The results of modelling with an initial livestock of the cattle - 30 heifers, 10 calves (all animals are about one year):
On the given schedules dynamics of transition of animals from one age groups in others is displayed.
We can see, that at achievement of the certain age heifers (a red line) are divided into two categories: milk cows (a green line) and cows (a blue line). Cows fatten the necessary weight, and then they are slaughtered. Through the certain time interval Milk cows give a gain of the herd and start to be milked.
We can see, that at achievement of the certain age three calves (a red line) become bulls (a blue line), the others remain calves, until they fatten the necessary weight. As soon as it occurs, they are slaughtered.