Studies of the nutrition of young animals. I. Energy exchanges in the growing pig.

Extract

The facts and considerations set out above provide the information necessary to enable an intelligent pig-keeper to compute on a logical and scientific basis a series of rations which from the energy point of view will produce any desired rate of live weight increase within the capacity of his animals. It is however necessary to make the reservation that the data apply strictly only to pigs of the Large White breed kept under good conditions and liberally fed.

It should also be noted that the method can only be applied to animals of known age and weight.

The method is applied as follows:

1. From the age of the animals read off from the basal metabolism chart, Fig. 1, the intensity of the basal metabolism per square metre per hour.

2. From the live weight—surface chart, Fig. 2—read off the surface area in square metres corresponding to the animal's live weight.

3. Multiply the basal metabolism per square metre per hour by the area of the animal's surface in square metres. The product multiplied by 24 gives the basal metabolism of the animal per day.

4. To get the practical maintenance requirement add to the basal metabolism per day 1000 calories to allow for an average amount of muscular effort.

5. Decide the growth rate in pounds of live weight increase per day at which it is desired to aim. The growth rate curve, Fig. 4, will help in assessing this figure.

6. Read off from Fig. 3 the calorie value per lb. of live weight increase corresponding to the live weight of the animals under consideration, and multiply the figure there found by the desired live weight increase in lb. per day. This will give the productive ration in calories per day.

7. The total ration is then found by adding together the maintenance requirement estimated in 4 above and the productive ration estimated in 6 above. This gives the total ration in calories of net energy.

8. Transform calories of net energy into lb. of meal on the assumption that 1 lb. of meal supplies to the pig 1000 calories, or preferably that 1 lb. of starch equivalent supplies 1500 calories.