The Potential Effects of Social Interactions on Reproductive Efficiency of Stallions

The reproductive efficiency of stabled domestic stallions is often lower than what could be expected from observations in feral herds. In the wild, stallions typically live with mares in harem bands, with other stallions in bachelor bands, or occasionally in mixed-sex transitional bands. We, therefore, argue that permanent contact with mares may increase reproductive efficiency of stallions suffering from low libido and/or fertility. We also provide a summary of our present knowledge of natural conditions, management, and husbandry of domestic stallions, and of intra- and intersexual behavioral interactions in horses.     

Instrumented treadmill for measuring vertical ground reaction forces in horses

OBJECTIVE: To develop and validate a novel instrumented treadmill capable of determining vertical ground reaction forces of all 4 limbs simultaneously in horses. SAMPLE POPULATION: Data obtained while a horse was walking and trotting on the treadmill. PROCEDURE: 18 piezo-electric force transducers were mounted between the treadmill frame and supporting steel platform to measure the actual forces at the corresponding bearing points. Each of the 18 sensor forces is equal to the sum of the unknown hoof forces weighted with the transfer coefficients of the corresponding force application points. The 4 force traces were calculated, solving at each time point the resulting equation system, using the Gaussian least-squares method. System validation comprised the following tests: determination of the survey accuracy of the positioning system, determination of the natural frequencies of the system, linearity test of the force transfer to the individual sensors, determination of superimposed forces with the treadmill-integrated force measuring system (TiF) in a static configuration, and comparison of vertical ground reaction forces determined simultaneously by use of TiF and force shoes mounted on the forelimbs of a horse. RESULTS: Comparison between static test loads and TiF-calculated forces revealed deviations of < 1.4%. Force traces of TiF-calculated values and those recorded by use of the force shoes were highly correlated (r > or = 0.998). CONCLUSIONS AND CLINICAL RELEVANCE: This instrumented treadmill allows a reliable assessment of load distribution and interlimb coordination in a short period and, therefore, is suitable for use in experimental and clinical investigations.     

Understanding the infrared spectrum of bare CH5+

Protonated methane, CH5+, continues to elude definitive structural assignment, as large-amplitude vibrations and hydrogen scrambling challenge both theory and experiment. Here, the infrared spectrum of bare CH5+ is presented, as detected by reaction with carbon dioxide gas after resonant excitation by the free electron laser at the FELIX facility in the Netherlands. Comparison of the experimental spectrum at approximately 110 kelvin to finite-temperature infrared spectra, calculated by ab initio molecular dynamics, supports fluxionality of bare CH5+ under experimental conditions and provides a dynamical mechanism for exchange of hydrogens between CH3 tripod positions and the three-center bonded H2 moiety, which eventually leads to full hydrogen scrambling. The possibility of artificially freezing out scrambling and internal rotation in the simulations allowed assignment of the infrared spectrum despite this pronounced fluxionality.     

Functional conversion between A-type and delayed rectifier K+ channels by membrane lipids

Voltage-gated potassium (Kv) channels control action potential repolarization, interspike membrane potential, and action potential frequency in excitable cells. It is thought that the combinatorial association between distinct alpha and beta subunits determines whether Kv channels function as non-inactivating delayed rectifiers or as rapidly inactivating A-type channels. We show that membrane lipids can convert A-type channels into delayed rectifiers and vice versa. Phosphoinositides remove N-type inactivation from A-type channels by immobilizing the inactivation domains. Conversely, arachidonic acid and its amide anandamide endow delayed rectifiers with rapid voltage-dependent inactivation. The bidirectional control of Kv channel gating by lipids may provide a mechanism for the dynamic regulation of electrical signaling in the nervous system.     

ImmuneDEX: a strategy for the genetic improvement of immune competence in Australian Angus cattle

In animal breeding and genetics, the ability to cope with disease, here defined as immune competence (IC), with minimal detriment to growth and fertility is a desired objective which addresses both animal production and welfare considerations. However, defining and objectively measuring IC phenotypes using testing methods which are practical to apply on-farm has been challenging. Based on previously described protocols, we measured both cell-mediated immune response (Cell-IR) and antibody-mediated immune response (Ab-IR) and combined these measures to determine an animal’s IC. Using a population of 2,853 Australian Angus steers and heifers, we compared 2 alternative methods to combine both metrics into a single phenotype to be used as a tool for the genetic improvement of IC. The first method, named Z_MEAN, is obtained by taking the average of the individual metrics after subjecting each to a Z-score standardization. The second, ImmuneDEX (IDEX), is a weighted average that considers the correlation between Cell-IR and Ab-IR, as well as the difference in ranking of individuals by each metric, and uses these as weights in the averaging. Both simulation and real data were used to understand the behavior of Z_MEAN and IDEX. To further ascertain the relationship between IDEX and other traits of economic importance, we evaluated a range of traits related to growth, feedlot performance, and carcass characteristics. We report estimates of heritability of 0.31 ± 0.06 for Cell-IR, 0.42 ± 0.06 for Ab-IR, 0.42 ± 0.06 for Z_MEAN and 0.370 ± 0.06 for IDEX, as well as a unity genetic correlation (r_g) between Z_MEAN and IDEX. While a moderately positive r_g was estimated between Cell-IR and Ab-IR (r_g = 0.33 ± 0.12), strongly positive estimates were obtained between IDEX and Cell-IR (r_g = 0.80 ± 0.05) and between IDEX and Ab-IR (r_g = 0.85 ± 0.04). We obtained a moderately negative r_g between IC traits and growth including an r_g = −0.38 ± 0.14 between IDEX and weaning weight, and negligible with carcass fat measurements, including an r_g = −0.03 ± 0.12 between IDEX and marbling. Given that breeding with a sole focus on production might inadvertently increase susceptibility to disease and associated antibiotic use, our analyses suggest that ImmuneDEX will provide a basis to breed animals that are both highly productive and with an enhanced ability to resist disease.     

Compensatory load redistribution of horses with induced weight-bearing forelimb lameness trotting on a treadmill

The study was performed to obtain a detailed insight into the load and time shifting mechanisms of horses with unilateral weight-bearing forelimb lameness. Reversible lameness was induced in 11 clinically sound horses by applying a solar pressure model. Three degrees of lameness (subtle, mild and moderate) were induced and compared with sound control measurements. Vertical ground reaction force-time histories of all four limbs were recorded simultaneously on an instrumented treadmill. Four compensatory mechanisms could be identified that served to reduce structural stress, i.e. peak vertical force on the affected limb: (1) with increasing lameness, horses reduced the total vertical impulse per stride; (2) the diagonal impulse decreased selectively in the lame diagonal; (3) the impulse was shifted within the lame diagonal to the hindlimb and in the sound diagonal to the forelimb; (4) the rate of loading and the peak forces were reduced by prolonging the stance duration. Except in the diagonal hindlimb, where peak vertical forces increased slightly in the moderate lameness condition, no equivalent compensatory overload situation was observed in the other limbs. Specific force and time information of all four limbs allow the unequivocal identification of the affected limb.     

Technology generation to dissemination: lessons learned from the tef improvement project

Indigenous crops also known as orphan crops are key contributors to food security, which is becoming increasingly vulnerable with the current trend of population growth and climate change. They have the major advantage that they fit well into the general socio-economic and ecological context of developing world agriculture. However, most indigenous crops did not benefit from the Green Revolution, which dramatically increased the yield of major crops such as wheat and rice. Here, we describe the Tef Improvement Project, which employs both conventional- and molecular-breeding techniques to improve tef—an orphan crop important to the food security in the Horn of Africa, a region of the world with recurring devastating famines. We have established an efficient pipeline to bring improved tef lines from the laboratory to the farmers of Ethiopia. Of critical importance to the long-term success of this project is the cooperation among participants in Ethiopia and Switzerland, including donors, policy makers, research institutions, and farmers. Together, European and African scientists have developed a pipeline using breeding and genomic tools to improve the orphan crop tef and bring new cultivars to the farmers in Ethiopia. We highlight a new variety, Tesfa, developed in this pipeline and possessing a novel and desirable combination of traits. Tesfa’s recent approval for release illustrates the success of the project and marks a milestone as it is the first variety (of many in the pipeline) to be released.     

Novel ferrihydrite sand coating process as a first step for designed technosols

Purpose

The production of technosols to remediate polluted or sealed urban soils to sustain new green areas is mainly empirical. For this, our research aims to contribute with the scientific knowledge base for purpose designing of technosols. Since iron minerals play an important role for many different functions of soils, we simplified a technique to incorporate and stabilize iron minerals in a substrate: a sand coated with an amorphous iron (hydr)oxide, a 2-line ferrihydrite (2L-FH).

Materials and methods

The 2L-FH was precipitated by neutralization of a concentrated FeCl₃ solution. The suspension was homogeneously mixed with the sand and the mixture was dried at 35 °C. The mechanical stability of the 21 2L-FH-coated sand was determined by shaking the aggregates in water for 0, 1, 10, 100, and 1 000 min. The degree of coating detachment and the properties of the coating after shaking were characterized through (a) Fe content, (b) zeta-potential and particle size of the detached particles, (c) the specific surface area (SSA) of the coated sand, and (d) its surface structure using scanning electron microscopy (SEM). A phosphate adsorption isotherm was performed to measure the P-sorption capacity of the shaken samples and to test the 2L-FH-quartz attachment stability against the surface charge reduction of the 2L-FH associated with P adsorption.

Results and discussion

A reduced Fe loss (30 %) and smaller sizes of the coating detached particles in the sample shaken for 1 000 min indicate that a fractioning and reattachment of these aggregates occurred during the agitation process, resulting in a smoother surface (SEM), and a larger SSA and P-sorption capacity. The coated shaken samples showed P-adsorption capacities (5.3–6.34 μmol P g^?1) comparable to high loadings of phosphate in soils, and low detachment of Fe (7–14 %) in spite of negativity surface charge increase.

Conclusions

The practical novel coating process along with the 1 000-min shaking produced a mechanical resistant and P-adsorptive effective coated sand that could sustain the needs of plants in further experiments.

     

Quantitative Analysis of Stress Echocardiograms in Healthy Horses with 2‐Dimensional (2D) Echocardiography,Anatomical M‐Mode,Tissue Doppler Imaging,and 2D Speckle Tracking

Background: Stress echocardiography is used to diagnose myocardial dysfunction in horses, but current methods are not well standardized. The influence of heart rate (HR) on measurements is largely unknown. Objectives: To investigate the use of 2‐dimensional echocardiography (2DE), anatomical M‐mode (AMM), tissue Doppler imaging (TDI), and 2D speckle tracking (2DST) at rest and after exercise for quantification of regional and global left‐ventricular (LV) function. Animals: Five athletic Warmblood horses; 11.6 ± 3.6 years; 529 ± 48 kg. Methods: Prospective study. Three separate echocardiographic examinations were performed before (baseline) and over 5 minutes after treadmill exercise with 2DE (1st, short‐axis view; 2nd, long‐axis view) and pulsed‐wave TDI (3rd examination). Offline analyses were performed at baseline and after exercise at HR 120, 110, 100, 90, and 80 minute^?1. Global and segmental measurements were compared by analysis of variance. Results: Quantitative analyses of stress echocardiograms were feasible in all horses. None of the AMM indices changed significantly after exercise. Stroke volume and ejection fraction by 2DE and strain by 2DST decreased, whereas strain rate by 2DST increased significantly at HR > 100 minute^?1. TDI analyses were technically difficult and provided little additional information. Conclusions and Clinical Importance: Volumetric indices by 2DE and strain and strain rate by 2DST are applicable for quantitative assessment of stress echocardiograms. In healthy horses, they are significantly altered at a HR > 100 minute^?1 and need to be evaluated in view of the instantaneous HR. Further investigations are needed to define the clinical value of stress echocardiography in horses with cardiac disease.