Search

In the donkey species, the application of cooled semen artificial insemination could aid the survival of endangered breeds. Fifteen ejaculates collected from three Amiata donkeys were used to evaluate the effect of three extenders on spermatozoal motility characteristics after cooling and preservation for up to 72 h. Semen was diluted at a 1:4 semen:extender ratio in INRA96, INRA82 and INRA82 added of 2% centrifuged egg yolk (INRA82-Y) and motility was evaluated by the computerized analyzer CEROS 12.1 at hours 0, 24, 48 and 72. Total motility, and rapid spermatozoa after 24, 48 and 72 h of preservation were higher in INRA82-Y than in INRA96 or INRA82, as was progressive motility after 72 h. INRA82-Y was thus used in a second study, where the effects of centrifugation and of removal of seminal plasma on cooled donkey semen were evaluated on 12 ejaculates from four males. Rapid spermatozoa after 24 and 72 h, and total motility after 72 h were better preserved in the non-centrifuged samples than when seminal plasma was removed, the contrary was true for the proportion of spermatozoa keeping their progressive motility at hour 48. In conclusion, INRA82-Y kept sperm motility characteristics during cooled storage better than INRA82 or INRA96, and removal of seminal plasma during in vitro preservation did not seemed advantageous. Further studies are needed to better understand the changes in motility patterns of donkey spermatozoa caused by seminal plasma and semen extenders, and their relation to fertility.

Scarcity of resources may result in high levels of animal aggregation; interference competition can occur in such a scenario and play a role in resource acquisition. Here, we test the hypothesis that animals could minimize interference competition by shifting their temporal niches in relation to competitors. In Hwange National Park, Zimbabwe, we monitored waterholes in order to study agonistic interactions between elephants and other herbivore species. We also used a long-term data set from a yearly survey of waterhole attendance by herbivores to evaluate the influence of the presence of elephants on the use of waterholes by other herbivore species. Our results show that in drier years, waterholes are crowded with elephants early in the afternoon. In general, the species most affected by interference competition with elephants shift their temporal niches at the waterholes, thus maintaining a constant temporal overlaps with elephants. The species less affected by interference competition with elephants show no temporal niche shifts and increase their temporal overlap with elephants at waterholes, as predicted from a noncompetition hypothesis. This study provides evidence that interference competition with a behaviorally dominant large species influences the temporal niches of smaller species, and suggests that the potential costs associated with interference between elephants and other herbivores at waterholes are linked to shifts in diurnal activities rather than interactions and water acquisition itself.

Interspecies competition is the main factor determining the trophic niche width of sympatric species on both ecological and evolutionary levels. In August 2004, a microscopic analysis of feces was made to analyze the diet compositions of Pantholops hodgsoni, Procapra picticaudata and Equus kiang under free-living circumstances between Chuma River and Wudaoliang in the Kekexili National Nature Reserve. The trophic niche widths and overlaps of these herbivorous ungulates were calculated based on the diet compositions, and the results showed that these three ungulates had similar foods, but the proportions of their diet compositions were different. Gramineous plants were the main food sources for P. hodgsoni, P. picticaudata and E. kiang, accounting for 58.7%, 44.57% and 92.28% of the diet, respectively. The trophic niche widths of P. hodgsoni, P. picticaudata and E. kianthese were 0.878, 0.735 and 0.695, and the niche overlaps of P. hodgsoni and E. kiang, P. hodgsoni and P. picticaudata, and E. kiang and P. picticaudata were 0.869, 0.985 and 0.785, respectively, which suggested that there was a potential intense competition among them, especially for P. hodgsoni and P. picticaudata. The relations between competition and coexistence among P. hodgsoni, P. picticaudata and E. kiang were discussed from the viewpoints of their ecological characteristics and trophic ecology.

Objective: To determine ECG and echocardiographic measurements in healthy anesthetized Grevy's zebras (Equus grevyi)., Animals: 20 healthy zebras., Procedures: Auscultation, base-apex ECG, and echocardiography were performed on anesthetized zebras., Results: Low-grade systolic murmurs were detected in the left basilar region in 4 of 20 zebras. Evaluation of ECGs from 19 zebras revealed sinus rhythm with a predominantly negative QRS complex and a mean +/- SD heart rate of 67 +/- 10 beats/min. Echocardiograms of sufficient image quality were obtained for 16 zebras. Interventricular septal thickness in diastole, left ventricular chamber in diastole and systole, left atrial diameter, and left ventricular mass were significantly and moderately correlated with estimated body weight (r values ranged from 0.650 to 0.884). Detectable swirling of blood in the right and sometimes the left ventricles was detected in 9 of 16 zebras, whereas physiologic regurgitation of blood was detected for the aortic valve in 3 zebras, pulmonary valve in 2 zebras, mitral valve in 2 zebras, and tricuspid valve in 1 zebra., Conclusions and Clinical Relevance: Results of this study provide reference information for use in the cardiac evaluation of anesthetized Grevy's zebras.

For species in which group membership frequently changes, it has been a challenge to characterize variation in individual interactions and social structure. Quantifying this variation is necessary to test hypotheses about ecological determinants of social patterns and to make predictions about how group dynamics affect the development of cooperative relationships and transmission processes. Network models have recently become popular for analyzing individual contacts within a population context. We use network metrics to compare populations of Grevy's zebra (Equus grevyi) and onagers (Equus hemionus khur). These closely related equids, previously described as having the same social system, inhabit environments differing in the distribution of food, water, and predators. Grevy's zebra and onagers are one example of many sets of coarsely similar fission-fusion species and populations, observed elsewhere in other ungulates, primates, and cetaceans. Our analysis of the population association networks reveals contrasts consistent with their distinctive environments. Grevy's zebra individuals are more selective in their association choices. Grevy's zebra form stable cliques, while onager associations are more fluid. We find evidence that females associate assortatively by reproductive state in Grevy's zebra but not in onagers. The current approach demonstrates the utility of network metrics for identifying fine-grained variation among individuals and populations in association patterns. From our analysis, we can make testable predictions about behavioral mechanisms underlying social structure and its effects on transmission processes.

Theory proposes that increased environmental stochasticity negatively impacts population viability. Thus, in addition to the directional changes predicted for weather parameters under global climate change (GCC), the increase in variance of these parameters may also have a negative effect on biodiversity. As a case study, we assessed the impact of interannual variance in precipitation on the viability of an Asiatic wild ass (Equus hemionus) population reintroduced in Makhtesh Ramon Nature Reserve, Israel. We monitored the population from 1985 to 1999 to determine what environmental factors affect reproductive success. Annual precipitation during the year before conception, drought conditions during gestation, and population size determined reproductive success. We used the parameters derived from this model to assess population performance under various scenarios in a Leslie matrix type model with demographic and environmental stochasticity. Specifically, we used a change in the precipitation regime in our study area to formulate a GCC scenario and compared the simulated dynamics of the population with a no-change scenario. The coefficient of variation in population size under the global change scenario was 30% higher than under the no-change scenario. Minor die-offs (> or = 15%) following droughts increased extinction probability nearly 10-fold. Our results support the idea that an increase in environmental stochasticity due to GCC may, in itself, pose a significant threat to biodiversity.

The distal forelimb of the horse has a complex array of ligaments that play a critical role in determining function of the digit and are often associated with the initiation of foot pathologies. The collateral ligaments of the distal sesamoid bone (CLDS) play an important role in digit stabilization near the end of foot contact and there is also limited evidence to suggest that the CLDS stabilize the proximal interphalangeal joint (PIPJ) during weight bearing. By virtue of their anatomical attachments where the ligaments pass dorsal to the axis of rotation of the PIPJ, it is reasonable to assume that the CLDS prevent flexion of the PIPJ during weight bearing or midstance in a moving horse. To test this functional hypothesis, forelimb specimens from three mixed-breed horses were loaded in compression in a materials testing frame. Limb loading was applied with the CLDS intact and following transection. Average PIPJ angle and metacarpophalangeal joint (MCPJ) angle at maximum load (approximately 3000 N) were calculated from angular changes of proximal and middle phalanges and the third metacarpal, which were compared between intact and transected trials. PIPJ angles were found to be the same (175 degrees) at maximum load for intact and transected trials. The proximal and middle phalanges rotated together remaining aligned, regardless of the CLDS condition. Contrary to expectation, however, the combined proximal and middle phalanges unit rotates less relative to the third metacarpal under load after transection, indicating less digit extension at the metacarpophalangeal (fetlock) joint without the influence of CLDS. Since the mechanical properties of the fetlock joint are unchanged by CLDS transection, observed proximal and middle phalanx motion is dependent on increased rotation of the distal phalanx after transection. The original hypothesis was not supported and the results suggest that at midstance the CLDS function primarily to stabilize the articulation of the middle phalanx about the distal phalanx to limit distal interphalangeal joint extension during weight bearing. Establishing the functional role of the CLDS may help to better understand the biomechanical consequences of ligament injuries and diseases of the pastern., (Copyright (c) 2006 Wiley-Liss, Inc.)

Reason for Performing Study: Despite the common use of equids as visitors to high altitude mountainous environments, there are a paucity of carefully orchestrated scientific approaches. Further, again as a function of a common perceived advantage of mules over horses in these similar environments there are needs for controlled comparisons between these 2 equids., Objective: To measure haematological and respiratory function in horses and mules at low altitude (225 m), at rest and post exercise. In addition the rate and magnitude of these changes were followed over a 13 day period at high altitude (3800 m) to contrast acclimatisation., Methods: Resting and exercise venous blood samples (1 min post exercise) were obtained from 6 horses and 5 mules housed at 225 m (LA) and then transported to 3800 m (HA) for 13 days. The standardised exercise tests at both LA and HA consisted of trotting (3.0 m/sec) up an incline (6%) for 2 km. Data were analysed with repeated measures ANOVA (comparison of altitude acclimatisation and species) for changes in haematological and respiratory gases., Results: At low altitude, no group differences were found with both resting (P = 0.69) and exercising (P = 0.74) heart rates. Resting PCV was 8% lower in the mules (P = 0.02) and 20% lower during exercise (P = 0.02). Horses had significantly higher 2,3-diphosphoglycerate (2,3-DPG)/g Hb at both rest (P = 0.003) and exercise (P = 0.03). Exercise at HA increased PCV (P = 0.03) in both groups, but the increase was attenuated in the mules compared to horses. The increase with 2,3-DPG/g Hb was expressed at HA in both groups (P = 0.001) and was also attenuated in mules (P = 0.03). Both groups were alkalotic compared to LA (P = 0.001), and there were no group differences (P = 0.95)., Conclusion: Of the variables measured, the most notable distinction between species was identified for only PCV and 2,3-DPG with both higher in horses, at both LA and HA. While the attenuated response of PCV in mules for the same exercise might argue for an improved adaptation to altitude, the lower 2,3-DPG might not. Other variables during the exercise bout were not different between species.

The master mammalian pacemaker in the brain controls numerous diverse physiological and behavioral processes throughout the organism. Timing information is continually transmitted from the master clock to peripheral organs to synchronize rhythmic daily oscillations of clock gene transcripts and control local physiology. To investigate the presence of peripheral clocks in the horse, quantitative real-time RT-PCR assays were designed to detect levels of equine clock genes. Expression profiles for Per2, Bmal1 and Cry1 were first determined in a synchronized equine cell line. Subsequently, expression in equine whole blood and adipose tissue was assessed. Robust circadian oscillations of Per2, Bmal1 and Cry1 were observed in vitro. A synchronized molecular clock was also demonstrated in equine adipose tissue although oscillation of Bmal1 was less robust than that of Per2 and Cry1. In contrast to previous studies in humans and rats however, there was no evidence of synchronized clock gene expression in equine peripheral blood. These studies suggest that synchronous control of clock gene oscillation in equine peripheral blood is not as tightly regulated as in other species and may reflect the influence of different evolutionary challenges modifying the function of a peripheral clock.

The use of high-frequency (5 MHz) ultrasonography was studied in 11 jennies (7 non-pregnant and 4 pregnant) to characterize the reproductive organs and follicular activities at different stages of reproduction. The result showed close similarity with the mare. The visibility of endometrial folds increased towards ovulation. A positive correlation (p < 0.001; tau = 0.79) was found between the score of the folds and the size of the dominant follicle. The diameter of the uterus and the size of the dominant follicle were significantly correlated (p < 0.001; r = 0.80). In pregnant jennies, an embryonic vesicle was detectable at 14 days. Follicular growth was characterized by more than one wave. The smallest ovarian follicle was 2 mm and the largest 40mm. Depending on the reproductive stage, up to 13 follicles were detected per ovary. After monitoring 84 cycles, a mean (+/- SD) diameter of 34.4 +/- 3.6 mm (27.5-40.2 mm) of the preovulatory follicle and 67.85% incidence of single ovulation were found. The mean (+/-SD) interovulatory interval was 25.7 +/- 6 days. This study proved that high-frequency ultrasonography is highly effective in characterizing the reproductive organs and follicular activity of jennies and could be useful in the reproductive management of donkeys.

A male Grant's Zebra (Equus burchelli boehmi) housed with two mares at the Indianapolis Zoo had a 9-yr history of intermittent aggressive behavior toward mares and other animals. Periods of separation allowed the mares time to heal after sustaining superficial bite wounds. On 26 March 2003, the male (890293) was started on altrenogest at a dosage of 19.8 mg orally once daily to allow reintroduction. The dosage was doubled (40 mg once a day) because of a perceived lack of response. Reintroduction to the mares occurred on 17 May 2003 with no signs of aggression noted. Treatment was reduced to 19.8 mg orally once a day and then discontinued. Altrenogest was restarted at 39.5 mg orally once a day because of the planned introduction of a new mare. There have been no major aggressive displays at this dosage of altrenogest and the dosage has recently been reduced following successful introduction of a new mare.

Serial ultrasonography was performed on seven jennies to study the effect of seasonally fluctuating body condition on ovarian activity during the dry, short rainy and long rainy seasons. Kendall Tau correlations and differences of least square mean values were compared. A distinct seasonal pattern was observed both in body condition and ovarian activity. The mean (+/-SD) Body Condition Score (BCS) was lowest during the dry season 2.6 +/- 0.45 when compared with 3.5 +/- 0.52 and 3.9 +/- 0.58 during the short and long rainy seasons, respectively. The mean (+/-SD) number of total follicles was also proportionally low 7.3 +/- 1.6 during the dry season compared with 9.6 +/- 2.4 and 11.3 +/- 3.3 found during the short and the long rainy seasons, respectively. The BCS was positively correlated to the total number of follicles and the diameter of the largest follicle during all seasons. Periods of increasing BCS and transition between seasons with both increasing and decreasing body conditions were strongly correlated to the number and size of ovarian follicles. Seasonal fluctuation in the body condition was found to be the result of variation in feed resource and ovarian activity was also closely following this seasonal pattern. The improvement in body condition has generally, a positive impact on emergence of small growing follicles there by having influence on the total count of ovarian follicles.

The effects of mild chronic dehydration on fermentation rate and mucosal surface area in the cecum, dorsa and ventral colon, and descending colon of the hindgut were investigated in South African donkeys (n = 11) in agricultural work. Dehydration representing a 6% drop in BW (n = 6) was associated with increased fermentation activity in the cecum (252 +/- 22.9 vs. 161 +/- 13.5 micromol/g of DM.h(-1), P < 0.01) and enhanced fluid retention in the ventral colon (0.81 +/- 0.026 vs. 0.73 +/- 0.034 mL/g gut, P < 0.05). Fermentation activity in the next segment of the hindgut, the ventral colon, of dehydrated donkeys was also greater numerically (92.5 +/- 22.60 vs. 77.9 +/- 10.40 micromol/g of DM.h(-1)), but this difference was not significant. Total mucosal and crypt surface area per unit volume of gut (Sv, microm2/microm3) was greater in dehydrated donkeys for the cecum (253 +/- 23.0 vs. 161 +/- 13.5, P < 0.01), the ventral colon (286 +/- 6.2 vs. 171 +/- 9.8, P < 0.01), the dorsal colon (276 +/- 18.2 vs. 256 +/- 11.0, P < 0.05), and the descending colon (260 +/- 20.3 vs. 191 +/- 15.2, P < 0.05). Enhanced fermentation activity and enhanced mucosal absorptive or secretory capacity within the hindgut during chronic dehydration was associated with an observed maintenance of appetite. These adaptations in the hindgut are valuable physiological attributes for working donkeys in semi-arid regions where they are frequently exposed to chronic dehydration.

Cloning is one of several new assisted reproductive techniques being developed for clinical use in the equine industry. Potential uses of equine cloning include: (1) the preservation of genetics from individual animals that would otherwise not be able to reproduce, such as geldings; (2) the preservation of genetic material of endangered and/or exotic species, such as the Mongolian wild horse (Przewalski's horse); and (3) because of the companion animal role that horses fill for some individuals, it is likely that some horse owners will have individual animals cloned for emotional fulfillment. Although equine cloning has been successful, like other species, it remains a very inefficient process (<3% success). In most species, the inefficiency of cloning results from a high incidence of embryonic, fetal and/or placental developmental abnormalities that contribute to extremely high rates of embryonic loss, abortion and stillbirths throughout gestation and compromised neonatal health after birth. The present review describes some of the ultrasonographic, endocrinological and histopathological characteristics of successful (produced viable offspring) and unsuccessful (resulted in pregnancy failure) cloned equine (mule and horse) pregnancies we have produced. A total of 21 cloned mule pregnancies were established using fetal fibroblast cells, whereas a total of seven cloned horse pregnancies were established using adult cumulus cells. Three of the cloned mule conceptuses were carried to term, resulting in the birth of three healthy clones. This information adds to an accumulating body of knowledge about the outcome of cloned equine pregnancies, which will help to establish when, and perhaps why, many cloned equine pregnancies fail.

The blood serum concentrations of progesterone and estradiol-17beta were measured at various stages of the oestrous cycle of seven female mules, and their reproductive tracts were examined ultrasonographically at the same stages.

The large fluctuations seen in cattle populations during periods of drought in sub-Saharan Africa are not evident in the donkey population. Donkeys appear to have a survival advantage over cattle that is increasingly recognized by smallholder farmers in their selection of working animals. The donkey's survival advantages arise from both socioeconomic and biological factors. Socioeconomic factors include the maintenance of a low sustainable population of donkeys owing to their single-purpose role and their low social status. Also, because donkeys are not usually used as a meat animal and can provide a regular income as a working animal, they are not slaughtered in response to drought, as are cattle. Donkeys have a range of physiological and behavioural adaptations that individually provide small survival advantages over cattle but collectively may make a large difference to whether or not they survive drought. Donkeys have lower maintenance costs as a result of their size and spend less energy while foraging for food; lower energy costs result in a lower dry matter intake (DMI) requirement. In donkeys, low-quality diets are digested almost as efficiently as in ruminants and, because of a highly selective feeding strategy, the quality of diet obtained by donkeys in a given pasture is higher than that obtained by cattle. Lower energy costs of walking, longer foraging times per day and ability to tolerate thirst may allow donkeys to access more remote, under-utilized sources of forage that are inaccessible to cattle on rangeland. As donkeys become a more popular choice of working animal for farmers, specific management practices need to be devised that allow donkeys to fully maximize their natural survival advantages.

This survey was conducted at three sites in Ethiopia. The purpose of the survey was to provide detailed information on donkey use in rural and peri-urban areas. The study revealed that donkeys are indeed of immense value to farmers and merchants, being used almost daily for income-generating activities. Unfortunately, they are rarely given any veterinary attention, they receive no feed supplements and their owners are often unaware of improved saddling techniques that would reduce the back sores their animals suffer from. An extension programme providing donkey owners with information on saddling, feeding and basic health care would improve the animals' productivity and improve the livelihoods of the owners.

Body measurements (length from nape of neck to the withers; height to withers; length from withers to tail root; length from shoulder to tuber ischii; thoracic circumference; umbilical circumference) were taken and correlated with live weight from 160 donkeys (mean +/- standard deviation = 6 +/- 2.6 years old) in Central Mexico. The age was assessed from dentition. Sex of the donkeys was also recorded. Sex was an important factor of variation (p = 0.011). Live weight was estimated using two allometric models. Model 1: Live weight = beta x (thoracic circumference)beta1. Model 2: Live weight = betao x (height to the withers) beta1 x (thoracic circumference) beta2. Separate prediction equations were produced for males and females, plus one for the total sampled. The 'best fit' models, were those using thoracic circumference to predict the live weight. Males: live weight = 0.018576 x (thoracic circumference)1.84107 (R2 = 0.9839). Females: live weight = 0.031255 x (thoracic circumference)1.72888 (R2 = 0.9839). The equations derived to estimate the live weight of donkeys in Britain, Morocco and Zimbabwe were less satisfactory for use with donkeys from Central Mexico because they overestimated the live weight.

The aim of this work was to describe the feeding strategies for donkeys used by peasant farmers in central Mexico. Feeding strategies for the dry and wet seasons are described, as well as the nutritional characteristics of the main forages and supplements used by the farmers. The extent to which the feeding practices used by farmers matched the digestible energy and crude protein requirements of donkeys for maintenance and work was determined. It was concluded that grazing on native grassland could provide enough energy and protein for donkeys at maintenance level and for those performing only a moderate amount of work. More research in required in order to have better estimates of intake and plant species preferred by donkeys under prevailing grazing conditions.

Anthelmintic treatment (A), feed supplementation (F), anthelmintic and feed supplementation (A+F) or traditional management (Control) was given to 166 pregnant female donkeys in three localities (Holetta, Debre Zeit and Adami Tulu) in Ethiopia during an on-farm study. Treatments started during the last trimester of pregnancy and continued until 6 months after parturition when the foals were weaned. The same treatments were administered to foals once they reached 1 month of age. Live weights of adults and foals were measured throughout the study along with work output of adult donkeys and survival to weaning of the foals. Faecal worm egg counts (FEC) and blood packed cell volumes (PCV) were recorded monthly. When applied alone, anthelmintic treatment (A) or feed supplementation (F) had no significant effect on live weight gain or foal survival. However, when combined, anthelmintic and feed supplementation (A+F) significantly (p<0.05) improved both live weight gain in adults and foals and foal survival. Workout was not affected by any of the treatments. Treatments A and A+F resulted in a highly significant (p<0.001) reduction in FEC in all three localities during the course of study and for at least 6 months after the last dose of anthelmintic in one of the study areas (Holetta). None of the treatments had any significant effect on PCV. Donkey owners in Ethiopia should be encouraged to adopt both anthelmintic treatment and feed supplementation if they expect tangible benefits in animal performance.

Twenty years ago, the field of ancient DNA was launched with the publication of two short mitochondrial (mt) DNA sequences from a single quagga (Equus quagga) museum skin, an extinct South African equid (Higuchi et al. 1984 Nature312, 282-284). This was the first extinct species from which genetic information was retrieved. The DNA sequences of the quagga showed that it was more closely related to zebras than to horses. However, quagga evolutionary history is far from clear. We have isolated DNA from eight quaggas and a plains zebra (subspecies or phenotype Equus burchelli burchelli). We show that the quagga displayed little genetic diversity and very recently diverged from the plains zebra, probably during the penultimate glacial maximum. This emphasizes the importance of Pleistocene climate changes for phylogeographic patterns in African as well as Holarctic fauna.

In this study, arteries that supply the septum interventriculare in donkeys, their course and variations, if present, were defined. Six hearts belonging to donkeys of varying age and sex constituted the material of the study. In order to expose the arteries, latex coloured with Rotring ink was injected into a. coronaria sinistra and a. coronaria dextra and dissection was performed. The arterial vascularization of the heart in donkeys is supplied by a. coronaria sinistra and a. coronoria dextra, which have their origin at the aorta. A. coronaria sinistra gives off two branches: one is ramus interventricularis paraconalis, which extends into the sulcus interventricularis paraconalis and the other is ramus circumflexus sinister, which lies within the sulcus coronarius. A. coronaria dextra is formed by the union of ramus interventricularis subsinuosus and ramus circumflexus dexter. Septum interventriculare is supplied by rr. septales, which originate from ramus interventricularis paraconalis, a branch of a. coronaria sinistra, as well as rami septales which have their origin in ramus interventricularis subsinuosus, a branch of a. coronaria dextra.

The vascular and nerve components of ovarian ligaments (proper and suspensory) of the sheep, cow and the donkey were examined in order to investigate the presence of blood flow-regulator endovasal devices, artero-venous anastomoses, free and/or encapsulated nerve endings and ganglion cells. Both the ligaments of the investigated species showed the presence of endovasal devices (valvular apparati, intimal and polypoid cushions) and artero-venous anastomoses, the latter structurally ascribed to the first and second type of Conti and Bucciante's classification. Moreover, although not constantly, both the examined districts showed an autonomic nerve support, while four Ruffini's corpuscles were found in the suspensory ligament just in one sheep.

Objective: To assess the hormonal, metabolic and physiological effects of laparascopic surgery performed under a sedative analgesic combination of detomidine and buprenorphine in standing horses., Study Design: Prospective study., Animals: Eight healthy adult Dutch Warmblood horses and five healthy adult ponies undergoing laparoscopy were studied. Five healthy adult horses not undergoing laparoscopy were used as a control group., Methods: The sedative effect of an initial detomidine and buprenorphine injection was maintained using a continuous infusion of detomidine alone. The heart and respiratory rate, arterial blood pH and arterial oxygen and carbon dioxide tensions were monitored, while blood samples were taken for the measurement of glucose, lactate, cortisol, insulin and nonesterified fatty acids (NEFA). The same variables were monitored in a control group of horses which were sedated, but which did not undergo surgery. At the end of the sedation period the effects of detomidine were antagonized using atipamezole., Results: The protocol provided suitable conditions for standing laparoscopy in horses. Laparoscopy induced obvious metabolic and endocrine responses which, with the exception of NEFA values, were not significantly different from changes found in the control group. While atipamezole did not produce detectable adverse effects, it is possible that anatagonism may not be essential., Conclusions: The technique described reliably produces adequate sedation and analgesia for laparoscopic procedures. The level of sedation/analgesia was controlled by decreasing or increasing the infusion rate. Antagonism of the effects of detomidine may not be necessary in all cases.

Unusual equids named hippidions inhabited South America for more than 2 MY (million years). Like many other animals they succumbed to the worldwide climatic change that occurred 10 KY (thousand years) ago and completely disappeared during the great late Pleistocene megafaunal extinction. According to fossil records and numerous dental, cranial, and postcranial characters, Hippidion and Equus lineages are known to have diverged prior to 10 MY. Some equid bones from Rio Verde and Ultima Esperanza (Patagonia, Chile) dating back to the late Pleistocene period (8-13 KY) have been identified as Hippidion saldiasi, while a few teeth have been assigned to Equus. Six samples of those remains have been obtained from the Zoological Museum of Amsterdam for ancient DNA analysis to try to place Hippidion in the evolutive tree of Perissodactyla. Two samples of Hippidion and one sample of Equus yielded 241-394 bp of the mtDNA control region and 172-296 bp of the cytochrome b gene. Unexpectedly, all the sequences clustered deep inside the Equus genus, casting doubt on the initial identification of the bones. For paleontologists, one of the striking and classical diagnostic characters of Hippidion is their extremely short and massive metapodials, a probable locomotory adaptation to the Andine steep slopes. However, our DNA analysis reveals that a very Hippidion-like metapod might also have been possessed by another South American equid, i.e., Equus (Amerhippus), an interpretation supported by complementary anatomical observations. This adaptive convergence between members of the two South American equid genera may lead paleontologists to limb bone misidentification.

The mule (Equus mulus mulus) is a sterile hybrid domestic animal that results from the breeding of a male donkey (Equus asinus) to a female horse (Equus caballus). Usually, spermatogenesis in mules does not advance beyond spermatocytes. In the present study, we performed a comparative and more accurate morphometric and functional investigation of the testis in donkeys and mules. Due to the smaller testis size, lower seminiferous tubule volume density, and fewer germ cells, the total length of seminiferous tubules in mules was significantly smaller than in donkeys. However, the percentage of seminiferous tubules containing germ cells (spermatogonia and spermatocytes) in mules was approximately 95%. The total number of Sertoli cells per testis observed in donkeys and mules was very similar. However, the total number of Leydig cells in mules was approximately 70% lower than in donkeys. At least in part, this difference was probably related to the lower number of germ cells present in mule seminiferous tubules. Although spermatogenesis in mules did not advance beyond secondary spermatocytes/newly formed round spermatids, germ cell associations in the seminiferous epithelium and pachytene spermatocytes nuclear volume in donkeys and mules were similar. The duration of spermatogenesis was estimated using intratesticular injections of tritiated thymidine. Each spermatogenic cycle in donkeys lasted 10.5 days. A similar value was found in mules ( approximately 10.1 days). Considering that the entire spermatogenic process takes approximately 4.5 cycles to be completed, its total duration in donkeys was estimated to last 47.2 days. The results found for mules suggest that the mechanisms involved in the determination of testis structure and function are probably originated from donkeys. Also, the data found for mules suggest that their seminiferous tubules are able to sustain complete spermatogenesis. In this regard, this species is a potential model for transplants of germ cells originated from donkeys and horses or other large animals.

Campesino systems on hill slopes in Central Mexico rely on equids for multiple activities and have a problem in adequately feeding them. A participatory trial was conducted to evaluate the inclusion of common vetch in the traditional forage oat crop to improve its feeding value. An agronomic evaluation was undertaken by intersowing common vetch at 40 kg seed/ha with oats at 80-100 kg/ha in small plots, recording the yield and the chemical composition of the fresh forage in ten plots at harvest. The data were analysed as a completely random design, taking each farmer/plot as a treatment. A feeding trial compared the live weight of 7 donkeys fed oats and vetch against 17 donkeys fed traditional forage. There were differences between farmers in forage yields (p < 0.01) that could not be explained as due to soil types or management. The mean yield of 31.0 t/ha of fresh forage of oats-vetch was 20.5% higher than that from monoculture, and had a higher crude protein content. Donkeys fed the oats-vetch were heavier (p < 0.001). The farmers evaluated the oats-vetch association positively, appreciating the higher yields and good condition of their equids. The combination is an appropriate technology for these campesino farming systems.

Objective: To describe the pharmacokinetics of phenylbutazone and oxyphenbutazone after IV administration in miniature donkeys., Animals: 6 clinically normal miniature donkeys., Procedure: Blood samples were collected before and 5, 10, 20, 30, 45, 60, 90, 120, 180, 240, 300, 360, and 480 minutes after IV administration of phenylbutazone (4.4 mg/kg of body weight). Serum was analyzed in triplicate by use of high-performance liquid chromatography for determination of phenylbutazone and oxyphenbutazone concentrations. The serum concentration-time curve for each donkey was analyzed separately to estimate model-independent pharmacokinetic variables., Results: Serum concentrations decreased rapidly after IV administration of phenylbutazone, and they reached undetectable concentrations within 4 hours. Values for mean residence time ranged from 0.5 to 3.0 hours (median, 1.1 hour), whereas total body clearance ranged from 4.2 to 7.5 ml/kg/min (mean, 5.8 ml/kg/min). Oxyphenbutazone appeared rapidly in the serum; time to peak concentration ranged from 13 to 41 minutes (mean, 26.4 minutes), and peak concentration in serum ranged from 2.8 to 4.0 mg/ml (mean, 3.5 microg/ml)., Conclusion and Clinical Relevance: Clearance of phenylbutazone in miniature donkeys after injection of a single dose (4.4 mg/kg, IV) is rapid. Compared with horses, miniature donkeys may require more frequent administration of phenylbutazone to achieve therapeutic efficacy.

Horses, donkeys, and therefore, probably all equids, secrete a nonglycosylated, progesterone-dependent, 19-kDa protein (P19) into the uterine lumen during early pregnancy, and significant quantities of it are taken up by the developing conceptus. Sequence analysis and structural modelling have identified P19 as a lipocalin with greatest similarity to the murine major urinary protein lipocalins. However, lack of strong identity with any particular group of lipocalins and several unusual structural features, including a unique amino acid triplet within one of the invariant domains and an unusual external tryptophan residue, classify it as a new member of the lipocalin family. P19 is therefore likely to be a transport protein involved in supporting early embryonic development. Preliminary evidence using recombinant-derived P19 and fluorescently tagged ligands suggests that it may transport a fatty acid or retinol-like molecule. Although an initial search failed to identify homologues of P19 in other mammals, they may nevertheless exist but are synthesised and secreted in much smaller quantities, making them difficult to detect. Equids appear to need particularly large quantities of the protein during early pregnancy because of the unusually late implantation in this species and the presence of a capsule surrounding the conceptus until about day 23 of gestation.

Based on observational studies comparing social organization and reproductive behavior of equids breeding under feral, semi-feral, and domestic conditions, a series of comparisons and findings on reproductive physiology and behavior are presented. Simple changes in management and handling of mares and stallions that can improve reproductive efficiency and fertility or that can overcome specific breeding problems are discussed.

We used implanted miniature data loggers to measure brain and arterial blood temperatures in three free-ranging zebras (Equus burchelli) in their natural habitat, every 5 min for 9 days. The animals experienced globe temperatures exceeding 40 C, and radiant heat load of about 1000 W m-2. Arterial blood exhibited a moderate amplitude (1.7 C) nychthemeral rhythm, with an acrophase at 19.00 h and a nadir late in the morning, at 10.00 h. Brain temperature consistently exceeded blood temperature, on average by 0.2-0.4 C, and changes in brain temperature closely tracked changes in blood temperature. There was no evidence of selective brain cooling, even during the hyperthermia which followed surgery or that associated with intense, short-duration exercise. The relationship between brain and arterial blood temperatures in free-ranging zebras was unlike that reported for horses in the laboratory. Our results do not support the view that mammals lacking a carotid rete can achieve selective brain cooling.

Socio-ecological explanations for intra- and interspecific variation in the social and spatial organization of animals predominate in the scientific literature. The socio-ecological model, developed first for the Bovidae and Cervidae, is commonly applied more widely to other groups including the Equidae. Intraspecific comparisons are particularly valuable because they allow the role of environment and demography on social and spatial organization to be understood while controlling for phylogeny or morphology which confound interspecific comparisons. Feral horse (Equus caballus Linnaeus 1758) populations with different demography inhabit a range of environments throughout the world. I use 56 reports to obtain 23 measures or characteristics of the behaviour and the social and spatial organization of 19 feral horse populations in which the environment, demography, management, research effort and sample size are also described. Comparison shows that different populations had remarkably similar social and spatial organization and that group sizes and composition, and home range sizes varied as much within as between populations. I assess the few exceptions to uniformity and conclude that they are due to the attributes of the studies themselves, particularly to poor definition of terms and inadequate empiricism, rather than to the environment or demography per se. Interspecific comparisons show that equid species adhere to their different social and spatial organizations despite similarities in their environments and even when species are sympatric. Furthermore, equid male territoriality has been ill-defined in previous studies, observations presented as evidence of territoriality are also found in non-territorial equids, and populations of supposedly territorial species demonstrate female defence polygyny. Thus, territoriality may not be a useful categorization in the Equidae. Moreover, although equid socio-ecologists have relied on the socio-ecological model derived from the extremely diverse Bovidae and Cervidae for explanations of variation in equine society, the homomorphic, but large and polygynous, and monogeneric Equidae do not support previous socio-ecological explanations for relationships between body size, mating system and sexual dimorphism in ungulates. Consequently, in spite of the efforts of numerous authors during the past two decades, functional explanations of apparent differences in feral horse and equid social and spatial organization and behaviour based on assumptions of their current utility in the environmental or demographic context remain unconvincing. Nevertheless, differences in social cohesion between species that are insensitive to intra- and interspecific variation in habitat and predation pressure warrant explanation. Thus, I propose alternative avenues of inquiry including testing for species-specific differences in inter-individual aggression and investigating the role of phylogenetic constraints in equine society. The Equidae are evidence of the relative importance of phylogeny and biological structure, and unimportance of the present-day environment, in animal behaviour and social and spatial organization.

A cytotoxic T-lymphocyte assay was used to determine whether equine chorionic girdle cells are susceptible to lysis by CD8+ cytotoxic T cells primed in vitro against allogeneic lymphocytes. Classical cytotoxic T-lymphocyte activity against fresh or cultured trophoblast targets was demonstrated using peripheral blood lymphocytes from nonpregnant mares. Lysis of allogeneic (horse) and xenogeneic (donkey) lymphocyte targets was used as a control for trophoblast lysis. The major histocompatibility complex (MHC) class I specificity of the cytotoxic T-lymphocyte reactions was determined using panels of MHC-typed target cells. The results of the present study demonstrate that the MHC class I antigens expressed on equine chorionic girdle cells are functional proteins, which can serve as targets for CD8+ allospecific cytotoxic T lymphocytes. Furthermore, these findings indicate strongly that, at least in the in vitro assay used, MHC class I positive chorionic girdle cells do not display any mechanisms that can protect them from lysis by activated maternal T cells.

Two mitochondrial genes, the protein-coding cytochrome c oxidase subunit II (COII) gene and a portion of the 12S rRNA gene, were used for phylogenetic investigation of the mammalian order Perissodactyla. The primary objective of the study was to utilize the extensive fossil record of perissodactyls for calibrating molecular clocks and comparing estimates of divergence times using both genes and two fossil calibration points. Secondary objectives included clarification of previously unresolved relationships within Tapiridae and comparison of the results of separate and combined analyses of two genes. Analyses included several perissodactyl lineages representing all three families (Tapiridae, Equidae, and Rhinocerotidae), most extant genera, all four species of tapirs, two to four species of rhinoceros, and two species of Equus. The application of a relatively recent fossil calibration point and a relatively ancient calibration point produced greatly different estimates of evolutionary rates and divergence times for both genes, even though a relative rates test did not find significant rate differences among taxa. A likelihood-ratio test, however, rejected a molecular clock for both genes. Neither calibration point produced estimates of divergence times consistent with paleontological evidence over a range of perissodactyl radiations. The combined analysis of both genes produces a well-resolved phylogeny with Perissodactyla that conforms to traditional views of interfamilial relationships and supports monophyly of neotropical tapirs. Combining the data sets increases support for most nodes but decreases the support for a neotropical tapir clade because the COII and 12S rRNA data sets are in conflict for tapir relationships.

Breeding records from a herd of mammoth asses (Equus asinus americanus) maintained on pasture in southeast Texas from 1990 to 1998 were reviewed. Jennies were pasture or hand mated, and estrus was either observed while the jennies were on pasture or when exposed to a jack after being penned. Eighty-one estrus periods and 43 diestrus intervals were recorded in 33 jennies over 4 seasons of the year (January-March, April-June, July-September, and October-December). Estrous cycle length and the duration of estrus were similar among seasons. Over all seasons, estrous cycle length was 23.3 +/- 2.6 d, duration of estrus was 5.9 +/- 2.1 d, and diestrus length was 17.4 +/- 2.6 d (mean +/- SD). During these same 9 yr, 58 injections of PGF2 alpha (5 mg, i.m.) were administered to 38 jennies without regard to stage of estrous cycle. Seventy-six percent (44/58) of the jennies showed signs of estrus after PGF2 alpha treatment, with an interval to estrus of 4.4 +/- 1.6 d and a duration of estrus of 5.6 +/- 1.7 d. Two estrus synchronization schemes were also assessed. Trial 1 was performed in October to November 1996, and Trial 2 was performed in February to March 1998. In Trial 1 (Group PE + PGF, n = 10), each jenny was injected intramuscularly once daily for 10 d with 150 mg progesterone and 10 mg estradiol-17 beta in sesame oil, and PGF2 alpha (10 mg) was injected intramuscularly on the last day of treatment. In Trial 2 (Group PGF-2X, n = 11), each jenny was injected intramuscularly twice, 16 d apart, with 10 mg PGF2 alpha. All Group PE + PGF jennies responded to treatment. One jenny in Group PGF-2X did not respond to either injection of PGF2 alpha, while 2 jennies responded to the first but not the second PGF2 alpha injection (8 of 11 jennies returned to estrus and ovulated after the second PGF2 alpha injection). Duration of estrus was 6.8 +/- 1.9 d for Group PE + PGF and 7.1 +/- 1.8 d for Group PGF-2X jennies. Interval to estrus and interval to ovulation following the last treatment were 9.0 +/- 0.9 d and 14.5 +/- 1.7 d, respectively, in Group PE + PGF jennies, and 4.5 +/- 0.9 d and 10.4 +/- 1.8 d, respectively, for Group PGF-2X jennies. In summary, estrous cycle characteristics of mammoth asses are similar to those reported for standard jennies, and estrus synchronization schemes used in horses are effective in mammoth asses.

The Schirmer tear test (STT) I was performed to evaluate tear production in 12 captive Nubian ibex (Capra ibex nubiana), 10 captive Burchell's zebras (Equus burchelli) and five Arabian oryx (Oryx leucoryx) at the Tel-Aviv Ramat-Gan Zoological Center (Israel). Mean (+/- standard deviation) STT values were 13.2 +/- 5.1 mm/min in the ibex, 23.4 +/- 3.4 mm/min in the zebra and 12.7 +/- 4.8 mm/min in the oryx. There were no significant effects of gender, age, weight, or side of the eye. There were no significant differences in STT values between ibex and oryx, but tear production in both species was significantly lower than in zebras. Knowledge of normal tear production values is important for the differential diagnosis of conjunctivitis and keratitis in these species.

A finite element model of donkey hoof wall was constructed from measurements taken directly from the hoof capsule of the left forefoot. The model was created with a 2 mm mesh and consisted of 11,608 nodes. A linear elastic analysis was conducted assuming isotropic material properties in response to a 375 newton (N) load, to simulate static loading. The load was applied to the wall via 400 laminae in order to simulate the way in which the pedal bone is suspended within the donkey hoof capsule. Displacement, stress concentration, principal strain, and force distribution across the hoof wall were evaluated. The hoof wall model revealed loading responses that were in broad agreement with previously reported in vivo and modelled observations of the equid hoof. Finite element analysis offers the potential to model hoof wall function at the macroscopic and microscopic level. In this way, it could help to develop further our understanding of the functional relationship between the structural organisation and material properties of the hoof wall.

Daily ultrasound examinations were conducted from Days 10 to 60 (ovulation = Day 0) of pregnancy to monitor the conceptus in jennies (n = 12). The embryonic vesicle was first detected on Day 11.5 +/- 0.9 (mean +/- SD; range 10 to 13 d) and was mobile until movement ceased (fixation) on Day 15.5 +/- 1.4 (range, 13 to 18 d). The vesicle was spherical from Days 10 to 18 (mean growth rate, 3.2 mm/d), non spherical (irregular) with a reduced growth rate (0.5 mm/d) from Days 19 to 29, and then grew at a moderate rate (1.6 mm/d) up to Day 46. On average, detection of the embryo proper (consistently located on the ventral aspect of the yolk sac) and embryonic heartbeat were Days 20.7 +/- 1.2 and 23.5 +/- 1.3, respectively. Formation of the allantoic sac was first detected on Day 24.4 +/- 1.7 and was complete on Day 36.8 +/- 1.6. Descent of the fetus (and formation of the umbilical cord) began on Day 37.9 +/- 1.7 and was complete on Day 44.1 +/- 2.1. Crown-rump length averaged 3.7, 15.4, 22.7, 37.5 and 59.6 mm on Days 20, 30, 40, 50 and 60, respectively. In general, morphologic features and dates of occurrence were similar to those reported previously in the mare.

The objectives of this study were to determine ovarian activity (with ultrasound) and plasma concentrations of progesterone and estradiol during pregnancy in jennies. There was considerable ovarian activity during the second month of pregnancy. Secondary corpora lutea (total of 2 to 7 per jenny) were formed (mainly by luteinization) starting on Day 41.8 +/- 1.0 (range Days 38 to 46; ovulation = Day 0). The echogenicity of the primary and secondary corpora lutea gradually decreased during pregnancy. Plasma progesterone concentrations increased between Days 0 and 10 (0.9 and 19.9 ng/mL, respectively), gradually decreased to Day 30 (12.1 ng/mL), increased between Days 30 and 40 (plateau, at approximately 17 ng/mL), gradually declined from Days 110 to 160 (nadir of approximately 6 ng/mL), and remained nearly constant until increasing again just before parturition. Plasma estradiol concentrations increased gradually from Day 65, peaked (1.2 ng/mL) on Day 165 (> or = 1 ng/mL on Days 150 to 210), and decreased thereafter, with very low concentrations during the last 20 d before parturition. Ovarian function and hormone profiles were generally similar to those previously reported during pregnancy in mares.

Twelve clinical biochemical parameters were determined in 97 animals of all age groups and both sexes of the endangered Catalonian donkey breed. Significant sex differences were observed for phospholipid concentration (P<0.01). Evaluating the effect of management practices on the various parameters showed significant differences for total bilirubin (P<0.001) and creatinine (P<0.05) concentrations and gamma-glutamyltransferase (P<0.05) activity. Moreover, it was observed that inorganic phosphorus concentration decreased with age (P<0.001), whereas albumin and triglyceride concentrations increased with age (P<0.01 and P<0.001, respectively). Comparison of biochemical ranges obtained for the Catalonian donkey breed with reference ranges for other breeds and populations (Mammoth, USA donkeys, UK donkeys, Indian donkeys and Poitou donkeys), indicated that most values were similar, with the exceptions of enzymatic activities mainly. The results reported in the present study could serve as reference ranges for donkey populations.

When aspirating ovarian follicles in pregnant mares to obtain oocytes for in vitro fertilisation (IVF), the effect of the manipulation on circulating concentrations of progesterone may be an important consideration in terms of the maintenance of pregnancy. The object of this study was to compare the effects of 3 different forms of transvaginal ultrasound-guided follicle aspiration (Treatment 1, no aspiration, n = 4; Treatment 2, aspirate only follicles > or =20 mm in diameter, n = 7; Treatment 3, aspirate all visible follicles, n = 7) on peripheral plasma progesterone concentrations between Days 21 and 150 of gestation in 9 mares carrying intraspecies horse and 9 mares carrying interspecies mule conceptuses. The 3 follicle aspiration treatments were applied at the peak of each follicular wave as determined by follicular mapping by means of transrectal ultrasonography on alternate days. The plasma progesterone profile in mares undergoing Treatment 1 was in close agreement with those reported previously in pregnant mares. A decline in plasma progesterone levels occurred after Day 53 of gestation in Treatments 2 and 3 mares, indicating that the follicular aspiration procedures did interfere with the formation of secondary corpora lutea. However, the levels in individual mares never dropped low enough to endanger the pregnancy. Mares carrying mule pregnancies exhibited higher mean plasma progesterone concentrations between Days 39 and 45 of gestation than mares carrying horse pregnancies, equivalent levels between Days 46 and 66 despite the lower circulating concentrations of chorionic gonadotrophin (mule CG) in their blood during this period and lower progesterone levels between Days 67 and 150 of gestation. The results indicate that the primary corpus luteum in the pregnant mare may be more sensitive to mule CG than horse CG. Furthermore, the earlier disappearance of CG from the circulation in mares carrying mule fetuses is reflected by an earlier decline in plasma progesterone concentrations in this type of equine pregnancy.

The aim of this study was to test the possibility that ovulation can occur from a preovulatory follicle emptied of its follicular fluid. Transport of the oocyte into the oviduct and fertilisation in 29% of cases demonstrated that ovulation can occur in the absence of follicular fluid but the higher fertility achieved in control mares (62.5%) suggested that follicular fluid does serve a role during ovulation, fertilisation and oviductal transport. Injection of horse oocytes into preovulatory follicles in mules after removal of the follicular fluid, followed by insemination of the mules with horse semen, resulted in the production of one horse x horse embryo.