A longitudinal study of the cultivable subgingival anaerobic bacteria isolated from sheep during the development of broken mouth periodontitis.

In a longitudinal bacteriological study of the cultivable subgingival anaerobic flora isolated from developing broken mouth periodontitis in sheep, samples were taken from five sheep on each of three farms on seven occasions over a period of 2.5 years. Ten different bacterial genera were isolated regularly but with fluctuating frequencies. Bacteroides and Fusobacterium organisms accounted for nearly 70% of the isolates. The Bacteroides and Fusobacterium isolates studied in detail from one farm were identified to species level. The fusobacteria comprised F. nucleatum-like organisms (68.6%). F. necrophorum (29.6%) and F. naviforme (1.8%). The Bacteroides spp. were divided into 11 main groups and included black-pigmented species similar to B. asaccharolyticus and B. gingivalis. On the farm studied in detail, the sheep could be allocated to two groups according to progression of periodontal disease. Most of the B. gingivalis-like isolates were from sheep with actively progressing disease, indicating that this organism may play a role in periodontal destruction in sheep.

Preliminary study of the anaerobic bacteria isolated from subgingival plaque from sheep.

A preliminary study was made to determine the genera of cultivable anaerobic bacteria which could be isolated from subgingival plaque of sheep. Samples were taken from 10 sheep on farms with a known record of broken mouth periodontitis. For assessment of the sampling technique, samples were also taken from freshly exposed tooth roots in killed sheep. The bacteria isolated on several selective and non-selective media were identified to genus level by a combination of Gram reaction, colony morphology and gas chromatographic analysis of volatile and non-volatile fatty acid metabolic end products. At least 10 different genera were isolated and these findings are discussed in relation to the bacteriology of human periodontitis and recent studies of sheep broken mouth periodontitis.

Dental disease in hill sheep: an abattoir survey.

Heads from 478 aged sheep of a predominantly hill breed population were examined in detail for evidence of dental disease, using both soft and hard tissue measurements around incisor and cheek teeth. Almost 60 per cent of this population (all over 2 1/2 years of age and with a mean age between 7 and 8 years) had either loose or missing teeth. Malalignment of cheek teeth and/or incisors was also common. Pocketing was seen in 87 per cent of the population, and was significantly correlated with tooth looseness. There was also a significant relationship between incisor and specific cheek tooth pocket depths. Whilst local alveolar bone loss was found, it was not a reflection of more general skeletal deterioration. The survey confirms the high incidence of broken mouth in the national flock and shows that wherever incisor problems occur there is a likelihood that cheek tooth disease is also present, a relationship not readily appreciated clinically.

Skeletal and blood biochemical characteristics of sheep during growth and breeding: a comparison of flocks with and without broken mouth.

Two-hundred female Scottish Blackface sheep ranging in age from 3 months to 5 1/2 years were used to investigate the relationships between blood biochemical characteristics, skeletal metabolism and dental health on 5 farms, 3 with broken mouth and 2 with no incidence of the disease. Skeletal growth to 6 months of age was faster in lambs from control flocks than in lambs from affected farms although growth thereafter was slower in the control group. A generally lower protein intake on control farms may account for this reduced growth rate. In general, adult dimensions of bones were attained between 14 and 30 months of age but age of maturation varied between bones; tibial endochondral growth ended after 14 to 21 months while the rib still showed evidence of endochondral growth at 70 months of age. This growth was episodic, being maximal during lactation and possible causes are discussed. There was no significant differences in calcium or phosphorus status between control and affected populations, an inadequate phosphorus intake during pregnancy was common to both groups. Lower serum magnesium concentration in affected than in control sheep was a consistent finding and is discussed.

A method for the measurement of the gingival sulcus of sheep.

A method for measuring and comparing the depths of the gingival sulcus of sheep in the incisor region at necropsy is described. The method was devised to assess and compare dental health in groups of sheep with and without premature loss of incisor teeth (broken mouth). The technique involves the use of paper spills in combination with dental plaster models.

Development of periodontal disease in a single flock of sheep: clinical signs, morphology of subgingival plaque and influence of antimicrobial agents.

The clinical development of broken mouth over a single reproductive year and the effect of two broad spectrum antibacterial agents upon it was followed in 72 Scottish Blackface ewes aged between two and three years. Using a number of dental health indices especially developed for the purpose, the amount of gingivitis, tooth movement, gum recession and pocketing were quantified and graphed for both the whole population and each group in the drug trial. All clinical features except movement fluctuated significantly with time, the fluctuations often being associated with nutritional or other environmental factors. Despite the extended use of large doses of two antimicrobial agents no significant reduction in the amount of clinical gingivitis or pocketing was evident.

Effects in sheep of high dietary levels of vitamin D3 as measured by circulating concentrations of some vitamin D metabolites and skeletal examination.

Housed non-pregnant ewes were given diets supplemented with five, 10, 20, 40 and 80 times the Agricultural Research Council's recommended requirement for vitamin D for 16 weeks. The effects on vitamin D status were assessed by measuring 25-hydroxylated vitamin D metabolites (25-OHD) in plasma at intervals. After 16 weeks, animals on the lowest and two highest vitamin D intakes were killed for histological examination of selected soft tissues and bones. Circulating concentrations of 25-OHD increased with intake and time during the experiment. However the increases were not proportional to intake and only when intakes exceeded 20 times the recommended requirement were concentrations greater than those seen in summer in grazing sheep. There was some evidence for the production of an additional vitamin D metabolite in animals on high vitamin D intakes. No abnormalities were detected in any of the tissues examined histologically.

The role of colostrum in glomerulonephritis of Finnish Landrace lambs: effect of cross-fostering newly born Finnish Landrace and Cheviot lambs.

Newly-born Finnish Landrace and Cheviot lambs were cross-fostered to determine the role of colostrum in the development of mesangiocapillary glomerulonephritis of the Finnish Landrace breed. Severe glomerulonephritis occurred in four Finnish Landrace lambs reared by their own dams. One of six siblings of affected lambs, all reared by Cheviot foster mothers, developed a milder focal form of the disease. No glomerulonephritis occurred in three Cheviot lambs reared by Finnish Landrace foster mothers whose own naturally reared lambs died of the disease. An artificially reared colostrum-free Finnish Landrace lamb became severely affected, though its naturally reared sibling had no renal disease in sequential biopsies. It is concluded that colostrum has no primary role in the development of the disease.