Marjorie B. Orr

Enzootic ataxia in Red deer

Abstract The occurrence of enzootic ataxia in fanned Red deer is reported. This syndrome occurred in a young adult and a mature deer, and was characterised by ataxia, swaying movements of the hindquarters, often the adoption of a dog-sitting posture and, eventually, inability to use the hind limbs. Spinal cord demyelination and mid-brain neuronal degeneration were the main histopathological lesions. Copper levels of feedstuffs on the property were normal but blood copper levels of unaffected animals in the herd were low. The aetiology of enzootic ataxia in deer is possibly multifactorial, although copper deficiency is a common finding in affected herds, and copper supplementation appears to prevent its occurrence.

Cryptosporidiosis in deer calves

Abstract Extract Madam:– Cryptosporidium sp. is a small ubiquitous protozoan parasite which lacks host-specificity. Clinical infections with diarrhoea and sub-clinical infections have been reported in many species.(1) The organisms are pathogenic for much younger animals than those affected by other coccidia,(8) and housed artificially reared calves,(1) lambs(7) and fawns(8) seem particuarly susceptible. Infection is diagnosed histologically or by the demonstration of oocysts (about 4μm diam.) in Giemsa stained faecal smears. The oocysts are very resistant to many commonly used disinfectants, but are destroyed by exposure to household ammonia or 10% formal saline.(6)

A syndrome of dental abnormalities of sheep: I. Clinical aspects on a commercial sheep farm in the Wairarapa.

Abstract A syndrome of dental abnormalities in sheep is described. The features of the syndrome include excessive wear of deciduous incisor teeth, maleruption of permanent incisors associated with an osteopathy of mandibular bone, and the frequent formation of dentigerous cysts. Periodontitis of incisor teeth was present in some cases, and excessive incisor wear and premature tooth-loss were recorded in most sheep over 3 years old. The syndrome has been recorded on a number of farms in the lower part of the North Island, but was probably exacerbated in the Wairarapa district by inclement weather during 1977 and 1978. Excessive wear of the incisor teeth of cattle was also recorded on the same farms that had the problem in sheep. The presence of low copper levels, determined by liver and blood analyses from affected animals, is discussed in relationship to the complex, and possibly nutritional, aetiology.

A syndrome of dental abnormalities of sheep: II. The pathology and radiology

Abstract Histological and radiographic examination of 23 ewe heads has revealed that mandibular osteopathy is a feature of the ovine dental abnormality syndrome described by Bruere et al.(3) The bone changes consisted of excessive irregular remodelling of bone with osteoporosis. Developmental faults were also demon-strated. The most dramatic of these were dentigerous cysts involving unerupted permanent incisors, although malposition-ing of permanent incisors was also observed. A histological feature of the excessive incisor wear was chronic pulpitis, perhaps a. result of the rate of wear exceeding the rate at which protective secondary dentine could be de-posited in the pulp cavity. A number of nutritional deficiencies is known to cause gener-alised osteoporosis. Recognition of the osteopathy described here thus supports the clinical evidence of Bruere et al.(3) that a nutritional disorder could be a major factor in the pathogenesis of this syndrome.

A survey of excessively worn incisors and periodontal disease in sheep in Dunedin City, Silverpeaks, Bruce and Clutha Counties.

To determine the prevalence of excessively worn incisors (XSW) and periodontal disease (PD) in sheep in Dunedin City, Silverpeaks, Bruce and Clutha Counties, the incisors of 4049 mixed age ewes on 83 farms selected at random were examined between December 1983 and February 1984. Of these ewes, 14.9% had XSW (11.7% moderate, 3.2% severe), 13.7% had PD (10.5% moderate, 3.2% severe) and 71.4% had sound mouths. An additional 43 ewes had miscellaneous incisor faults, and these were excluded from the survey. Seventeen (>20.5%) and 25 (>30.1%) farms had 20% ewes with XSW and PD respectively. On two farms only did XSW and PD each occur at a prevalence of 15%. No association was found between the prevalence of XSW or PD and body condition score, breed or farm topography.

A study of periodontal disease in sheep over a twelve month period.

Sheep affected by broken mouth periodontal disease (P.D.) were examined over a twelve month period for different clinical parameters. It is suggested that P.D. in sheep is an episodic phenomenon similar to human P.D., and that only a few animals with signs of P.D. may undergo clinically significant destruction over a yearly period. No single parameter could reliably predict future deterioration in other parameters.

Estimation of gestational age of lambs based on fleece development.

Abstract Extract Sir:— Various techniques are employed to determine the gestational age of foetal lambs. Most are quantitative, based on weight or length measurements. Often crown anus length is used .(1)

A field study of the association between periodontal disease and body condition in sheep.

Three farms with a high prevalence of periodontal disease (PD) were selected using data from a December 1983/January 1984 survey. On each of these farms in August 1984, the incisor condition and body condition score of about 50 ewes were noted. Two of the farms and an additional farm with a high prevalence of PD were visited again in August 1985, and on each, incisor condition and body weights of about 150 ewes were recorded. On one farm only was there a significant association between PD and body condition or weight, and it occurred in both years.

Recurrence of a hairy shaker disease outbreak on an Otago sheep farm.

Abstract The affected farm near Dunedin runs 300ndash;400 breeding ewes with a lambing percent usually around 115ndash;118%. Hairy shaker disease had not been seen on the property until 1983, when there was a major outbreak. In March of that year, the farmer purchased ewes from a number of sources to bring his flock size up to about 400 ewes. As lambing approached, there were a few late abortions, and at lambing about 130 lambs died within a few days of birth, many of them being small and coarse-fleeced (hairy). Two hundred and seventy lambs survived, giving a lambing percentage of 68%. Many of the surviving lambs were hairy and in the next few months most of these developed scours or arthritis and were unthrifty. A diagnosis of hairy shaker disease was made on clinical grounds, and this was confirmed by the culture of the virus from several hairy lambs. It seemed likely that the infection had been introduced with the ewes purchased around tupping time.

Live sheep exports

Abstract Extract Madam:- The export of live sheep for slaughter raises several important animal welfare issues.