An Analysis of Strain Response to Dietary Protein Levels

Inbreeding Effects on Layer Performance at Two Levels of Protein Intake

“…The absence of any major genotype-protein level interaction in this study is in agreement with recent results of Hamilton (1978) but in contrast to results published by Deaton and Quisenberry (1965) for 14% to 17% protein rations and four egg production stocks; by Moreng et al (1964) for 13 to 17% protein and four commercial egg stocks; and by Harms et al (1966) for 11% to 17% protein and six stocks. In the last study, the interaction involved either the one meat line or ration protein levels outside the range of the present study.…”

“…The lack of strain x protein level interaction in Hamilton's (1978) report may be explained by the small direct effects of either strain or protein levels on performance. Moreng et al (1964) concluded that their interaction was probably due to the failure of one strain to assimilate sufficient quantities of at least one amino acid. The lack of interaction in our study suggests that the different genotypes evaluated were similar in their requirements for limiting amino acids.…”

“…Others have investigated genotype x diet interaction (Hull and Gowe, 1962;Harms and Waldroup, 1962;Gowe et al, 1962;Hull et al, 1963;Moreng et al, 1964;Owings, 1964;Sharpe and Morris, 1965;Deaton and Quisenberry, 1965;Harms et al, 1966;Balloun and Speers, 1969;Krautmann, 1969;Marks et al, 1969;Aitken et al, 1972Aitken et al, , 1973Nesheim, 1975;Lagervall, 1977) but little attention has been given to possible effects of inbreeding (or heterosis) on response to dietary changes.…”

Genotype—Nutrition Interactions in White Leghorn Strains

“…Clearly expressed strain x protein or energy interactions for one or several egg production traits have earlier been found by Harms & Waldroup (1962, 1966 ' Deaton & Quisenberry (1965), Moreng et al (1964), Kondra & Sell (1966 and, as just mentioned, also by Krautmann (1971). However, no evident interactions of the same kindwere observed by Thornton & Whittet (1960), Kolstad et al (1969) and Marks et al (1969).…”

Evidence of Genetic Variability for Lysine Utilization

“…Thornton and Whittet (1960) presented evidence that commercial strains of layers had a slightly different protein requirement for maximum egg production. Moreng et al (1964) reported variations in ability among four commercial strains as measured by…”