Abstract
Summary
Two sows which consumed synthetic diets and were given injections of approximately 400 μg each of vit. B12 reared their first litters. The weights of the pigs when weaned at 8 weeks were subnormal, 20 and 26 lbs., and there were other signs of mild nutritional deficiency. One of the sows received by injection 2,380 μg of the vitamin during a second gestation and lactation and reared a litter of 7 pigs with the unusual average weaning weight of 47 lbs. The other sow consumed during her second gestation and lactation a diet that contained a water extract of liver and weaned a litter of 7 with an average weight of 35 lbs. The inclusion of a liver extract in the synthetic diet was not more effective than was the injection of vit. B12 and the evidence indicates that swine can complete a normal life cycle on diets that contain no unrecognized nutrients.
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