2010, Vol. 5 No. 1, Article 54

Characterizations of Chestnut in Relation to Age, Height and Body Weight in Equines

Gholam Ali Kojouri¹*, Mohammad Shadkhast², Bijan Ziaiie³, and Camellia Taghadosi³

¹Associate Professor, Department of Clinical Science
²Assistant Professor, Department of Basic Sciences
³DVM, Graduated Veterinary Student
School of Veterinary Medicine, Shahrekord University, P. O. Box 115, Iran.

*Corresponding Author; e-mail address: kojouri@vet.sku.ac.ir

ABSTRACT

A study was carried out on 100 horses of Thoroughbred (20), Arabian (20) and Akhal-Teke breeds (60) to determine chestnut dimensions and its relation with age of horse and length of respective limbs. Results showed that the means of forelimb chestnut length (2.604±0.601 cm) and width (1.617±0.41 cm) were significantly more (P<0.01) than hind limb chestnut length (2.202±0.627 cm) and width (1.313±0.388 cm). In Thoroughbreds hind limb length was significantly more than that of Arabian and Akhal-Teke breeds and in Arabian breeds it was more than Akhal-Teke (P<0.05). The length of fore limb in Akhal-Teke breed was significantly less than that of Arabian breed (P<0.014). The length of chestnut increased (r= +0.829, P_value= 0.021) and and width decrease (r= -0.724, P_value= 0.043) with aging in Arabian and Thoroughbred horses, the chestnut dimensions varied with the age, body weight and length of respective limbs in horses.

KEY WORDS

Chestnut, Equine, Arabian breed, Akhal-Teke breed, Thoroughbred.

INTRODUCTION

Chestnut (Torus carpus, Torus tarsseus) is a keratinized process with a thick end containing keratinized membrane and corium. This process originates from hypodermal glands without any sweat/sebum glands and appears like a frog in histological resection (Nickle et al. 1986; Sisson and Grossman 1997; Raymond and Ashdown 1996). The equine chestnuts may be of oval shape with round ends in forelimbs to irregular shape with sharp ends in hind limbs (Nickle et al. 1986) and are bigger in horses with heavier body weight (Vega et al. 1997 ). Principally, chestnuts in forelimbs are longer than those of hind limbs, chestnut in onager, donkey and mule is a highly pigmented area that has a round shape with smooth and soft surface (Sisson and Grossman 1997). Merge information is available about the shape and characterization of hind and fore limb chestnut of the Thoroughbred, Arabian and Akhal-Teke) breeds of horses, The present study was therefore under taken to determine the dimension and shape of chest nut and its relation to the length of hind and fore limbs, age and body weight in these equine breeds.

MATERIALS AND METHODS

The study was carried out on 100 pure breed horses comprising, of Thoroughbred (20), Arabian (20) and Akhal-Teke breeds (60), aged (7.84±3.32) years, weighing( 623.6±471.7) Kgs to determine the shape and dimensions of chestnut in fore and hind limbs with relation to, age body weight and length of respective limbs of the horse. The distances from shoulder joint and tuber ischium to the ground level was taken as the length of fore limb and hind limb respectively. After hoof trimming, all four limb chestnuts were molded using special human dentistry powder (Albejinat Beyer^®) One teaspoon of the powder was mixed with 50 ml water and after one minute, the paste was spread over a plastic ribbon. The ribbon was applied on the chestnut to mould within 5 minutes. After separating the ribbon, length, width, and depth of each chestnut mould was recorded with caliper., taking two dimensional views from the surface and depth of the moulds by using 3dmax computer programme Results were analyzed by Sigmastat (2nd version) program, using One Way Analysis of Variance (ANOVA) and Pearson Correlation at the level of P<0.05.

RESULTS and discussion

The shape of equine chestnut was highly variable, from oval to circular oval, amygdalate, gyrate, bean shape and in some cases indistinguishable.( table 1 and figures 1 to 4). The correlation between the chestnut size and length of respective limbs, age and body weight of horses is indicated at table 2 & 3.
The length of hind limb in Akhal-Teke horses was significantly (P<0.001) less than that of Arabian and Thoroughbreds. Arabian horses had significantly shorter (P<0.004) hind limbs than those of Thoroughbreds. Akhal-Teke breed had significantly (P<0.014) shorter forelimbs than those of Arabian breed. The length of hind limb chestnuts was significantly (Left P<0.014 and right P<0.028) more in Thoroughbreds than in Akhal-Teke breed.
In Thoroughbred horses, there was a negative and significant correlation between the left hind chestnut width and age (r= -0.724, P_value= 0.043) and a positive correlation between the body weight, and length of hind limb (r= +0.723, P_value= 0.0425). A significant negative correlation between the width of left hind limb chestnut and the age of horses was also observed.
In Arabian breed a positive and significant correlation was recorded between chestnut length of the left front and the age of the horse (r= +0.829, P_value= 0.021). Also, a positive and significant correlation existed between the length and the width of the right front chestnut (r= +0.818, P_value= 0.0246) and there was a negative and significant correlation between the fore limb length and body weight (r= -0.799, P_value= 0.0309). These finding were in conformity with the reports of Nickle et al. (1986).
A positive and significant correlation was observed between the length and the width of right hind chestnut of Akhal-Teke horses (r= +0.922, P_value= 0.0013). On increase in body weight of this breed, the width of the left hind chestnut showed a significant decrease (r= -0.819, P_value= 0.0129). Also, there was a negative and significant correlation between the width of left hind chestnut and the hind limb length (r= -0.701, P_value= 0.05). The present findings indicated that the chestnut dimensions are affected by the age of the horse , its body weight and length of the respective limbs.

REFERENCES

1. Ensminger ME. Horse and Horsemanship (1990). 6th (Ed), Interstate publishers, United State of America.

2. Judith D (1997). The new guide to horse breed.1st (Ed), Ultimate edition, United Kingdom.

3. Nickle R, Schummer A, Seiferle E (1986). The anatomy of the domestic animals. Berlin, Humburg: Verley Poul Parcy, 3.

4. Raymond R, Ashdown SD (1996). Color Atlas of Veterinary Anatomy. London: Mosby-Wolf, 2.

5. Sisson S, Grossman JO (1975). The anatomy of domestic animals. Philadelphia: WB Saunders, 3.

6. Vega JL, Molina A, Valera M, et al. (1997). Conservation of an equine feral breed: the Asturcón Pony. Animal Genetic Resources Information, 22, 29-42.

7. Wattle OS (2001). Cytokeratins of the matrices of the chestnut (torus carpeus) and periople in horses with acute laminitis. American Journal of Veterinary Research, 62, 425-432.

8. Wattle O (1998). Cytokeratins of the equine hoof wall, chestnut, and skin: bio- and immunohisto-chemistry. Equine Veterinary Journal Supplement, 66-80.

Table 1: chestnut shape in different breeds of horses

Figure 1: Circular oval shape chestnut mold (Right front of Arabian breed)

Figure 2: Bean shape chestnut mold (Left front of Thoroughbred horse)

Figure 3: Elongated oval shape chestnut mold (Right front of Thoroughbred horse)

Figure 4: Indistinguishable shape chestnut mold (Left hind of Thoroughbred horse)

Table 2: Results of performing ANOVA test on chestnut and other parameters data's in three different breed of horses
(click to enlarge)

Table 3: Results of performing Pearson correlation test on chestnut and other parameters data in three different breed of horses
(click to enlarge)