A Multicycle Comparison of Dietary Zinc and Feed Removal Molting Procedures: Production and Income Performance

Abstract

Two experiments were conducted to evaluate performance and income factors associated with zinc oxide and feed removal multicycle molt programs. Experiment 1 compared two strains of commercial White Leghorn layers molted with 20,000 ppm zinc oxide in the feed for 4 days with a feed removal program of 10 days followed by 10 days of cracked corn. Experiment 2 compared a single strain of White Leghorn layers molted with 20,000 ppm zinc oxide with feed removal for 4 and 10 days.Body weight loss during molt averaged 25 to 30% for the longer duration molt programs compared to 14 to 16% for the short duration programs. Differences in body weight loss between zinc oxide and feed removal programs employing the same durations of treatment were not significant (P>.05). In addition, no significant (P>.05) differences were observed between zinc oxide and feed removal programs for hen-housed egg production, days to reduce egg production to 0%, feed usage, or mortality rates. Differences in egg sizes and egg grade distributions were observed among molting programs and strains.Incomes over pullet and feed costs for the molted flocks were greatest during the first molt cycle. Incomes over pullet and feed cost during the second molt cycle were generally negative. The longer duration molt programs resulted in total incomes over feed and pullet costs averaging 5.0¢doz more than the shorter 4-day duration programs. Duration of molt-inducing periods had greater effects on performance and income results than did the method used to induce rest.