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The effect of age on tooth loss and the performance of Masham ewes

1984; Cambridge University Press; Volume: 39; Issue: 3 Linguagem: Inglês

10.1017/s0003356100032153

1748-748X

J. E. Newton, Caroline Jackson,

Ruminant Nutrition and Digestive Physiology

ABSTRACT The rate of incisor, pre-molar and molar tooth loss was studied in two groups of Masham ewes, one from 8·75 to 12·25 years of age, and the other from 7·25 to 9·25 years of age. Incisors were lost at the rate of 0·93 per year in group 1 and pre-molars from the lower jaw at the rate of 1·04 per year. The rate of loss of molars from the lower jaw and pre-molars from the upper jaw was much slower, whilst there was virtually no loss of molars from the upper jaw. Mean litter size declined gradually from age 7 in group 1, but there was no decline up to age 9 years in group 2. Lambing percentage declined gradually from age 6 years, with a marked drop after age 10 years caused by an increase in barrenness and lamb mortality. Selling percentage also began to decline from age 6 years but dropped sharply after age 9 years following an increase in the number of lambs having to be reared by hand. Ewe live weight, lamb birth weight and lamb growth to 4 weeks of age showed no decline up to 12 years of age.