Four female Tokara goats were used to investigate the relationship between lying behaviour and social dominance. Agonistic behaviour was recorded by observation and a dominance hierarchy was determined. Lying location, the interindividual distance and the order of lying down and standing up for each of four goats were recorded. The results obtained were as follows : 1. Dominant animals had priority over subordinate animals in the selection of lying position in the pen. 2. Twins were closely connected. 3. Subordinates kept dominants at a distance for flight and had a tendency to orient their sides toward the dominants. Jpn. J. Livest. Management, 33(1) : 1-8. 1997. Received November 28,1996. Accepted February 17,1997.

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The thermoregulatory responses of heifers of Holstein and Holstein crossed with Japanese Black Cattle were compared in order to explain breed differences in terms of thermosensitivity. The heifers were exposed to environmental temperatures (Te) of 23,28,33 and 38 PC under controlled conditions of heat production (HP) from ingested feed both during the day and during the night. HP was greater in Holstein than in cross bred heifers both during the day and night. Against increased Te, the vaginal temperature (Tv), mean skin temperature (mTs), mean body temperature (Tb), respiration rate (RR), heart rate (HR) and standing time (ST) increased significantly (P<0.05) during the day and/or night. During the night, against Te the Tv, Tb and ST of Holstein heifers was significantly greater than that of cross bred heifers. These differences between breeds were explained using thermosensitivity as was done in an earlier study. Thermosensitivity was greater in cross bred than in Holstein heifers and during the day than during the night, because in cross bred heifers at high Te and during the day, heat balance was maintained at a lower body temperature than in Holstein and during the night. These breed and day-night differences in thermosensitivity are important in breed selection and thermal management in warm and hot conditions. Jpn. J. Livest. Management, 33(1) : 9-15. 1997. Received January 16,1997. Accepted March 17,1997.

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[in Japanese]

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