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Murray, R. C., Branch, M. V., Dyson, S. J., Parkin, T. D. H., & Goodship, A. E. (2007). How does exercise intensity and type affect equine distal tarsal subchondral bone thickness? J Appl Physiol, 102(6), 2194–2200.
Abstract: Adaptation of osteochondral tissues is based on the strains experienced during exercise at each location within the joint. Different exercise intensities and types may induce particular site-specific strains, influencing osteochondral adaptation and potentially predisposing to injury. Our hypotheses were that patterns of equine distal tarsal subchondral bone (SCB) thickness relate to the type and intensity of exercise, and that high-intensity exercise leads to site-specific increases in thickness. SCB thickness was measured at defined dorsal and plantar locations on magnetic resonance images of cadaver tarsi collected from horses with a history of low [general purpose (n=20) and horse walker (n=6)] or high [elite competition (n=12), race training (n=15), and treadmill training (n=4)] exercise intensity. SCB thickness was compared between sites within each exercise group and between exercise groups. SCB thickness in elite competition and race training, but not treadmill training, was greater than low-intensity exercise. For general purpose horses, lateral SCB thickness was greater than medial throughout. Horse walker exercise led to relatively thicker lateral and medial SCB compared with the midline. Elite competition was associated with increased SCB thickness of the proximal small tarsal bones medially and the distal bones laterally. For race training and treadmill training, there were minimal differences between sites overall, although the lateral aspect was greater than medial, and medial greater than midline at a few sites for race training. In conclusion, different types of high-intensity exercise were associated with different patterns of SCB thickness across the joints from medial to lateral and proximal to distal, indicating that both exercise intensity and type of exercise affect the SCB response at any particular site within the equine distal tarsal joints.
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McCrory, P., Turner, M., LeMasson, B., Bodere, C., & Allemandou, A. (2006). An analysis of injuries resulting from professional horse racing in France during 1991-2001: a comparison with injuries resulting from professional horse racing in Great Britain during 1992-2001. Br J Sports Med, 40(7), 614–618.
Abstract: BACKGROUND: It has been previously shown that professional jockeys suffer high rates of fatal and non-fatal injuries in the pursuit of their occupation. Little is known, however, about differences in injury rates between countries. AIM: To determine the rate of fatal and non-fatal injuries in flat and jump jockeys in France and to compare the injury rates with those in Great Britain and Ireland Method: Prospectively collected injury data on professional jockeys were used as the basis of the analysis. RESULTS: Limb fractures occur four times more often in both flat and jump racing in France than in Great Britain. Similarly dislocations are diagnosed 20 times more often in flat and three times more often in jump racing. This difference is surprising given that French jockeys have fewer falls per ride than their British counterparts in flat racing, although they do have more falls than the British in jump racing. Similarly concussion rates seem to be higher in French jockeys, although there may be a difference in the diagnostic methods used in the different countries. By contrast, soft tissue injuries account for a far smaller percentage of injuries than in Great Britain. CONCLUSION: There are striking differences in injury rates between countries which may be explained in part by a difference in track conditions-for example, harder tracks in France-or different styles of racing--for example, larger fields of horses per race in France.
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Bergman, T. J., Beehner, J. C., Cheney, D. L., & Seyfarth, R. M. (2003). Hierarchical classification by rank and kinship in baboons. Science, 302(5648), 1234–1236.
Abstract: Humans routinely classify others according to both their individual attributes, such as social status or wealth, and membership in higher order groups, such as families or castes. They also recognize that people's individual attributes may be influenced and regulated by their group affiliations. It is not known whether such rule-governed, hierarchical classifications are specific to humans or might also occur in nonlinguistic species. Here we show that baboons recognize that a dominance hierarchy can be subdivided into family groups. In playback experiments, baboons respond more strongly to call sequences mimicking dominance rank reversals between families than within families, indicating that they classify others simultaneously according to both individual rank and kinship. The selective pressures imposed by complex societies may therefore have favored cognitive skills that constitute an evolutionary precursor to some components of human cognition.
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Crosby, M. B., Svenson, J. L., Zhang, J., Nicol, C. J., Gonzalez, F. J., & Gilkeson, G. S. (2005). Peroxisome proliferation-activated receptor (PPAR)gamma is not necessary for synthetic PPARgamma agonist inhibition of inducible nitric-oxide synthase and nitric oxide. J Pharmacol Exp Ther, 312(1), 69–76.
Abstract: Peroxisome proliferation-activated receptor (PPAR)gamma agonists inhibit inducible nitric-oxide synthase (iNOS), tumor necrosis factor-alpha, and interleukin-6. Because of these effects, synthetic PPARgamma agonists, including thiazolidinediones, are being studied for their impact on inflammatory disease. The anti-inflammatory concentrations of synthetic PPARgamma agonists range from 10 to 50 microM, whereas their binding affinity for PPARgamma is in the nanomolar range. The specificity of synthetic PPARgamma agonists for PPARgamma at the concentrations necessary for anti-inflammatory effects is thus in question. We report that PPARgamma is not necessary for the inhibition of iNOS by synthetic PPARgamma agonists. RAW 264.7 macrophages possess little PPARgamma, yet lipopolysaccharide (LPS)/interferon (IFN)gamma-induced iNOS was inhibited by synthetic PPARgamma agonists at 20 microM. Endogenous PPARgamma was inhibited by the transfection of a dominant-negative PPARgamma construct into murine mesangial cells. In the transfected cells, synthetic PPARgamma agonists inhibited iNOS production at 10 microM, similar to nontransfected cells. Using cells from PPARgamma Cre/lox conditional knockout mice, baseline and LPS/IFNgamma-induced nitric oxide levels were higher in macrophages lacking PPARgamma versus controls. However, synthetic PPARgamma agonists inhibited iNOS at 10 microM in the PPARgamma-deficient cells, similar to macrophages from wild-type mice. These results indicate that PPARgamma is not necessary for inhibition of iNOS expression by synthetic PPARgamma agonists at concentrations over 10 microM. Intrinsic PPARgamma function, in the absence of synthetic agonists, however, may play a role in inflammatory modulation.
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Spadavecchia, C., Arendt-Nielsen, L., Spadavecchia, L., Mosing, M., Auer, U., & van den Hoven, R. (2007). Effects of butorphanol on the withdrawal reflex using threshold, suprathreshold and repeated subthreshold electrical stimuli in conscious horses. Vet Anaesth Analg, 34(1), 48–58.
Abstract: OBJECTIVE: To assess the effects of a single intravenous dose of butorphanol (0.1 mg kg(-1)) on the nociceptive withdrawal reflex (NWR) using threshold, suprathreshold and repeated subthreshold electrical stimuli in conscious horses. STUDY DESIGN: 'Unblinded', prospective experimental study. ANIMALS: Ten adult horses, five geldings and five mares, mean body mass 517 kg (range 487-569 kg). METHODS: The NWR was elicited using single transcutaneous electrical stimulation of the palmar digital nerve. Repeated stimulations were applied to evoke temporal summation. Surface electromyography was performed to record and quantify the responses of the common digital extensor muscle to stimulation and behavioural reactions were scored. Before butorphanol administration and at fixed time points up to 2 hours after injection, baseline threshold intensities for NWR and temporal summation were defined and single suprathreshold stimulations applied. Friedman repeated-measures analysis of variance on ranks and Wilcoxon signed-rank test were used with the Student-Newman-Keul's method applied post-hoc. The level of significance (alpha) was set at 0.05. RESULTS: Butorphanol did not modify either the thresholds for NWR and temporal summation or the reaction scores, but the difference between suprathreshold and threshold reflex amplitudes was reduced when single stimulation was applied. Upon repeated stimulation after butorphanol administration, a significant decrease in the relative amplitude was calculated for both the 30-80 and the 80-200 millisecond intervals after each stimulus, and for the whole post-stimulation interval in the right thoracic limb. In the left thoracic limb a decrease in the relative amplitude was found only in the 30-80 millisecond epoch. CONCLUSION: Butorphanol at 0.1 mg kg(-1) has no direct action on spinal Adelta nociceptive activity but may have some supraspinal effects that reduce the gain of the nociceptive system. CLINICAL RELEVANCE: Butorphanol has minimal effect on sharp immediate Adelta-mediated pain but may alter spinal processing and decrease the delayed sensations of pain.
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Milinovich, G. J., Trott, D. J., Burrell, P. C., van Eps, A. W., Thoefner, M. B., Blackall, L. L., et al. (2006). Changes in equine hindgut bacterial populations during oligofructose-induced laminitis. Environ Microbiol, 8(5), 885–898.
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.
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Villani, M., Cairoli, F., Kindahl, H., Galeati, G., Faustini, M., Carluccio, A., et al. (2006). Effects of mating on plasma concentrations of testosterone, cortisol, oestrone sulphate and 15-ketodihydro-PGF2alpha in stallions. Reprod Domest Anim, 41(6), 544–548.
Abstract: Very little information is available regarding the physiological mechanisms involved in the normal sexual activity in the stallion and, in particular, the endocrine control of reproduction is still not clearly understood. This experiment was designed to determine the short-term effect of sexual stimulation on plasma concentrations of testosterone, cortisol, oestrone sulphate and 15-ketodihydro-PGF(2alpha) in stallions. Semen samples were collected from 10 lighthorse stallions of proven fertility using a Missouri model artificial vagina. At the same time, blood samples were collected from the jugular vein with heparinized tubes, 20 and 10 min before oestrous mare exposure, at exposure and 10, 20, 30 min after dismounting. Testosterone concentrations showed a sharp rise 10 min after mating (p < 0.001), reached a plateau, and then showed a further increase 30 min after mating (p < 0.001). Cortisol concentrations increased 10 min after mating (p < 0.001) and remained at high levels in the subsequent samples taken. A peak of oestrone sulphate was observed 10 min after mating (p < 0.001). 15-Ketodihydro-PGF(2alpha) concentrations decreased rapidly at the moment of the exposure of the stallions to an oestrous mare (p < 0.05), returned to pre-mating concentrations and then decreased again 30 min after mating (p < 0.05).
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Clauss, M., Castell, J. C., Kienzle, E., Schramel, P., Dierenfeld, E. S., Flach, E. J., et al. (2007). Mineral absorption in the black rhinoceros (Diceros bicornis) as compared with the domestic horse. J Anim Physiol Anim Nutr (Berl), 91(5-6), 193–204.
Abstract: To test whether mineral recommendations for horses are likely to guarantee adequate mineral provision for black rhinoceroses (Diceros bicornis), we investigated the apparent absorption (aA) of macro- and microminerals in eight black rhinoceroses from three zoological institutions in a total of 32 feeding trials with total faecal collection, with additional data from three unpublished studies (18 feeding trials). Feeds and faeces were analysed for Ca, P, Mg, Na, K, Fe, Mn, Cu, Zn and Co. The resulting aA coefficients, and the linear relationships of apparently absorbable dietary mineral content to total dietary mineral content [per 100 g dry matter (DM)], were compared with data for domestic horses. Rhinoceroses had significantly higher aA coefficients for Ca and Mg (because of a higher calculated 'true' absorption), and lower ones for Na and K (because of calculated higher endogenous faecal losses). High absorption efficiency for divalent cations is hypothesized to be an adaptation to a natural diet of particularly high Ca:P ratio (approximately 14:1); an effective removal of Ca from the ingesta guarantees sufficient P availability at the fermentation site in the hindgut. Higher faecal losses of Na and K are hypothesized to be linked to a higher faecal bulk per DM intake in black rhinoceroses as compared with horses because of a generally lower digestive efficiency. There were no relevant differences in the absorption patterns of microminerals. In particular, there were no discernable differences in Fe absorption within the rhinoceroses for diets with and without tannin supplementation. Several of the zoo diets assessed in this study were deficient in Cu, Mn or Zn, and most contained excessive levels of Fe when compared with horse requirements. The findings of this study indicate that differences in mineral absorption between occur even between species of similar digestive anatomy; that in particular, Ca absorption might vary between hindgut fermenters with Ca:P ratio in their natural diet; that Na might be a particularly limiting factor in the ecology of free-ranging rhinoceroses; that moderate doses of tannins do not seem to markedly influence mineral absorption; and that diets for captive animals should contain adequate, but not excessive mineral levels.
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Turner, K. K., Nielsen, B. D., O'Connor, C. I., & Burton, J. L. (2006). Bee pollen product supplementation to horses in training seems to improve feed intake: A pilot study. J Anim Physiol Anim Nutr (Berl), 90(9-10), 414–420.
Abstract: The objective of this study was to determine the efficacy of supplementation of Dynamic Trio 50/50, a bee pollen-based product, to improve physical fitness, blood leukocyte profiles, and nutritional variables in exercised horses. Ten Arabian horses underwent a standardised exercise test (SET), then were pair-matched by sex and fitness and randomly assigned to BP (receiving 118 g of Dynamic Trio 50/50 daily) or CO (receiving 73 g of a placebo) for a period of 42 days. A total collection was conducted from days 18 to 21 on six geldings to determine nutrient retention and neutral detergent fibre (NDF) and acid detergent fibre (ADF) digestibility. Horses were exercise conditioned and completed another SET on day 42. V160 and V200 were calculated from SET heart rates (HR). Lactate, glucose, haematocrit (HT) and haemoglobin (HB) concentrations were determined from SET blood samples. Total leukocyte count, and circulating numbers of various leukocytes and IgG, IgM and IgA concentrations were determined in rest and recovery blood samples from both SETs. Geldings on BP (n = 3) ate more feed than CO. BP had less phosphorus excretion, and tended to retain more nitrogen. BP tended to digest more NDF and ADF while having lower NDF digestibility and tending to have lower ADF digestibility. No treatment differences existed for V160 and V200, HR, lactate, HT and HB. There was a trend for lymphocyte counts to be lower in BP than CO on day 42. Dynamic Trio 50/50 supplementation may have a positive effect on performance by helping horses in training meet their potentially increased nutrient demands by increasing feed intake and thus nutrient retention.
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Zhao, C. J., Qin, Y. H., Lee, X. H., & Wu, C. (2006). Molecular and cytogenetic paternity testing of a male offspring of a hinny. J Anim Breed Genet, 123(6), 403–405.
Abstract: An alleged male foal of a female mule, whose sire and grandparents were unknown, was identified for its pedigree. Parentage testing was conducted by comparing polymorphism of 12 microsatellite DNA sites and mitochondrial D-loop sequences of the male foal and the female mule. Both the sequence analysis of species-specific DNA fragments and a cytogenetic analysis were performed to identify the species of the foal and its parents. The results showed that the alleged female mule is actually a hinny, and the male foal, which possesses 62 chromosomes, qualifies as an offspring of the female hinny and a jack donkey.
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