The performance of the finite difference reciprocity method (FDRM) to solve the inverse problem in EEG dipole source analysis is investigated in the analytically solvable three-shell spherical head model for a large set of test dipoles. The location error for a grid with 2 mm and 3 mm node spacing is in general, not larger than twice the internode distance, hence 4 mm and 6 mm, respectively. Increasing the number of scalp electrodes from 27 to 44 only marginally improves the location error. The orientation error is always smaller than 4 degrees for all the test dipoles considered. We have also compared the sensitivity to noise using FDRM in EEG dipole source analysis with the sensitivity to noise using the analytical expression for the forward problem. FDRM is not more sensitive to noise than the method using the analytical expression.

The objective of this study was to evaluate the accuracy of a novel, portable device (iSperm® Equine for assessing concentration and motility of stallion semen). In the first experiment, semen concentration was determined by the iSperm® Equine (Aidmics Biotechnology), Androvision® (Minitube) and NucleoCounter® SP‐100™ (ChemoMetec). The total motility and progressive motility were determined by the iSperm® Equine and the Androvision® using the manufacturer's guidelines. Frozen/thawed semen samples (n = 33) at various dilutions were analysed for concentration and motility with the above‐mentioned devices. There was a significant correlation between the concentrations measured with iSperm® and NucleoCounter® at all the measured dilutions. Moreover, <10% difference in concentrations was observed between the iSperm® and NucleoCounter® using the Bland–Altman test. There was also a significant correlation between iSperm® and Androvision® for total and progressive motility. In the second experiment, the parameters used in the Androvision® were modified to match those of the iSperm®. Total motility and progressive motility of frozen/thawed semen samples (n = 10) were determined, and the similarity between the Androvision® and iSperm® was confirmed by correlation studies and Bland–Altman test. The results of these experiments demonstrate that the iSperm® offers a reliable and practical alternative for the semi‐automated measurement of concentration and motility of stallion semen in the field. The iSperm® enables the practitioner to obtain objective and repeatable measurements on a variety of semen types (fresh, cooled and frozen) in the field at the time of insemination and thus acquire more insight into the quantity and quality of the provided insemination doses. This mare‐side diagnostic tool may help practitioners in identifying presumed subfertility problems more rapidly and act accordingly.

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Several methods have been proposed to advance the onset of the breeding season in horses. Most of them are based on the exposure to an artificial lighting period combined with hormonal treatments. Mares exposed to an artificial photoperiod are most often housed indoors where the ambient temperature is often higher than the outside temperature. Mares held in barns are also exposed to different daylight intensities than horses kept outside, depending on the architecture. In the current study, we evaluated the impact of ambient temperature, daylight intensity and changes in body condition score (BCS) on the timing of first ovulation after winter anestrus in mares exposed to an artificial photoperiod. Mares (n = 211) were housed in barns with different ambient temperature and daylight exposure but with the same artificial photoperiod exposure (except for a natural photoperiod control group). Artificial photoperiod as well as an increase in BCS over the winter significantly advanced the first spring ovulation. The BCS at the start and end of the anestrus period did not have an effect on the interval to first ovulation and neither did the modest increase in ambient temperature in the barn. However, a higher light intensity during the daytime significantly advanced the first spring ovulation. The results of this study suggest that exposure to more sunlight advances the onset of the breeding season. This effect is likely mediated through the biological effect of short wavelength blue light and its impact on melatonin suppression and biological rhythms. We suggest that greater/direct exposure to the blue light component of daylight improves the response to the artificial photoperiod. The results of the present study can further assist to optimize the conditions that lead to an efficient spring transition of breeding mares.