South American camelids in Switzerland. II. Reference values for blood parameters

In order to establish reference values for blood parameters of South American camelids in Switzerland, 273 blood samples were collected from 141 llamas and 132 alpacas. These animals were classified in three categories (young animals < six months, adult females and males). Forty-one parameters were measured (red blood cell count, white blood cell count, electrolytes, metabolites and enzymes). Significant differences between llamas and alpacas were evident for 26 parameters. This study also showed that differences between young animals, females and males must be taken into consideration. A comparison of blood values with the results of fecal analysis for parasite eggs showed that an infestation with Dicrocoelium dendriticum was associated with elevated activity of two liver enzymes (GLDH and gamma-GT) in the serum. In contrast, no differences were found in the results of blood analyses between animals shedding eggs of gastrointestinal strongyles or not.     

Venous aneurysm of the jugular vein in horses

Venous anomalies of the jugular vein are uncommon in the horse. Jugular venous aneurysms (congenital or pseudoaneurysm) in horses usually present as a compressible asymptomatic cervical mass enlarging on manual congestion of the jugular vein. They can be classified into primary (congenital) and acquired lesions. Primary venous aneurysms are true venous aneurysms because in these lesions the venous wall is intact, whereas false or pseudoaneurysm has a disruption of the inner layers of the venous wall. Two types of jugular vein aneurysm can be identified, fusiform or saccular, the former being the most common in people. Doppler ultrasound imaging confirms the diagnosis. Surgical treatment, aneurysmectomy with venorraphy or venoplasty is indicated in case of progressive aneurysmal expansion. This clinical commentary describes a 4-month-old foal presented with a primary aneurysm of the right jugular vein in the midcervial region. Treatment consisted of partial aneurysmectomy and venorraphy. Four years later, the horse had a patent jugular vein with a normal diameter and was trained without clinical signs of venous distension.     

Eastern equine encephalitis in 9 South American camelids

BACKGROUND: Eastern equine encephalitis (EEE) virus is a mosquito-borne togavirus (alphavirus) that causes severe (often fatal) encephalitis in many mammalian species, but it has not been reported previously in South American camelids. Hypothesis: South American camelids can become naturally infected with EEE virus and show encephalitic signs similar to those observed in other affected species. ANIMALS: Nine cases (8 alpacas and 1 llama, aged 3.5 weeks to 12 years) were identified; 4 of 9 were 510 weeks old. All cases were from the East Coast of the United States and presented in late summer and fall. METHODS: A retrospective study was performed to include confirmed cases of EEE in camelids in North America before 2006. RESULTS: Eight of nine (89%) camelids died or were euthanized in extremis, with the mean time to death of 2 days. Clinical signs were consistent with encephalitis and included fever, lethargy, ataxia, seizures, recumbency, torticollis, opisthotonus, and vestibular signs. No consistent hematologic abnormalities were identified, and cerebrospinal fluid contained an increased protein concentration in the single camelid analyzed. No successful therapy was identified. EEE was confirmed by alphavirus detection by using immunohistochemistry (IHC) and polymerase chain reaction (PCR) in the central nervous system (CNS) and by serology. Findings included polioencephalitis with lymphocytic perivascular cuffing; neutrophil infiltration; gliosis; neuron satellitosis; necrosis; and edema, with intracytoplasmic alphavirus within neurons and glial cells. No virus was detected in extraneural tissues. CONCLUSIONS AND CLINICAL IMPORTANCE: In endemic areas, EEE should be considered a differential diagnosis for young and adult camelids with CNS disease. Brain histopathology with indirect IHC or PCR is diagnostic.     

Correlation between jugular and central venous pressures in laterally recumbent horses

Objective To compare and correlate right atrial pressure, which represents central venous pressure (CVP) to jugular vein pressure (JVP) in laterally recumbent horses under anesthesia. Study design Retrospective clinical trial. Animals Seven adult healthy horses (411 ± 8.7 kg). Methods Horses were sedated with IV xylazine and anesthesia was obtained with IV ketamine and diazepam. Anesthesia was maintained with sevoflurane in oxygen. All horses were positioned in left lateral recumbency. An 8F catheter introducer was inserted into the right jugular vein to measure JVP. An 8F catheter introducer was inserted into the left jugular vein to be used as the port for a 7F 110 cm catheter that reached the right atrium to measure CVP. Both, CVP and JVP were measured simultaneously with a water calibrated aneroid manometer using the sternum as the 0 cmH₂O reference point. Measurements were compared using Spearman correlation and the Bland‐Altman plot. Results Twenty paired samples were obtained over a period of 2 hours. The CVP ranged from 7 to 31 cmH₂O, while the JVP ranged from 5 to 30 cmH₂O. The Spearman correlation coefficient indicated that CVP and JVP had a strong correlation with r = 0.88. The Bland‐Altman plot showed a bias of 0.7 cmH₂O. Conclusion and clinical relevance Jugular vein pressure showed a strong correlation with CVP in healthy, euvolemic, laterally recumbent anesthetized adult horses. Thus, JVP cannot replace CVP but it may be used clinically to monitor CVP in laterally recumbent horses.     

Detection of antibodies to mycoplasmas in South American camelids

Indirect haemagglutination tests on sera from 757 South American camelids (alpacas, llamas and vicunas) carried out in the Andean region of Peru, revealed evidence of exposure mainly to Mycoplasma mycoides subspecies mycoides LC. The incidence of detectable antibodies to this mycoplasma in 554 alpacas was 5.0 per cent and in 141 llamas 15.6 per cent. Antibody to Mycoplasma capricolum and the F38 biotype was detected in 0.9 per cent and 0.2 per cent of alpacas, respectively. In a group of 62 vicunas only one reactor to both M m mycoides LC and M capricolum was observed. No reactors to M mycoides subspecies capri or M agalactiae were observed in the flocks examined. Antibodies to mycoplasma were also detected in nine out of 10 goat flocks tested. The incidence of antibodies to M m mycoides LC was 13.8 per cent, 3.8 per cent for M capricolum and 1.8 per cent for the F38 biotype. In a group of 110 sheep, six reactors (5.5 per cent) to M m mycoides LC and one (0.9 per cent) to F38 were observed. The implications of these results are discussed in relation to the involvement of mycoplasmas in existing disease in camelids in Peru.     

Treatment of long bone fractures in South American camelids: 5 cases

An adult llama and four alpacas were referred with long bone fractures. The llama presented with a closed, comminuted fracture of the right metatarsal bones. Two of the alpacas presented with comminuted fractures of the proximal radius. One fracture was closed and one was open. One alpaca had a closed, comminuted fracture of the distal radius, and the final alpaca had a closed, oblique fracture of the metatarsus. A diagnosis was made in each animal on the basis of clinical examination and radiographs. All fractures were managed by open reduction and internal fixation using selective placement of lag screws and dynamic compression plates. Four animals made uneventful recoveries and no long-term complications were encountered. One alpaca was re-admitted for plate failure and non-union of the fracture 5 weeks after surgery. The plate and screws were removed and a transfixation cast was applied. The fracture healed, however the alpaca showed signs of radial nerve paralysis after the cast was removed. With confinement in a small yard, full function gradually returned to the leg over the ensuing 4 months. Using techniques recommended in other species, South American camelids are suitable candidates for long bone fracture repair using open reduction and internal fixation.     

Suspected venous air embolism in a Finnhorse

Vascular air embolism (VAE) is the entrainment of air from the operative field or other communication with the environment into the venous or arterial vasculature, producing systemic effects. The horse described in this report, after having been discovered to have dislodged the extension set from the jugular vein catheter, demonstrated clinical signs considered most likely to have resulted from a VAE, and represents a case of primarily neurological signs resolving spontaneously. Emphasis is given to the prevention and prompt recognition of this event and to the use of all available tools in the management of cardiovascular complications.     

Immunophenotyping of lymphosarcoma in South American camelids on six British premises

Six cases of lymphosarcoma (LSA) in South American camelids (SACs) were selected from submissions to a diagnostic laboratory network servicing England and Wales. Immunophenotyping was carried out using anti-human CD3 and anti-human CD5 for T-cells; and anti-human CD79a and anti-human CD79b for B-cells/plasma cells. On the basis of labelling with mainly anti-CD3, four of the tumours were classified as T-cell tumours. One case was labelled with anti-CD79a and anti-CD79b, and was classified as a B-cell tumour. In the other case the majority of cells were labelled with anti-CD3, anti-CD79a and anti-CD79b, and was classified as a mixed T- and B-cell tumour. To the authors' knowledge this is the first reported attempt at immunophenotyping LSA in SACs on British premises and is only the second time that a presumptive mixed T- and B-cell LSA has been reported in alpacas and the veterinary literature in general.     

South American camelids in Switzerland. III. Digestibilities of different feedstuff

Feces from 15 adult llamas were collected in 4 herds and the exact diet was determined, either of the group or of individual animals, to examine apparent digestibility. A questionnaire was submitted to the animal owners. The questionnaire included questions about the animals in the herd (number, age, gender, origin), management methods, pastures, watering and feeding facilities for the animals, hay supplementation, composition of the ration and fodder additives used. Analysis of the feed revealed an average apparent digestibility for dry matter of 81+/-4%, for the organic matter 77+/-7%, for crude protein 69+/-10%, for nitrogen-free extract 83+/-5%, for calcium 60+/-17%, for phosphorus 54+/-11% and 81+/-9% for crude fiber. All feed components seem to be digested similarly to domestic ruminants whereas the apparent digestibility of crude fiber was high, which indicates that the digesting system seems to be more effective.     

Evaluation of a polyurethane jugular catheter in cats placed using a modified Seldinger technique

OBJECTIVE: To describe and evaluate the placement of a new design of polyurethane jugular catheter in cats using a modification of the technique of Seldinger. The maintenance and use of these catheters for repeated blood sampling over several days in healthy and diabetic cats is reported. PROCEDURE: Thirty polyurethane jugular catheters were placed in 10 clinically healthy cats and 10 cats with diabetes mellitus using the modified Seldinger technique. Catheters were placed while the cats were under general anaesthesia. RESULTS: The catheters remained in place for a range of 2 to 14 days (median 5 days) with no major complications. In all cats patency of the catheters was maintained until removal. All cats examined had patent jugular veins when assessed 4 or more weeks after the catheters were removed. CONCLUSIONS: These polyurethane jugular catheters, when placed by a modified Seldinger technique, are effective and safe in cats, and jugular patency returns after the catheters are removed.     

Toxoplasma gondii and Neospora caninum seroprevalences in domestic South American camelids of the Peruvian Andes

The objective of this study was to investigate the presence of Toxoplasma gondii- and Neospora caninum-specific antibodies in domestic South American camelids (SAC) (llamas and alpacas) from the Peruvian Andes through a cross-sectional study. A wide panel of serum samples collected from 1,845 llamas and 2,874 alpacas from the two main SAC production areas of Peru was selected. Immunofluorescence antibody technique was employed to detect and titrate specific anti-T. gondii and anti-N. caninum immunoglobulins G in serum samples. The association between T. gondii and N. caninum seroprevalence and the geographical origin (Central and South Peruvian Andes) was evaluated. Anti-T. gondii antibodies were found in 460 (24.9 %) llamas and 706 (24.6 %) alpacas, whereas anti-N. caninum antibodies were detected in 153 (8.3 %) llamas and 425 (14.8 %) alpacas. Toxoplasma gondii infection was strongly associated with the South Peruvian Andes where moderate climate conditions, larger human population, compared to the Central region, and the presence of wildlife definitive hosts could favor horizontal transmission to SAC. In contrast, N. caninum infection was not associated with the geographical region. These results indicate that T. gondii and N. caninum infections are highly and moderately widespread, respectively, in both species of domestic SAC studied in the sampled areas and appropriate control measures should be undertaken to reduce the prevalence of both parasitic infections.     

Effects of topical nitroglycerine patches and ointment on digital venous plasma nitric oxide concentrations and digital blood flow in healthy conscious horses

OBJECTIVE: To measure and compare palmar digital venous plasma nitric oxide (NO) concentrations and digital arterial blood flow after application of topical nitroglycerine (NTG). STUDY DESIGN: Experimental study. ANIMALS: Healthy adult horses (n=8). METHODS: Digital blood flow was measured by an ultrasonic Doppler flow probe surgically implanted around the medial palmar digital artery. Blood was collected from a catheter placed in the medial palmar digital vein for quantification of NO. NTG patches, NTG ointment or control patches were placed over the palmar digital vessels at the level of the fetlock. Two horses had an intra-arterial infusion of an NTG solution into the medial palmar digital artery in a pilot study. RESULTS: Digital arterial blood flow did not change significantly with application of the NTG patches, NTG ointment, or control patches. There were no statistically significant or biologically important changes in digital venous NO concentrations across time or between treated and control horses. In the pilot study, digital arterial blood flow and palmar digital venous NO concentrations increased with intra-arterial infusion of NTG. CONCLUSIONS: In clinically healthy horses, digital arterial blood flow and digital venous plasma NO concentrations did not change significantly with application of the NTG patches/ointment. These treatments are unlikely to have an effect on the digital vasculature of laminitic horses, however, further investigation is warranted. CLINICAL RELEVANCE: Although NTG patches have been used as a method of decreasing vasomotor tone and improving digital blood flow in horses with laminitis, this study provides evidence in healthy conscious horses that this treatment is not effective in altering digital blood flow.     

Postal survey of the population of South American camelids in the United Kingdom in 2000/01

The members of the two leading British camelid breeders associations were surveyed by means of a postal questionnaire between December 2000 and January 2001; 696 questionnaires were posted and 218 usable responses were returned. A total of 3520 camelids were recorded, of which 2719 (77.2 per cent) were alpacas (Lama pacos) and 726 (20.6 per cent) were llamas (Lama glama). Ninety-four per cent of the camelid herds were of one species, and 70 per cent of the animals were kept for more than one purpose. Camelids imported from South America were present on 45 per cent of the units surveyed. Husbandry procedures and preventive health measures were uniform; 92.2 per cent of the animals were kept on pasture all year round, 99 per cent were supplemented with hay and 97.7 per cent with concentrate feed; 88.1 per cent were vaccinated against clostridial disease with a multivalent vaccine licensed for sheep, and 96.3 per cent were treated periodically with anthelmintic drugs. During 2000, ill health, other than dermatological conditions, was reported by 24.3 of respondents, and 32 different conditions were described. Skin disease was reported by 51 per cent of breeders. Zinc deficiency was diagnosed presumptively as the cause of skin disease by 31.9 per cent of the respondents, and ectoparasitism by 26.4 per cent. Of those who treated a skin condition, 71.9 per cent reported an improvement, but less than half of them considered the improvement to have been permanent.     

The effect of elemental Zn boluses on concentrations of Zn in serum and faeces of South American camelids

ABSTRACT

Aims: To monitor the effect of using long-acting Zn boluses on the Zn status of a group of South American camelids, using measurements of concentrations of Zn in faeces and serum.

Methods: As part of a facial eczema (FE) prevention programme, 15 camelids were treated with long-acting Zn boluses designed for preventing FE in sheep. Based on bodyweight, 13 alpacas (Vicugna pacos) received two boluses (26.4?g Zn/bolus) and two llamas (Lama glama) received three boluses. In order to monitor Zn status, measurements were made of concentrations of Zn in serum and faeces immediately prior to bolus treatment (Week 0) and 4, 6, 8 and 10 weeks later. Gamma glutamyl transferase (GGT) activity in serum was measured at Weeks 0 and 8.

Results: Two alpacas regurgitated the boluses; in one case the animal was quickly re-treated but this was not possible in the second animal. Mean concentrations of Zn in faeces were higher at all time points compared to Week 0 (p?<?0.001). Peak concentrations were measured at Week 8, and concentrations >120?mg/kg fresh weight (FW), suggested as being protective in calves, were only measured in all (13/13) treated camelids at Week 6. Mean concentrations of Zn in serum differed between weeks of sampling but changes were not consistent, and concentrations did not exceed 18?μmol/L following treatment. There was no evidence of a natural sporidesmin challenge during the study period and activity of GGT in serum of all animals was <45?IU/L.

Conclusions: Treatment with Zn boluses significantly increased concentrations of Zn in faeces but not in serum, but peak concentrations in faeces were only detected 8 weeks after treatment.

Clinical Relevance: The delay in achieving concentrations of Zn in faeces which were associated with protection against FE in calves, combined with the difficulties of administering boluses to camelids, means that we do not believe that Zn boluses should be used as the primary method for preventing FE in camelids. We recommend that FE prevention in camelids should focus on minimising spore production in pasture through the use of fungicides, grazing management and alternative forages, with boluses only used when it is thought that these methods are unlikely to provide sufficient protection against FE. Such use should always be under the guidance of a veterinarian and monitoring of serum GGT activity should be used to ensure that FE control is being achieved.     

河曲马牧草和全血矿物质营养状况的研究

对河曲马主要牧草和全血１０种矿物质营养状况进行了研究,结果表明,当地牧草中Ｓｅ、Ｚｎ含量极显著低于ＮＲＣ（１９８９）规定的马营养需要量（Ｐ〈０．０１）,而Ｃａ含量较高,Ｐ含量较低,造成牧草中Ｃａ、Ｐ比较严重失谳（Ｃａ：ｐ达７．６～８．３：１）,同时发现牧草中Ｃｕ含量在马营养需要量的临界水平,全血矿物元素含量的分析表明,所测元素性别间均无显著差异（Ｐ〉０．０５）。