Spengler M.I., & Rasia M. (2001). Influence of Plasma Proteins on Erythrocyte Aggregation in Three Mammalian Species. Vet.Res.Comm, 25(7), 591–599.
Abstract: The aggregation capacity of human erythrocytes lies between that of the non-aggregating bovine erythrocytes and the remarkably aggregating equine ones. As the ability to aggregate is attributed to cell factors and the composition of the plasma proteins, the role that plasma proteins play in the aggregation process in these three species was studied. Washed erythrocytes were suspended in phosphate-buffered saline (PBS; pH 7.4, 300 mOsm/L) plus polyvinylpyrrolidone (PVP) in a suitable concentration to obtain an average intensity of aggregation (control media). The superimposed effect of replacing 80% of the medium by either autologous plasma, serum or albumin solution was studied. The plasma proteins appeared to enhance aggregation by human and equine erythrocytes, but impaired this process in bovine erythrocytes. Some evidence was obtained supporting the existence of serum factors capable of reducing aggregation of erythrocytes in cattle and it was concluded that the non-aggregating behaviour of bovine erythrocytes may be due to the cells interacting particularly with the macromolecules in the serum.
|
McGreevy, P. D., Webster, A. J., & Nicol, C. J. (2001). Study of the behaviour, digestive efficiency and gut transit times of crib-biting horses. Vet. Rec., 148(19), 592–596.
Abstract: The spontaneous behaviour and the apparent digestibility of dry matter and fibre and transit times of digesta were compared in four normal horses and four crib-biters. A technique was developed for measuring total gut transit times (TGTT) by using single-stool analysis of the passage of radio-opaque polyethylene markers. Longer TGTT were recorded in the crib-biters than in the normal horses but the orocaecal transit times did not differ. The crib-biters rested less than the normal horses.
|
McBride, S. D., & Long, L. (2001). Management of horses showing stereotypic behaviour, owner perception and the implications for welfare. Vet. Rec., 148(26), 799–802.
Abstract: A telephone survey was conducted of 100 racing stables, 100 riding schools and 100 competition establishments (8,427 horses in total) to determine what management practices were being applied to horses showing stereotypic behaviour, and to determine the underlying reasons for them by assessing the perceptions and opinions of the people working with the horses. The results indicated that horse owners are concerned about stereotypic behaviour, first, because it reduces the performance of the animal (31, 30 and 27 per cent of the owners of racing stables, riding schools and competition establishments respectively), secondly, because it has adverse clinical effects on the horse (52, 55 and 56 per cent), and thirdly, because it reduces the monetary value of the animal (45, 59 and 31 per cent). The belief that these behaviours are learnt or copied also affects the management of affected horses: they are not allowed on to the premises by 4, 32 and 17 per cent of owners of racing stables, riding schools and competition establishments, respectively; attempts are made to remove the causal factors of the stereotypy by 35, 43 and 36 per cent; the behaviours are physically prevented by 77, 67 and 79 per cent, and the affected horses are kept separate from other horses by 39, 30 and 48 per cent.
|
Jansen, W. L., van Alphen, M., Berghout, M., Everts, H., & Beynen, A. C. (2001). An approach to assessment of the efficiency of dietary energy utilization by horses and ponies kept at riding schools. Vet Q, 23(4), 195–198.
Abstract: The ratio of calculated net energy intake (NEi) to calculate net energy requirement (NEr) might serve as an indicator of the efficiency of dietary energy utilization. The ratio was determined for 93 horses and ponies from 10 riding schools. For each animal with an assumed constant body weight, energy intake and energy requirements were assessed. On average, the estimated NEi was 14% greater than NEr. There was a significant, negative association between crude fibre intake and the NEi: NEr ratio. Earlier work indicated that extra fat intake may lead to over estimation of the calculated energy value of the ration due to changes in macronutrient digestibility. Dietary fat concentration was found to range from 32 to 52 g/kg dry matter (5 to 6 g/MJ net energy), but on the basis of digestibility trials this range in fat concentration is too small to significantly influence the NEi: NEr ratio. This study shows that assessment of the efficiency of dietary energy utilization under normal conditions, on the basis of the NEi: NEr ratio is fraught with uncertainty.
|
Miller, R. M. (2001). Behavior and misbehavior of the horse. Vet Clin North Am Equine Pract, 17(2), 379–87, ix.
Abstract: For decades after the discipline of psychiatry had been established as an accepted specialty, many medical schools continued to fail to train their students in the fundamentals of this discipline. Medical students all have at least cursory exposure to psychiatric principles and basic psychology. Unfortunately, the veterinary profession has lagged behind human medicine in this regard. Until recently, veterinary students received no training in animal behavior, and there were no available residencies within our schools for developing board-certified behavioral specialists.
|
Baragli, P., Tedeschi, D., Masini, A. P., Magnaghi, N., Martelli, F., & Sighieri, C. (2001). Estimation of performance in elite endurance horses by means of an exercise test in field conditions. Valutazione della performance in cavalli da endurance di elite mediante test diesercizio in campo, 12(1), 13–19.
Abstract: In human sports medicine exercise tests are normally used to check training progression. Correlation tests between blood lactate concentration and exercise speed are often used for this purpose. Studies have been done to adjust exercise tests for athletic horses using the same principle. The aim of this work was to verify the practical possibility that the anaerobic threshold in elite endurance horses could be calculated by adjusting a submaximal exercise field test in order to obtain reference parameters for endurance horses. Ten selected horses from the Italian National Endurance Team were used for this study. The tests were conducted on an 800 meters grass oval. Horses performed three steps (800 meters every step), at increasing speed with two minute intervals between each step. Riders were informed of the ideal speed for every step (5, 7.5, 10 m/s) and the real velocity was calculated on the basis of time taken to finish a single step. Blood samples were obtained via venipuncture from the jugular vein, immediately before the beginning of the test and 60 seconds after the end of each step. The following parameters were evaluated for each horse: individual anaerobic threshold (VSI), anaerobic threshold (V4) and exercise velocity corresponding to a lactate concentration of 2 mM/I (V2). Analysis of results indicate that lactate concentration is exponentially related to exercise speed for the entire test. VSI, V4, V2, were (mearttsd): 25.7±5.1; 30.5±2.5; 21.1±2.9 km/h respectively.
|
Creel, S. (2001). Social dominance and stress hormones. Trends. Ecol. Evol, 16(9), 491–497.
Abstract: In most cooperatively breeding birds and mammals, reproductive rates are lower for social subordinates than for dominants, and it is common for reproduction in subordinates to be completely suppressed. Early research conducted in captivity showed that losing fights can increase glucocorticoid (GC) secretion, a general response to stress. Because GCs can suppress reproduction, it has been widely argued that chronic stress might underlie reproductive suppression of social subordinates in cooperative breeders. Contradicting this hypothesis, recent studies of cooperative breeders in the wild show that dominant individuals have elevated GCs more often than do subordinates. The findings that elevated GCs can be a consequence of subordination or a cost of dominance complicate the conventional view of social stress, with broad ramifications for the evolution of dominance and reproductive suppression.
|
Bolhuis, J. J., & Macphail, E. M. (2001). A critique of the neuroecology of learning and memory. Trends. Cognit. Sci., 5(10), 426–433.
Abstract: Recent years have seen the emergence of neuroecology, the study of the neural mechanisms of behaviour guided by functional and evolutionary principles. This research has been of enormous value for our understanding of the evolution of brain- and species-specific behaviour. However, we question the validity of the neuroecological approach when applied to the analysis of learning and memory, given its arbitrary assumption that different [`]problems' engage different memory mechanisms. Differences in memory-based performance in [`]natural' tasks do not prove differences in memory capacity; similarly, differences in the use of memory in the natural environment do not provide a sound basis for expecting differences in anatomical structures that subserve learning and memory. This critique is illustrated with examples taken from the study of the neurobiology of food storing and song learning in birds.
|
|
Maestripieri, D. (2001). Comparing cognition in animals, and researchers. Trends Cogn Sci, 5(10), 452–453.
|
Slotnick, B. (2001). Animal cognition and the rat olfactory system. Trends Cogn Sci, 5(5), 216–222.
Abstract: Is smell a 'primitive' sense used primarily to guide biologically basic behaviors or might it be the sensory modality that allows some species to express complex learning and other forms of cognitive behavior? Historically, the olfactory system has been considered primitive and it is not surprising that, until recently, cognitive neuroscientists have ignored odor-guided behavior. However, we now know that the olfactory system has projections to the prefrontal cortex, entorhinal cortex and hippocampus, and that these connections support the acquisition of simple and higher-order instrumental tasks, as well as a robust memory for odors. It appears that animals with a well-developed sense of smell have the neural machinery to think with their noses.
|
