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Nutrient Requirements of Poultry: Ninth Revised Edition, 1994
insemination may be individually fed. The major advantage of separate feeding is control of body weight and its subsequent impact on fertility and mating ability. Thus a set of nutrient requirements for male meat-type breeders, although limited in scope, is listed in Table 2-8. It should be noted that diets intended for use by the breeder hen, when fed to control male body weight, appear to have no detrimental effects on male performance.
Protein requirements of breeder cockerels have been evaluated during the growing and adult periods by using both White Leghorn and Meat-type cockerels. In studies with Single Comb White Leghorn (SCWL) cockerels, low crude protein levels fed during the grower period reduced body weights and delayed testicular development, but, on subsequent feeding of adequate protein, reproductive performance was not impaired (Wilson et al., 1965; Jones et al., 1967). Diets containing 12.4 percent crude protein offered for ad libitum consumption to broiler breeder males during the period of 7 to 21 weeks of age were adequate for development of the reproductive system and subsequent
TABLE 2-8 Nutrient Requirements of Meat-Type Males for Breeding Purposes as Percentages or Units per Rooster per Day (90 percent dry matter)
NOTE: For nutrients not listed, see requirements for egg-type pullets (Table 2-3) as a guide. Where experimental data are lacking, values typeset in bold italics represent an estimate based on values obtained for other ages or related species.
a Energy needs are influenced by the environment and the housing system. These factors must be adjusted as required to maintain the body weight recommended by the breeder.
b Broilers do not have a requirement for crude protein per se. There, however, should be sufficient crude protein to ensure an adequate nitrogen supply for synthesis of nonessential amino acids. Suggested requirements for crude protein are typical of those derived with corn-soybean meal diets, and levels can be reduced somewhat when synthetic amino acids are used.
c Amino acid requirements estimated by using the model of Smith (1978).
reproductive performance (Wilson et al., 1971). Broiler breeder males can be fed 12 to 14 percent crude protein on a restricted basis after 4 weeks of age with no adverse effects on final body weight, sexual maturity, or semen quality; a greater number of males produced semen through 53 weeks when fed 12 percent crude protein than when fed higher levels (Wilson et al., 1987a). In a subsequent study (Wilson et al., 1987b), a 9 percent crude protein diet fed beginning at 43 days and continuing through 50 weeks was adequate to support maximum reproductive performance. In both these studies, amino acid content was maintained at a constant percentage of the protein level. There were no differences in semen characteristics of broiler breeder males fed 12 to 18 percent crude protein during the period from 4 to 20 weeks; males fed 15 percent crude protein during the period from 1 to 4 weeks had significantly higher fertility from 24 to 27 weeks than did males fed 20 percent crude protein (Vaughters et al., 1987). Semen production of broiler breeder males kept in cages can be maintained from 20 to 60 weeks on a daily protein intake of 10.9 to 14.8 g per day (Buckner and Savage, 1986).
Daily energy intakes of 400 (McCartney and Brown, 1980) and 458 kcal ME per bird (Brown and McCartney, 1983) have been reported as adequate for broiler breeder males maintained on litter. For broiler breeder males maintained in cages, 346 (Brown and McCartney, 1986) or 358 kcal ME per bird daily (Buckner et al., 1986) were sufficient.
The calcium requirement of the breeder cockerel is much lower than that of the hen, but levels fed to the hen apparently are not detrimental to the reproductive performance of the male. Wilson et al. (1969) indicated that the calcium requirement of SCWL cockerels did not exceed 0.2 percent, but that levels as high as 3 percent were not detrimental. In calcium balance studies with SCWL cockerels, Norris et al. (1972) found that the daily requirement was 7.98 mg per kg of body weight. Kappleman et al. (1982) concluded that there were no differences in the reproductive performance of broiler breeder cockerels fed 0.5 to 7 g of calcium daily per bird.
Norris et al. (1972) found that diets containing 0.1 percent nonphytate phosphorus were satisfactory for SCWL cockerels. Bootwalla and Harms (1989) found that no more than 110 mg of nonphytate phosphorus per bird daily were needed for maintaining reproductive capacity and bone integrity in broiler breeder cockerels.