Effect of dietary concentrate content on feed intake,feed efficiency,and meat quality of Holstein steers fattened in a hot environment

The objective of this study was to investigate the effect of feeding high and low concentrate diets on feed intake and feed efficiency, the morphological characteristics of the rumen papillae, and meat quality of Holstein steers fattened under hot climate conditions in Oman. Ten male Holstein calves, of 5 months of age, were selected for the experiment. The animals were fed concentrate and Rhodes grass hay and were divided into two groups of high concentrate (HC, n = 5) and low concentrate diets (LC, n = 5), in which their feed intake, weight gain, and feed efficiency were evaluated across three growing periods. Feed intake and efficiency and average daily gain (ADG) of the HC group were significantly greater than for the LC group and were affected by the diet (p < .01) and the period (p < .001). Across the fattening periods, ADG declined in both groups, with ADG improved by 35% for steers on the HC diet compared to steers on the LC diet. Carcass meat quality was not affected significantly by the dietary concentrate level. In conclusion, our results can be used to make improvements in feed efficiency of Holstein steers under hot climate conditions.     

Soybean shoot metabolism of isopropyl-3-chlorocarbanilate: Ortho and para aryl hydroxylation

This laboratory reported that isopropyl-3-chlorocarbanilate-phenyl-U-¹⁴C (chlorpropham-phenyl-¹⁴C) was absorbed, translocated, and metabolized by soybean plants. Both polar metabolites and insoluble residues were found in roots, whereas only polar metabolites were found in shoot tissues. In both roots and shoots the polar metabolites were shown to be the O-glucoside of isopropyl-2-hydroxy-5-chlorocarbanilate (2-hydroxy-chlorpropham). In shoot tissue there were other polar metabolites that were not identified. The experiments with soybeans have been repeated, but with new isolation and purification procedures. The plants were root treated with both chlorpropham-phenyl-¹⁴C and isopropyl-3-chlorocarbanilate-2-isopropyl-¹⁴C. The roots and shoots were extracted and separated into the polar, nonpolar, and insoluble metabolic components, using the Bligh-Dyer extraction method. The polar metabolites were separated by gel permeation chromatography. Further purification was accomplished on Amberlite XAD-2. The polar metabolites from the shoot and root tissues were hydrolyzed either by β-glucosidase or hesperidinase. The enzyme liberated aglycones were derivatized and separated by gas-liquid chromatography, and the components were characterized by mass spectrometry or NMR. The results of this study showed that the polar metabolites of soybean shoots were 2-hydroxy-chlorpropham and isopropyl-4-hydroxy-3-chlorocarbanilate (4-hydroxy-chlorpropham). These two hydroxy-chlorpropham metabolites were found in soybean shoots at a ratio of approximately 1:1. The only aglycone found in root tissue was 2-hydroxy-chlorpropham. Using the new procedures, no evidence was obtained for the presence of the unidentified polar metabolites that were previously observed in shoot tissues.     

Influence of heat processing of African yam bean seed (Sphenostylis stenocarpa) flour on the growth and organ weights of rats

The influence of heat processing of African yam bean seed flour on the growth and organ weights of rats was studied. Body weight change, feed utilization and feed conversion ratio were improved by heat processing. All rats significantly (p0.05) gained weight except those fed raw African yam bean and basal diets (diets 3 and 1 respectively). Raw African yam bean diet decreased the growth of rats and had negative effect on the organ weights especially the pancreas which was enlarged. The results indicate that heat processing improved the growth of rats and organ weights due to heat inactivation of toxic factors especially trypsin inhibitors.     

Identification and mapping of adult‐plant stripe rust resistance in soft red winter wheat cultivar ‘USG 3555’

Little is known about the extent or diversity of resistance in soft red winter wheat (Triticum aestivum L.) to stripe rust, caused by the fungal pathogen Puccinia striiformis f.sp. tritici. The soft red winter (SRW) wheat cultivar ‘USG 3555’ has effective adult‐plant resistance to stripe rust, which was characterized in a population derived from ‘USG 3555’/‘Neuse’. The mapping population consisted of 99 recombinant inbred lines, which were evaluated for stripe rust infection type (IT) and severity to race PST‐100 in field trials in North Carolina in 2010 and 2011. Genome‐wide molecular‐marker screenings with 119 simple sequence repeats and 560 Diversity Arrays Technology (DArT) markers were employed to identify quantitative trait loci (QTL) for stripe rust resistance. QTL on chromosomes 1AS, 4BL and 7D of ‘USG 3555’ explained 12.8, 73.0 and 13.6% of the variation in stripe rust IT, and 13.5, 72.3 and 10.5% of the variation in stripe rust severity, respectively. Use of these and additional diagnostic markers for these QTL will facilitate the introgression of this source of stripe rust resistance into SRW wheat lines via marker‐assisted selection.     

Idiopathic brood disease syndrome and queen events as precursors of colony mortality in migratory beekeeping operations in the eastern United States

Using standard epidemiological methods, this study set out to quantify the risk associated with exposure to easily diagnosed factors on colony mortality and morbidity in three migratory beekeeping operations. Fifty-six percent of all colonies monitored during the 10-month period died. The relative risk (RR) that a colony would die over the short term (～50 days) was appreciably increased in colonies diagnosed with Idiopathic Brood Disease Syndrome (IBDS), a condition where brood of different ages appear molten on the bottom of cells (RR = 3.2), or with a “queen event” (e.g., evidence of queen replacement or failure; RR = 3.1). We also found that several risk factors—including the incidence of a poor brood pattern, chalkbood (CB), deformed wing virus (DWV), sacbrood virus (SBV), and exceeding the threshold of 5 Varroa mites per 100 bees—were differentially expressed in different beekeeping operations. Further, we found that a diagnosis of several factors were significantly more or less likely to be associated with a simultaneous diagnosis of another risk factor. These finding support the growing consensus that the causes of colony mortality are multiple and interrelated.     

Biorefining of perennial grasses: Development of visible and near infrared tools for assessing fineness of extracted fibre

The biorefining of grass offers an opportunity to integrate primary production agriculture with the extraction of fibre. The study was aimed at developing protocols for processing ryegrass to determine fibre content and to generate visible and near infrared reflectance (Vis-NIR) calibrations for estimating fibre fineness with the aid of a new reference airflow method. The method for determining fineness of processed fibres has been adapted from flax fibre protocols. A Vis-NIR calibration using partial least squares (PLS) regression method was employed to generate models with a calibration set consisting of 85 samples obtained from fresh and ensiled grasses. The PLS model was successfully validated with 21 independent samples with a prediction error of 1.26 dtex. An optimised PLS model (r² = 0.86) consisting of 106 samples has been developed. The quality assurance protocols could be used for assessing fibre content and quality of silage, hay and fresh grass.     

Economic feasibility of introducing pulsed‐flow aquaculture into the irrigation system of cotton farms in Arizona

Abstract

The objective was to evaluate the economic feasibility of introducing fish culture into irrigated cotton production on farms in central Arizona. Water as a production variable was calculated only for the additional quantity required to keep water in the ditches during the growing season for fish. Raising tilapia in pulsed‐flow culture systems on Arizona cotton farms is economically feasible. Production function estimates indicate that profits can be increased through additional use of feed. At any ditch capacity, a density of six fish/m³ provided the optimal economic results, as the value of marginal product (VMP) equalled the price of fingerlings stocked/m³. This optimum fish production scenario would increase the net income for a typical irrigated cotton farm by 7 per cent. Increasing the initial size of the fingerlings improved the percentage of fish reaching marketable size and perhaps will increase economic returns, a question to be studied by future research.