Anthelmintic use in goats and the effect of route of administration

The control of gastrointestinal parasites in goats by the use of anthelmintics has been and continues to be problematic. Products used successfully in sheep sometimes appear to be less effective than expected when used in goats. Parasites resistant to ivermectin have been reported in goats in New Zealand but not in sheep. I write to report a case that raises issues pertaining to the relative effectiveness of different routes of anthelmintic administration in goats.     

Bilateral ovarian adenocarcinoma in a mare causing haemoperitoneum and colic

Abstract

CASE HISTORY: A 13-year-old Thoroughbred mare was presented with a history of mild colic over 3 days. This colic had acutely exacerbated and was unresponsive to analgesic treatment, and was referred to Massey University Veterinary Teaching Hospital.

CLINICAL FINDINGS: On examination the heart rate was 100 beats per minute, and mucous membranes were pale and tacky. A large mass was detected on transrectal palpation in the caudal abdomen to the left of midline. Explorative laparotomy revealed severe haemoperitoneum and several masses that were associated with the reproductive tract. The mare was then subject to euthanasia. On post-mortem examination, adjacent and attached to each ovary were soft, lobulated dark red masses up to 200 mm in diameter. Similar masses were present in the omentum and on the peritoneal surface of the diaphragm and the serosa of the spleen and liver. Histopathology revealed that the neoplastic component of the masses comprised proliferating cuboidal to columnar cells forming disorganised acini and cords separated by dense collagenous stroma. Immunohistochemistry showed the neoplastic cells were positive for cytokeratin AE1/AE3 and vimentin, but negative for cytokeratin 7 and inhibin α.

DIAGNOSIS: Bilateral ovarian adenocarcinoma with transcoelomic metastasis and terminal decompensation due to rupture of a neoplastic mass and consequent haemoperitoneum.

CLINICAL RELEVANCE: To the authors' knowledge, bilateral ovarian adenocarcinoma has not been previously reported in a horse. Ovarian adenocarcinoma should be considered when horses present with haemoperitoneum and colic. Further research is required on the immunohistochemical differentiation of adenocarcinoma of ovarian and intestinal origin in the horse.     

Musculoskeletal responses of 2-year-old Thoroughbred horses to early training. 3. In vivo ultrasonographic assessment of the cross-sectional area and echogenicity of the superficial digital flexor tendon

AIM: To determine if the superficial digital flexor tendon (SDFT) of young Thoroughbred horses changed in size and echogenicity in association with early race training.

METHODS: Cross-sectional area (CSA) and echogenicity were determined ultrasonographically at five levels of the SDFT of the forelimbs of 2-year-old fillies (n=14), corresponding to 4, 8, 12, 16 and 20 cm distal to the accessory carpal bone (DACB). Measurements were made before and after a 13-week period in which a trained group of seven horses was compared with another group of seven untrained horses.

RESULTS: Level below the accessory carpal bone had a significant effect on CSA and Level 8 was smaller than all other levels except Level 12, while Level 12 was smaller than Levels 4 and 20 but not different from Levels 8 and 16. There was a significant interaction between level and time due to effects observed at Level 8. The CSA at Level 8 measured pre-training was different from that of Levels 4 and 20 in both pre- and post-training groups (p<0.05), but when measured post-training was not different from any other measurement. There was also a significant interaction between treatment group and time. There was no difference between CSA for the untrained and trained groups at the pre-training observation (p=0.9), but post-training the CSA (pooled over all levels) in trained horses was significantly larger than that of the untrained horses both post-training (p=0.019) and pre-training (p=0.034), and was not different from the pretraining CSA recorded in the trained group (p=0.29). Treatment group had no effect on echogenicity (p=0.43), while echogenicity was less at the end of the trial in both trained and untrained horses (p<0.001).

CONCLUSIONS: Early training for racing was associated with an increase in mean CSA of the SDFT. Other factors such as age and maturity may play a role in limiting this increase.     

Musculoskeletal responses of 2-year-old Thoroughbred horses to early training. 1. Study design,and clinical,nutritional, radiological and histological observations

AIMS: This is the first in a series of papers reporting studies in 2-year-old Thoroughbred racehorses that aimed to determine the response of musculoskeletal tissues to early training on grass and sand racetracks. In this paper, the experimental set-up of the whole study is described, and nutritional, workload, and clinical, radiographic and pathological outcomes are reported, including semi-quantitative assessment of macroscopic changes in articular cartilage.

METHODS: The study group comprised 14 two-year-old Thoroughbred fillies reared entirely at pasture. Of these, seven were selected by a licensed racehorse trainer to undergo a 4-week period of initial training in which they were taught to accept saddle and rider, followed by a 13-week period of flatrace training at a racetrack (Weeks 1–13); the other seven fillies were confined to large grass enclosures and were not trained. Nutrient, including macro- and trace-element intakes were estimated. Distances cantered or galloped and average velocities were quantified for the trained horses. All horses were observed daily, weighed approximately weekly, and underwent a clinical lameness examination at Weeks 5, 9 and 13. Distal forelimbs were radiographed prior to Week 1, during Weeks 7–8, and again at the end of the study, when macroscopic changes in articular cartilage of the proximal surface of the proximal phalanx were also scored after staining with India ink.

RESULTS: Dietary intakes met or exceeded recommended requirements for all nutrients except sodium, which was low in the trained horses. Bodyweight increased throughout the study in the untrained horses, and increased until Week 7 and then decreased slightly in the trained horses. Mean velocity data were used to define three stages of the training programme: Stage 1 comprised canter in Weeks 1–4; Stage 2 comprised canter in Weeks 5–8; and Stage 3 comprised canter in Weeks 9–13 and galloping twice weekly. Four of seven horses completed training. These covered a mean distance of 179.2 km at mean velocities (excluding gallops) of 7.63 m/sec (SD 0.58), 8.99 m/sec (SD 0.56), and 8.43 m/sec (SD 0.74) for Stages 1–3, respectively, and galloped 4.45 km at 14.4 (SD 0.1) m/sec. The three horses that did not complete training became lame in Weeks 9, 10 and 11, and covered 147.9 km at velocities of 7.38 m/sec (SD 0.44), 8.88 m/sec (SD 0.33) and 8.43 m/sec (SD 0.59) and galloped 2.1 km. Overall, slight or intermittent lameness in trained horses was noted on 76/655 (12%) of horse observation days. Swelling was evident on 284/655 (41%) of horse observation days in the metacarpophalangeal (MCPJ) and metatarsophalangeal (MTPJ) joints (92%), palmar metacarpal tendon region (7%) or carpus (1%). Swelling of the MCPJ or MTPJ was not associated with obvious lameness. Radiographic changes were minor and no gross lesions in bone or tendon tissue were evident except for one case of dorsal metacarpal disease. Post mortem, the cartilage of some MCPJ and MTPJ had obvious wear lines and high lesion scores, which were not consistently related to clinical evidence of pain, lameness or joint swelling. Mean lesion scores were not significantly different between the MCPJ and MTPJ, or between trained and untrained horses.

CONCLUSIONS: Workload can be readily quantified in racehorses under semi-commercial training conditions. Obvious lesions in cartilage of the MCPJ or MTPJ were present in some trained and some untrained horses and not consistently associated with clinical evidence of lameness, joint swelling or change in other connective tissues.

CLINICAL RELEVANCE: Workload data in racing horses are likely to be highly relevant for studying the pathogenesis of changes in bone, tendon and cartilage during training, for training management and for risk analysis in racehorse populations. Although obvious cartilage lesions produced little clinical effect, such lesions have previously been shown to be progressive and to prejudice athletic capability. Detection of such occult lesions in young horses will require more sophisticated detection methods.     

The relationships between scrotal surface temperature,age and sperm quality in stallions

In horses, spermatogenesis normally occurs at an average intratesticular temperature of 35 °C; therefore, mechanisms for testicular thermoregulation are essential. Measuring the scrotal surface temperature by thermography is one of the methodologies used to evaluate the effectiveness of testicular thermoregulation. The objective of this study was to determine the relationship between the control of scrotal surface temperature and sperm quality in horses of different ages. In total, 24 Quarter Horse stallions were divided into three groups: YS (young stallions), AS (adult stallions) and OS (old stallions). Initially, we calculated the testicular volume (TV) and evaluated various aspects of the semen (sperm kinetics, plasma membrane integrity and sperm morphology) for all the animals. We also evaluated rectal temperature (RT), body surface temperature (BST,) and average scrotal surface temperature in the testicular region (SST) before (M0) and after sun exposure (M1). Differences were observed (p<0.05) between the RT and BST before and after sun exposure in all three groups. However, there were no differences (p>0.05) in the SST values at these two time points, thus demonstrating the efficiency of the mechanisms for testicular thermoregulation. The SST was similar (p>0.05) among all three groups. Based on these results, we conclude that fertile stallions of different age groups are able to maintain SST and measuring the heat radiating from the scrotum using a digital infrared thermographer. We can also conclude that measuring the heat radiating from the scrotum using a digital infrared thermographer is a practical and efficient tool for monitoring SST in horses.     

Evaluation of cytokines and sialic acids contents in horses naturally infected with Theileria equi

This study was undertaken to assess the effects of T. equi infection on serum concentrations of some important cytokines including interferon-γ (IFN-γ), tumor necrosis factor-α (TNF-α), and interleukin-1 beta (IL-1β), IL-1α, IL-4, IL-6, IL-8, IL-10, IL-12α, IL-12β, IL-18, as well as total, protein and lipid binding sialic acids (TSA, PBSA and LBSA). Furthermore, any probable relation among the parasitemia, cytokines and sialic acids (SAs) were calculated using Pearson correlation and simple linear regression. Almost 300 draft horses (Kurdish-breed) with age of 3–4 years old from north-west of Iran were examined and an infected group comprised of 28 mares, naturally infected with T. equi, was identified and divided into 3 subgroups according to their parasitemia rates (low <1 %, moderate 1–3 % and high 3–5 %). Twenty healthy horses were considered as a control. Characterization and differentiation of piroplasmosis were conducted using routine hematological procedures and specific PCR assay. The results revealed a significant increase (P < 0.05) in all of the cytokines and SAs in a parasitic burden-dependent fashion. Additionally, a strong and positive relation was detected among the parasitemia, cytokines and SAs. Conclusively, T. equi infection is associated with induction of severe inflammatory processes in horses and SA plays a pivotal role in pathophysiology of the disease as it is tightly correlated with the parasitemia rate.     

Long-Term and Immediate Effects of Whole Body Vibration on Chronic Lameness in the Horse: A Pilot Study

The effects of whole body vibration (WBV) in horses with chronic lameness were evaluated in an experimental, single subject, repeated measure design. To assess the long-term effect of WBV, eight horses not previously exposed to WBV were subject to WBV, 30 minutes twice daily, five days a week, for 60 days in addition to their regular exercise routine. Lameness was assessed subjectively and objectively 30 days before the start, at the start and 30 and 60 days after the start of the treatment (WBV). The immediate effect of WBV was assessed in four horses accustomed to WBV, by comparing lameness before and within 30 minutes of a single 30-minute WBV session at four different time intervals. Change in lameness was sought using paired t tests on the kinematic data. A P-value of <.05 was considered statistically significant. Intraindividual change was sought using a subjective and objective scoring system. No statistically significant change in lameness was seen after 30 or 60 days of WBV, respectively, in the chronically lame horses not previously exposed to WBV. However, a trend toward improvement was observed after the first 30 days of WBV, but this improvement appeared to be lost during the second 30 days of WBV. Although a statistically significant worsening of front limb lameness was seen immediately after a single 30-minute WBV session in the chronically lame horses accustomed to WBV, this result was largely attributed to a very significant worsening of the front limb lameness in one horse within that group.