CALCULATING RATIONS FOR ANIMALS (Continued) TIME: FALL OR SPRING TERM Object: To learn how to balance rations for different animals under different conditions. Material needed: Paper and pencil. DIRECTIONS Select your own feeds and balance rations for the animals mentioned in the table below. The number of pounds of dry matter and the nutritive ratios are given in the same table. POUNDS OF FOOD REQUIRED A DAY FOR 1,000 POUNDS LIVE WEIGHT FEED AFFECTING THE FLAVOR OF MILK TIME: SPRING TERM Object: To learn how feeding stuffs affect the flavor of milk. Material needed: Rape, cow, milk. DIRECTIONS Ask some student, on whose father's farm rape is grown, to feed one of the milch cows some rape in 'the afternoon, and to save a small amount of milk at milking time. Carry the milk to school and see whether the students can detect any change in the flavor due to the rape. QUESTIONS 1. Name some other substances that produce bad flavors in milk. 2. Is milk a direct product of food or the blood? 3. At what time does grass most affect the flavor of milk? SOURING OF MILK TIME: FALL OR SPRING TERM Object: To find a means of preventing the souring of milk. Material needed: Several small milk bottles, milk, thermometer. DIRECTIONS 1. Clean several small bottles and dry them in the sun. Fill the bottles with fresh milk and divide into three lots. Stopper well so as to exclude the air. 2. Boil one lot for a few minutes. This boiling should kill nearly all the bacteria. 3. Pasteurize the second lot, i.e., place the bottles of milk in water which has been heated to 155° F. Leave 20 minutes and set aside to cool. Leave the third lot untreated. QUESTIONS 1. How long does the milk keep sweet in each lot? 2. Does boiling or pasteurizing alter the flavor of milk? A TEST FOR FORMALIN IN MILK TIME: WHENEVER CONVENIENT Object: To determine whether milk has been treated with formalin. Material needed: Milk, formalin, sulphuric acid. DIRECTIONS Pour a small amount of formalin into a glass of milk and stir. Next pour sulphuric acid into the milk, letting it run down the side of the glass. Do the same with some milk which has no formalin in it. A purple color at the junction of the milk and acid indicates the presence of formalin. Persons living in the city should occasionally test their milk for formalin, as many milkmen use it to prevent their milk from souring. Pasteurizing is legitimate, but the use of formalin should be condemned. Milk treated with formalin is very harmful to infants. TEMPERATURE FOR CHURNING BUTTER TIME: DURING WARM WEATHER Object: To determine whether a high or a low temperature is better for churning butter. Material needed: Milk ready for churning, churn, hot water, cold water, thermometer. DIRECTIONS Have older pupils at whose homes large quantities of butter are made divide the cream into two parts. Churn one lot at about 58° or 60°, and the other at, say, 80° to 85°. With the aid of a thermometer the temperature can be regulated by hot and cold water. When the two lots have been churned, note any difference in the appearance of the butter. QUESTIONS 1. Which lot was longer in churning? 2. What difference do you notice in the granular structure? 3. Why is cream usually kept in a warm place before churning? |