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On three occasions during the period l91S-1956 field observations were made on coat shedding in B. indicus, B. taurus, and B. indicus x B. taurus cattle, and hair and skin samples taken. Measurements of hair length, diameter, and weight per unit area of skin were made, and stages of hair growth within the follicle observed. On two occasions hair data included measurements of length and diameter on individual hairs. Two shedding periods were observed. in spring and in autumn. Approximately 4 months was required for the complete change from m-inter to summer coat, the change in appearance being dramatic. Less time was required for autumn shedding and there was a less dramatic change in the appearance of the coat. Histological data from skin samples supported these observations and showed that during shedding almost all mature hairs were lost from the skin follicles. All types of cattle had characteristically short, light summer coats and long, heavy winter coats. No difference in hair diameter was observed between summer and winter coats in B. taurus, but in B. indicus hair diameter was much greater in the summer coat. In all seasons 01 the year B. indicus had the shorter and lighter coats. The minter coat in long-coated B. tauws did not appear to hare an undercoat, whereas short-coated B. taurus and B, indicus had distinct undercoats. In B. indicus x B. taurus F1 crossbreds coats were as'short in summer as those of B. indicus, and as long in winter as those of B. taurus. Differences between species in shedding, and in coat characteristics at different seasons of the year, may be of ecological importance. |
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