FURTHER OBSERVATIONS ON LYSINE AND PROTEIN REQUIREMENTS OF 23 TO 89 KILOGRAM PIGS

Abstract

The results of four related experiments are presented. The first involved three levels of lysine (0.58, 0.68, 0.78%) and cross-treatments of brewers’ yeast and alfalfa meal. The pigs were individually fed linear-programmed rations based on National Research Council standards from 23 to 57 kg. The pigs averaged 0.64 kg gain/day. No response was obtained to lysine beyond 0.58%. Feeding alfalfa resulted in increased feed intakes. In the second trial, the 0.68 and 0.78% lysine levels were obtained by adding lysine to the 0.58% lysine formula. The pigs fed 0.68% lysine gained faster and more efficiently. In the third trial, pigs were fed 0.58 and 0.78% lysine rations ad libitum and responded better to the 0.78% level. In the fourth experiment, the pigs were fed 0.68% lysine rations ad libitum and gained 0.74 kg/day, equal to the response to the 0.78% level in the previous trial.It was concluded that the lysine requirement for 23- to 57-kg pigs fed rations containing 3,330 kcal digestible energy/kg is about 0.7%. After they reached 57 kg, the pigs were fed 14 or 16% finisher rations. In general, responses to the high-energy rations tested were equal. Some carryover effects of grower rations on carcass characteristics were observed.