Post by Falcon Boy on Aug 14, 2006 16:58:24 GMT -5
This is extracted from the Raptor Nutrition Pamplet, produced and copywrited by Neil A. Forbes and Colin G. Flint, Copyright 2000, Honeybrook Farms Animal Foods. Any spelling errors are my own and i apologize.
"Day-old chicks are often, mistakenly, considered to have the equipvalent nutritional value of a single hen's egg. This is not the case. The formation of an embryo within an egg and the development and subsequent hatching of a chick dramatically changes th echemical and nutritional value of yolk and albumen (table 3). Day-olds are used as the basis of a staple diet fo ra majority of species of birds of prey. Offering a high protein, low fat diet with good levels of vitamins and calcium.
In a recent study, the body composition of young Americna Kestrels (falco sparverius) fed on a diet of either day-old cockerals or mice were compared. This comprehensive study (Lavigne et al. 1994a ET 1994b) provides ample evidence as to the nutritional adequacy of day-old cockerals as a food source for American kestrels. Indeed those kestrels fed on a diet of mice showed evidence of protein deficiency with lower growth rates and slower fledging. It should be notied, however, that the lipid (fat)/protein ratios of the mice in Levigne's study vary considerably from the mice analysed in this study and by other authors (Gessaman 1987), (table 3). It may be that the mice used by Levigne were considerably older i.e. having higher fat reserves than those examined by other authors.It is essential in studying the results of analysis of any food item, to appreciate that the analysis results does relate specifically to the food which was tested, and both day olds and rodents do vary in nutritional values dependent on age, source and what they were fed on.
Cooper (1978) has discussed possible low levels of calcium in day-old chicks, yetthe figures outlined in Table 3, based on current and extensive study, give little credence to the possibilities of deficiency. The calcium levels, which are required by growing birds of prey, would be met by any of the whole prey outlined in Table 3 (Dierrenfeld et al. 1994, Robbins 1983).
Calcium levels, however, also need to be evaluated in relation to both dietary phosphorus (P) and vitatmin D3. Ca:P ratios of 1:1 - 2:1 have been reported for indeterminate egg layers (poultry) with determinate egg layers i.e. those birds which lay eggs during a specific breeding season e.g. raptors, requiring lower levels (Bird ET Ho 1976; Dierenfeld et al. 1994). Day-olds have the correct Ca: P ratio (the most important factor) as well as good overall levels of calcium. It is note worthy that Vit A, Vit E, and Ca:P ratio are all reduced by de-yolking day-old chicks and hence this once recommended technique may now be contraindicated.
The conclusion, therefore, is that day-old chicks are the ideal staple diet for most species of birds of prey, beingnutritionally sound, with high ME/GE ratios, as well as being economically priced, readily availible and convienent to use. As previously discussed, however, it woudl be most unwise to feed exclusively one type of food, therefore, consideration shuld be given to the other types of hawk food that are readily availible."
"Day-old chicks are often, mistakenly, considered to have the equipvalent nutritional value of a single hen's egg. This is not the case. The formation of an embryo within an egg and the development and subsequent hatching of a chick dramatically changes th echemical and nutritional value of yolk and albumen (table 3). Day-olds are used as the basis of a staple diet fo ra majority of species of birds of prey. Offering a high protein, low fat diet with good levels of vitamins and calcium.
In a recent study, the body composition of young Americna Kestrels (falco sparverius) fed on a diet of either day-old cockerals or mice were compared. This comprehensive study (Lavigne et al. 1994a ET 1994b) provides ample evidence as to the nutritional adequacy of day-old cockerals as a food source for American kestrels. Indeed those kestrels fed on a diet of mice showed evidence of protein deficiency with lower growth rates and slower fledging. It should be notied, however, that the lipid (fat)/protein ratios of the mice in Levigne's study vary considerably from the mice analysed in this study and by other authors (Gessaman 1987), (table 3). It may be that the mice used by Levigne were considerably older i.e. having higher fat reserves than those examined by other authors.It is essential in studying the results of analysis of any food item, to appreciate that the analysis results does relate specifically to the food which was tested, and both day olds and rodents do vary in nutritional values dependent on age, source and what they were fed on.
Cooper (1978) has discussed possible low levels of calcium in day-old chicks, yetthe figures outlined in Table 3, based on current and extensive study, give little credence to the possibilities of deficiency. The calcium levels, which are required by growing birds of prey, would be met by any of the whole prey outlined in Table 3 (Dierrenfeld et al. 1994, Robbins 1983).
Calcium levels, however, also need to be evaluated in relation to both dietary phosphorus (P) and vitatmin D3. Ca:P ratios of 1:1 - 2:1 have been reported for indeterminate egg layers (poultry) with determinate egg layers i.e. those birds which lay eggs during a specific breeding season e.g. raptors, requiring lower levels (Bird ET Ho 1976; Dierenfeld et al. 1994). Day-olds have the correct Ca: P ratio (the most important factor) as well as good overall levels of calcium. It is note worthy that Vit A, Vit E, and Ca:P ratio are all reduced by de-yolking day-old chicks and hence this once recommended technique may now be contraindicated.
The conclusion, therefore, is that day-old chicks are the ideal staple diet for most species of birds of prey, beingnutritionally sound, with high ME/GE ratios, as well as being economically priced, readily availible and convienent to use. As previously discussed, however, it woudl be most unwise to feed exclusively one type of food, therefore, consideration shuld be given to the other types of hawk food that are readily availible."