Two experiments were conducted to determine the extent to which performance and egg shell quality might be influenced by dietary calcium level, source and particle size. In the first experiment of 48 weeks duration, Hy-Line 934-E hens were fed five particle sizes of limestone (fine, medium and coarse ground; chick and hen bits) at either 2.5, 3.0 or 3.5% dietary calcium level. Production, feed efficiency and egg weight were not significantly (P < 0.05) affected by treatments. Egg shell breaking strength was significantly (P < 0.05) influenced by calcium level and a trend was evident for increased shell strength with the larger particle sizes. Percent checked and cracked eggs were significantly (P < 0.05) lower for hen bits. No differences were observed for calcium levels. Definite trends for higher specific gravity of eggs with increasing calcium level and larger particles were observed.In the second experiment, which was 52 weeks duration, Babcock B-300 hens were given the following treatments: fine ground limestone (FLS); Cage-Cal, mixture of pullet and hen size limestone (CC); and combinations of 1/4 FLS and 3/4 pullet or hen size oyster shell (POS, HOS) or limestone (PLS or HLS). Egg production rate was not significantly (P < 0.05) affected by dietary treatments. Feed efficiency of hens fed HOS was significantly (P < 0.05) improved over those fed CC or POS. Egg weight was significantly (P < 0.05) greater for hens receiving POS. Egg shell breaking strength was significantly (P < 0.05) greater for CC as compared to PLS or HLS. Percent cracked and checked eggs was reduced with HOS and HLS. Percent soft shelled eggs was greatly reduced with the feeding of HOS. Based on prevailing prices for eggs and feed, HOS proved to be the most economical form of supplemental dietary calcium. ABSTRACTA total of 25, 992 eggs were examined during a three year study to determine the incidence, type, position and area of crack occurring from the time of lay to packing in boxes at the end of the grading line. The incidence of cracks which occurred during laying, gathering and packing ranged from 1.1 to 1.7 percent and during shipping, washing, grading and packing from 4.6 to 14.5 percent. Cracks occurring at the grading station or during shipping were mainly of the pressure type; while shell damage from time of lay until shipping to the grading station resulted largely from an impact of some type. Medium size eggs (1 3/4-2 oz.) had the highest incidence of cracks. The area of the shell affected and the location of the crack differed significantly with respect to the incidence of impact versus pressure type cracks.

No abstract

Apparent solubility rates for oyster shell (OS) and limestone (LS) were determined in two experiments. Twelve hours after force-feeding 10 grams of either hen size oyster shell or hen size limestone to 30 fasting hens, retention of hen size LS in the gizzard was significantly (P<0.01) greater than for hen size OS. In vitro solubility determinations revealed no differences between LS and OS. However, the solubility rate was slightly faster for pullet size than for hen size particles of both LS and OS.

This study was conducted to assess the effect of the coccidiostat halofuginone (Stenorol) on growth, feed consumption, and survival of Chukar partridge. Halofuginone was fed to three replicates (14 chicks per replicate) of chukar chicks from 2 to 7 d of age at levels of 0, 1.5, 3.0, 6.0 and 12 ppm. Mortality from 2 to 7 d was 0, 0, 0, 11, and 21 birds, respectively, by treatment. Seven-day body weight showed a significant linear decrease with increasing halofuginone level (P < 0.01). On the 7th d, replicates receiving 6.0 and 12.0 ppm halofuginone were transferred to unmedicated feed for the remainder of the test due to excessive mortality. The other groups were continued until 6 wk of age. At 6 wk, chicks fed 6 or 12 ppm halofuginone from 2 to 7 d and then unmedicated feed did not differ in body weight from those fed the unmedicated control diet. A significant difference in mortality was not observed among the other three treatment groups to 6 wk of age. A linear depression in 3-, 4-, 5-, and 6-wk body weight with increasing halofuginone level was observed within the first three treatment levels (P < 0.05). It was concluded that 1.5 ppm halofuginone depressed growth of young chukars and that 6 ppm resulted in increased mortality.

Three experiments of 28 days duration were conducted to evaluate phosphated egg shell and fertilizer phosphates as supplemental phosphorus sources. Large White, female poults of the Nicholas strain were used in all studies. The birds were fed a corn-soybean meal basal diet containing 28 percent protein. Phosphorus sources and calcium carbonate were added to furnish the desired levels of Ca and P. Dietary treatments and tap water were given ad libitum and birds were raised in battery brooders with raised wire floors.Bioavailability of phosphorus from two fertilizer phosphates, concentrated super phosphate (CSP) and diammonium phosphate (DAP), was high. Relative biological values for CSP and DAP were 95 and 96 percent, respectively, as compared to 100 percent for mono-sodium phosphate (NaH 2 P0 4 -H 2 0), the reference standard. The relative biological value of phosphated egg shell was 99.5 and 100.1 percent in two separate experiments. CSP and DAP contained 2.35 to 2.48 percent of fluorine and were somewhat toxic, depressing body weight gain and feed efficiency when fed to supply recommended or higher than recommended levels of supplemental phosphorus. Depressions in body weight gain and feed efficiency were observed in two experiments.High fluorine levels from CSP and DAP apparently did not affect tibia breaking strength and percent tibia ash in these short term experiments. Fluorine content of tibia ash was significantly (P < 0.05) increased with CSP and DAP treatments.