Intake capacity of 8 heifers (from 370 to 470 kg) was individually recorded during 3 periods (4 to 8 weeks) at 4‑month intervals. Intake capacity of 8 mature dry cows (740 kg) and 8 female calves (300 kg) was also measured in the last period. The animals were fed the same hay in the first and the last period, and grass in the second period, both cut from a natural meadow.
Information was also collected from published intake data of cattle (80 to 700 kg) at pasture, in order to calculate relationships between herbage intake and live weight, age of cattle, and herbage digestibility.
Live weight explained better intake variability than age of cattle. A concomitant effect of age was also significant in the bibliographic data base (P<0.01). Intake per kg live weight decreased as the animal grew. More digestible forages were eaten in greater amounts. Allometric coefficient of intake in relation to live weight (from 1 to 0.77) fell as cattle increased in size, but faster in early‑maturing breeds (dairy breeds). This means that development of intake capacity occurs later in beef cattle, and thus younger animals are more sensitive when they are fed low quality forages.