Grazing behavior and rumen characteristics of Japanese Black Cattle were examined on two paddocks (B : 1st trial and C : 2nd trial) in a native pasture with different botanical composition. The grazing pattern and rumination time of three animals showed variations between paddocks B and C on 24 hour behavioral observations. An increase in grazing time on the paddock C was observed as compared to the paddock B. Diet selection was evaluated by bite count method. In paddock B, the cattle grazed initially Imperata cylindrica more highly but later Miscanthus sinensis and Eremochloa ophiuroides by bite count method. The cattle selected M. sinensis as the first choice for a few days after transfer to the paddock C, and I. cylindrica and E. ophiuroides more during the later stage of grazing period. Total volatile fatty acids (VFA) concentrations in the rumen fluid were higher in the samples collected on the 7th or 9th day than on the 1st day of the grazing before transfer, irrespective of paddocks (paddock B : 5.27 to 6.76 mmol dl^<-1>, paddock C : 6.87 to 7.53 mmol dl^<-1>). NH_<3->N concentration in the rumen fluid remained stable around 4.33 mg dl^<-1>. Total protozoa counted 3.0×10^5 ml^<-1> on the 4th day after moving and similar during the 1st trial, while in the 2nd trial 4.1×10^5 ml^<-1> on the 4th day after moving and then increased to 5.9×10^5 ml^<-1> on the 9th day. Total protozoa counted higher in the 2nd trial than in the 1st one. Number of bacteria ranged from 1.1×10^9 ml^<-1> to 7.1×10^9 ml^<-1> and cocci (-) and cocci (+) were detected in large percentages throughout the experimental period.

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The objective of this study was to examine the cows ' visit and utilization of each milking robot in a loose barn that had two milking robots for a group of cows. The data were collected in a Wada farm located Nagano prefecture. Two milking robots (DeLaval "VMS^<TM>") were installed in the loose barn. The survey was carried out in June 2003 and the data was collected from October 28 to November 10, 2003 for 98 cows. In the Wada farm, the utilization characteristics were as follows : 1) both robots performed over 120 milkings per day, and the operating situation in Wada farm was in good condition; 2) the number of times that cows could visit each milking robot was significantly different between the milking robots (VMS-1; 154±4 times/d, VMS-2; 167±17 times/d, p<0.05); 3) twenty-six cows visited one of two robots over 90%. Fourteen cows frequently used one milking robot, and twelve cows used another robot; 4) these inequable-visiting cows tended to visit the milking robot in low frequency (42±12 times/d, p<0.05) and they occupied milking robot longer (7.2±1.8 minutes, p<0.05) compared with; 5) from six to eight cows could visit the milking robot per hour except when the robot was in self-cleaning mode. In the utilization of two milking robots for one group of cows in a loose barn, it was concluded that there were some inequable-visiting to the milking robot by cows, and it might be necessary to balance the number of such cows to achieve high performance in the automatic milking system.

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[in Japanese]

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