Effect of Body Weight, Feed Allowance, and Dietary Protein Intake During the Prebreeder Period on Early Reproductive Performance of Broiler Breeder Hens

Two basal feeds (118 and 175 g protein/kg) with similar balanced amino acid mixtures were appropriately blended to produce six experimental diets differing in protein. These were fed for six weeks to 180 broiler breeder hens (Ross 308) housed in individual cages from 26 w of age. A 13 h photoperiod was applied. Half the birds were restricted to 160 g of feed/d, whilst the others were fed ad libitum. The treatments were randomly allocated within six blocks. At the end of the six-week period the mean voluntary intake of the ad libitum-fed birds was 169 g/d whereas the intake of hens on feed restriction was 155 g/d. In spite of the range of protein intakes from 18.5 and 28.8 g/bird, no differences were observed in rate of laying between the two feeding strategies or dietary protein levels, nor were there differences in the proportions of yolk or albumen between these treatments. Egg weight, egg output and weight gain increased with protein intake as did energy retention (kJ/d) whereas heat output (kJ/d) decreased as protein intake increased. Even though dietary protein intake had no effect on rate of lay, the resultant decrease in heat output at high protein intakes suggests that this might be a useful strategy to consider for overcoming mild heat stress.Keywords: Ad libitum feeding, heat production, energy retention, egg composition

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Reproductive performance, growth rate and body composition of broiler breeder hens differing in body weight at 21 weeks of age

Canadian Journal of Animal Science ◽

10.4141/cjas91-145 ◽

1991 ◽

Vol 71 (4) ◽

pp. 1223-1231 ◽

Cited By ~ 2

Author(s):

F. E. Robinson ◽

N. A. Robinson

Keyword(s):

Body Composition ◽

Body Weight ◽

Reproductive Performance ◽

High Weight ◽

Embryo Viability ◽

Broiler Breeder ◽

Breeder Hens ◽

Low Weight ◽

Broiler Breeder Hens ◽

Medium Weight

The effects of variation in body weight at 21 weeks of age on subsequent growth rate, body composition and reproductive performance were studied in broiler breeder hens from 22 to 62 weeks of age. Pullets were sorted into three groups on the basis of body weight (low, medium and high) at 21 weeks of age. Pullets of the low-weight group contained a greater percentage of carcass water and less carcass fat at 22 weeks of age than did the medium- and high-weight pullets, and less carcass protein than the high-weight birds. The relative difference in body weight between the three groups of hens was maintained to 62 weeks of age, the high-weight hens being heavier than the low- and medium-weight hens at the end of the study. The low-weight birds began to lay later than the medium- and high-weight pullets. The low- and medium-weight birds were lighter in weight compared to the high-weight pullets at sexual maturity. Total egg output was lower in the low-weight hens than in the medium- and high-weight hens. No difference was seen in sequence and intersequence pause parameters or in fertility, embryo viability or embryo production between the three groups of hens. On a percentage basis, there were no differences in body composition between groups of birds at 62 weeks of age. It was concluded that pullets which are underweight at 21 weeks of age exhibit a poorer production record than do pen-mates which are of normal or greater than normal body weight. Key words: Broiler breeder hens, egg production, body weight, body composition, sequence length, fertility, embryo viability

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