Correlation between radiographie and arthroscopic findings in the equine carpus

The radiographic and arthroscopic findings in 150 carpal joints in 114 lame horses were compared. Chip, slab, or sagittal fractures were identified in 130 (87%) joints. In 101 (78%) of these there was good agreement between radiographic and arthroscopic findings on the number and position of fractures. In 23 (18%) joints, chip fractures additional to those seen radiographically were found arthroscopically. In one joint a large chip fracture from the craniolateral aspect of the distal radius was identified only by arthroscopy, while in 6 joints fractures were identified only by radiography. Observed causes of lameness, other than intra-articular fractures, included degenerative joint disease, synovitis, ruptured intra-carpal ligaments, and haemarthrosis. Correlation between the radiographic and arthroscopic assessment of degenerative joint disease was poor. It was concluded that both radiography and arthroscopy should be used to obtain the most accurate assessment of the equine carpus.     

Myofibroblastic fibrosarcoma with multifocal osseous metaplasia at the site of equine influenza vaccination

We describe a fibrosarcoma in a 12-year-old Quarterhorse × Arabian gelding as a sequela to equine influenza vaccination. Shortly after the second vaccination, swelling at the site was noticed by the owner and it continued to increase in size over the following 6 months. Biopsy of the mass indicated a fibrosarcoma had developed at the vaccination site. It was approximately 20 cm in diameter and elevated well above the level of the skin. There was no clinical evidence of metastases to the lungs or local lymph nodes. Surgical resection of the mass was performed and the wound healed by first and second intention. Histopathological examination and immunohistochemical staining confirmed a myofibroblastic fibrosarcoma with multifocal osseous metaplasia. To the authors' knowledge, this is the first equine case of a vaccine-associated fibrosarcoma.     

Chronic inflammatory disorders of the gastrointestinal tract of companion animals

In the inflammatory bowel diseases (IBD) that affect dogs and cats there appears to be dysregulation of normal mucosal immunity, characterised by polyclonal lymphocytic infiltrates which are presumably specific for luminal antigens. There is an absence of a classical polarisation of either T-helper (Th) 1 or Th2 cytokine responses, although increased expression of mRNA for interleukin (IL) 2 and IL-12p40 and a shift towards mucosal immunoglobulin (Ig) G production are consistent findings, whilst variable responses are seen in tumour necrosis factor-α (TNF-α), IL-1, IL-4, IL-6, and interferon-γ (IFN-γ). Increased mucosal permeability and deranged intestinal motility are common sequelae.

Despite obvious similarities with Crohn’s disease and ulcera- tive colitis in humans, important differences exist. Of these, the diffuse superficial nature but with no Th1 or Th2 bias, and the prevalence of proximal small intestinal disease are notable. Potential hypotheses for these disparities include specific differences in the types or locations of “agonistic” gut flora, diffuse abnormalities in microbial-host interactions, a greater importance of diet, or anatomical or cellular differences in mucosal immune responses.

Although specific pathogens and genetic susceptibilities may be involved, quantitative or qualitative changes in the normal flora or abnormal responses to a normal flora are more likely to be involved in the immunopathogenesis. Dietary influences include a large source of antigen, promotion of abnormal microbial growth through Maillard compounds within canned diets, and specific macro- and micronutrient deficiencies. Although dependent on a histopathological diagnosis, limitations of biopsies procured endoscopically, lack of histopathological standardisation and difficulty distinguishing inflammation from neoplasia remain significant problems. Clinician-pathologist dialogue, immunohistochemistry, cytokine profiling and lymphocyte-clonality assessment may lead to more accurate diagnoses, a deeper understanding of the immunopathogenesis, and ultimately to new therapies or prevention of disease induction.     

Osteochondral fragmentation of the plantar/palmar proximal aspect of the proximal phalanx in racing horses

SUMMARY The clinical presentation and outcome of treatment is presented for 26 cases of osteochondral fragmentation of the plantar/palmar proximal aspect of the proximal phalanx. Twenty-three were racing Standardbreds and three were racing Thoroughbreds. The most common reason for presentation was an inability to run straight at high speed. Only eight horses presented for lameness, although on examination 19 were lame. A positive flexion test was recorded in 90% of affected fetlock joints and effusion in 48%. Arthroscopic fragment removal was performed on 23 occasions in 21 horses and arthrotomy in one horse. Of the 16 horses that had returned to racing, 12 had improved their performance, while three showed no improvement, and one was retired for other reasons. In three horses refragmentation occurred after surgery, two of which had improved after initial arthroscopic removal. Degenerative changes within the fetlock joint were detected at surgery in eight horses. Of the four horses treated conservatively, one returned to its previous level of performance temporarily after intra-articular medication, one showed no improvement and two were still resting. Plantar/palmar osteochondral fragmentation of the proximal aspect of the first phalanx is a common cause of low-grade lameness in racing horses, and arthroscopic removal results in improvement in race performance in a high percentage of cases.     

An epidemiological investigation of an idiopathic myopathy in hunting dogs in New Zealand

AIM: To conduct an epidemiological investigation of an idiopathic myopathy, known as “Go Slow” (GSM), which was initially recognised in dogs used for pig hunting. A secondary aim was to describe the hunting activities, diet and health of dogs used for pig hunting in New Zealand.

METHODS: A retrospective cohort study was conducted between June 2014–June 2017. Cases of GSM in dogs were diagnosed by veterinarians using a combination of clinical history, physical examination findings, serum biochemistry and/or skeletal muscle histology. A telephone interview was conducted with the owner or primary veterinarian to provide information regarding the dog’s diet and exercise over the 7 days preceding the onset of clinical signs. In August 2015, a separate online survey of owners of dogs used for pig hunting was conducted to characterise the normal hunting activities, diet and health of these dogs.

RESULTS: A total of 86 cases of GSM were recruited, of which 58 (67%) were pig hunting dogs, 16 (19%) pet dogs and 12 (14%) working farm dogs. Cases were most commonly reported in the upper North Island, and 65 (76 (95% CI=67–85)%) were from the Northland region. Processed commercial dog food had been fed to 93 (95% CI=88–98)% of affected dogs. Ingestion of raw, frozen or cooked wild pig in the preceding week was reported for 76 (88 (95% CI=82–95)%) dogs with the myopathy. In the survey of owners of healthy pig hunting dogs, 203 eligible responses were received; pig hunting was reported to most commonly occur in Northland (20.2%), Waikato (22.3%) and Bay of Plenty (23.2%) regions. Commercial dog food was fed to 172 (85 (95% CI=80–90)%) of the dogs included in this survey, and 55 (27 (95% CI=20–33)%) had eaten wild pig in the preceding week. The most common reported health problem in pig hunting dogs was traumatic wounds.

CONCLUSIONS: Cases of GSM were most commonly recognised in dogs used for pig hunting, but also occurred in pet and working farm dogs. The disease was most frequently reported in the upper North Island of New Zealand and ingestion of wild pig was a consistent feature in cases of this myopathy.

CLINICAL RELEVANCE: To minimise the risk of dogs developing this myopathy, it would seem prudent to avoid feeding any tissues from wild pigs to dogs in areas where the disease is known to occur.     

Does the Amount of Progesterone in Intravaginal Implants Used to Synchronise Oestrus Affect the Reproductive Performance of Brahman Heifers Artificially Inseminated at a Fixed Time

The study tested the hypothesis that reduced intravaginal implant progesterone (P₄) concentration to synchronise oestrus would increase pregnancy rates to fixed‐time artificial insemination (FTAI) in Bos indicus heifers. Brahman heifers (n = 294; 2 year) were body condition scored (BCS), weighed and scanned for presence of a corpus luteum (CL). Only cyclic heifers were selected and allocated randomly within BCS and 25 kg bodyweight category to one of three P₄ treatment groups. On day 10, heifers received a P₄ implant (CueMate‐1‐pod, 0.78g P₄; CueMate‐2‐pod, 1.56g P₄; or CIDR‐B, 1.9g P₄), 2 mg oestradiol benzoate (ODB) intramuscularly (IM) and 250 ug cloprostenol IM. At day 2, the implant was removed, 250 ug cloprostenol was injected IM and tail paint applied. The heifers received 1 mg ODB 24 h later and were FTAI 48–54 h after implant removal (day 0). Ten randomly selected heifers per group were blood sampled and scanned at days 10, 2, 0 and 6 to define the P₄ profiles pre‐ and post‐FTAI. Heifers were heat‐detected 18–20 days post‐FTAI and oestrous heifers AI’d by the AM/PM rule. Bulls joined the heifers on day 27 post‐FTAI. Transrectal ultrasonography estimated conception date on day 72. Statistical analysis examined the effects of treatment, technician, semen, ovarian status, BCS and liveweight, on pregnancy rate (PR) to FTAI. There was no significant difference (p = 0.362) in PR between treatment groups (CueMate 1‐pod, 36.4%; CueMate 2‐pod, 39.6%: CIDR‐B, 28.3%), but PR was higher in those heifers with increased BCS between FTAI and pregnancy diagnosis (p = 0.005). Thirty‐three per cent of monitor heifers had plasma P₄ concentrations of <1 ng/ml on day 6 after FTAI; only 20% of these conceived vs 60% of heifers with P₄ ≥ 1 ng/ml. In summary, no significant difference in PR was identified between treatments but good BCS and a rising plane of nutrition were critical to PR of these pure grade Brahman heifers in northern Australia.     

Use of Vaginal Electrical Resistance to Diagnose Oestrus,Dioestrus and Early Pregnancy in Synchronized Tropically Adapted Beef Heifers

The primary objective of this study was to determine whether a single measurement of intravaginal electrical resistance (VER), using the commercially available Ovatec^® probe, can discriminate between dioestrus and oestrus in Bos indicus females, which had been treated to synchronize oestrus. Santa Gertrudis heifers (n = 226) received one of three oestrous synchronization treatments: double PGF_2α 10 days apart, 8‐day controlled internal drug release (CIDR) treatment or CIDR pre‐synchronization + PGF_2α 10 days after CIDR removal. The heifers were inseminated within 12 h following observed oestrus, or, if not observed, at a fixed time approximately 80 h, following the last synchronization treatment. They were palpated per rectum for signs of pregnancy 9 weeks after artificial insemination (AI). Vaginal electrical resistance measurements were taken at the completion of synchronization treatments (presumed dioestrus), immediately prior to AI (oestrus), and then at 3 and 9 weeks post‐AI. Mean VER differed between presumed dioestrus and oestrus (113.7 vs 87.4, p < 0.001). The area under the receiver operating characteristics (ROC) curve was 0.925, indicating that VER was highly discriminatory between dioestrus and oestrus. Vaginal electrical resistance at time of AI was negatively associated with odds of conception when all inseminations were included in the analyses [odds ratio (OR) = 0.97; 95% CI 0.95–1.00; p = 0.018], but not when fixed time AIs were excluded (OR = 1.00; 95% CI 0.97–1.03; p = 0.982). Mean VER readings differed between pregnant and non‐pregnant animals at both 3 weeks (120.5 vs 96.7, p < 0.001) and 9 weeks (124.0 vs 100.3, p < 0.001) post‐AI. However, 3‐ and 9‐week VER measurements were not highly discriminatory between pregnancy and non‐pregnancy (area under ROC curve = 0.791 and 0.736, respectively). Mean VER at time of AI for animals diagnosed in oestrus differed between each of the oestrous synchronization treatments (84.7, 73.6 and 78.9, groups 1–3 respectively, p < 0.001). These findings suggest that measurement of VER may improve accuracy of oestrus diagnoses when selecting cattle for AI following oestrous synchronization programmes involving tropically adapted cattle.     

Health screening for a translocation of captive-reared tuatara (Sphenodon punctatus) to an island refuge

AIMS: To screen tuatara undergoing translocation from a captive crèche to an island refuge for evidence of health and known diseases, and apply basic epidemiological techniques to assess the significance of disease test results.

METHODS: Tuatara (n=353) were physically examined and samples were taken from a random selection (n=30) for estimated white cell counts, screening for haemoparasites, and culture for Salmonella, Yersinia, Aeromonas and Campylobacter spp. Direct faecal smears were carried out on-site, and faecal floats were later performed to assess levels of endoparasitism with helminths and protozoa (n=69). Modified Ziehl-Neelsen staining was used to screen faecal smears, and positive specimens were further screened using an immunofluorescence antibody (IFA) test for Cryptosporidium oocysts.

RESULTS: There was no evidence of external parasites on any of the animals examined and only one animal had a gross abnormality. All estimated white cell counts were in the range 2.8– 17.5 × 10⁹/L. No haemoparasites were observed. There were no enteric pathogens cultured, indicating the intestinal carriage of these bacteria in the tuatara was 9.4%. Of the 69 individual faecal samples examined, 12 (17%) had unidentified coccidial oocysts, 21 (30%) had nematode ova of various kinds, and 12 (17%) had intestinal carriage of motile protozoa consistent with Trichomonas spp and another unidentified organism. Nineteen (28%) tuatara had acid-fast oocysts present; however, IFA staining failed to detect any Cryptosporidium oocysts.

CONCLUSIONS: Our understanding of the diversity of gastrointestinal endoparasites affecting tuatara is inadequate as many of the parasite ova seen could not be identified. This is the first record of tuatara as a host for Trichomonas spp of protozoa in the gastrointestinal tract.