What makes a host profitable? Parasites balance host nutritive resources against immunity

Numerous host qualities can modulate parasite fitness, and among these, host nutritive resources and immunity are of prime importance. Indeed, parasite fitness increases with the amount of nutritive resources extracted from the host body and decreases with host immune response. To maximize fitness, parasites have therefore to balance these two host components. Yet, because host nutritive resources and immunity both increase with host body condition, it is unclear whether parasites perform better on hosts in prime, intermediate, or poor condition. We investigated blood meal size and survival of the ectoparasitic louse fly Crataerina melbae in relation to body condition and cutaneous immune response of their Alpine swift (Apus melba) nestling hosts. Louse flies took a smaller blood meal and lived a shorter period of time when feeding on nestlings that were experimentally food deprived or had their cutaneous immune response boosted with methionine. Consistent with these results, louse fly survival was the highest when feeding on nonexperimental nestlings in intermediate body condition. Our findings emphasize that although hosts in poor condition had a reduced immunocompetence, parasites may have avoided them because individuals in poor condition did not provide adequate resources. These findings highlight the fact that giving host immunocompetence primary consideration can result in a biased appraisal of host-parasite interactions

Effect of Crude Glycerin Concentration on Growing Steer Performance in Forage Diets

The effect of increasing crude glycerin concentration was evaluated in a 91- d growing trial utilizing 60 steers. Crude glycerin was included at 0, 4, 8, and 12% of dietary DM in diets consisting of 50% wheat straw; 22.9- 37.0% wet corn bran, and 8.0- 10.1% soybean meal. Crude glycerin replaced wet corn bran and soybean meal was added to maintain dietary CP. Steer ending BW was not different among treatments. Th ere was a quadratic increase in DMI from 0 to 8% crude glycerin and subsequent decrease at 12%. Th ere was no difference in ADG or feed efficiency among crude glycerin concentrations. Therefore, crude glycerin appears to have an energy value slightly less than wet corn bran in a forage- based diet

Anaerobic Digestion of Finishing Cattle Manure

Utilizing manure from cattle fed distillers grains in anaerobic digesters improved methane production and DM degradation of manure compared to manure from cattle fed no distillers grains. Manure from cattle fed in open lot pens had soil contamination which decreased OM content and led to decreased total methane production (L/day), but not when expressed as methane/g OM. If ash buildup is avoided, open lot manure can be used as anaerobic digester feedstock

Evaluation of Changes in Nutritional Quality of Corn Residue Over Time

Irrigated corn residue was sampled across time in order to determine changes in quality and proportion of corn residue as the plant dried and was exposed to effects of weathering. Corn plants from two hybrids were planted on two different planting dates and harvested at periodic intervals from August 2012 to December 2012. Proportions of stem, blade/sheath, husk/shank, and cob made up smaller components of total plant DM as it matured, with the largest relative reduction occurring in the blade/sheath or stem. Hybrid impacted TDN values primarily because the 119 day hybrid was less mature at the early sampling dates

A System for Wintering Beef Heifers Using Dried Distillers Grains

A two-year experiment compared two systems for wintering pregnant heifers. The standard system used by the ranch served as the control (CON) and the treatment system (TRT) included a dried distillers grains based supplement. Heifers in the TRT system were heavier and had greater body condition score at end of supplementation. Calving difficulty, percentage of live calves weaned and subsequent pregnancy rate were similar between systems. Calves born to heifers in the TRT system were heavier at birth and weaning. The TRT system cost $10.47/heifer less than the CON system and resulted in equivalent or improved heifer and calf growth performance

N-alkane as an Internal Market for Predicting Digestibility of Forages

Independent digestion trials were conducted with three immature grasses, mature grass hay, and alfalfa hay to compare n-alkane with indigestible ADF (IADF) as internal markers to predict in vivo dry matter digestibility (DMD). Forage DMD estimated with n-alkane ratios were lower than in vivo DMD. N-alkanes predicted higher DMD than IADF for alfalfa hay and two of the immature grasses. Comparison of freeze-drying and oven-drying on fecal n-alkane concentrations showed oven drying reduced amounts of n-alkane extracted for alfalfa hay but had no effect on grass hay. Although fecal recovery of markers was incomplete, more n-alkane was recovered than IADF

Acesso à educação de artes no ensino médio: Porque a participação dos alunos é tão importante quanto à disponibilidade do Curso

There is renewed interest in the role of arts education in the curriculum of U.S. public schools not only because of the intrinsic value of the arts and its believed impact on achievement, but because cultivating creativity is thought to promote innovation and fuel economic growth. Still, we know little about basic access to arts education. Using individual-level administrative data from The University of Texas at Dallas Education Research Center (UTD-ERC), we develop several distinct indices of access to identify high schools rich in the arts. We find that high schools offering an extensive number of courses in the arts do not necessarily enjoy high rates of student participation. Policymakers who examine access based only on course counts in the arts will identify predominately large, non-rural high schools as having arts-rich environments. Evaluating arts programs along a single dimension, as is common in federal reports and other studies, fails to provide an accurate representation of access to arts education. Any examination of access to arts education should jointly consider course availability and student engagement in the arts. Policymakers can follow our approach and develop similar indices to assess the current state of arts education in their states.Existe un renovado interés en el papel de la educación artística en el currículo de las escuelas públicas de Estados Unidos, no sólo por el valor intrínseco de las artes y su impacto en el rendimiento, sino porque el cultivo de la creatividad se cree promueve la innovación y el crecimiento económico. Sin embargo, sabemos muy poco sobre el acceso básico a la educación artística. Utilizando los datos administrativos a nivel individual del Centro de Investigación en Educación de la Universidad de Texas en Dallas (UTD-ERC), desarrollamos varios índices de acceso para identificar las escuelas secundarias con mayor acceso a las artes. Encontramos que las escuelas secundarias que ofrecen un gran número de cursos de artes no disfrutan necesariamente de altas tasas de participación de los estudiantes. Las autoridades que examinan acceso basado únicamente en número de cursos de arte identificarán las escuelas secundarias predominantemente grandes, en zonas no rurales, como poseedoras de ambientes ricos en arte. La evaluación de los programas de arte en una sola dimensión, como es común en los informes federales y otros estudios, no proporcionan una representación precisa del acceso a la educación artística. Cualquier examen de acceso a la educación artística debe considerar conjuntamente disponibilidad del curso y la participación del estudiante en las artes. Los políticos pueden seguir nuestro enfoque y desarrollar índices similares para evaluar el estado actual de la educación artística en sus estados.Há um interesse renovado no papel da educação de artes no currículo das escolas públicas dos Estados Unidos, não só por causa do valor intrínseco das artes e seu acreditável impacto no sucesso, mas porque cultivar a criatividade é considerado promover a inovação e servir como combustível no crescimento econômico. Ainda assim, nós sabemos pouco sobre o acesso básico à educação de artes. Usando dados administrativos a nível individual na Universidade de Texas no Centro de Pesquisa Educação Dallas (UTD-ERC), nós desenvolvemos vários índices distintos de acesso para identificar escolas de ensino médio ricas em artes. Nós achamos que escolas de ensino médio que oferecem uma extensa série de cursos em artes não necessariamente desfrutam de altos índices de participação dos alunos. Os legisladores, que examinam o acesso com base apenas na contagem de cursos de artes identificará predominantemente grandes escolas de ensino médio, não-rurais como tendo ambientes ricos em artes. Avaliação de programas de artes ao longo de uma única dimensão, como é comum em relatórios federais e outros estudos, não fornecem uma representação precisa do acesso à educação de artes. Qualquer exame de acesso à educação de artes deve considerar em conjunto a disponibilidade do curso e o envolvimento dos alunos nas artes. Os formuladores de políticas podem seguir nossa abordagem e desenvolver índices semelhantes para avaliar o estado atual da educação de artes em seus estados

N-alkane as an Internal Market for Predicting Digestibility of Forages

Independent digestion trials were conducted with three immature grasses, mature grass hay, and alfalfa hay to compare n-alkane with indigestible ADF (IADF) as internal markers to predict in vivo dry matter digestibility (DMD). Forage DMD estimated with n-alkane ratios were lower than in vivo DMD. N-alkanes predicted higher DMD than IADF for alfalfa hay and two of the immature grasses. Comparison of freeze-drying and oven-drying on fecal n-alkane concentrations showed oven drying reduced amounts of n-alkane extracted for alfalfa hay but had no effect on grass hay. Although fecal recovery of markers was incomplete, more n-alkane was recovered than IADF

Undegradable Intake Protein Supplementation of Compensating Spring-Born Steers and Summer-Born Steers During Summer Grazing

Three trials were conducted to determine the effects of previous winter gain (Trials 1 and 3) and age of calf (Trials 1 and 2) on response to undegradable intake protein (UIP) supplementation during summer grazing. In Trial 1, 48 spring-born steers (243 kg) were used in a 4 &#;&#;2 factorial arrangement. Steers were wintered at four rates of gain: 0.65 (FAST), 0.24 (SLOW), 0.38 (S/F), and 0.38 (F/S) kg/d. The intermediate rates of gain (S/F and F/S) were created by switching steers from slow to fast or fast to slow midway through the wintering period. Following winter treatments, steers were assigned to one of two summer treatments: supplemented (S) or nonsupplemented (NS). In Trial 2, 32 summer-born steers were wintered at an ADG of 0.25 kg/d and allotted to the same summer treatments as Trial 1. The supplement was formulated to supply 200 g/d of UIP. Steers from both trials grazed upland Sandhills range from May to September 1998. In Trial 3, 49 spring-born steers (228 kg) were used in a 2 &#;&#;7 factorial arrangement of treatments. Steers were wintered at two rates of gain, 0.71 (FAST) and 0.24 kg/d (SLOW) and then assigned randomly to one of six levels of UIP supplementation or an energy control. Protein supplements were formulated to deliver 75, 112.5, 150, 187.5 225, or 262.5 g/d of UIP. Sources of UIP for all trials were treated soybean meal and feather meal. In Trial 1, there were no (P \u3e 0.05) winter by summer treatment interactions, and UIP supplementation increased (P = 0.0001) pasture gains over NS steers. In Trial 2, supplementation increased (P = 0.001) pasture ADG of summer-born steers by 0.15 kg/d compared with NS steers. In Trial 3, a winter gain by UIP supplementation interaction was observed (P = 0.09). Gain of FAST steers responded quadratically (P = 0.09) across UIP levels, with the maximum gain occurring at the 150 g/ d UIP level. The SLOW steers responded linearly (P = 0.02) to increasing UIP levels; however, the response was negative. Levels of UIP above 150 g/d reduced steers gains; therefore, the data were reanalyzed excluding these levels. These new analyses showed that FAST steers responded linearly (P = 0.08; 0.2 kg/d) to increasing UIP, whereas the SLOW steers had no response to UIP. In Trials 1 and 3, SLOW steers experienced compensatory gain and had higher gains overall. We concluded that previous winter gain affected the response to UIP supplementation with the FAST winter gain group having a greater response

Range or Meadow Regrowth Grazing and Weaning Effects on Two Year-Old Cows

Body condition of cows at calving affects pregnancy rate and breeding date. Body condition at calving of spring calving cows wintered on range is influenced by fall body condition. A Montana study showed that lactating cows grazing range lost body condition during August and September. The loss of body condition was attributed to an inadequate consumption of crude protein. Diet samples of cattle grazing Sandhills range during August to October contain 6% to 8% crude protein. Loss of body condition of spring calving, primiparous cows grazing Nebraska Sandhills range during the fall is a concern. Subirrigated meadow regrowth is a higher quality forage than upland range in the fall. Diet samples collected from cattle grazing regrowth from subirrigated meadow during October contained approximately 11% crude protein. Two potential ways of maintaining or increasing cow body condition during the fall is to wean the calf, thus reducing the cow\u27s nutrient requirements, or increase the potential to meet crude protein requirements with higher quality forage. Our objectives were to determine if September weaning or grazing subirrigated meadows would improve body condition score of spring calving primiparous beef cows during September and October. and to determine nutrient intakes by dry and lactating cows grazing native range or subirrigated meadow regrowth