Calcium Metabolism in Broiler Breeder Hens

Abstract

Experiments were conducted to determine the influence of time of dietary calcium intake on eggshell quality in broiler breeder hens. In Experiment 1, 60 hens were randomly divided among three treatment groups. The control group received 155 g feed (3.1% calcium) per day at 0800 hr whereas the morning- (a.m.) and evening-fed (p.m.) treatments received a .42% calcium diet (155 g/bird) and were intubated with 4.2 g calcium at 0800 or 1600 hr, respectively. Egg weight, shell weight, and specific gravity were determined at 3-day intervals for 15 days. In Experiment 2, 150 breeder hens were randomly divided among two treatment groups. They were fed 122 g per hen during a 2.5-hr feeding time at 0700 to 0930 or 1530 to 1800 hr. Eggs were collected for egg weight, shell weight, and specific gravity determinations. At the end of the 5th week, 10 hens from each treatment group were sacrificed at various times throughout a 24-hr period and the contents of each segment of the GI tract and feces were analyzed for moisture, dry matter, and calcium. In Experiment 3, two commercial broiler-breeder houses with 5,000 hens each were used. They were fed 132 g/hen per day at 0530 hr daily with water provided ad lib. The feeding time of one house was moved forward by 2 or 2.5 hr per day until the feeding time was 1600 hr. Eggs were collected for 2 weeks following pretreatment data and values determined for specific gravity. Eggs were also candled at 7 days incubation to determine embryonic mortality and fertility. Hens intubated at 0800 hr with their daily supply of calcium did not maintain shell quality equivalent to controls (Experiment 1). However, hens intubated at 1600 hr had no difficulty maintaining shell quality. Hens fed at 1530 hr had significantly better shell quality during all weeks tested compared to hens fed at 0700 hr (Experiment 2). The p.m.-fed hens had 66.9% more calcium available at 1800 hr (2.07 vs. 1.24 g) compared to a.m.-fed hens. Hens fed at 1600 hr in the commercial houses (Experiment 3) had significantly better eggshell quality (specific gravity) than hens fed at 0530 hr. There was no significant difference in percent embryonic mortality or percent fertility when eggs were candled after 7 days of incubation. It was concluded that p.m.-fed hens had significantly more calcium available during the stages of eggshell calcification. The result was significantly better eggshell quality.

Prototypes for Application of Choice Feeding in Caged Laying Hens Using Flat Chain Feeders

“…As the concentrate (placed upon the grains) is transported along the circuit, it successively falls through and mixes with the grain, concentrate thus being consumed first by the birds at the start of the run and later by birds at positions further on along the circuit. Several authors have reported inferior egg shell quality in hens receiving the calcium early in the day before egg shell calcification occurs, compared to calcium offered late in the day closer to the calcification phase (Mongin & Saveur, 1979;Hellwig et al, 1982;Farmer et al, 1983;Roland, 1984). Although the trends in SCF-B would not be a serious problem in longer circuits, they raise the question of the optimum time for delivery of concentrate.…”

“…(Petersen, 1972(Petersen, , 1977Blair et al, 1973;Emmans, 1975Emmans, . 1977Emmans, and 1982Dun et al, 1978;Heam et al, 1979;Leeson & Summers, 1979;Herstad, 1980;Summers & Leeson, 1981;Farmer et al, 1983;Elwinger & Nilsson, 1984;Saveur & Clavreul, 1984;Robinson, 1985). Production results compared to all mash meal feeding have varied according to models used.…”

The effect of different feeding schedules on egg quality, blood, and bone parameters in broiler breeders

“…It normally begins in the afternoon or evening, and the utilization of dietary Ca in morning-fed broiler breeders is poor due to the inability of these hens to maintain Ca from the crop to the lower digestive tract at a uniform rate (Farmer et al, 1983a). Feeding broiler breeders later in the day supplies dietary Ca at times that correspond more closely to periods of shell deposition (Farmer et al, 1983a), resulting in a better Ca utilization (Farmer et al 1983b;Roland and Farmer, 1984), which is usually manifested as an increase in egg specific gravity, eggshell weight and shell thickness (Backhouse and Gous, 2006). In this study, the highest egg specific gravity was observed in hens fed at 3:00 PM (Table 3).…”

Influence of high environmental temperature on egg production and shell quality: a review

“…The ability of hens to produce good quality shell depends largely on the availability of calcium (Ca) from the ingested food and skeletal reserves (Farmer et al, 1983). Washburn (1982) corroborated that Ca is the most important dietary factor affecting shell quality.…”