6 .117 Most of the colony vegetables have high forage value including tomato, cucumber, melon vines, and tomato and cabbage roots and leaves. Ruminants can convert such waste into milk. A comparison of the two most common milk- producing ruminants follows (6 . 4): (per day) (per day) (mass ratio) Animal Weight Dry Feed Intake Milk Produced Milk/Feed goat 56 kg 2 kg 5 kg 2. 5 cow 540 kg 20 kg 20 kg 1.00 As can be seen, a goat produces more than twice as much milk for given amount of feed as a cow. If half of the daily per person grain allotment is used to supplement forage for goats (one goat per 2.4 people), 2 kg milk is returned with more than twice the protein content of the sacrificed grain, with a better amino acid balance, and higher mineral and vitamin content. The flavor of goat's milk is acceptable, and the unacceptable odor of male goats can be avoided by using artificial insemination. The milk can also be processed into cream, butter, cheese, and ice cream (6.4). Table 6.15 summarizes the major components of the proposed diet per person. It contains 3000 C, but could be raised to 4300 C by substituting more potatoes and soybeans (6.4). Assuming the crops and animals are carefully controlled, the food production part of the space colony should be stable. The allotted portions are generous, and the colony could withstand a substantial loss without being seriously affected. However, even if all the crops were lost at once, the food production would be well on its way back to normal in two weeks. All animals that could not be fed on any remaining feed would be butchered and their meat preserved. After clearing the area, the fastest growing seeds available would be planted, which would begin to bring the carbon dioxide level down in one week. In two weeks, animal forage would be available and stability would be reached in three months. Even if nothing could grow, the carbon dioxide level would not become uncomfortable for two weeks which would allow time for an Earth rescue mission to arrive (6.4).
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