Protein and Amino Acid Intakes for Optimum Growth Rate in the Young Pig

Abstract

Experiments were conducted to ascertain the level of protein required by the young pig at two different ages to support maximum body weight gain and efficiency of food utilization when dried skim milk provided the sole source of protein. When baby pigs were fed ad libitum from 3 to 28 days of age, a protein level of 10.2 percent yielded slow growth, low feed intake, and inefficient weight gains. However, performance improved gradually with increasing protein levels up to 22.4 percent. Further studies, where the equal feeding technic was used, showed that the pig from 1 to 4 weeks of age requires 22 percent milk protein in synthetic milk diets of the caloric density used in these tests. For the growing pig from 5 to 9 weeks of age, equalized feeding studies showed that 12 percent milk protein is the minimum requirement for satisfactory performance. Similar results were obtained regardless of whether the pigs were dry-fed or gruel-fed the diet, although considerably greater feed intake and hence greater body weight gains were observed when the pigs were gruel-fed. The results indicated that a moderately depressed feed intake and hence decreased rate of gain did not influence the determined protein requirement. Estimated amino acid requirements to support maximum growth at optimal levels of dietary protein in the suckling pig and in the weanling pig are also presented. The data stress the need for further studies on the lysine and tryptophan requirements of the weanling pig. Copyright © . .