Monday, August 24, 2020

Capturing horses with a drone

https://www.dreamstime.com/horses-walking-line-pasture-drone-view-green-landscape-herd-brown-horses-horses-walking-line-pasture-image157415572#res1853317
Feral populations of horses often roam over extensive areas. When it becomes necessary to confine them for management purposes – for contraceptive treatment, for example - it becomes necessary to round them up.

Current methods of trapping are based on chasing the animals into a corralled area – often using helicopters.

Is there another way?  A less stressful, less expensive, and safer alternative? Sue McDonnell  and Catherine Torcivia, of the University of Pennsylvania School of Veterinary Medicine New Bolton Center, believe  that there is.

They investigated whether it would be possible to get free-roaming horses to follow a drone into a corral. They explain “This concept is based on the natural instinctive behavioural tendency of horses to become alert to intruders or novel objects and to respond as a herd according to the level of sympathetic arousal evoked.”

They used a consumer-grade quadcopter drone to lead the university’s herd of 123 semi-feral ponies into corrals. Reporting their work in the journal Animals, they write: “The technique was successful on the first attempt as well as for seven of nine additional attempts over a period of 4 weeks, repeatedly to the same as well as to different destinations. The pace of following was primarily a fast walk, with occasional slow trot. Family integrity was maintained.”

The authors add that “In all cases, one or more stallions were the first to alert to the approach of the drone as well as to initiate following of the drone’s retreat. Those stallions vocalized in a characteristic loud distant call back to the remainder of the herd, which then reflexively coalesced and followed en masse.”

They found that to catch the horses’ interest, the drone was most effective when flying at 2-6 metres above the ground and within 10m ahead of the leading animals.

The authors conclude that their work shows preliminary proof of the concept of repeated capture of horses by leading with aircraft rather than chasing. They now plan to repeat the project on a herd of feral horses in a much larger enclosure than that in which these ponies were living.

“If successfully demonstrated in more extensive rangeland conditions, this method may eventually provide a lower-stress, more repeatable option of capturing feral horses, with implications for improved animal and human safety and welfare.”


For more details, see:

Preliminary Proof of the Concept of Wild (Feral) Horses Following Light Aircraft into a Trap.

McDonnell S, Torcivia C.

Animals (Basel). (2020) Jan 2;10(1). pii: E80.

https://doi.org/10.3390/ani10010080

Sunday, August 23, 2020

Cooling hot horses

Horses working hard in hot and humid conditions may suffer heat-related stress, particularly if they have not had time to acclimatise to the environmental conditions. Treatment requires rapid cooling to bring the horse’s temperature down to more acceptable levels. But what is the most effective way of cooling a horse? Different methods have been proposed and opinions vary as to the most effective procedure.

A study from Japan Racing Association’s Equine Research Institute found that a continuous shower of tap water was the most effective method.

Five Thoroughbreds were included in the study, which was carried out under hot and humid conditions (maintained at 31.8 °C +/- 0.1°C with heaters and mist sprays)

The horses were exercised on a treadmill until the temperature measured in their pulmonary artery reached 42°C. They were then cooled down following one of five protocols and their pulmonary artery and rectal temperatures and blood lactate levels were monitored.

Cooling protocols comprised:

  • walking, with no additional cooling (control);
  • walking, with fans producing an air current of 3.0 m/s
  • walking, with the intermittent application of cold water (10°C) with scraping
  • walking, with the intermittent application of cold water (10°C) without scraping
  • stationary, with the continuous tap water (26°C) application via shower hoses

Researchers repeated the experiment weekly until all horses had experienced each cooling method.

They found that showering with tap water was significantly more effective than any other cooling method.

A full report of the work is published in the Journal of Equine Veterinary Science. The authors conclude: “The essential feature is not the water temperature or the use of scraping but that the horse is kept covered in water cooler than its body temperature over an extended period.”


For more details, see:

A Comparison of Five Cooling Methods in Hot and Humid Environments in Thoroughbred Horses

Yuji Takahashi 1, Hajime Ohmura 2, Kazutaka Mukai 1, Tomoki Shiose 3, Toshiyuki Takahashi

J Equine Vet Sci (2020) 91:103130.

 https://doi.org/10.1016/j.jevs.2020.103130


Saturday, August 22, 2020

Early pregnancy loss research


Research from the Royal Veterinary College (RVC) has demonstrated that a chromosomal defect is responsible for a significant proportion of horse pregnancies that fail within the first two months of development.

These findings will pave the way for new diagnostic tests for, what could be, one of the most common causes of pregnancy loss in mares.

Pregnancy loss is a notoriously difficult condition for veterinary surgeons to manage. Up to 10% of confirmed mare pregnancies end in the first two months, and in over 80% of those cases the cause is unknown

In this study, researchers found that aneuploid pregnancies (in which a copy of a whole chromosome is either duplicated or missing) are a key cause of equine pregnancy loss.

The research team, led by Dr Mandi de Mestre, Reader in Reproductive Immunology and Head of the Equine Pregnancy Laboratory at the RVC, collaborated with seven different veterinary practices to gain access to samples from across the UK and Ireland. They found that around 20% of the pregnancies lost were aneuploid. Charlotte Shilton, RVC PhD student who performed the analysis, applied three different genetic approaches to confirm the results.

Work is now underway to identify the underlying cause of these aneuploid pregnancies, with early data from this study suggesting it is most commonly introduced via the egg or sperm. Until now, chromosomal defects such as aneuploidy have only been reported as a rare condition in young horses with developmental disorders.

This study explains why the condition is so rare in horses, with most embryos and fetuses possessing this genetic change dying very early in development, as also occurs in humans. The study highlights the need to reconsider this genetic condition both in pregnancy loss but also for early developmental disorders.

Dr de Mestre said: “Early pregnancy loss remains a very frustrating condition for clinicians to treat as the underlying cause is unknown in around 80% of cases. These findings will allow researchers to develop new diagnostic tests for pregnancy losses, which would offer hope to thousands of owners of breeding mares that suffer this condition.

“A diagnostic test would allow them to make informed decisions on treatment strategies and to advise on whether they should invest in further attempts to breed their mare benefiting both horses and their breeders alike in the future.

She added, ”I would like to thank both the Thoroughbred Breeders Association and our collaborators at Texas A&M University and the participating veterinary surgeons for their support on this project.

 

For more details, see:

Whole genome analysis reveals aneuploidies in early pregnancy loss in the horse

Charlotte A. Shilton, Anne Kahler, Brian W. Davis, James R. Crabtree, James Crowhurst, Andrew J. McGladdery, D. Claire Wathes, Terje Raudsepp & Amanda M. de Mestre

Scientific Reports (2020) vol 10, Article number: 13314

https://www.nature.com/articles/s41598-020-69967-z

Bronze Age horsemanship

 New research suggests that horse riding may have emerged earlier than generally thought.

Scientists have discovered new facts about the use of horses in the Bronze Age. A team of scientists, from Khazakhstan, Russia and the US, showed that people of the Andronova culture mastered horse riding several centuries earlier than is commonly believed.

The researchers came to this conclusion when working with the remains of two Late Bronze Age horses from Kurgan (burial mound) no 5 of the Novoil’inovskiy 2 Cemetery, near the city of Lisakovsk in the  Republic of Kazakhstan.

They discovered that changes on the horses’ skulls that were consistent with having been bridled.  Remnants of bridles were found near the horses, including cheekpieces that showed wear that could have been caused by use with soft bits.

The scientists conclude that the bone pathologies and the wear on the cheekpieces were most consistent with the horses being used for riding or chariotry.

Igor Chechushkov, of the South Ural State University (SUSU) took part in the laboratory and analytical part of the study. He analysed the burials, and radiocarbon dating information from the horse bones and artifacts removed from the site.

"We received radiocarbon dates that made it possible to date the complex with an accuracy of several decades. A comparison of these dates with the known ones allowed us to conclude that horsemanship, that is, the use of horses in military affairs, began to be practiced much earlier than many researchers had previously expected.”

It had been thought that horsemanship evolved around 900 BC. But Chechushkov points out “Our materials suggest that armed horsemen who fought on horseback could have appeared in the Eurasian steppes no later than 1600 BC.”

For more details, see:

Early evidence for horse utilization in the Eurasian steppes and the case of the Novoil’inovskiy 2 Cemetery in Kazakhstan

Igor V.Chechushkov, Emma R.Usmanova, Pavel A.Kosintsev

Journal of Archaeological Science: Reports Volume 32, August 2020, 102420

https://doi.org/10.1016/j.jasrep.2020.102420

 

See also:

On the Earliest Use of Plate-Formed Cheekpieces and the Emergence of Horse Riding (Based on Finds from the Novoilyinovskiy II Cemetery in Northern Kazakhstan)

I.V. Chechushkov, A. A. Ovsyannikov, E. R. Usmanova

Archaeology, ethnology & anthropology of Eurasia (2020) Vol 48, No 2

https://doi.org/10.17746/1563-0110.2020.48.2.049-058

Friday, August 21, 2020

Zebra stripes and the aperture effect

Researchers have long pondered over the reason for zebra’s stripes.

Over the past decade, Professor Tim Caro at the University of Bristol’s School of Biological Sciences has examined and discredited many popular theories such as their use as camouflage from predators, a cooling mechanism through the formation of convection currents and a role in social interactions.

Stripes acting to confuse predators is another common explanation, but it too is flawed when looking at the scientific data. Instead, mounting evidence suggests that it is parasitic flies that are confounded by the zebra’s distinctive patterning.

In a new paper published in the journal Proceedings of the Royal Society B, the Bristol scientists have now provided significant depth to this hypothesis by narrowing down the possible mechanism.

Previously, the same researchers had shown that blood-sucking horseflies would approach horses in striped rugs as often as plain rugs, but then fail to land or slow down when they got close.

It seems the stripes dazzled the flies, forcing them to collide with the skin or fly away altogether. In their new study, the research team explored a potential mechanism explaining how stripes could lead to this outcome: the “aperture effect.”

Lead author Dr Martin How, also from Bristol’s School of Biological Sciences, explains: “The aperture effect is a well-known optical illusion that, in human vision, is also known as the barber-pole effect. Moving stripes, such as those on the rotating barber-pole signs outside barbershops, appear to move at right angles to the stripe, rather than in their true direction, so the pole appears to move upwards, rather than around its axle.

“We set out to see if this illusion also takes place in the eyes of biting flies as they come to land on striped hosts.

“As any fly approaches a landing surface, it will adjust its speed according to how quickly the surface expands across its vision, enabling a slowed and controlled landing.

“Stripes however could disrupt this ‘optic flow’ through the aperture effect, leading the fly to believe the landing surface is further away than reality. Thus, the fly fails to slow down or land successfully.”

This latest study assessed flies landing on horses wearing striped, checked, or plain grey rugs. The researchers found that flies hardly landed on checked or striped rugs at all.

The researchers explain that, since checked rugs provide visual input free from the aperture effect, one would have expected flies to land on them without difficulty. But they didn’t.

So, it is not only stripes that deter tabanid horseflies, other patterns can be effective too. As the “aperture effect” would not apply to the checked pattern, the researchers could discount it as the mechanism behind fly confusion.

Professor Caro, the paper’s senior co-author, added: “Not only do these exciting studies bring us closer to understanding one of the world’s most iconic and photogenic species, they will be of great interest to farmers attempting to reduce the damage caused by fly bites and even general horse-wear companies.”


For more details, see:

Zebra stripes, tabanid biting flies and the aperture effect

Martin J. How, Dunia Gonzales, Alison Irwin and Tim Caro

Proceedings of the Royal Society B Volume 287 Issue 1933

https://doi.org/10.1098/rspb.2020.1521