Sunday, February 7, 2010
On The Vertical
One feature that attracted me to classical dressage is the science behind it. Personally I do not have a strong commitment to a given theory and I am open to new ideas and try to continuously question my beliefs. This approach is a great way to continue learning, but faced with conclusive scientific research I find myself committed to the evidence. One area where I've found myself drawing a hard line is "on the vertical".
Vets have known for decades that when the horse's face approaches the vertical the horses' ability to breath decreases. Cook, in 1981, was the first to comment on the relationship of the vertical to a decrease in the ability to breathe. In 1995 Petsche and Derksen conducted research on head position and breathing obstruction. The findings of the study conclude that as the horse approaches the vertical the horse's ability to breathe will decrease proportionally. The study reports that a horse on the vertical will have 50% impairment in breathing. Derksen later comments on going behind the vertical and rollkur, "An increase would make a big difference. So, for example, if you double the bend you would more than double the resistance. (Horses For Life)" A later study by the University of Bristol confirms Petsche and Derksen's research, "The findings of this study demonstrate that dynamic obstruction of the URT is a common cause of poor performance in sport horses and is frequently complex in nature. Excessive poll flexion is an important contributing factor.”
These studies have found that the angle of the poll changes the shape of the trachea. The trachea becomes long and narrow as the poll angle increases and impedes the horses ability to breathe. The studies found that the horses can breathe out, but not in.
At A (138 degree poll angle), the position of the head held during running, the horse has the least obstruction to the airway. As the poll angle increase from A through to C the horse's ability to breathe will be reduced. At D the horse's ability to breathe will have been reduced by 50% . At E the horse's ability to breathe will have been reduced exponentially past 50%. In other words, the behind the vertical position seriously obstructs the horses ability to breathe.
The heavy horse can tell us a great deal about the effects of the poll angle on the horse. The heavy horse, like other horses, are a completely hind driven breed as their impulsion motor is located in the rear of the horse. When a heavy horse pulls a light load such as a plough or a cart the horse naturally goes into collection. The driver exerts no force on the bit but simply takes up the slack in the reins. In exerting force to pull a plough the horse will begin by pushing off with more force in the hind legs and stepping under so that leg lands at the centre of the horse's body. The increase rear force will cause the rear joins to flex and the hip to lower. The spine will then rise at point were the withers connect to the neck. The lifting of the withers causes the neck to hang relaxed in an arch and the horse's head will hover around the vertical.
Since the horse is allowed to work in any position that it chooses, this tells us that a head position that hovers around the vertical, but does not go behind it, is a position that the horse is conformable with. As long as the horse is allowed to choose the position itself and the nose is allowed to move back and forth from the vertical to ahead of the vertical the horse is happy with the position and is comfortable working in this position.
The classical head position is the same as the one chosen by the heavy horse . If you watch the Spanish riding school or dressage from decades ago, such as the dressage demonstrated by Klimke, you will see the horse's head bobbing in front of the vertical, but never behind it and never held in position.
In summary, these studies have shown that behind the vertical will cause serious breathing problems for your horse. Although it's been the fashion in show dressage for at least three decades to ride the horse behind the vertical or with the head held in place, these teachings will cause harm to your horse. The horse is comfortable with the classical view the vertical and will be comfortable with working in this position.
Wednesday, February 3, 2010
Wednesday, January 13, 2010
Wild Iberian horses played part in horse domestication
January 8, 2010
A feral herd of modern Northern Iberian horses. © Carlos Puga
Workers dig at the Portalón archaeological site in the Sierra de Atapuerca (Spain). © Jaime Lira, Centro Mixto UCM-ISCIII
A modern lusitano. © US
Scientists have found evidence that wild horses from Iberia played a part in the domestication of the horse.
The earliest known domestic horses date to 4600 years ago. They originated on the steppes between modern Ukraine and Kazakhstan.
Two different hypotheses have been suggested:
That domestic horses spread from this area over the rest of Eurasia;
That horse domestication was a multiregional process, having occurred several times in different local places.
"Previous analysis on mitochondrial DNA from modern Iberian horses pointed to the D1 haplogroup as the most likely group involved in an independent domestication event, maybe in Iberia or in North Africa" explains Anders Götherström, from the Department of Evolutionary Biology at Uppsala University, who headed the project, together with Juan Luis Arsuaga of the Centro Mixto UCM-ISCIII from Madrid, Spain.
The researchers compared ancient DNA sequences from Iberian horse remains from the Neolithic, Bronze Age and Middle Ages obtained in this study with more than 1000 modern horse sequences from different Iberian and non-Iberian breeds, as well as with ancient sequences from other studies.
The researchers found the earliest occurrence of the D1 group in Iberia in a medieval horse. "We have not found sequences from the Neolithic or the Bronze Age period associated to the most important modern Iberian haplogroup, the D1 group," says Jaime Lira, of the Centro Mixto UCM-ISCIII from Madrid, and the main author of this study.
"That means that D1 group can be a foreigner group, which entered in Iberia during historical times."
The researchers unearthed evidence that wild horses from Iberia contributed to the domestication process, and the Lusitano group C is a witness from this event.
"The Lusitano C is a small group constituted only by modern horses from Iberian origin," explains Arsuaga.
"We have found that maternal lineages from this group were already present in wild Iberian horses from the Early Neolithic, continuing through the Bronze Age until nowadays."
These results suggest the possibility of a completely independent domestication episode, or the use of Iberian maternal lineages in a restocking process from the wild.
Collaborators on the research included scientists from Centro UCM-ISCIII de Investigación sobre Evolución y Comportamiento Humanos in Spain, Universidad Complutense de Madrid in Spain, Stockholm University in Sweden, Universitat Jaume I in Spain, Swedish University of Agricultural Sciences, University of Copenhagen in Denmark and Uppsala University in Sweden.
Ancient DNA reveals traces of Iberian Neolithic and Bronze Age lineages in modern Iberian horses Jaime Lira, Anna Linderholm, Carmen Olaria, Mikael Brandström Durling, M. Thomas P. Gilbert, Hans Ellegren, Eske Willerslev, Kerstin Lidén, Juan Luis Arsuaga and Anders G�therström
A feral herd of modern Northern Iberian horses. © Carlos Puga
Workers dig at the Portalón archaeological site in the Sierra de Atapuerca (Spain). © Jaime Lira, Centro Mixto UCM-ISCIII
A modern lusitano. © US
Scientists have found evidence that wild horses from Iberia played a part in the domestication of the horse.
The earliest known domestic horses date to 4600 years ago. They originated on the steppes between modern Ukraine and Kazakhstan.
Two different hypotheses have been suggested:
That domestic horses spread from this area over the rest of Eurasia;
That horse domestication was a multiregional process, having occurred several times in different local places.
"Previous analysis on mitochondrial DNA from modern Iberian horses pointed to the D1 haplogroup as the most likely group involved in an independent domestication event, maybe in Iberia or in North Africa" explains Anders Götherström, from the Department of Evolutionary Biology at Uppsala University, who headed the project, together with Juan Luis Arsuaga of the Centro Mixto UCM-ISCIII from Madrid, Spain.
The researchers compared ancient DNA sequences from Iberian horse remains from the Neolithic, Bronze Age and Middle Ages obtained in this study with more than 1000 modern horse sequences from different Iberian and non-Iberian breeds, as well as with ancient sequences from other studies.
The researchers found the earliest occurrence of the D1 group in Iberia in a medieval horse. "We have not found sequences from the Neolithic or the Bronze Age period associated to the most important modern Iberian haplogroup, the D1 group," says Jaime Lira, of the Centro Mixto UCM-ISCIII from Madrid, and the main author of this study.
"That means that D1 group can be a foreigner group, which entered in Iberia during historical times."
The researchers unearthed evidence that wild horses from Iberia contributed to the domestication process, and the Lusitano group C is a witness from this event.
"The Lusitano C is a small group constituted only by modern horses from Iberian origin," explains Arsuaga.
"We have found that maternal lineages from this group were already present in wild Iberian horses from the Early Neolithic, continuing through the Bronze Age until nowadays."
These results suggest the possibility of a completely independent domestication episode, or the use of Iberian maternal lineages in a restocking process from the wild.
Collaborators on the research included scientists from Centro UCM-ISCIII de Investigación sobre Evolución y Comportamiento Humanos in Spain, Universidad Complutense de Madrid in Spain, Stockholm University in Sweden, Universitat Jaume I in Spain, Swedish University of Agricultural Sciences, University of Copenhagen in Denmark and Uppsala University in Sweden.
Ancient DNA reveals traces of Iberian Neolithic and Bronze Age lineages in modern Iberian horses Jaime Lira, Anna Linderholm, Carmen Olaria, Mikael Brandström Durling, M. Thomas P. Gilbert, Hans Ellegren, Eske Willerslev, Kerstin Lidén, Juan Luis Arsuaga and Anders G�therström
Horses can count, new study says
By Nic Fleming, Science Correspondent, 04 Apr 2008
Horses can count, according to a new study that suggests they are more intelligent than previously thought.
Researchers found that, when offered a choice, they consistently choose buckets containing higher numbers of apples.
Babies aged from 10-months-old have been shown to have an innate tendency to opt for containers holding larger numbers of food items, as have many non-human primates such as rhesus macaques and lemurs. Dr Claudia Uller, of the University of Essex, was inspired to investigate whether horses could count by the story of Clever Hans, a horse that caused a sensation 100 years ago with his apparent abilities to simple arithmetic and keep track of the calendar.
In public performances in Germany he is said to have communicated the answers to questions by tapping his foot.
However psychologist Oskar Pfungst carried out an investigation and reported in 1911 that Clever Hans was not performing arithmetic, but had learnt to obtain the required answers by interpreting the reactions of his maths teacher owner and other observers.
Dr Uller, speaking at the British Psychological Society conference in Dublin yesterday said: "Nobody has been able to show any mathematical abilities in horses since then.
"However our results suggest that horses too, and not only primates, are able to spontaneously discriminate between two small numbers.
"It shows horses are more intelligent than we thought. This may be another piece in the jig saw explaining the evolutionary origins of our ability to count."
Dr Uller and colleague Jennifer Lewis carried out a series of experiments involving riding school and privately owned horses stabled near Colchester, Essex.
In one task, 11 of 13 horses consistently selected buckets containing three plastic apples over another containing two when offered a choice. Fake fruit was used to ensure no difference in smell.
Researchers then showed 12 different horses a box holding either two identical small apples or another containing one large apple with double the surface area. Again, all but two selected the greater number of apples.
In a study published in February, Italian researchers found certain species of fish can count up to four.
Monday, January 11, 2010
Dressage Physiology: Uphill Part 1
In the following articles I will focus on horse physiology to explain form and function of body types in regards to dressage. This will, hopefully, dispel myths about movement and breeds. In these articles I will discuss the basic concepts of classical dressage and discuss myths surrounding the heavy horse or, as some prefer to call them, the draft horse.
There has been much discussion whether a horse should be determined to be uphill by looking at how the (1) seventh cervical vertebrae connects to the spine or should a horse be diagnosed as uphill solely by (2) drawing a line from the top of the withers through to the top of the hip. It should be emphasized that the (3) slope on to the fore has to be considered as well to get the full picture.
Method 1
Connection of the cervical vertebrae to the spine
In the first image of an Arabian horse skeleton, a red line is drawn to show the spine and a purple arrow indicates the seventh cervical vertebrae (the vertebrae that connects the neck to the spine). Notice that with the Arabian skeleton and the Clydesdale skeleton the spine runs strait on to the seventh cervical vertebrae. Now compare the Arabian and Clydesdale to the Thoroughbred. With the Thoroughbred the seventh cervical vertebrae is below the line of the spine. This indicates that the natural build of the Thoroughbred leans forward and places more weight on to the fore. The purpose of the Thoroughbred's lean on to the fore is to place more weight on the front allowing for a more powerful take off while running (see image below).
Other horses who do not have the heavy fore of the thoroughbred will not dip down and dig into the ground during running.
The Spanish horse, in the above image, is shown at the same phase of the stride. In comparison to the Thoroughbred, the Spanish barely dips down. This is a desirable trait in a dressage horse, but not on in a race horse.
When the seventh cervical vertebrae connects straight to the spine the result is a horse with a high stet neck. The high set neck more desirable for dressage horse as it lightens the fore and makes collection easier. Horses with a high set neck are cobs, Spanish horses, Classical horse, Baroque horses, Medieval horses, Heavy horses, Morgans, Saddlebreds etc.
The Warmblood is unusual for a Thoroughbred based breed in that some possess a high set neck.
Sunday, January 10, 2010
Saturday, January 2, 2010
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