Water Intake in Growing Beef Cattle

Water is an essential part of livestock and human diets and is often thought of as an inexpensive, readily available renewable natural resource. However, the amount of competition between humans, wildlife, feed production, and livestock for high-quality water is increasing, not only from the effects of drought but from the pressure of a growing global population (Nardone et al., 2010). With limited resources available for production agriculture, there is a need to identify and select for efficient animals that can produce more product with fewer inputs. Although some work has been done in dairy cattle, very little data is available on individual animal water intake in modern beef cattle (Brew et al., 2011). The majority of the water intake data available in growing beef cattle is derived from dividing the total amount of water drunk in a pen divided by the number of animals in that pen (Sexson et al., 2010; Mader and Davis, 2004). Data derived from groups are not generally useful for the purposes of genetic evaluation, which aims to quantify individual animal variation in a trait for selection. However, in order to practice selection on a large scale, parameters for collecting phenotypic data must be established. The objectives of this study were to measure daily water intake on a large number of beef steers and to estimate the number of test days necessary to collect accurate water intake phenotypes

Kombinatorische Methoden zur effizienteren Entwicklung von Katalysatoren. Teilprojekt: Automation Schlussbericht

Available from TIB Hannover: F04B399 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEBundesministerium fuer Bildung und Forschung, Berlin (Germany)DEGerman

Simplicity in melt densification in multicomponent magmatic reservoirs in Earth’s interior revealed by multinuclear magnetic resonance

Pressure-induced changes in properties of multicomponent silicate melts in magma oceans controlled chemical differentiation of the silicate earth and the composition of partial melts that might have formed hidden reservoirs. Although melt properties show complex pressure dependences, the melt structures at high pressure and the atomistic origins of these changes are largely unknown because of their complex pressure–composition dependence, intrinsic to multicomponent magmatic melts. Chemical constraints such as the nonbridging oxygen (NBO) content at 1 atm, rather than the structural parameters for melt polymerization, are commonly used to account for pressure-induced changes in the melt properties. Here, we show that the pressure-induced NBO fraction in diverse silicate melts show a simple and general trend where all the reported experimental NBO fractions at high pressure converge into a single decaying function. The pressure-induced changes in the NBO fraction account for and predict the silica content, nonlinear variations in entropy, and the transport properties of silicate melts in Earth’s mantle. The melt properties at high pressure are largely different from what can be predicted for silicate melts with a fixed NBO fraction at 1 atm. The current results with simplicity in melt polymerization at high pressure provide a molecular link to the chemical differentiation, possibly missing Si content in primary mantle through formation of hidden Si-rich mantle reservoirs

OFF ganglion cells cannot drive the optokinetic reflex in zebrafish

Whereas the zebrafish retina has long been an important model system for developmental and genetic studies, little is known about the responses of the inner retinal neurons. Here we report single-unit ganglion cell recordings from 5- to 6-day-old zebrafish larvae. In wild-type larvae we identify at least five subtypes of ganglion cell responses to full-field illumination, with ON-OFF and ON-type cells predominating. In the nrc mutant retina, in which the photoreceptor terminals develop abnormally, we observe normal OFF responses but abnormal ON-OFF responses and no ON responses. Previously characterized as blind, these mutants lack an optokinetic reflex (OKR), but in another behavioral assay nrc mutant fish have near-normal responses to the offset of light and slow and sluggish responses to the onset of light. Pharmacological block of the ON pathway mimics most of the nrc visual defects. We conclude that the abnormal photoreceptor terminals in nrc mutants predominantly perturb the ON pathway and that the ON pathway is necessary to drive the OKR in larval zebrafish

Effects of beef cattle temperament on feed and water intake

Temperament scoring systems encompass a variety of subjective and objective methods. Chute scoring may be the most common subjective method, and is often used by breed associations in their docility genetic evaluations. The most commonly used objective method is exit velocity, which is calculated from the amount of time it takes for an animal to cross 1.83 meters when exiting the working chute. Measurements of temperament collected using both objective and subjective methodologies have been shown to be heritable, and are associated with differences in cortisol levels and average daily gain in the scientific literature. Thus, the objective of this study was to characterize individual animal variation in feed and water intake and evaluate the relationship between beef cattle temperament and feed and water intake. Five objective (exit velocity; EV) and subjective (chute scores; CS) temperament measures were collected on 106 beef steers every 2 weeks over a 70 d feed and water intake test, CS were ordinal, and reflected the temperament of the animal in the chute (1=calm, 4= continuous resistance). EV was calculated using times recorded by electronic eyes (FarmTek). Entry scores were also collected as a control variable and reflected the mechanisms used to encourage the steers to enter the chute. Daily feed and water intakes on each individual animal were recorded using an Insentec system. All data were averaged over the 70 d test period and included length of each feeding/watering event, number of daily intake events, and mean intake. A general linear model was utilized to evaluate the relationships between temperament measures and intake. CS (averaged over the 5 timepoints) and EV (averaged over the 5 timepoints) did not have a significant impact on feed or water intake (P > 0.05). It is possible that this result is due to the fact that most animals in the study were calm, and thus did not include a lot of variation in these traits. Variation in feed and water intake as described by the standard deviation of all daily intake measures was related to overall feed and water intake, and animals that tend to have higher intakes also have higher variability in their daily feed and water intakes (P, 0.05). In addition, the number of daily feed events and the length spent at the bunk are both significant predictors of feed and water intake (P < 0.05)

Retinal function and morphology in two zebrafish models of oculo-renal syndromes.

We characterized visual system defects in two recessive zebrafish mutants oval and elipsa. These mutants share the syndromic phenotype of outer retinal dystrophy in conjunction with cystic renal disorder. We tested the function of the larval visual system in a behavioural assay, eliciting optokinetic eye movements by high-contrast motion stimulation while recording eye movements in parallel. Visual stimulation did not elicit eye movements in mutant larvae, while spontaneous eye movements could be observed. The retina proved to be unresponsive to light using electroretinography, indicative of a defect in the outer retina. Histological analysis of mutant retinas revealed progressive degeneration of photoreceptors, initiated in central retinal locations and spreading to more peripheral regions with increasing age. The inner retina remains unaffected by the mutation. Photoreceptors display cell type-specific immunoreactivity prior to apoptotic cell death, arguing for a dystrophic defect. Genomic mapping employing simple sequence-length polymorphisms located both mutations on different regions of zebrafish linkage group 9. These mutants may serve as accessible animal models of human outer retinal dystrophies, including oculo-renal diseases, and show the general usefulness of a behavioural genetic approach to study visual system development in the model vertebrate zebrafish