Sunday, November 20, 2011
Seasonal pasture myopathy research
Ancient artists spot on
Ancient cave paintings probably give an accurate portrayal of the horses that roamed the earth at the time, according to new research.
For years, archaeologists have debated whether cave paintings were intended as a realistic portrayal of life as seen by the artist, or whether they were a flight of fancy, having symbolic significance. The latter view was fuelled by the fact that, although genes for bay and black hair colour had been identified in ancient DNA, the gene for spotted coat colouring had not been found. Now a multicentre research project has found the gene responsible for leopard spotted coat colouration in DNA from prehistoric horses.The international team of researchers has found that all the colour variations seen in Palaeolithic cave paintings – including distinctive ‘leopard’ spotting - existed in pre-domestic horse populations, lending weight to the argument that the artists were reflecting their natural environment. Professor Michi Hofreiter, from the Department of Biology at the University of York, said “...our results suggest that, at least for wild horses, Palaeolithic cave paintings, including the remarkable depictions of spotted horses, were closely rooted in the real-life appearance of animals. “While previous DNA studies have produced evidence for bay and black horses, our study has demonstrated that the leopard complex spotting phenotype was also already present in ancient horses and was accurately depicted by their human contemporaries nearly 25,000 years ago. “Our findings lend support to hypotheses that argue that cave paintings constitute reflections of the natural environment of humans at the time and may contain less of a symbolic or transcendental connotation than often assumed.” Read more at equinescienceupdate.comThursday, October 27, 2011
Management affects large intestinal motility
A possible explanation for the increased risk of impaction colic in stabled horses has been revealed by a study that shows that they have lower large intestinal motility compared with horses at pasture.
The research team, led by Dr Sarah Freeman at the University of Nottingham School of Veterinary Medicine and Science, measured the motility of the large intestine at three regions of the large intestine, using transcutaneous ultrasound. The study involved sixteen clinically normal horses, which were divided into two groups.Group A: Horses were stabled continuously throughout the study.Group B: Horses were initially at pasture 24hr/day. Over a 2 week period they were gradually changed to the same stabling/dietary management as group A. The researchers assessed the motility of large intestine twice daily for two consecutive days. They recorded the number of contractions at each of three sites: the caecum, sternal flexure, and left ventral colon. Overall large intestinal motility as assessed by transcutaneous ultrasound was lower in stabled horses. In particular, stabled horses showed significantly fewer contractions in the sternal flexure and left ventral colon. Read more at www.equinescienceupdate.com
Laminitis due to endocrine disorders
Hormonal disturbance (endocrinopathy) appears to be a common underlying cause of laminitis according to research from Finland.
The study, conducted at Helsinki University Equine Teaching Hospital, looked for signs of endocrinopathy in all cases of laminitis presented for examination. Almost 90% of horses with laminitis had endocrine abnormalities. Hyperinsulinaemia, associated with obesity was the most common cause, accounting for two thirds of all cases of endocrinopathic laminitis. Cushing’s disease (or Pituitary Pars Intermedia Dysfunction: PPID) was responsible for a third of the endocrine-associated laminitis cases. Dr Ninja Karikoski and colleagues examined 36 horses and ponies with laminitis. Thirty-two of them (89%) had signs of endocrinopathy. Eleven horses had signs of PPID - hirsutism (long curly coat) and increased basal ACTH concentration or typical response to a dexamethasone suppression test. Twenty-one horses had raised basal levels of insulin in the blood without signs of hirsutism. All but one of these hyperinsulinaemic horses were overweight. Twelve had a body condition score (BCS) of four, (on a scale from zero to five, where five is obese) and eight had BCS of five. The researchers conclude that, in this study, most cases of laminitis were associated with an underlying hormonal disturbance. They suggest that endocrine testing should be performed on all cases of laminitis unless there is a clear inflammatory or gastrointestinal cause. Read more at www.equinescienceupdate.comJet lag benefits racehorses
They research showed that horses adapted very quickly to a shift in time zone. Importantly, this rapid adaptation was not accompanied by an increase in the level of stress, but by alterations in endocrine systems that favour an enhancement of the horse’s physical capacity during the process.
In fact, following experimental jetlag, horses experienced improved athletic performance, being able to run at full gallop for an additional 25 seconds before reaching fatigue.
This improved performance did not persist, however, and had returned to pre-shift values after 14 days in the new lighting conditions. Read more at www.equinescienceupdate.com
Comparing positive and negative reinforcement training methods.
Progress towards a vaccine against deadly foal pneumonia
Ancient wild horses help reveal past
Thursday, August 25, 2011
Identifying the cause of Foal Immunodeficiency Syndrome
Effect of blinkers
How do horses respond to partial loss of vision?
In a study at Texas A & M University, eight driving horses were assessed to see if they responded differently to stimuli when wearing blinkers or not. A racing hood with half cup blinkers was used to restrict the field of view behind the horse. A similar racing hood without blinkers was used as a control. One experimenter administered one of four stimuli while standing about nine strides behind the horse:- a length of steel chain was dropped onto an aluminium sheet
- a children's toy gun was fired
- an aluminium can containing coins was shaken
- an umbrella was rapidly opened
The horse's heart rate was recorded after each stimulus. They found that wearing blinkers was significantly associated with an increase in heart rate when worn by horses experiencing a noise for the first time. On the other hand, blinkers were significantly associated with a decrease in heart rate when worn by horses exposed to a primarily visual stimulus (the umbrella opening). "It would seem logical that wearing blinkers would be advantageous when a visual distraction is hidden by the blinkers. Because the horses cannot see the object, he has no reaction to this object which is potentially frightening" they comment. However, sounds are different. "This paper shows that horses wearing blinkers react more when they are exposed to unexpected noises." They point out that this reaction is not necessarily seen by an observer - most of the horses in the study showed little visible reaction to the noise stimuli. There was, however, a dramatic increase in heart rate. The researchers suggest that this model of restricted vision could be used to investigate how horses react to other visual deficits such as total blindness, or the changes that occur after cataract surgery.More details at www.equinescienceupdate.com
Catching things from horses
The authors suggest that the foal was the most likely source of the infection. In fact, the foal itself had been hospitalised in an equine clinic two months earlier for treatment of a wound infection.Another report describes a surgical operation that became infected with Streptococcus equi. S. equi, the cause of strangles in horses, is a cause of great concern to many horses' owners, but is rarely a danger to humans or other domestic species.The patient, a professional racehorse trainer, underwent treatment for an aortic aneurysm - a condition in which the walls of the main artery leaving the heart are weakened and balloon outwards. If untreated there is a risk of sudden rupture leading to sudden death. A specialised endovascular technique was used, in which a stent, a tubular framework, was inserted into the femoral artery in the groin, and passed up the artery until it came to lie within the affected vessel. The stent became infected and the causative organism was identified as Streptococcus equi. Read more at www.equinescienceupdate.com
Faecal egg counts after tapeworm treatment
Thursday, July 28, 2011
Does soaking make hay safer for laminitics?
An important part of treatment and prevention of laminitis is to limit the water soluble carbohydrate (WSC) intake. To achieve this, access to pasture is restricted and the horse or pony is fed hay instead.
But even hay may not be safe for horses with laminitis. Most authorities suggest that horses and ponies prone to laminitis or with insulin resistance should ideally receive hay that has a water soluble carbohydrate concentration not exceeding 100g/kg on a dry matter basis (DM) However, in northern Europe pasture grasses often contain high levels of WSC (>300g WSC/kg DM), which may result in hay with WSC content up to 200g/kgDM.It is often suggested that soaking the hay may reduce its water soluble carbohydrate content and thus make it safer for laminitis-prone horses and ponies. However, the studies that have supported this approach have often used large quantities of water and, as well, the hay may have been chopped prior to soaking. Often owners do not go to such lengths. What is the effect of soaking hay when carried out according to common practice?Dr Annette Longland, Clare Barfoot and Dr Pat Harris conducted an investigation into whether the degree of soaking that is in common use in the UK would have an effect on the WSC content of various hays. The study looked at the loss of WSC and crude protein from a range of British hays, which were either shaken or left compacted in the "flake" and then soaked in just enough water to cover the hay, for various lengths of time. The authors found that soaking hay for up to 16 hours produced variable and incomplete loss of WSC.As would be expected, the dry matter content of the hays fell after soaking - there was a significant reduction in DM content after 20 minutes soaking, and a continued fall with longer periods of soaking. However, regardless of the duration of soaking or whether the hay was shaken up or left compacted the WSC content of most of the hays remained above the recommended limit for laminitics of 100g/kgDM.The researchers found no significant difference between the compacted or shaken hays. They conclude that soaking cannot be relied on to make hay suitable for feeding to laminitic horses. They recommend that hay for animals prone to laminitis be analysed for WSC content, and only hay that is low in WSC is fed to horses prone to laminitis. Soaking can be used as an extra safeguard.
Friday, July 22, 2011
How does a brumby stallion spend his day?
Magdalena Zabek's latest report on the feral horses of central Australia is now available. Click here to read
Thursday, June 23, 2011
Research confirms effectiveness of grazing muzzles
Making sense of flexion tests
Saturday, June 18, 2011
Treponemes found in canker lesions
Thursday, June 02, 2011
Effect of psyllium on glucose and insulin
Psyllium, a sort of "super-bran", is already used in horses, particularly for treatment and prevention of sand colic. When mixed with water, it swells to up to 10 times its original volume, turning into a jelly-like substance which is thought to ease the passage of sand through the digestive tract.
Tuesday, May 31, 2011
Is your vet a health risk?
Read more at www.equinescienceupdate.com
Wednesday, May 18, 2011
Hendra virus vaccine progress
Australian scientists have succeeded in developing an experimental vaccine to protect horses against Hendra virus.
Hendra virus (HeV) was first isolated in September 1994 from an outbreak at a training complex in Hendra (a suburb of Brisbane, Queensland, Australia) after which the virus was named. During that initial outbreak 14 horses died. Seven other horses were found to have been infected and were humanely destroyed. Two humans were affected, one of whom died.In five of the 14 known outbreaks, the infection has spread to people. The virus has killed four of the seven people infected. Fruit bats (Pteropus spp), commonly known as flying foxes, have been identified as the natural host for the Hendra virus.“Our trials so far have shown that the vaccine prevents the infection of horses with Hendra virus,” said Dr Deborah Middleton from the Australian Animal Health Laboratory (AAHL). Stopping the disease in horses could also help protect people from the disease."All the human infections have come from contact with infected horses," Dr Middleton explains. So if you can control the disease in horses, you break the transmission cycle to people as well as protecting the health of horses. Studies so far have shown that the vaccine will prevent horses becoming infected. It also protects them from developing the disease and shedding the virus.Further work, including field trials and product registration, is still required. However, if all goes well, the vaccine may be available as soon as 2012. Dr Barry Smyth, President of the Australian Veterinary Association, said that both vets and horse owners would welcome the news on the vaccine.“It’s important that veterinarians and horse owners continue with precautions that reduce the risk of spreading the virus and that they report suspected cases immediately,” Dr Smyth said. Read more at: www.equinescienceupdate.com