The effect of degree of competition for feeding space on the silage dry matter intake and feeding behaviour of dairy cows

Twenty five late lactation dairy cows were allocated to 5 treatments with either 1, 3, 5, 7 or 9 cows per feeding space. Each feeding space consisted of a Calan gate with access to silage blocks placed on a load platform. Eating behaviour was monitored by identifying cows using collar borne transponders. Animals had access to silage throughout the day, with fresh silage being offered daily at 09:30 h. No concentrates were offered during the experiment. Cows were allocated to a Graeco-Latin square design with 5 periods. Each period consisted of 14 days, and one cow per treatment was recorded for each period, with additional cows used to reach the required level of competition. All cows were rotated across treatments and gates over periods. As the degree of competition increased, animals modified their feeding behavior, with a linear increase (P < 0.001) in both number of meals per day and eating rate. Increasing level of competition resulted in linear reductions (P < 0.01) in total feeding time, feeding time per meal and average meal size. Total dry matter intake was reduced both by the absence of competition and at high levels of competition, showing a quadratic trend (P < 0.05) with increasing competition. It is concluded that at low levels of competition, cows ate relatively few, large meals, but as competition increased cows consumed silage in a large number of small meals. At moderate levels of competition (3-7 cows/feeding space) cows maintained their intake as a result of marked changes in feeding behavior.