LACTOSE, CALCIUM RELATIONSHIPS AND THEIR INFLUENCE ON FEED INTAKE AND EGG PRODUCTION CHARACTERISTICS IN LAYING HENS

ALI ALI SALIM, University of Nebraska - Lincoln

Abstract

Six experiments were conducted to study some aspects of lactose feeding, method of calcium supplementation and calcium particle size on feed intake and laying hen performance with special interest in egg shell breaking strength. In Experiment 1, four levels of lactose (0, 1, 1.5 and 2%) were fed. The results showed that feed intake, egg production level, egg weight and body weight gain were not significantly affected by treatment. Egg shell strength was significantly (P < .05) improved over the control diet by feeding 1% lactose. In Experiment 2, the 47 week old hens had better production, egg shell strength and body weight gain than the 61 week old hens. Lactose level significantly (P < .05) affected feed intake. The 3% lactose level significantly stimulated feed consumption. There was a trend for egg shell strength to improve from feeding 1% lactose over the total experiment. Dietary calcium level had no significant affect on any of the parameters measured. Three sources of lactose (pure lactose, dried skim milk and dried whey) with three levels of lactose (1, 2 and 3%) and three levels of calcium (3, 4 and 5%) in all combinations made up the 27 treatments in Experiment 3. Neither lactose source or level and calcium level significantly affected feed consumption, egg production or egg weight. However, egg production was improved slightly by feeding 3% lactose or 4% calcium, regardless of the lactose source. Dried whey as a lactose source resulted in the best egg production. Hens fed dried whey and dried skim milk gained more weight though non-significant, than those fed pure lactose. There was a significant (P < .05) depression in body weight gain from feeding the 3% calcium level. The feeding of 1% lactose significantly improved egg shell breaking strength over the 3% level. The final three experiments were designed to study the hens ability to regulate calcium intake, method of supplementation and calcium particle size on feed intake and laying hen performance. In Experiment 4, the results showed that feeding a low dietary calcium level (0.5 and 2.5%) without oystershell supplement (WO/OS) significantly (P < .05 or less) reduced production level and egg shell strength below the controls. In addition, hens fed 0.5% calcium (WO/OS) consumed significantly (P < .01) less feed and total calcium, lost weight and had a high mortality rate. There were no significant differences among groups fed 1.5, 2.5 and 3.5% calcium when they were fed free-choice oystershell supplement (W/OS). But these groups consumed significantly (P < .01) more total calcium than the controls. In Experiment 5, the results indicated that the feeding of a deficient calcium diet (0.06%) even with free-choice limestone supplement, caused a significant (P < .05 or less) and a sudden drop in feed intake, egg production and body weight. In addition, most of the hens fed these diets showed signs of calcium deficiency. After the switch to a normal diet (3.5% calcium) there was some recovery in body weight gain and feed consumption but not in egg production. In Experiment 6, the results showed that the inclusion of dietary calcium as half or totally large particle size limestone did not significantly improve egg production or egg shell quality over the fine source. The hens given free-choice supplement consumed a significantly (P < .01) larger amount of total calcium than needed to meet their requirements. It appears from these results that laying hens are unable to adjust calcium intake according to their metabolic needs.

Subject Area

Nutrition

Recommended Citation

SALIM, ALI ALI, "LACTOSE, CALCIUM RELATIONSHIPS AND THEIR INFLUENCE ON FEED INTAKE AND EGG PRODUCTION CHARACTERISTICS IN LAYING HENS" (1981). ETD collection for University of Nebraska-Lincoln. AAI8120171.
https://digitalcommons.unl.edu/dissertations/AAI8120171

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