K. Parton

Isocupressic acid, an abortifacient component of Cupressus macrocarpa

Anecdotal reports suggest that abortion occurs in New Zealand cattle after ingestion of macrocarpa (Cupressus macrocarpa). The clinical signs observed are similar to those seen in abortions caused by ponderosa pine (Pinus ponderosa Laws). Isocupressic acid has been identified as an abortifacient component of the needles of ponderosa pine. Macrocarpa collected from the Palmerston North area contained 0.89% and 1.24% isocupressic acid, compared to 1.70% isocupressic acid in Ponderosa pine needles from Oregon in the United States as analysed by the USDA-ARS Poisonous Plant Research Laboratory. These findings support observations that macrocarpa causes abortion in late gestation cattle in New Zealand and suggest the causal agent is probably isocupressic acid.

Isolation of Helicobacter mustelae from ferrets in New Zealand.

Abstract dAims:The bacterial genus Helicobacter contains over 20 species, including the human gastric pathogen H. pylori, and the mustelid-specific H. mustelae. A previous study in this country failed to isolate H. mustelae from a captive breeding colony of ferrets. We sought to confirm whether or not H. mustelae was present in this country. dMethods: A combination of bacterial culture, phenotypic testing and molecular techniques were used to isolate and identify gastric bacteria from captive and wild populations of ferrets in the New Zealand North Island. dResults: Bacteria were isolated from captive and wild ferrets which were phylogenetically identical to the type strain of H. mustelae. A mild to moderate gastritis was seen in five of six animals examined, and an antibody response to H. mustelae proteins was demonstrated. dConclusions: Helicobacter mustelae is not exotic to New Zealand, but is present in two populations of ferrets tested in the North Island.

A missense mutation in AGTPBP1 was identified in sheep with a lower motor neuron disease

A type of lower motor neuron (LMN) disease inherited as autosomal recessive in Romney sheep was characterized with normal appearance at birth, but with progressive weakness and tetraparesis after the first week of life. Here, we carried out genome-wide homozygosity mapping using Illumina Ovine SNP50 BeadChips on lambs descended from one carrier ram, including 19 sheep diagnosed as affected and 11 of their parents that were therefore known carriers. A homozygous region of 136 consecutive single-nucleotide polymorphism (SNP) loci on chromosome 2 was common to all affected sheep and it was the basis for searching for the positional candidate genes. Other homozygous regions shared by all affected sheep spanned eight or fewer SNP loci. The 136-SNP region contained the sheep ATP/GTP-binding protein 1 (AGTPBP1) gene. Mutations in this gene have been shown to be related to Purkinje cell degeneration (pcd) phenotypes including ataxia in mice. One missense mutation c.2909G>C on exon 21 of AGTPBP1 was discovered, which induces an Arg to Pro substitution (p.Arg970Pro) at amino-acid 970, a conserved residue for the catalytic activity of AGTPBP1. Genotyping of this mutation showed 100% concordant rate with the recessive pattern of inheritance in affected, carrier, phenotypically normal and unrelated normal individuals. This is the first report showing a mutant AGTPBP1 is associated with a LMN disease in a large mammal animal model. Our finding raises the possibility of human patients with the same etiology caused by this gene or other genes in the same pathway of neuronal development.

A lower motor neuron disease in newborn Romney lambs

AIM To determine the cause and nature of a disease in newborn New Zealand Romney lambs characterised by progressive weakness and premature death. METHODS Affected lambs were examined clinically, humanely killed and submitted to necropsy. Selected fonmalin-fixed tissues were examined histologically. Data on the parentage of the lambs were collected. RESULTS The principle lesions found were degeneration and loss of neurons in ventral horns of the spinal cord and brain stem and Wallerian degeneration of motor nerves and denervation atrophy of skeletal muscles fibres. CONCLUSION The lesions are those of a lower motor neuron disease which appeared to have a genetic cause.

Plant poisoning of livestock in New Zealand

Abstract Extract British settlers introduced large numbers of grazing animals, notably sheep, cattle and horses, to New Zealand during the latter half of the 19th century. They also brought many new trees, garden plants and grasses from their homeland, which soon became widespread in this country. The introduction of grazing animals unacquainted with indigenous plant varieties set the scene for inevitable and often serious stock losses from plant poisoning. Problems were further exacerbated by the large amount of stock droving that took place and the frequent absence of fences to contain stock on safe pastures during the early years following settlement.

Onion toxicity in farmed animals.

Abstract extract Feeding cull onions (A llium cepa) to livestock is practised in onion growing regions around the world. While sheep are able to tolerate onions in their diet, cattle are susceptible to toxicity. Onion poisoning has recently been reported in dairy cows in New Zealand (Carbery, 1999). Given the recent seasonal abundance of onions available for feeding to stock, it seems timely to draw attention to this syndrome.

Suspected Vestia foetida poisoning in young goats.

Abstract CASE HISTORY: Two crossbred, castrated male goats, a 5-month-old and an 8-month-old, were observed ingesting Vestia foetida (Solanaceae). Later, the goats were seen standing splay-legged and apparently disoriented. CLINICAL FINDINGS: When examined, both goats were in sternal recumbency and had mydriasis; the younger goat had a diminished menace response. When the goats were made to stand, they were ataxic and had muscle fasciculations of the hindquarters and face. Both had halitosis consistent with the odour of crushed Vestia leaves. The animals were treated with a mixture of vitamins and intravenous diazepam. The older goat recovered but the younger goat died and was necropsied. This animal had severe periacinar necrosis and fatty change in the liver, as well as fatty nephrosis. DIAGNOSIS: Probable Vestia foetida poisoning. CLINICAL RELEVANCE: The introduction of Vestia foetida to New Zealand and the apparent palatability of the plant necessitate that veterinarians and owners be knowledgeable about its potential toxicity. Differential diagnoses for the liver lesions (in New Zealand) would include Cestrum poisoning, acute seneciosis, acute blue-green algal poisoning, and acute and chronic copper poisoning.

Macrocyclic lactone toxicity due to abamectin in farm dogs without the ABCB1 gene mutation

Abstract CASE HISTORY: A 5-year-old entire female Huntaway from a sheep and beef farm was one of four dogs that developed clinical signs including hypersalivation, depression, blindness and ataxia after the death of another dog. A 4-year-old female Huntaway farm dog from a second farm was observed to be sitting down more often than usual on the day after being fed part of a calf carcass that had been treated with an abamectin pour-on. CLINICAL FINDINGS: The first dog was ataxic and depressed but did respond to sound. The second dog presented with an acute onset of blindness, mydriasis, absence of a menace response, hypersalivation, gait abnormalities (e.g. high stepping gait and ataxia), and depression. Other presenting signs included muscle tremors, dehydration and difficulty eating. No abnormalities were detected from routine haematology and biochemistry. Analysis of samples of plasma from both dogs revealed concentrations of abamectin of 0.149 mg/L and 0.260 mg/L for the first and second dogs, respectively. Buccal swabs taken from the first dog for DNA testing for the ABCB1 gene mutation, gave a negative result. DIAGNOSIS: In addition to the presenting signs which suggested a toxicosis, both dogs had measurable concentrations of abamectin in plasma confirming exposure. CLINICAL RELEVANCE: Farm dogs exposed to concentrated pour-on products containing abamectin have been poisoned and recover or die. The product labels do not carry any warnings as to the risk of poisoning to dogs. This paper discusses two incidents affecting six farm dogs, but the authors are aware of more toxicoses in farm dogs exposed to abamectin.

Detection and isolation of Helicobacter mustelae from stoats in New Zealand

Abstract AIM: To determine the incidence of Helicobacter mustelae in stoats (Mustela erminea) in New Zealand. METHODS: Helicobacter-like organisms and total genomic DNA were isolated from gastric tissue of stoats and identified using a combination of bacterial culture, phenotypic testing and molecular techniques. RESULTS: A Helicobacter-specific 16S rRNA polymerase chain reaction product was detected in 16/32 gastric tissue biopsies tested. Nine of 13 partially sequenced 16S rRNA DNA identified H. mustelae 16S DNA. Bacteria, subsequently identified as H. mustelae, were successfully cultured from the stomachs of 4/32 stoats. Other Helicobacter species were also identified by DNA sequence analysis, but were not cultured. CONCLUSIONS: Helicobacter mustelae is present in stoats from both the North and South Islands of New Zealand.

A case of “watery mouth” in a New Zealand Romney lamb

Watery mouth was diagnosed as the cause of illness and subsequent death in a 3-day-old Romney lamb which had not received early colostrum. The history, clinical signs and post-mortem findings were typical of the disease as seen in other countries, including Great Britain. The diagnosis was based on the clinical signs and was supported by an absence of post-mortem findings of other specific neonatal diseases. The potential importance of watery mouth under conditions of intensive husbandry in New Zealand is discussed.