lot systems, respectively. Steer performance measures consisted of ADG, DMI, and G:F. Carcass characteristics were HCW, fat thickness, LM area, KPH percentage, marbling score, USDA yield grade, and USDA quality grade. No year, season, or pen (management system) main effects, or season × management system and year × management system interactions were observed for any of the items measured related to cattle performance or carcass characteristics (P > 0.05). Final mud scores (a subjective evaluation of the amount of soil and manure adhering to the hair coat of the animals) were greater for the steers from the open-lot system compared with those from the hoop-barn system (P < 0.02), suggesting steers in the hoop-barn system carried less mud than steers from the open-lot system. Average daily cornstalk bedding use in the hoop-barn system was 2.3 kg/steer during summer-fall and 2.6 kg/steer during winter-spring. The performance of finishing cattle managed in a hoop-barn system was not different from the performance of cattle managed in an open-feedlot system with shelter during summer and winter. Managing beef cattle in hoop barns required more bedding but resulted in decreased mud scores compared with cattle managed in an open-lot system with shelter. Hoop barns are a viable alternative housing management system for finishing beef cattle. is an article that is not peer-reviewed in Journal of Animal Science 88 (2010): 2797, doi:10.2527/jas.2009-2521. Posted with permission.
This method of storage for wet distillers' grain proved to be very effective with a total shrink of 9.0% from purchase to feeding. The 80/20 blend proved to work well in the storage bag and was eagerly and readily consumed with little to no waste by a large number of fall calving, mature, lactating Angus females.The storage aspects of the modified distillers' grain with solubles in the bag seem to be different than the wet distillers' grain and hay mixture. Tendencies for spoilage in the modified product seemed greater with molds occurring (Picture 4). Total shrink from purchase to feed out was 16.7%. However, this product, in spite of the shrink, was successfully stored and fed for over 200 days. Cost analysis indicated that utilizing bagging procedures may not be a competitive methodology, therefore, lower cost storage systems need further research.
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