Hyperlipidemia in Caspian miniature horses: Effects of undernutrition

The susceptibility of Caspian miniature horses to hyperlipidemia was followed in a study of healthy Caspian miniature horses in which food but not water was withheld for 48 hours. Two months before the study, the horses were fed a high-energy diet. The mean of weight gain was 26.46 kg per horse during this period. All horses had a normal rectal temperature, respiratory rate, and pulse throughout the experiment. During the period of food deprivation, levels of serum triglyceride, aspartate aminotransferase, and alanine aminotransferase significantly (P < .05) increased and glucose concentration decreased. As a conclusion, Caspian miniature horses were susceptible to hyperlipidemia, but they did not show classic hyperlipemia syndrome.     

Characterization of age- and location-associated variations in the composition of articular cartilage from the equine metacarpophalangeal joint

Objective: To characterize the impact of age, gender, location and individual animal variation on the composition of articular cartilage from the metacarpophalangeal joint of horses. Design: Cartilage specimens were obtained from the metacarpophalangeal joints of 28 male, female and castrated male horses ranging in age from one day to 27 years of age. Cartilage samples from the distal metacarpus, proximal first phalanx and proximal sesamoids were analyzed separately. Chondrocyte number, DNA content, proteoglycan concentration and total collagen content were determined for each animal and joint location. Results: Age and joint location had a significant effect on chondrocyte number and DNA content with higher cell counts and DNA content detected in cartilage from the youngest age groups and in cartilage from the metacarpus and proximal sesamoids. The influence of age on chondrocyte numbers was not significant in horses over two years of age. Both age and joint location also influenced total proteoglycan and collagen content. Lower proteoglycan and collagen concentrations were detected in younger horses, and cartilage from the metacarpus had lower proteoglycan and collagen concentrations than that from other joint locations. Gender did not appear to influence chondrocyte number or matrix content of equine articular cartilage. However, there was significant residual variation in cellularity, proteoglycan levels and collagen content between individual animals that could not be explained by the signalment factors considered in this study. Conclusions: Future studies examining equine articular cartilage should avoid direct morphologic comparisons between animals of different ages, and any comparisons made between individuals should be interpreted cautiously. In addition, in vitro tissue culture models should avoid the use of cartilage pooled from different animals or from different locations within the same joint.     

How to make models of equine feet for accurate measurement and long-term study

The shape of equine hooves is difficult to measure and quantify. Scientific research on the effects of hoof conformation on normal and abnormal locomotion often requires precise characterization of hoof conformation. This technique produces accurate, life-size, permanent models of the hoof quickly and inexpensively from dental plastic powder and dental plaster.     

Percutaneous catheter-based treatment of pulmonic stenosis and patent ductus arteriosus in a dog

A 6-months old female German shepherd dog was referred for management of congenital heart disease. A diagnosis of pulmonic stenosis (PS) and patent ductus arteriosus (PDA) was confirmed by Doppler echocardiography and cardiac catheterisation. The conditions were treated during a single cardiac catheterisation procedure using percutaneous techniques. Gianturco coil embolisation was used to close the PDA, and the PS was relieved using a balloon valvuloplasty technique.     

Testicular fine needle aspiration cytology from a stallion with testicular degeneration after external genitalia trauma

A seven-year-old Quarter Horse had a serious external genitalia trauma with severe swelling of ventrum, penis, prepuce and scrotum after falling over a fence. Appropriated treatment was rapidly started after clinical examination. During recovery period, the spermatogenesis assess by semen evaluation was not possible due to stallion's inability to ejaculate. Therefore, for testicular evaluation fine needle aspiration cytology (FNAC) was performed. The first FNAC showed a deviation of germ cell line towards immature cells, mainly by primary spermatocytes (59.5%) with very few late spermatids and spermatozoa (2.5% each), and an increased Sertoli cells/germ cells ratio (478/100), which characterized testicular degeneration. One month after the first FNAC, the second exam presented a drastic decrease of Sertoli cells/germ cells ratio (7/100) and marked increase of mature cell number, specially by early and late spermatids (50% and 24.5%, respectively). In this case, the results of both FNAC could demonstrate a partial recovery of spermatogenesis activity. Two months later, the stallion had mated two mares successfully and they became pregnant. In conclusion, the adequate treatment allowed a complete recovery of the stallion's reproductive function, and since semen collection was impossible during treatment, testicular FNAC showed to be an efficient diagnostic method for evaluating acute damage in the spermatogenesis.     

Effect of purified equine follicle-stimulating hormone on follicular development and ovulation in transitional mares

Horse owners want to have their mares bred as early as possible in the breeding season after February 1. Numerous medical treatments, such as progesterone, dopamine antagonists, and gonadotropin-releasing hormone have been administered to anestrous or transitional mares in an attempt to induce follicular development. Some of these treatments are ineffective or impractical, so there is a need in the horse industry to develop alternative techniques to stimulate follicular development and ovulation early in the breeding season. Twenty transitional mares were assigned to one of two treatment groups. Mares in group 1 (n = 10) served as untreated controls, and mares in group 2 (n = 10) were administered 12.5 mg of purified equine follicle-stimulating hormone (eFSH) (Bioniche Animal Health USA, Inc., Athens, Ga) intramuscularly twice daily for a maximum of 15 consecutive days. Mares were considered to be in transition when the diameter of the largest follicle was ≥25 mm. Once one or more follicles >35 mm were detected, eFSH treatment was discontinued and human chorionic gonadotropin was administered intravenously. The percentage of mares ovulating during the 15-day observation period was compared by means of chi-square analysis. The interval to ovulation and the number of ovulations per mare were compared between the two groups by Student t test. In 8 of 10 mares treated with eFSH follicles developed and ovulation occurred during the 15-day observation period, compared with 0 of 10 control mares. Interval from onset of treatment to ovulation was 7.6 ± 2.4 days for these eight mares. The eight mares were treated for an average of 5.2 ± 1.3 days with eFSH. Thus, the eFSH treatment was effective in advancing the first ovulation of the year in transitional mares.     

The influence of bedding on the time horses spend recumbent

To determine if bedding has any influence on the time horses spend recumbent, 8 horses kept on straw and 8 kept on wood shavings were observed from 10:00 to 5:30 for two successive nights. Observations were conducted using time-lapse video recordings. Lying down and rising behavior, as well as frequency and duration of bouts spent in lateral and sternal recumbency, was registered. The results showed that horses on straw were lying in lateral recumbency three times longer than horses on shavings (P < .001), whereas the time horses spent in sternal recumbency did not differ. The longest period of noninterrupted lateral recumbency was longer for horses on straw than for those on shavings. Because horses must lie down, preferably in lateral recumbency, to achieve paradoxical sleep, the reduced time spent in lateral recumbency in horses on wood shavings may affect their welfare and performance. Independent of the bedding, we further observed that, as the horses got up from recumbency, most of them made attempts to roll over before rising. This behavior appeared to be caused by some difficulty in rising, possibly due to the box size, and might have a connection with the fact that horses sometimes get stuck against the box wall.

Introduction

Many riding horses spend the majority of their life in an artificial environment. Horse owners keep their horses under certain conditions because of tradition, because they want to make the horse feel comfortable from a human point of view, or to reduce the amount of work involved in horse husbandry. Often the choice of bedding substrate is made from a subjective point of view without assessing both short-term and long-term effects of the bedding. Part of the reason is that only few studies have analyzed horses' preferences for different bedding substrates and their effect on the time horses spend recumbent. In one study comparing straw and wood shavings, no significant preference was found.[1] In another study comparing plastic, wheat straw, and wood shavings, the time horses spent standing, sleeping, or lying down was not affected significantly by the bedding substrates. [2] Mills et al [3] found that horses, given a choice between straw and wood shavings, spent significantly more time on straw. Whereas the substrates had no significant effect on behaviors such as eating, lying, and standing alert, horses spent more time performing bedding-directed behaviors on straw but more time dozing on shavings. Finally, it has been reported that the use of nonstraw bedding may increase the risk of abnormal behaviors such as weaving. [4]As far as bedding properties are concerned, Airaksinen et al[5] concluded that air quality in the stable and utilization of manure can be improved by selecting a good bedding material. According to Reed and Redhead, [6] both straw and shavings are economical and easy to obtain, and they make a bright, comfortable bed. Straw bales are convenient to store, but may be eaten by the horse, are labor intensive, and may be dusty or contain fungal spores. Wood shavings are not eaten by the horse and are good for respiratory problems but need to be kept very clean because they are porous. In addition, they are not as warm as straw because they do not trap air the way straw does.Electroencephalographic (EEG) studies in cats have demonstrated that sleep can be divided into two stages of differing electrocorticographic (EcoG) patterns, ie, slow-wave-sleep (SWS) and paradoxical sleep (PS).[7] During PS, bursts of rapid eye movements (REM) can be seen at irregular intervals. [8] In humans, dreaming occurs during this stage. [9 and 10] Horses are able to sleep while standing, [11] but in this position they only go into SWS. [14, 15 and 16] During PS there is a complete abolition of muscular tone of antigravity muscles and of neck muscles, as shown in cats. [17] In horses, there is a gradual loss of muscular tone until the middle of the recorded SWS period, whence it decreases to a negligible amount during PS. [15] Consequently, muscular tone disappears entirely at the onset of PS. [18] Horses are unable to complete a sleeping cycle without lying down to enter PS. [8, 19 and 20] They normally fall asleep while standing and, when they feel confident about their environment, lie down in sternocostal recumbency. [8] Thereafter, they proceed to lateral recumbency and enter PS. [14 and 19] Dallaire and Ruckebusch [18] demonstrated that the SWS state was infrequent in the standing animal and most often occurred during sternocostal recumbency with the head resting or not on the ground. PS occurred in both sternocostal and lateral recumbency, although the animal frequently had to readjust its position into sternocostal recumbency due to the disappearance of neck muscular tone.The sleep pattern of horses depends on many circumstances, such as age,[21, 22 and 23] diet, [16] and familiarity with the environment. When horses are put outdoors it may take some days before they lie down. If one horse that is familiar with the environment lies down, the others usually follow. [8 and 13] Dallaire and Ruckebusch [16] subjected three horses to a four-day period of perceptual (visual and auditive) deprivation. After this period total sleep time increased due to an augmentation of both SWS and PS. Finally, there is large individual variation between horses in the time they spend recumbent and sleeping. [15]Horses spend 11% to 20% of the total time in recumbency.[11 and 15] Lateral recumbency represents about 20% of total recumbency time, and uninterrupted periods of lateral recumbency vary from 1 to 13 minutes (mean, 4.6 min). [14 and 16] Steinhart [11] found that the mean length of uninterrupted lateral recumbency periods was 23 minutes, the longest period being one hour. Total sleeping time in the stabled horse averages 3 to 5 hours per day or 15% of the total time. [8, 13 and 16] Keiper and Keenan [24] found similar time budgets in feral horses that were recumbent approximately 26% of the night. PS is about 17% to 25% of total sleeping time, and the mean length of a single PS period is 4 to 4.8 minutes. [13 and 18]In stabled horses sleep is mainly nocturnal and occurs during three to seven periods during the night.[8, 13 and 16] Ruckebusch [13] observed that neither sleep nor recumbency occurred during daytime in three ponies observed for a month and, in another experiment conducted on horses, PS occurred only during nighttime. [15] A group of ponies observed for more than a month between 8:45 and 4:45 spent only 1% of the daytime recumbent.[25] The maximum concentration of sleep occurs from 12:00 to 4:00 .[8, 16, 18 and 24]The purpose of this study was to examine two groups of horses in a familiar environment, one group kept on a bedding consisting of straw, and the other kept on wood shavings, and to determine if there was any difference between the two groups in the time they spend recumbent.

Materials and methods

Housing. The study was conducted in one of the biggest riding clubs in Denmark, housing about 150 horses. The 18 horses used in the study stood in three different parts of the stable. They were all stabled in boxes measuring 3 × 3 m and subjected to the same feeding and management routine. They were unable to see their next-door neighbor because of a tall wooden board, but they were able to see the horses stabled on the opposite side of the corridor through bars. Nine horses were stabled on wheat straw (15 cm long, dry matter content 87-88%) and nine on oven-dried wood shavings (80% spruce and 20% pine, dry matter content 82%).Animals. All horses used in the study were privately owned. They had been kept in the boxes in which they were observed a minimum of three weeks. Three of the horses were mares and 15 were geldings. Most of them were Danish Warmblood used for dressage riding. Their ages ranged from 5 to 18 years (mean, 10.6 y) and their height ranged from 1.60 to 1.76 m (mean, 1.68 m). All horses wore a blanket. Age and sex distribution between the two groups is shown in Table 1.     

A new alternative for embryo transfer and artificial insemination in mares: ultrasound-guided intrauterine injection

A transvaginal ultrasound-guided intrauterine injection (IUI) technique was developed for embryo transfer and for injection of small quantities of sperm in mares. The target area of a horn was positioned by transrectal manipulation against the wall of the vaginal fornix over the face of a transvaginal transducer. A needle with a catheter containing the embryo or semen was inserted through the needle guide of the transducer into the uterine lumen. The tips of the needle and catheter, the movement of the catheter in the uterine lumen, and the ejection of fluid was monitored on the ultrasound screen. Pregnancy rate 15 days after ovulation for the IUI embryo transfer technique (30/39, 77%) was similar to the pregnancy rate for transcervical (TC) embryo transfer (30/38, 79%). The pregnancy rate for IUI insemination of 20 × 10⁶ progressively motile sperm into the tip of the uterine horn ipsilateral to ovulation was 5/10 (50%). Results indicated that the IUI approach is a viable alternative for embryo transfer. Results also supported the potential of IUI for insemination of low numbers of sperm, but more extensive studies with various doses of sperm are needed.