Repeated Early Embryonic Loss in a Thoroughbred Mare with a Chromosomal Translocation [64,XX,t(2;13)]

Peripheral blood samples from a 13-year-old Thoroughbred mare were submitted for chromosome analysis. The mare had a poor reproduction record only producing four live foals during her 10 years as a broodmare. She had remained barren or experienced early embryonic loss in the other 6 years. Chromosomal analysis revealed the mare carried a rare nonreciprocal translocation involving chromosomes 2 and 13 [64,XX,t(2;13)]. Fluorescence in situ hybridization with probes specific for horse chromosomes 2 and 13 were used to confirm the nonreciprocal translocation. Both conventional and molecular cytogenetic techniques are important for identifying and characterizing chromosomal abnormalities in horses with poor reproductive performance, particularly in mares experiencing repeated early embryonic loss.     

Laparoscopic Gonadectomy in Two Intersex Warmblood Horses

Two phenotypically female Warmblood horses were presented at the Clinic for Horses owing to stallion-like behavior. One mare had an enlarged clitoris, whereas the other one showed no signs of ambiguous external genitalia. In both cases, intra-abdominal testicles were removed by laparoscopy. Hormone status, cytogenetic evaluation, and histopathological examination of the gonads were performed. One animal was diagnosed as having XX disorder of sexual development; the other one, as male pseudohermaphrodite.     

A de novo reciprocal chromosomal translocation t(3;6)(p14;q26) in the black Lucano pig

In the past two decades, several cytogenetic screening programmes identified different chromosome rearrangements in pig, most of which represented by reciprocal translocation (rcp). This chromosome abnormality does not involve the variation in the number of chromosomes, but only the rearrangement of genetic material, resulting in phenotypically normal carriers with fertility problems. During an occasional cytogenetic screening, a new reciprocal translocation was detected in the black Lucano pig native breed. We analysed 15 animals reared by a family-run piggery in Basilicata region (Southern Italy). After karyotyping, four pigs (two boars and two sows) revealed two unpaired chromosomes. Analysis of the RBA karyotype and the dual-colour FISH technique confirmed that these pigs showed the same reciprocal translocation involving the chromosomes SSC3 and SSC6. The precise location of breakpoints was identified by RBH-FISH t(3;6)(p14;q26), whereas the analysis of the pedigree showed a case of Mendelian inheritance within a family, after the de novo occurrence of the new rcp. Considering the consequences of the rcp on the fertility, this study points out the importance of the cytogenetic screening in the native breeds for the safeguard of the genetic biodiversity and the sustainability of the rural areas.     

Successful reduction of a monozygotic equine twin pregnancy via transabdominal ultrasound‐guided cardiac puncture

In horses, twin pregnancy is pathological and represents a potentially life‐threatening condition to the mare and foal. Twinning occurs in approximately 2% of pregnancies. Of these, the majority of cases are dizygotic twins, resulting from 2 ovulations and monozygotic twins are rare. A 12‐year‐old Quarter Horse mare was presented for breeding management with shipped cooled semen and embryo transfer. Seven days post ovulation, a single late morula/early blastocyst was recovered and transferred immediately to a recipient mare. Thirty‐six days after transfer, transrectal ultrasound examination revealed the presence of 2 embryos. A transcutaneous reduction of one of the fetuses was performed successfully at 128 days of gestation. This report is the first to describe a successful reduction of monozygotic twins by transcutaneous ultrasound‐guided cardiac puncture.     

Reciprocal translocations in cattle: frequency estimation

Chromosomal anomalies, like Robertsonian and reciprocal translocations, represent a big problem in cattle breeding as their presence induces, in the carrier subjects, a well‐documented fertility reduction. In cattle, reciprocal translocations (RCPs, a chromosome abnormality caused by an exchange of material between non‐homologous chromosomes) are considered rare as to date only 19 reciprocal translocations have been described. In cattle, it is common knowledge that the Robertsonian translocations represent the most common cytogenetic anomalies, and this is probably due to the existence of the endemic 1;29 Robertsonian translocation. However, these considerations are based on data obtained using techniques that are unable to identify all reciprocal translocations, and thus, their frequency is clearly underestimated. The purpose of this work is to provide a first realistic estimate of the impact of RCPs in the cattle population studied, trying to eliminate the factors that have caused an underestimation of their frequency so far. We performed this work using a mathematical as well as a simulation approach and, as biological data, we considered the cytogenetic results obtained in the last 15 years. The results obtained show that only 16% of reciprocal translocations can be detected using simple Giemsa techniques, and consequently, they could be present in no <0.14% of cattle subjects, a frequency five times higher than that shown by de novo Robertsonian translocations. This data is useful to open a debate about the need to introduce a more efficient method to identify RCP in cattle.     

Anaplastic malignant melanoma of the tail in non‐grey horses

Information regarding signalment, clinical findings, treatment and outcome of 5 previously reported cases of anaplastic malignant melanoma of the tail in non‐grey horses and of 5 additional cases are summarised. Age was recorded for 9 horses and mean age was 16 years, range 8–23 years. Gender was recorded for 8 horses and 6 of these 8 horses were male horses over 14 years of age. The most common coat colour was bay (6 horses). Other coat colours were palomino (one horse), chestnut (one horse) and black (one horse); coat colour of one non‐grey horse was not specified. Follow‐up information was available for 9 horses and only one horse, a palomino, survived more than 10 months following diagnosis and tail amputation. Surgical excision, including tail amputation and medical therapy with oral cimetidine, was not effective in non‐grey, non‐palomino horses. Tumour recurred on tail tissue remaining after amputation in 2 horses, widespread metastases were documented in 4 cases and metastasis was suspected at the time of death or euthanasia in 3 cases, including one case with amputation site regrowth. No subjective histopathological differences were detected in the palomino horse that survived as compared to horses of other coat colours. Findings suggest that anaplastic malignant melanoma of the tail in non‐grey horses is most often a very aggressive neoplasm, but that there are rare exceptions.     

Pelger-Huët anomaly in an Arabian horse

Abstract Abstract: A 9‐year‐old Arabian mare was evaluated for a 7‐day history of malaise. Results of a CBC included a leukocyte concentration within the reference interval (8.4 × 10³/μL, reference interval 6.0–14.0 × 10³/μL) with an apparent degenerative left shift (segmented neutrophils 1.2 × 10³/μL, reference interval 2.5–7.5 × 10³/μL; hyposegmented neutrophils 1.8 × 10³/μL, reference interval 0.0–0.2 × 10³/μL). Serum clinical chemistry results included increased aspartate transaminase, alkaline phosphatase, and gamma‐glutamyltransferase activities. A presumptive diagnosis of hepatitis or cholangiohepatitis was made. The horse was treated with antimicrobials and the malaise quickly resolved. However, in a recheck CBC on day 13, the apparent degenerative left shift remained. Further evaluation of the blood smear revealed many hyposegmented granulocytes with coarse mature chromatin and normal cytoplasmic features. On the basis of the microscopic examination, the horse was diagnosed with Pelger‐Huët anomaly. The patient's offspring was subsequently also diagnosed with Pelger‐Huët anomaly on the basis of blood film examination. Neutrophil, eosinophil, and basophil mean nuclear scores in both affected horses (mare, range 1.5–2.6; offspring, range 1.6–3.2) were lower than those in 2 unrelated Arabian horses (range, 2.8–5.0) and 5 non‐Arabian control horses (range, 2.8–5.0). Results of immunophenotyping and phagocytosis/oxidative burst assays via flow cytometry showed no difference in the expression of myeloid–specific or adhesion molecules or in neutrophil function between affected and control horses. This is the second known report of equine Pelger‐Huët anomaly, both of which affected Arabian horses.     

Hereditary equine regional dermal asthenia (HERDA) in Quarter Horses: A review of clinical signs,genetics and research

Hereditary equine regional dermal asthenia (HERDA) results from a genetic mutation which affects the skin and other tissues of Quarter Horses and horses with Quarter Horse lineage. The disease HERDA has an autosomal recessive mode of inheritance and has become a significant concern in the Quarter Horse industry due to the high frequency of heterozygote carriers. Affected homozygous horses appear normal at birth; however, within the first 2 years of life they usually acquire loose, hyperextensible skin and wounds which result in disfiguring scars either spontaneously or from minor trauma. Some severely affected horses also develop haematomas and seromas. Consequently, most affected horses are subjected to euthanasia at an early age. No treatment options other than palliative therapy currently exist. As part of a five panel test ( http://www.aqha.com/News/News-Articles/2013/April/04292013-Genetic-Testing.aspx ) the American Quarter Horse Association presently requires DNA testing for HERDA on all breeding stallions. There are currently no restrictions on registration of horses heterozygous or homozygous for the HERDA mutation. Due to the autosomal recessive nature of the disease, Quarter Horse mares and horses of all breeds from HERDA‐associated bloodlines should also be tested.     

Haemoperitoneum in a pregnant mare with an ovarian haematoma

Haemoperitoneum is a rarely reported but life‐threatening complication of a multitude of disease processes that can affect horses. This report describes an unusual case of haemoperitoneum in a pregnant mare attributed to a unilateral ovarian haematoma during early gestation. The mare was treated with supportive care and discharged 8 days after initial presentation. Following discharge, the mare maintained her pregnancy to term and delivered a live colt at 321 days of gestation.     

XO-gonadal dysgenesis in the mare (report of two cases).

TWo cases of XO-gonadal dysgenesis in the mare are presented. Case No 1 was a pure 63, XO, while Case No 2 was a mosaic with a preponderance of XX cells. The clinical picture was one of phenotypically normal female mares with small uteri and infantile ovaries. The ovaries lacked germ cells, and consisted of stroma only. This study emphasizes the importance of chromosome analysis in providing information concerning the mechanisms involved is some cases of equine infertility.     

Premature luteal regression in a pregnant mare and subsequent pregnancy maintenance with the use of oral altrenogest

Premature luteal demise or luteal insufficiency is not well characterised as a cause of pregnancy loss in domestic species, including horses. In this report, a mare inseminated with cooled‐transported semen at our facility returned for a routine pregnancy diagnosis at 15 days post ovulation. Ultrasonography per rectum revealed endometrial oedema and the absence of visual indication of a corpus luteum on either ovary. Nonetheless, an embryonic vesicle small for the gestational age was identified. Daily oral altrenogest treatment was implemented immediately. Serum progesterone concentration was 0.67 ng/ml, which is below the threshold considered adequate for pregnancy maintenance in the mare. Examinations were repeated at 17, 25, 30, 39, 49, 72 and 120 days post ovulation. At 25 days post ovulation the embryonic vesicle presented normal development for the gestational age. In addition, sequential blood samples were collected to measure progesterone, equine chorionic gonadotrophin and oestrone sulphate concentrations. Although progesterone concentration did not exceed 2 ng/ml until 72 days post ovulation, all other results were unremarkable and a healthy filly was born uneventfully at 344 days post ovulation.     

Successful treatment of a horse with presumed parasitic encephalitis

Verminous myeloencephalitis is a rare, but predominately fatal, cause of neurological disease in horses. A 6‐year‐old mare was admitted to the Royal Veterinary College Equine Referral Hospital following acute onset of depression, central unilateral blindness and compromised vision in the opposite eye. Based on pronounced eosinophilic inflammation detected in the cerebrospinal fluid (CSF) and diagnostic imaging findings indicating a space‐occupying lesion within the brain, a presumptive diagnosis of aberrant parasitic migration causing parasitic encephalitis was made. Treatment consisted of anti‐inflammatories and high doses of an anthelmintic. The horse's condition improved, the neurological deficits and observed space‐occupying lesion within the brain resolved completely and the mare returned to full work. To the authors’ knowledge, this is the first report describing complete recovery from suspected aberrant parasite migration in the CNS and will hopefully encourage treatment of suspected cases in the future.     

Sex determination by simultaneous amplification of equine SRY and amelogenin genes

A quick method for sex determination of horses was developed. Simultaneous amplification of the equine sex-determining region of the Y chromosome gene (SRY) and amelogenin gene (AMEL) accomplished the determination of the presence of both the Y chromosome and SRY gene. In agarose gel electrophoresis, a normal stallion showed 1 SRY band and 3 AMEL (AMELX, AMELY, and AMELX/AMELY heteroduplex) bands, and a normal mare showed a single AMELX band. In XY-mares, 3 AMEL bands were detected as in a normal stallion, but no SRY band. The present method enables a quick diagnosis for XY-mare prior to cytogenetic analysis.     

Frequency of the severe combined immunodeficiency disease gene among horses in Morocco

Severe combined immunodeficiency disease (SCID) of horses is an autosomal, recessive hereditary disease occurring among Arabian or crossbred Arabian horses. The genetic defect responsible was previously identified as a 5‐base pair deletion in the gene encoding the catalytic subunit of the DNA dependant protein kinase (DNA‐PKcs). This study was carried out to determine the frequency of SCID and identify horses carrying the gene for SCID among Arabian and Arabian crossbred stallions and mares in Morocco using a DNA‐based test. Twenty‐one horses were SCID carriers: 14 (7%) Arabians, 6 (4%) Arab‐Barbs and one (3.3%) Anglo‐Arab. After analysing their genealogy, 3 imported stallions were identified that disseminated the mutant gene of DNA‐PKcs in Morocco.     

A Tapered‐Sleeve Transcortical Pin External Skeletal Fixation Device for Use in Horses: Development,Application, and Experience

Objective— To report development, configuration, application, and results of a tapered‐sleeve transcortical pin external skeletal fixation device (TSP ESFD) for use on fractures of the distal aspect of the equine limb. Study Design— Optimization analysis of a TSP ESFD was carried out with mechanical testing and review of clinical case outcomes. Animals— Cadaveric adult third metacarpal bones (MC3) for mechanical testing; horses (n=7) with severely comminuted proximal (6; P1) or second (1) phalanx fractures. Methods— Mechanical testing of methods for attachment of TSP to the sidebars were tested as well as optimization of pin diameters. Outcome of clinical cases managed with the TSP ESFD were compared with outcomes of horses treated with previous ESFD. Results— A TSP ESFD using 7.94 mm diameter pins was used. Survival rate was 71%. One horse with an infected P1 fracture and contralateral laminitis subsequently fractured MC3 through the distal pin hole while wearing the TSP ESFD. One mare with contralateral laminitis was euthanatized. Three horses had open fractures. Conclusions— Design improvements incorporated into the TSP ESFD should increase treatment success. Clinical Relevance— External skeletal fixation continues to be a viable treatment alternative for severe injuries of the distal aspect of the equine limb. TSP ESFD should improve on the success of treatment by decreasing complications of bone fracture at the pin interface.     

Type IV rectal prolapse secondary to a long‐standing urinary bladder lithiasis in a donkey

Rectal prolapse has been attributed to conditions generating tenesmus or increasing abdominal pressure in both horses and donkeys. This report presents the case of a 7‐year‐old gelded donkey that sustained a type IV rectal prolapse secondary to a long‐standing cystic calculus after several episodes of intermittent mucosal prolapse. Rectal prolapse was addressed first on an emergency basis by colorectostomy. After medical stabilisation, pain and straining management with repeated epidural drug administrations, a laparoscopic‐assisted cystotomy was performed one week later to remove the calculus. The donkey was discharged and resumed his normal life at pasture.     

Centric fusion translocations in cattle: a review

The incidence of centric fusion (Robertsonian) translocation in cattle breeds is reviewed. Thirteen different centric fusions have been identified in cattle, with few breeds carrying more than one translocation. Of the commercial breeds, Friesian-Holstein cattle appear to be free of translocations, while the Simmental is the only one which carries three translocations. The major effect of centric fusion is on fertility, causing unbalanced gametes and hence unbalanced zygotes to be formed, leading to early embryonic death. However, to discard all translocation-carrying animals may be misguided as they represent genetic variation and a source of desirable traits.     

Nutritional management and practical feeding of the orphan foal

Foals are dependent on a milk‐based diet for the first 3–4 months of life. If they are orphaned during this period they require appropriate nutritional and behavioural management to allow them to develop into sound, well‐grown horses and ponies with well established normal behavioural patterns. In order to meet these needs it is necessary to understand the metabolic requirements of the foal and the composition of mares' milk. Usually managing these foals requires short‐term, emergency feeding of the foal while a long‐term option is sought. Long‐term options include use of a foster mare, induction of lactation in a parous, barren mare or hand rearing with suitable equine company. It is important to monitor growth and development of these foals to ensure that over the long term their nutritional needs are being met to allow normal growth and development.     

Laparoscopic techniques for investigating the equine oviduct

Reasons for performing study: The diagnostic and therapeutic options for oviduct disorders in the mare are limited. The current best techniques require exploratory surgery under general anaesthesia or flank laparotomy. Hypothesis: The orthograde flushing of the oviduct for diagnostic or therapeutic options is possible using laparoscopic techniques in the standing sedated mare. Methods: Development of a laparoscopic technique for catheterisation of the infundibulum and flushing of the oviduct (sterile methylene blue solution) in the standing sedated mare was examined in 2 experiments. The first involved a transvaginal laparoscopic approach, the second a laparoscopic flank approach. Passage of fluid into the uterus was assessed by post operative hysteroscopy. Results: In Experiment I, visualisation of the infundibulum was possible (left side 7/8 cases, right side in 6/8 cases). The beginning of the oviductal ampulla could be seen in 3 of 8 cases on the left side. An adequate opening of the infundibulum and visualisation or catheterisation of the abdominal ostium were not possible. In Experiment II, catheterisation of the ampulla was successful in 7 of 11 cases, and in 5 of these 7 cases the injected fluid could be identified in the uterus by post operative hysteroscopy. Conclusion: A transvaginal laparoscopic approach to the oviduct is not appropriate for oviductal flushing in the mare. However, a laparoscopic flank‐approach permits investigation and flushing of the oviduct. Potential relevance: Laparoscopic flushing could become a practical method for diagnosis and therapy of oviduct disorders and a minimally invasive technique for collection of young embryos or the transfer of gametes (GIFT).