Effects of insoluble grit on the productive performance of ten white leghorn strains 1

Self Cite

One thousand five hundred and thirty-six individually caged S.C.W.L. hens were fed corn, wheat, soybean diets formulated to contain 0.55, 0.50, 0.45 and 0.40% available or 0.47, 0.43, 0.38 and 0.33% inorganic phosphorus from 140 to 497 d. of age. The hens were from three commercial strains, three 2-way and three 3-way strain crosses and from a control strain. Egg quality measurements were taken on eggs laid over 5 d. intervals seven times during the experiment. Chemical analyses indicated that the diets fed contained 0.58, 0.55, 0.50 and 0.45% available and 0.48, 0.45, 0.42 and 0.38% inorganic phosphorus. Phosphorus level had no significant effect on feed intake or efficiency, egg production, sexual maturity, egg weight, blood spots or mortality but had a significant effect on 497 d. body weight and egg specific gravity at 165, 225, 277, 335, 390, 445 and 490 d.j however, the differences were small for this latter trait and probably of little practical importance. Strain of bird had a significant effect on all traits except mortality and blood spots. There were very few diet X strain interactions. The results indicate that a level of 0.45% available phosphorus is adequate for laying hens under practical conditions.

Section: Resultssupporting

confidence: 86%

Section: Methodsmentioning

confidence: 95%

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The Effects of Dietary Phosphorus on Productive Performance and Egg Quality of Ten Strains of White Leghorns

Hamilton¹,

Sibbald²

1977

Self Cite

“…Postmortem examination showed little evidence of calcium deficiency for the chicks given the lower calcium diets. The mortality results for strains 7 X 7, 2 x 3, and 4 x 1 agreed with those reported by Sibbald and Gowe (1977).…”

Section: Methodssupporting

confidence: 90%

Effects of Dietary Calcium Levels During the Brooding, Rearing, and Early Laying Period on Feed Intake, Egg Production, and Shell Quality of White Leghorn Hens

Hamilton¹,

Cipera²

1981

The effects of decreasing the calcium (Ca) level of the diet during the growing and early laying period were investigated with Single Comb White Leghorn pullets. In the first experiment, lowering the dietary Ca level from 3.2 to 2.0 or 1.0% between 154 and 182 days of age or to 2.0% between 183 and 211 days influenced egg specific gravity (P<.001) and shell weight at 177 and 205 days but had no effect (P>.05) on subsequent measurements. Dietary Ca level had no effect on feed intake and efficiency, egg production and yield, egg weight, and Haugh units during the laying period from 154 and 439 days. In a second experiment containing chicks from each of four 2-way crosses, three commercial and a control strain, the dietary Ca level was lowered during the rearing (1 to 143 days) and laying (144 to 354 days) period. Mortality was higher and body weight lower (P<.001) for chicks reared on diets containing .51% Ca than those given the control diets containing .78% Ca. In the laying period, egg production, feed intake and efficiency, and egg specific gravity were lower and mortality, Haugh units, and blood spots were higher for pullets given a diet containing 2.2% Ca between 144 and 242 days or 144 and 340 days than for those receiving a 3.2% Ca laying diet. The hens given the 2.2% Ca laying diet previously had received the .51% Ca diets during the rearing period. There were differences (P<.05) among strains for the aforementioned variables, except feed intake and efficiency, but there were few strain X dietary Ca interactions. These results indicate that egg shell quality was only temporarily improved when the dietary Ca was decreased and subsequently increased during the laying period. (

“…During the brooding and rearing period (1 to 142 days) the birds were group housed in wire cages and were managed as previously described (Hamilton and Sibbald, 1977), except that all of the chicks received insoluble granite grit. No insoluble grit was given during the laying period because no advantage was found with mash laying diets (Sibbald and Gowe, 1977).…”

Section: Methodsmentioning

confidence: 99%

The Effects of Dietary Protein Level on Productive Performance and Egg Quality of Four Strains of White Leghorn Hens

Hamilton¹

1978

The effects of a mid-laying period reduction in dietary protein level on productive performance was studied with 576 individually caged Single Comb White Leghorn hens from four strains. The hens on treatments 1 and 2 received diets that contained by calculation 17 and 15% protein, respectively, between 143 and 507 days of age, while those on treatment 3 received 17 and 13% protein diets from 143 to 325 and 326 and 507 days, respectively. For treatment 4, diets containing 15 and 13% protein were given during the same periods as for treatment 3. Egg quality measurements were taken on eggs laid over 5-day intervals when the birds were 182, 252, 316, 380, 436, and 485 days of age. Dietary protein level had no significant effects on feed intake, mortality, body weight, egg production, egg grade, specific gravity, egg weight, Haugh units, or blood spots. Protein intake had no effect on the 507-day body weights and on hen-day egg production, except for a small decrease for treatment 4, although the intakes of protein, leucine, and lysine were lower for treatments 3 and 4 between 326 and 507 days of age than the NRC requirements. Level of dietary protein had no effect on kg feed/dozen eggs but had a significant (P<.01) effect on kg feed/kg eggs. Strain of bird had a significant effect on body weight, egg production, specific gravity, egg weight, Haugh units, and blood spots at 485 days. There were no significant protein level X strain interactions.