Effects of corn grinding and time of corn feeding on growth, starch utilization and digesta passage characteristics of growing steers fed hay-based diets

Two forms of corn, whole (WC) and ground (GC), were fed with hay (WH; 900) or 4 h after hay (AH; 1300) feeding to evaluate their effects on growth, starch utilization and digesta passage characteristics in growing steers. Twenty-four Angus steers with ad libitum access to fescue hay were individually limit-fed ground or whole corn (2.27 kg/d) in a 2 x 2 factorial arrangement of treatments: GC- WH, GC-AH, WC-WH and WC-AH. Average daily gain was improved with feeding GC (P less than .08), especially when fed at the same time as hay. Fecal starch (%) was less (P less than .001) for GC (7.07) than for WC (15.68). No difference was observed in rate of liquid or solid (hay) passage. Mean retention time (MRT) of whole corn (stained with neutral red and crystal violet) was decreased (P less than .07), and rate of corn passage tended to be faster for steers fed WC-AH than for those fed WC-WH. Although time of corn feeding had no effect on performance, steers fed WC-AH had more whole corn particles recovered from the feces and the MRT for whole corn particles was reduced, indicating that time of supplementation may affect passage characteristics. Altering time of supplement feeding may have applications in other feeding situations, such as with protein supplementation where ruminal escape would be advantageous.     

Comparison of the NegFry decision suport system with routine fungicide application for the control of potato late blight in Ireland

Summary Field experiments between 1996 and 2000 compared the efficacy of fungicide programmes applied in accordance with the NegFry and Met éireann (Mé) decision support systems (DSS) for the control of late blight with 7- and 10-day routine fungicide programmes. The Mé DSS reduced fungicide use by 68% and 54% respectively while NegFry reduced fungicide use by 49% and 27% compared with the 7- and 10-day programmes. The NegFry DSS was similar to the 10-day routine programme in terms of late blight control, quality and marketable yield. A similar result was found when the NegFry DSS was compared with a 7-day routine mancozeb programme (included for two seasons only). Within the NegFry DSS the use of fluazinam resulted in improved yield, foliage blight and tuber blight control compared with mancozeb, but this benefit was significant for tuber blight only. The Mé DSS resulted in inferior disease control, yield and quality.     

Some considerations on the washout of sulfate from stack plumes

A theoretical analysis of the contribution to rainwater sulfate concentration by precipitation scavenging of gaseous S0₂ and sulfate containing aerosols is presented. Aspects, such as the proper choice of mean raindrop diameter, are discussed in detail, and guidelines for their use are explored. Sample calculations are provided in which emissions from a hypothetical stack are considered as the source of the gaseous S0₂ and sulfate aerosol. The basic assumption of irreversible sorption behavior is discussed and utilized to obtain an upper limit to the resulting sulfate concentration. The effect of raindrop diameter on the sulfate concentration is not consistent. However, for a given drop diameter the sulfate concentration decreases as the precipitation rate increases. The sulfate concentration resulting from aerosol scavenging depends on the particle diameter and the precipitation rate. The sulfate concentration shows a maximum with respect to particle size; at moderate distances from the source, it is maximum for particles having aerodynamic equivalent diameter of about 5 to 10 gm.     

Use of the mercury cycling model (MCM) to predict the fate of mercury in the Great Lakes

In response to U.S. EPA's proposed Great Lakes water quality criteria for mercury (Hg), a fieldvalidated Hg cycling model (MCM) was used to predict Hg levels in the abiotic and biotic components of Lake Superior and Lake Erie. The U.S. EPA criteria are based on water column Hg concentrations and simple trophic level transfer and, thus, do not consider sediment interactions and water chemistry factors. The model, using data from published reports, was run to simulate a 25 year steady state period. For these simulations, methylmercury (MeHg) represented 5% of total Hg in Lake Erie and 8% of total Hg in Lake Superior. These proportions are roughly 3–5 times lower than U.S. EPA's estimate that MeHg contributes about 25% of total Hg in the water column of the Great Lakes. The predicted median concentrations of total Hg in top-carnivore fish were 0.13 mg/kg in Lake Superior and 0.16 mg/kg in Lake Erie. Predicted median MeHg concentrations in Lake Superior and Lake Erie (water column) were 0.019 and 0.075 ng/L, respectively. For both lakes, most (>55%) of the Hg was partitioned to sediments. Although the MCM simulation does have practical limitations (e.g., lakes are treated as fully-mixed open systems), the results demonstrate that generic assumptions of Hg behavior in all Great Lakes waterbodies are too simplistic.     

A Cross‐Sectional Study Examining the Prevalence and Risk Factors for Anti‐Microbial‐Resistant Generic Escherichia coli in Domestic Dogs that Frequent Dog Parks in Three Cities in South‐Western Ontario,Canada

Anti‐microbial resistance can threaten health by limiting treatment options and increasing the risk of hospitalization and severity of infection. Companion animals can shed anti‐microbial‐resistant bacteria that may result in the exposure of other dogs and humans to anti‐microbial‐resistant genes. The prevalence of anti‐microbial‐resistant generic Escherichia coli in the faeces of dogs that visited dog parks in south‐western Ontario was examined and risk factors for shedding anti‐microbial‐resistant generic E. coli identified. From May to August 2009, canine faecal samples were collected at ten dog parks in three cities in south‐western Ontario, Canada. Owners completed a questionnaire related to pet characteristics and management factors including recent treatment with antibiotics. Faecal samples were collected from 251 dogs, and 189 surveys were completed. Generic E. coli was isolated from 237 of the faecal samples, and up to three isolates per sample were tested for anti‐microbial susceptibility. Eighty‐nine percent of isolates were pan‐susceptible; 82.3% of dogs shed isolates that were pan‐susceptible. Multiclass resistance was detected in 7.2% of the isolates from 10.1% of the dogs. Based on multilevel multivariable logistic regression, a risk factor for the shedding of generic E. coli resistant to ampicillin was attending dog day care. Risk factors for the shedding of E. coli resistant to at least one anti‐microbial included attending dog day care and being a large mixed breed dog, whereas consumption of commercial dry and home cooked diets was protective factor. In a multilevel multivariable model for the shedding of multiclass‐resistant E. coli, exposure to compost and being a large mixed breed dog were risk factors, while consumption of a commercial dry diet was a sparing factor. Pet dogs are a potential reservoir of anti‐microbial‐resistant generic E. coli; some dog characteristics and management factors are associated with the prevalence of anti‐microbial‐resistant generic E. coli in dogs.     

Heritage trees and landscape design in urban areas of Rwanda

Trees play a key role in neighborhood landscapes, a belief that has been widely held for millennia in areas beyond Sub-Saharan Africa. Unfortunately, awareness of modern landscape architecture was almost absent in Rwanda until the late 20th century. Today, houses with surrounding decorative and amenity plants are a common feature in Rwanda’s neighborhood landscapes and, as the villagization of settlements progresses, new kinds of landscapes are emerging. This paper explores neighborhood tree planting around human settlements in the country. Remote sensing, photogrammetry, photo interpretation, and plant surveys were the core methods used. The average tree cover fraction ranged between 10%–35%. As the result of what is hereafter referred to as the “luxury effect,” a discrete gradient was detected along which the diversity of ornamental and amenity trees increases with the socio-economic status of neighborhoods: from rural settlements to urban residences via a series of intermediate designs, in which different levels of human-built vegetated areas alternate with non-landscaped spaces. Showy, non-productive amenity trees tend to occur more in wealthy quarters of the inner core of cities while edible ornamentals and other productive neighborhood trees prevail in rural and spontaneous settlements. In general, the practice of landscape plant design, in spite of its constant improvement, is still striving to get established as a profession in the country.     

Technique and Preliminary Observations on Growth of the Roots of Glasshouse Tomatoes in Relation to That of the Tops

The use of glass-sided boxes and trenches for observing the growth of the roots of glasshouse tomatoes has been investigated. Marked seasonal trends have been found with two varieties in two years. There was a rise to a peak followed by a rapid fall in total root length, due to death and disappearance of the roots, with a subsequent recovery. This trend occurred in all horizons of soil.

Growth of the stem and leaves was relatively steady from planting-out (March) until mid-May, when there was a slight decrease with subsequent recovery until the main stem and laterals were “stopped” in July.

The number of flowers per truss was high in the bottom five or six trusses, in which fruit set was high, fell in the median trusses which had low set, and rose in the uppermost trusses accompanied by increased set. The resulting production of fruit weight was high in the bottom trusses and low in the top.

The peak of root length development coincided with the swelling of the fruit in the bottom trusses; a trough occurred when the number of flowers per truss and the number set were low, and root length recovered when the first trusses were picked.     

Economic impacts of glyphosate-resistant crops

Glyphosate-resistant crops have been widely planted since their introduction in 1996. Growers have numerous choices for herbicide treatments and have chosen to plant glyphosate-resistant crops on the basis of economic factors. The economic effects of the widespread planting of glyphosate-resistant crops have included reductions in herbicide expenses, increases in seed costs, increased yield and changes in the relative profitability of crops that has resulted in changes in which crops are planted. In addition, non-pecuniary benefits have accrued as a result of the simplicity of weed management in the glyphosate-resistant crop systems.