160 



C. R. BARNICOAT 



Fig. 3. Excessively worn mouth of 4-year-old ewe, showing caries-like ap- 

 pearance due to staining of plugs of secondary dentine. 



able mouths of breeding ewes and, more important, of rams, it is 

 possible to "grade up" gradually the quality of the mouths of the 

 whole flock. 



An interesting feature is that in flocks of sheep noted for sound 

 teeth, these faults may merely be latent in the animals while grazing 

 "good teeth" country. When the sheep are transferred at an early 

 age to "improyed" high-yielding pastures, a surprising range of de- 

 fective mouths usually develops as they mature. 



Nutritional Factors 



Results of nutritional trials with sheep emphasize the importance 

 of adequate intakes of calcium and phosphorus. 



Franklin (1950) found that diets (grains) which were deficient, 

 particularly in calcium, caused a general stunting of the whole skele- 



