Abstract: The objective of the study was to analyze certain factors influencing the condition of free-ranging Konik Polski horses in a fenced area measuring 200 ha located in the Biebrza National Park (Biebrza NP). The Body Condition Scoring system (BCS) was used not only as means of assessment of health and fitness of the horses but also for evaluation of the quality and productivity of the grazing area selected for horses, as well as stocking rate. Body Condition Scoring was determine with a 9-point scale by averaging the scores that were assigned to each of the six body areas that are most responsive to changes of body fat (Hennecke, 1983). The condition of horses was assessed 7 times from February 2009 to December 2011 on a total of 59 horses (3 stallions (n= 12 observations), 21 females 3–8 year olds (n=81) and 35 youngsters (up to 2 year olds) (n=88). The number (from 1 to 3) and composition of family bands varied throughout the period of investigation. The horse population in the Biebrza NP consist of horses from 3 different breeding centers. The analysis of variance (GLM) was used to investigate the effects of the fixed factors – weather conditions, family band, breeder of the horses, age and sex, on the mean of BCS points of horses (SPSS, version 19.0). The most important factor influencing the condition of free-ranging Konik Polski horses in the Biebrza NP were weather conditions, what is shown by the data concerning temperature from 3-month period preceding condition scoring (P < 0.01). This factor influenced not only animals, but also vegetation characteristics. The highest BCS means of horses (5.09) were achieved when average temperature during the 3-month period preceding condition scoring amounted between +1 to +8°C, and was better than obtained when average temperature amounted +18°C (4.80). The last temperature seems too high for horses and can be connected also with other factors, like high incidence of insects which could deteriorate grazing activity of animals. The lowest BCS means (4.56) were obtained when mean temperature was below 0°C. Other factors had no significant effect on the BCS means. As concern to breeder, the highest BCS means achieved mares from Popielno (5.08) – the oldest Polish free-ranging population of Konik Polski horses, which confirms that horses from this breeding center are justly considered to be the toughest and well adapting to difficult environmental conditions. The horses from the Biebrza NP achieved also high BCS means (4.79) which prove that they were well suited to the specific conditions of this habitat, which is overgrown mostly with forest – 73,7%, and willow and birch shrubs – 13,3% of area. The grazing area measures about 40 hectares and consists of wetlands dominated by sedges (Carex sp.). The horses moved from the Seven Island Reservation to Biebrza NP achieved the poorest results as far as adaptation to the conditions of the new habitat, and reached the lowest BCS means (4.57). The youngest horses (up to 2 year olds), 3-5 year olds, and 6-8 year olds had similar BCS means (respectively 4.94, 4.83, 4.68) which indicates good acclimatization of horses from different age categories to the grazing resources in the Biebrza NP. The highest means achieved by youngest horses indicate important trait of Konik Polski horses – mare`s careful care of offspring. The BCS means of horses from different family groups show the highest value of horses from family group of the most experienced stallion – Mrok (4.97). In every BCS scoring, stallions achieved the highest means, which was the reason to exclude their results from analysis. The results of this study suggest that the Body Condition Scoring of horses in the Biebrza National Park depends primarily on the acclimatization of horses to harsh environmental conditions and less importantly to belonging to a specific breeder, family band, age or sex.

Abstract: In the horse, carbohydrate overload is thought to play an integral role in the onset of laminitis by drastically altering the profile of bacterial populations in the hindgut. The objectives of this study were to develop and validate microbial ecology methods to monitor changes in bacterial populations throughout the course of experimentally induced laminitis and to identify the predominant oligofructose-utilizing organisms. Laminitis was induced in five horses by administration of oligofructose. Faecal specimens were collected at 8 h intervals from 72 h before to 72 h after the administration of oligofructose. Hindgut microbiota able to utilize oligofructose were enumerated throughout the course of the experiment using habitat-simulating medium. Isolates were collected and representatives identified by 16S rRNA gene sequencing. The majority of these isolates collected belonged to the genus Streptococcus, 91% of which were identified as being most closely related to Streptococcus infantarius ssp. coli. Furthermore, S. infantarius ssp. coli was the predominant oligofructose-utilizing organism isolated before the onset of lameness. Fluorescence in situ hybridization probes developed to specifically target the isolated Streptococcus spp. demonstrated marked population increases between 8 and 16 h post oligofructose administration. This was followed by a rapid population decline which corresponded with a sharp decline in faecal pH and subsequently lameness at 24-32 h post oligofructose administration. This research suggests that streptococci within the Streptococcus bovis/equinus complex may be involved in the series of events which precede the onset of laminitis in the horse.

Abstract: Chemical relaxation studies on the system horse liver alcohol dehydrogenase, nicotinamide adenine dinucleotide, and ethanol were conducted observing fluorescence changes between 400 and 500 nm. Temperature-jump experiments were performed at pH 6.5, 7.0, 8.0, and 9.0; concentration-jump experiments at pH 9.0. The reciprocal of the slowest relaxation time was found to be linearly dependent upon the enzyme concentration for relatively low enzyme concentrations, as predicted earlier. Use of the wide pH-range necessitated expression of the four apparent dissociation constants of the catalytic reaction cycle in terms of pH-independent constants. The system was described in terms of only one (or two) catalysis-linked protons not associated with the electron transfer. Protonic steps in a buffered system are in rapid equilibrium, too fast to be measured with the equipment available. Assuming only two of the four bimolecular reaction steps in the four-step cycle are fast compared to the remaining two, six cases may be considered with six expressions for the reciprocal of the slowest relaxation time. Comparison with the experimental data revealed that the bimolecular reaction steps governing the slowest relaxation time change with pH. Above the effective time resolution of the temperature-lump instrument with fluorescence detection (0.1 msec) only one other relaxation time was detectable and only at pH 9. This relaxation time, found to be independent of the concentration of all reactants within experimental error (r = 10 +/- 5 msec), is most likely due to an interconversion among ternary complexes.

Abstract: The objective was to determine whether collected trot, passage and piaffe could be distinguished as separate gaits on the basis of temporal variables. Sagittal plane, 60 Hz videotapes of 10 finalists in the dressage competitions at the 1992 Olympic Games were analysed to measure the temporal variables in absolute terms and as percentages of stride duration. Classification was based on analysis of variance, a graphical method and discriminant analysis. Stride duration was sufficient to distinguish collected trot from passage and piaffe in all horses. The analysis of variance showed that the mean values of most variables differed significantly between passage and piaffe. When hindlimb stance percentage was plotted against diagonal advanced placement percentage, some overlap was found between all 3 movements indicating that individual horses could not be classified reliably in this manner. Using hindlimb stance percentage and diagonal advanced placement percentage as input in a discriminant analysis, 80% of the cases were classified correctly, but at least one horse was misclassified in each movement. When the absolute, rather than percentage, values of the 2 variables were used as input in the discriminant analysis, 90% of the cases were correctly classified and the only misclassifications were between passage and piaffe. However, the 2 horses in which piaffe was misclassified as passage were the gold and silver medallists. In general, higher placed horses tended toward longer diagonal advanced placements, especially in collected trot and passage, and shorter hindlimb stance percentages in passage and piaffe.

Abstract: Four Arabian horses and one Thoroughbred were presented with a series of two-choice color vs. gray discrimination problems. Testing was done in a stall containing a wall with two translucent panels that were illuminated from behind by light projected through color or gray filters to provide the discriminative stimuli. Horses first learned to push one of the panels in order to receive the food reward behind the positive stimulus in an achromatic light-dark discrimination task, and were then tested on their ability to discriminate between gray and four individual colors: red (617 nm), yellow (581 nm), green (538 nm), and blue (470 nm). The criterion for learning was set at 85% correct responses, and final testing for all color vs. gray discriminations involved grays of varying intensities, making brightness an irrelevant cue. Three subjects were tested with all four colors. Two of those subjects successfully reached the criterion for learning on all four color vs. gray discriminations, while the third reached criterion with red and blue, but performed at chance levels for yellow and green. A fourth horse was only tested with green and yellow, and a fifth only with blue, and both of those horses successfully reached criterion on the discriminations they attempted. With the exception of the one subject's poor performance with yellow and green, there was no significant difference between horses on any of the discrimination tasks, and no significant difference in their performance with different colors. The results suggest that horses have color vision that is at least dichromatic, although partial color-blindness may occur in some individuals.