The Effect of Various Particle Sizes of Oyster Shell and Limestone on Performance of Laying Leghorn Pullets

Abstract

Commercial strain cross Leghorn pullets were fed a basal diet and either ground limestone (GL), ground oyster shell (GOS), screened pullet size oyster shell (POS), screened hen size oyster shell (HOS) or screened coarse limestone (CL). All 1272 birds were fed 2.5% calcium from 20 to 60 weeks of age then some were placed on a 3.5% calcium diet to 68 weeks.Egg shell rigidity was greatest from birds supplied non-flour calcium sources as compared to the flour calcium sources. Shell deformation means over the three years in 0.001 mm. were 16.6, 16.2, 15.9, 15.5, 14.9 for the cage and 16.7, 16.7, 16.3, 15.7, 15.1 for the floor treatments respectively. The various particle sizes did not consistently influence egg weight, egg production (average 74%), feed consumption, bone mineralization or egg breakage at point of lay.Increasing the calcium level near the end of the experimental period which terminated in August of three successive years did not statistically (P > 0.05) increase shell rigidity over the lower calcium levels.Following the processing of sound eggs through a washer-grader, the observed breakage was greater than the random breakage for deformation values above 18 (.001 mm.) indicating that rigid egg shells resist breakage. It was also shown that: the mean deformation is an indicator of potential shell breakage; shell quality can be affected in both the early and late stages of production; a bag of coarse calcium source contains widely varying quantities of each particle size; and the hens will not consume all the coarse calcium source presented in a diet with 3.5% calcium.

Effects of Dietary Calcium Sources and Particle Size on Laying Hen Performance

“…As shown in Table 1, neither calcium source nor level of calcium in the laying hen diet had a statistically significant effect on egg weight, percent hen-day egg production, or feed conversion, which is in agreement with the studies conducted by Watkins et al (1977), Kuhl et al (1977), and Miller and Sunde (1975). Figure 1 shows a comparison of effects of hensized oyster shell versus pulverized calcium sources on egg weight.…”

“…Various calcium sources, in both the pulverized and granulated form, have been examined for subsequent egg shell formation. Scott et al (1971), Miller and Sunde (1975), Watkins et al (1977), and Kuhl et al (1977) all reported that the substitution of large particle calcium for a portion of the pulverized supplemental calcium improved egg shell strength. Roland et al (1974) in three short 6-week studies and Muir et al (1975) in a 50-week study utilizing low producing laying hens (67% production) concluded that the large particles of calcium carbonate had no influence on egg shell quality if the birds were receiving adequate calcium.…”

Effect of limestone particle size on bone quality characteristics of hens at end-of-lay

“…However, different particle sizes limestone had no (P >0.05) effect on tibia bone ash and humerus breaking strength and -stress. Results of the present study is in accordance with that of Miller & Sunde (1975), Cheng & Coon (1990) and Guinotte & Nys (1991) who reported that larger particles limestone resulted in a higher tibia bone breaking strength than ground sources, especially during the later stages (>66 weeks of age) of production (Fleming et al, 1998b). The improvement in bone breaking strength by using larger particles limestone (Cheng & Coon, 1990;Guinotte & Nys, 1991) are mainly ascribed to the increased medullary bone content and the decreased loss of cancellous bone (Rennie et al, 1997;Fleming et al, 1998b).…”

Effect of Calcium Supplement Particle Size and Source on the Performance of Laying Chickens

“…Renewed interest in this subject was evident early in the 1970's as a result of several reports indicating markedly improved egg shell breaking strength when hen-size oyster shell replaced a portion of the ground limestone in laying hen diets. Miller and Sunde (1975) presented an excellent review of the literature on this subject. Most of the past data indicate large particle size calcium supplements to be superior to ground or small particle size supplements.…”