Publications by authors named "Sharon May-Davis"

In recent years, equine complex vertebral malformation (ECVM) has been of concern in the equine community, with studies identifying numerous associative morphological variations. Here, we examine the morphological association between C6 and C7 for dependency in ECVM cases, where the partially absent ventral process of C6 transposes on the ventral surface of C7. A C6 ventral process presents two tubercles, one cranial (CrVT) and one caudal (CVT).

View Article and Find Full Text PDF

This study examined the anomalous variations of the ventral process of C6 in modern The aim was to provide an incremental grading protocol measuring the absence of the caudal ventral tubercle (CVT) in this ventral process. The findings revealed the most prevalent absent CVT (aCVT) was left unilateral ( = 35), with bilateral ( = 29) and right unilateral ( = 12). Grading was determined in equal increments of absence 1/4, 2/4, 3/4, with 4/4 representing a complete aCVT in 56/76, with a significance of 0.

View Article and Find Full Text PDF

In this study, we examined the ventral process of C6 in extinct and extant (sister taxa to only) with the purpose of describing normal morphology and identifying anomalous variations relevant to recent studies describing a congenital malformation in . Overall, 83 specimens from 9 museums and 3 research/educational facilities were examined, totalling 71 extinct specimens from 12 species and 12 extant specimens from 5 species. The lateral view revealed that a large convexity exists in the ventral process between the cranial ventral tubercle (CrVT) and the caudal ventral tubercle (CVT) in the earliest ancestor, , from 55 mya, which receded throughout the millennia to become a smaller convexity in and the sister taxa.

View Article and Find Full Text PDF

The Yonaguni pony is a rare breed of pony that has remained isolated on the westernmost island of Japan and may well retain normal morphological traits currently lost in most domestic horses (Equus caballus), such as the attachment of the nuchal ligament lamellae (NLL) from C2-C7. Recent research has found that NLL attachments are no longer present at C6 and C7 in most modern domesticated horses. This study investigated the attachments of the NLL in three Yonaguni ponies; 2 were examined in situ(deceased), and 1 was examined in vivo via ultrasound.

View Article and Find Full Text PDF

Ultrasound is a well-established modality in equine investigative and diagnostic procedures. Although to date, it has not been utilized in examining the attachments of the equine nuchal ligament lamellae (NLL) onto the cervical vertebrae, for which a noninvasive technique is currently lacking. This study presents a standardized methodology for investigating the equine NLL using ultrasonography, and further evaluates the ultrasound images against postmortem dissection in two nonrelated horses.

View Article and Find Full Text PDF

For over 200 years, equine anatomic literature has chiefly portrayed the attachment points of the nuchal ligament lamellae (NLL) from the second to the seventh cervical vertebrae (C2-C7). However, recent studies have shown that the modern domestic horse, Equus caballus, primarily exhibits the attachments points from C2-C5. Here we present the rare finding of a complete NLL attached from C2-C7 in one Australian Stock Horse (ASH) and discuss the potential implications of these findings.

View Article and Find Full Text PDF

Conflicting data predominantly describes the equine nuchal ligament lamellae (NLL) attachments as C2-C6 or C2-C7; however, preliminary evidence suggests C2-C5. This study aimed to identify morphological variations in the attachments of the NLL in four species of the family equidae and determine if the variations were species or breed linked. Cadaveric examination evaluated 98 equids; Equusasinus (n = 2), Equus ferus caballus (n = 93), Equus przewalskii (n = 2), and Equus quagga boehmi (n = 1).

View Article and Find Full Text PDF

The 55-million-year history of equine phylogeny has been well-documented from the skeletal record; however, this is less true for the soft tissue structures that are now vestigial in modern horse. A recent study reported that two ligamentous structures resembling functional interosseous muscle II and IV were evident in Dutch Konik horses. The current study investigates this finding and compares it to members of the genus to identify either a breed anomaly or functional primitive trait.

View Article and Find Full Text PDF

Hereditary multiple exostoses (HME) is a condition rarely diagnosed in horses, which has not been previously reported in Dutch Warmblood horses. Its presentation resembles that diagnosed in humans, and it is predominantly active during periods of skeletal maturation. This case study reports a link between a granddam with no obvious HME lesions and its first and second generations presenting with HME, albeit with different sires.

View Article and Find Full Text PDF

The Dutch Konik is valued from a genetic conservation perspective and also for its role in preservation of natural landscapes. The primary management objective for the captive breeding of this primitive horse is to maintain its genetic purity, whilst also maintaining the nature reserves on which they graze. Breeding selection has traditionally been based on phenotypic characteristics consistent with the breed description, and the selection of animals for removal from the breeding program is problematic at times due to high uniformity within the breed, particularly in height at the wither, colour (mouse to grey dun) and presence of primitive markings.

View Article and Find Full Text PDF