اندازه‌گیری فعالیت نشخوار با دستگاه ثبت خودکار فعالیت جویدن در گاوهای شیری تغذیه شده با علوفه یونجه با اندازه ذرات متفاوت

In order to design, manufactur and use chewing activity automatical recorder and more accurate assessment of livestock nutrition from 8 Holstein dairy cattle were used with similar production, weight, age, breed and health in change over design 2×2 in two 21-day periods (2 weeks to adapt to the diet and 7 days for sampling). Treatments were 2 diets with the same chemical composition and different alfalfa hay particle size. The geometric mean of coarse and fine alfalfa hay, and geometric mean of two experimental rations were 3.09, 4.65, 2.91, and 3.6 mm, respectively. Animal chewing activity was recorded with visual observation and chewing activity automatically recorder. Rumination time in cows fed fine particle size was lower (P= 0.0159). Eating time was not significant different by visual observation and chewing activity automatical recorder. The jaw displacement during each a rumination meal was 334.34 and 295.47 cm for fine and coarse diet, respectively (P= 0.0001). The each rumination time In this study was ranged from 68.93 to 55.33 seconds for diets containing fine and coarse particles (P= 0.0001). The chewing of a rumination meal was reduced by increasing of particle size. The movement of jaw in one second of rumination was 4.86 and 5.34 for diets containing fine and coarse particles, respectively (P= 0.1706). The degree of displacement in a jaw movement of one minute of rumination did not change with increasing feed particles size (P= 0.1706). The jaw movements in resting time between each meal of rumination were 4.61 and 4.46 seconds for fine and coarse diets. In current experiment, In addition to evaluating the chewing activity automatical recorder was confirmed accuracy and the precision of its operation.