التسنين في الخيول_horse dentition

بسم الله الرحمن الرحيم

التسنين في الخيول

اولا : تنقسم اسنان الحصان تبعا لوضعها و شكلها الى ما يلى:

1. القواطع وتوجد فى بداية الفك و تشمل الثنائيان و الرباعيان و القارحان

2. الانياب و تقع بين القواطع و الضروس و توجد فى الذكور فقط

3. الضروس و تشمل ضروس المقدمة و ضروس المؤخرة

ثانيا : تنقسم الاسنان حسب الظهور الى اسنان لبنية و اسنان مستديمة

الاسنان اللبنية تتكون من :

القواطع : تشمل الثنائيان تظهر فى الاسبوع الثانى.

و الرباعيان تظهر من الشهر الثانى الى السادس.

و القارحان تظهر فى الشهر السادس الى التاسع

الضروس الامامية : وتشمل

الضرس الاول و تظهر فى الشهر الثانى

و الضرس الثانى يظهر فى الشهر الثانى

و الضرس الثالث يظهر فى الشهر الثانى

ثم يحدث عملية استبدال لها باسنان مستديمة

الاسنان المستديمة :

القواطع : تشمل الثنائيان تظهر عند عمر 2.5 عام.

و الرباعيان تظهر عند عمر 3.5 عام.

و القارحان تظهر عند عمر 4.5 عام.

الانياب : وتظهر عند عمر من 4 _ 5 اعوام

الضروس الامامية : وتشمل الضرس الاول يظهر عند عمر 2 _3 عام

و الضرس الثانى يظهر عند عمر 2 _ 3 عام

و الضرس الثالث يظهر عند عمر 3 _ 4 عام

الضروس الخلفية : وتشمل الضرس 1 يظهر عند عمر 1 عام

و الضرس 2 يظهر عند عمر 2 _ 3 عام

و الضرس 3 يظهر عند عمر 3 _ 4 عام
صورة توضح شكل الاسنان المستديمة فى الخيل وظهور الناب

كيفية التميز بين الاسنان اللبنية والمستديمة :

وتتميز المجموعة اللبنية عن المستديمة بان لها عنق واضح و جذر دقيق كما انها اصغر حجما و اكثر بياضا
عند تقدير العمر فى الخيول يرلعى الى جانب معرفة اوقات ظهور الاسنان وتبديلها ايضا فحص العلامات الخاصة والمميزة لها وهى:
1- سطح القواطع Occlusal surface
ويختلف مظهره الخارجى فيكون بيضاويا (عند عمر 4 _ 7 سنوات) و بتقدم العمر يصبح دائرى (عند 8 سنوات) ثم مثلث (عند 9 سنوات)
2- التجويف Infundibulum
انخفاض على سطح القواطع مخروط الشكل قاعدته لاعلى اسود اللون نتيجة امتلاءه بالمواد الغذائية

ويكون بيضاوى الشكل (عند عمر 4 _ 8 سنوات) و بتقدم العمر يصبح دائرى (عند 9 سنوات) الى ان يصبح نقطة صغيرة (عند عمر 12 سنة)
3- النجمة السنية Dental star
خط دقيق امام التجويف يكون لونه عاجيا
يبدا ظهوره (عند عمر 9 سنوات) عندما تصبح السنة مثلثة
تتضح عند عمر العاشرة كخط طولى على سطح القواطع بالعض خلف الحافة الخارجية للسنة مباشرة
4- اخدود جلفاين
اما بالنسبة الى العمر من 11 الى 30 عام فيكون عن طريق اخدود جلفاين الذى يظهر على بداية القارح الاعلى و يمتد حتى يصل الى منتصف القارح فى عمر 15 عام و يمتد الى نهاية القارح فى عمر 20 عام و يبدىء فى الاختفاء من اعلى حتى يختفى نصفه العلوى فى عمر 25 عام ثم يختفى تماما فى عمر 30 عام

 

 

الرسم التخطيطى التالى يوضح وضع الاسنان فى الخيل

لاحظ شكل ووضع القواطع فى شكل جانبى والشكل الاخر يوضح شكل قمة القواطع
كما لاحظ بالشكل الايمن وع الانياب

 

By one year old, your foal will have a mouth full of
24 deciduous baby teeth and two wolf teeth.

The first permanent incisors will come in at 2 ½ years as will
the second premolars.
Permanent central incisors have erupted baut are not in
contact. Lowers are not yet free of the gum over much of
their surface.
The chewing surface of the intermediates is worn to smooth.
Corners show definite wear.
The teeth then alternate their arrival with the 3rd premolars
at 3 years, second incisors at 3 ½ years, 4th premolars at 4
years, and third incisors at 4 ½ years.
The third molars also come between 3 ½ - 4 years.

In male horses, the canines will appear in the bars of their
mouth at 4 to 5 years of age.
Some mares may develop rudimentary canines depending on
the presence of canines and wolf teeth.
Permanent dentition is complete. All teeth are in
wear.
The canine teeth have erupted fully.
The centrals and intermediates show wear on the chewing
surfaces, but cups are still visible and are completely
encirecled by enamel.
Corners are beginning to wear.
By the time your horse is five years old, all the permanent teeth should be through and the gums should be a healthy pink colour with no bruising.

The angle of the horses jaw and
teeth is increasingly oblique.
The chewing surfaces of the lower
centrals and intermediates are
rounded.The dental star is more distinct
and near the centre of the teeth.
Upper intermediates are nearly
smooth with cups disappearing.
Galvaynes groove appears on the
upper corner incisor.
Your adult horse will have 36 to 42 permanent teeth.

The lower incisors may appear shorter than the
uppers when viewed from the front.
Galvaynes groove extends halfway down the
outer (lip) side of the upper corner incisor.
The lower centrals and intermediates appear
triangular on the chewing surface.
All incisors show a distinct dark round dental
star in their centres.

Angulation of the jaw is
distinctly oblique.
Galvaynes groove extends the
entire length of the upper
corner incisor.
All incisors are triangular.
Each dental star is round near
the centre.
There is considerable spacing
between the teeth.
The lowers may be worn almost to the gum.

As you can see by the Blue dots above the upper inscissors show an uneven growth or emergance. The red line connecting the dots shows the growth line of the upper inscissors and shows how uneven it realy is. The bottom red line shows how the ends of the upper inscissors are affected by the growth pattern. They are not even. This can hinder aging a horse but there are a few other guide lines to show the age. The longer teeth are the more correct.

As you can see by the third upper inscissor the Galvayne's groove is running the whole length of the tooth thus again giving the suggestion that the horse is about 20 years old. On this side of the mouth you can also see the forward angulation occuring esp with the lower inscissors. The last two upper inscissors show the forward angulation occuring which this side is showing closer to a normal growth and wear pattern.

The lower inscissors show the angulation of the teeth as indicated by the red lines. The older the horse the more the teeth begin to angle more forward. The bottom inscissors are more in line and have a more precise wear pattern. The third upper inscissor does show the more forward angulation occuring (black arrow) and shows the Galvayne's groove very plainly. The Galvayne's groove (if showing up well, for not all Galvayne's groove show up nicely) This is a good aging indicator. The Galvayne's groove when showing from the top of the tooth at the gum line and is evident all the way down the tooth (like its showing) means the horse is 20 (or very close to it). The Galvayne's groove begins at the top of the tooth at age 10, once its half way down the horse is about 15 and the whole way down the horse is about 20. After that the Galvayne's groove begins to disappear at the top and the teeth become more angled forward and more round. The dental star will become more round and centered. The Disappaering Galvayne's groove happens when the horsebegin to be about 20-23 years and half way gone is 25, all the way gone is 30. Once a horse hits over the age of 10 its gets harder to age a horse. Usualy an aproximation is used after the age of 10 to 15. An margin of error is 3 years. Also circled in green is a small tush which is more common in male horses can indeed occur in females though they are usualy much smaller in size

This is photograph of an upper corner incisor in a 5 year old Quarter Horse mare. A Galvayne's groove is not visible. That isn't surprising since a Galvayne's groove is not expected to begin showing until a horse is approximately 10 years old. NOTE: A groove can be seen in the tooth to the right, but it is not a Galvayne's groove. A Galvayne's groove has a dark or brownish color, and this groove has no color

This is photograph of a Galvayne's groove in a 15 year old Quarter Horse gelding. It is almost halfway down the tooth. Since a Galvayne's groove is expected to first be visible at the top of the tooth around age 10, and to extend about halfway down the tooth at age 15, this horse's groove is representing his age accurately.

This is a Galvayne's groove in a 26 year old one-half Quarter Horse, one-half Belgian gelding. According to the the generally accepted theories regarding the groove, this one is not representing the horse's age accurately and is indicating he is younger than he actually is. By age 20 the groove should extend all the way from the top of the tooth to the bottom, and at age 26 this horse's groove still hasn't reached the bottom. In addition, after age 20 the groove is expected to begin to disappear from the top of the tooth, and this horse's groove is still clearly visible at the top.

This is a Galvayne's groove in a 26 year old Quarter Horse mare. Similar to the horse immediately above, the groove alone is not indicating her age accurately and is making her appear younger than she actually is. It has barely reached the bottom of her tooth and is still clearly visible at the top. Using the Galvayne's groove alone, you would guess this mare to be about age 20

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