Two experiments were conducted to determine linear growth and mineral deposition in the tibiae of Vantress x Arbor Acres broilers. In Experiment 1, birds were maintained in battery brooders for 21 days then housed in floor pens from Day 22 to 70. In the second experiment, birds were reared either in battery brooders and grow-out cages or floor pens from Day 1 to 63. Males and females were maintained separately. Birds in both trials were weighted at weekly intervals and three birds of each sex per treatment were euthanatized weekly to obtain tibia samples. Tibiae were cleaned of muscle and connective tissues, dried, extracted with diethyl ether, measured for length in centimeters, weighed, and ashed. Results from both experiments show a curvilinear response for weight gain, bone length, and bone ash weight. In some cases, sex by week or week by rearing interactions (P less than .001) were observed. As expected, males had greater weight gain and bone length than females. In Experiment 2, birds grown in floor pens had greater (P less than .05) bone length, tibia weight, and tibia ash weight than cage-reared birds, but percentage tibia ash was not different between the two rearing systems. Tibia growth and mineral deposition were influenced by gender and rearing systems. Bone ash weight data for females in both trials had a response curve that approached a sigmoidal shape. Response curve for males tended to be more quadratic, indicating a significant (P less than .003) week by week by sex interaction. Thus, there was evidence for bone growth differences not only between rearing systems, but also between sexes, the latter not unexpected.

Three low-tannin sorghum grains and one high-tannin variety were grown at the same location in 1985,1986,1987, and 1988. The relative CP content of the grains varied among the years. The proteins of sorghum grain contained, on the average, higher concentrations of Ala, Asp, Glu, Leu, lie, Phe, Tyr, and Val; and lower concentrations of Arg, Gly, and His than did the protein of yellow corn. Both contained similar concentrations of Ser, Lys, Met, Cys, and Thr. An increase in the CP of sorghum grain did not result in a proportional increase in the amino acid content when expressed as a percentage of the CP. Levels of Met, Cys, Lys, Arg, and Thr decreased as a percentage of the CP when CP increased. However, Glu, Asp, Leu, lie, and Val increased as the CP increased. The ether extract content of yellow corn was 1 to 2% higher than that found in sorghum grain. Ash, Ca, P, and neutral detergent fiber (NDF) levels between the two grains showed minor differences. Sorghum grain contained higher levels of acid detergent fiber (ADF) than did yellow corn. Compared to the low-tannin sorghum, the high-tannin variety contained higher levels of both ADF and NDF. Xanthophyll levels were low in all grain sorghums compared to yellow corn. The MEQ content of low-tannin sorghum was not different from yellow corn. However, the MI^ of the high-tannin sorghum was lower (P<.05) than yellow com and the low-tannin sorghum varieties. (

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Relative biological values (BV) of 36 feed phosphates were determined with female turkeys in bioassays of 21-day duration using three response criteria: weight gain, tibia ash percentage, and gain:feed ratio. Calcium phosphate, dibasic dihydrate (United States Pharmacopeia) was the reference standard. Nine mono-dicalcium phosphates (M-DCP, 21.0% phosphorus), 13 di-monocalcium phosphates (D-MCP, 18.5% phosphorus), and 14 defluorinated phosphates (DFP, 18.0% phosphorus) were evaluated. The average relative BV for M-DCP, D-MCP, and DFP samples were 97.6, 94.6, and 90.8%, respectively. Solubility of phosphates was determined by four recognized methods. The solvents were water, .4% HCl, 2.0% citric acid (CA), and neutral ammonium citrate (NAC). Water solubility of M-DCP samples was greater (67.5%) than that of D-MCP (38.8%) and DFP (8.9%) samples. Correlation of water solubility of phosphates to their relative BV was quite low, and water solubility was a poor indicator of BV. When .4% HCl was the solvent, correlation coefficients (r) were .55, .33, and .72 for M-DCP, D-MCP, and DFP, respectively. Based on these results and prediction equations, .4% HCl solubility would be inappropriate for estimating BV of M-DCP and D-MCP samples. Solubility of feed phosphates (mainly D-MCP and DFP) in 2.0% CA or NAC was positively correlated with BV; the r values were .87 to .95. Both of these solubility tests provided a good index of BV. However, it would seem inappropriate and risky to replace bioassays totally with these tests. Feed phosphate users could perform either the 2.0% CA or NAC solubility test easily as a screen for BV along with other quality control procedures (i.e., phosphorus, calcium, sodium, and fluoride determinations).