Influence of Constant Elevated Temperature and Diet on Egg Production and Shell Quality

Abstract

A total of 216 individually caged Single Comb White Leghorn pullets were divided into two equal groups and subjected to either a 21 ± 0.75° Cor a 32 ± 0.5° C. environmental temperature, both with 50% relative humidity. The birds in each group were fed either a typical corn-soy laying diet (15% prot., 2.8% Ca, 0.57% avail. P, 2,915 cal. M.E./gm. plus vitamins and minerals) or a "High Nutrient Density" (HND) diet (20% more of all nutrients except energy which was increased only 10%). The data collected during 8 three-week periods indicated that % nitrogen in the shell increased under heat stress, whereas the following parameters decreased: (1) food consumption; (2) egg production; (3) egg weight; (4) specific gravity of eggs; (5) shell thickness; (6) true shell expressed as % of egg weight; (7) plasma calcium; (8) hematocrit values; (9) partial pressure of C0 2 in blood. The use of the "HND" diet partially alleviated the effects of heat stress on egg weight and egg production, and also decreased slightly the amount of nitrogen in the shell; however, this decrease was not accompanied by any significant improvement in specific gravity, and therefore the increase in shell thickness observed with the HND diet appears to be solely due to an increase in egg weight. Diet had little effect on the other parameters listed above with the exception that food consumption was decreased at either temperature by the "HND" diet. Neither the ash nor the calcium content of femurs, removed at the end of the experiment, was affected by environment or diet. Similarly, the calcium content of the shells was not influenced by temperature or diet. Reversal of the environmental temperatures at the end of the sixth period resulted in an inverse response in all parameters measured.

Relationship between egg‐shell colour and two measurements of shell strength in the Vasca breed

“…It is then necessary to take additional care during the summer months to reduce negative effects on egg quality. The decrease in egg weight during July, although not significant, agrees with the results of De Andrade et al (1976) in high environmental temperatures.…”

Effect of acute heat exposure on blood flow and its distribution in the unrestrained laying fowl (Gallus domesticus)

“…Most of the studies in laying hens have revealed detrimental effects of heat exposure on egg production and eggshell quality (Mueller, 1986;Smith, 1973Smith, , 1974de Andrade et al, 1974de Andrade et al, , 1976de Andrade et al, , 1977Wolfenson et al, 1978Wolfenson et al, , 1979. It has been variously suggested that decreased plasma concentration of calcium, respiratory alkalosis or blood flow redistribution might be responsible for these effects.…”

Broiler breeder egg production and quality are affected by timing of increased dietary Ca relative to photostimulation

“…Also, the little work done in this area has investigated the interaction of heat stress and diet on laying hens rather than feed-restricted broiler breeder hens. Tanor et al (1984) reported decreased feed consumption and body weight due to shortterm heat stress and de Andrade et al (1976) reported similar results under constant, long-term heat stress in laying hens. de Andrade (1977) reported that heat stress decreased egg production and blood pCO 2 in laying hens.…”

“…Vo et al (1978) found the feed intake of Leghorn hens housed at 35°C was half of that of hens kept at 21°C. Loss of appetite has also been reported in hens subjected to heat stress, accompanied by decreases in body weight (de Andrade et al 1976 For personal use only.…”