Ultrasonographic characterization of ovarian events and fetal gestational parameters in two southern black rhinoceros (Diceros bicornis minor) and correlation to fecal progesterone.

A tremendous potential exists for the application of transrectal ultrasonography as a tool to enhance the captive management of endangered species. Reproductive study of two southern black rhinoceros (Diceros bicornis minor) females was performed daily to every other day for a approximately 60 day period to document ovarian changes, and three times weekly in early pregnancy to once monthly in late pregnancy in order to characterize changes in fetal parameters throughout gestation. All ovarian and fetal anatomical structures were measured in millimeters. The mean (+/- SD) length of the estrous cycle or interovulatory period was 26 +/- 1.4 days (n=2 cycles). Follicular growth rate of a dominant follicle was approximately 3 mm/day once the follicle reached 35 mm in diameter. Ovulation was observed to occur at a mean (+/- SD) follicular diameter of 49.5 +/- 2.6 mm (n=4) and within 48 to 72 h after observed estrus (n=2). Large ovarian structures [mean (+/- SD) diameter of 71.7 +/- 2.9 mm; n=3], considered analogous to equine anovulatory hemorrhagic follicles, were observed to form in the winter months and suggest seasonal periods of reduced fertility. Fecal progesterone assays confirmed ultrasonographic events. Although preliminary, the results of fetal sexing are presented and compared to the horse. Our data indicate that fetal eye or fetal foot diameter measurements can be used to accurately predict gestational age from about 2 months to term, providing useful information to managers of both captive and wild rhino populations. The ability to identify and quickly release animals in late term pregnancy in the wild and thereby reduce-abortions and neonatal mortalities in holding bomas is one potential practical conservation benefit of the fetal age predictive models.

Brucella melitensis biotype 1 outbreak in goats in northern KwaZulu-Natal.

Brucella melitensis biotype 1 was confirmed in indigenous, outbred goats in three northern districts of the KwaZulu-Natal province following the diagnosis of human Malta fever in the same area. Six foci of infection were found during an extensive serological survey involving 6266 goats carried out in most of the districts of the KwaZulu-Natal province. The prevalence in the positive herds varied between 17% and 100%. The diagnosis was confirmed by culturing milk samples from serologically positive animals. Infected goats were found in only three districts (Ubombo, Ingwavuma and Pongola) and all infected herds fell within a 50-km radius.

The 621 periodontal probe.

This brief paper describes the construction and method of use of a periodontal probe specifically designed for the assessment of the periodontal treatment needs of populations.

Some considerations on the role of cementum in periodontal disease.

The protective role of cementum against root resorption is discussed in relation to buried teeth, orthodontic treatment, replantation and periodontal disease. The essential feature seems to be a layer of partially calcified precementum or vital cementoblasts. Root resorption close to the epithelial attachment, although not common, is probably the result of death of cementoblasts caused by irritants from bacterial plaque, and the presence of severe of prolonged inflammation. Cementum exposed in the pocket can be affected in different ways by these irritants, and rendered unacceptable for re-attachment to periodontal tissue. Successful re-attachment procedures involve either the removal of the affected cementum or its treatment with agents partially to decalcify such as acids, or detoxify by phenol for example. Examples of treatment embodying some of these principles are illustrated by two case histories of localised gingival recession and one of intra-bony pocketing associated with an acute lateral periodontal abscess. In this case a follow-up radiograph taken 16 years later is presented as evidence of the permanence of repair which can be achieved. Root resorption which often follows the use of fresh autogenous bone from the ilium is then discussed and the conclusion reached that the vital cells in the transplant discourage the migration of cementoblasts from the adjacent periodontium. The cementum and dentine thus remain unprotected and susceptible to resorption.

Controlled clinical trials in periodontal disease by general practitioners.

The general practitioner with loyal and regular patients is in a good position to undertake long-term clinical trials of periodontal treatment. Ethically, these should be comparisons of agents or procedures acknowledged to be beneficial but lacking confirmation of the long-term effects. Standardized bite-wing radiographs can represent a valuable record in this type of study.