Mean phosphorus (P) content in bovine rib bone was 102.9, 108.3, and 182.7 mg/g of bone on fresh, dry, and ash weight bases, respectively. Values for calcium (Ca) were 194.3, 203.7, and 344.6 mg/g, respectively, and for magnesium (Mg) were 5.3, 5.5, and 9.4 mg/g, respectively. Mean percentage of ash in rib bone was 59.12%. Expected concentrations of Ca, P, and Mg were determined on fresh, dry, and ash weight bases and for 3 age groups, 3 breeds, and bulls, females, and steers. On an ash weight basis, cattle 6 to 18 months old had 185.74 mg of P/g, 372.52 mg of Ca/g, and 12.37 mg of Mg/g. Those 19 to 36 months old had 182.02 mg of P/g, 322.35 mg of P/g, and 8.09 mg of Mg/g. Those > 36 months old had 174.80 mg of P/g, 340.36 mg of Ca/g, and 6.62 mg of Mg/g. Steers had 183.93 mg of P/g, 352.73 mg of Ca/g, and 10.15 mg of Mg/g. Females had 178.47 mg of P/g, 320.28 mg of Ca/g, and 6.5 mg of Mg/g. Males had 176.15 mg of P/g, aH on an ash weight basis. Dairy breeds were found to have 186.08 mg of P/g, 351.25 mg of Ca/g, and 10.47 mg of Mg/g. Cattle of mixed breeding had 177.42 mg of P/g, 341.28 mg of Ca/g, and 6.54 mg of Mg/g. The Africander breed of beef cattle had 167.07 mg of P/g, all on an ash weight basis.

To determine the effects of age on each analyte, CSF variables were evaluated in healthy foals from birth through 42 days of age. Cerebrospinal fluid was collected from 14 clinically normal, naturally delivered cross-bred foals and was analyzed for glucose, sodium, potassium, magnesium, and total protein concentrations, total and differential WBC counts, RbC count, and lactate dehydrogenase, aspartate transaminase, and creatine kinase activities. Samples were collected in 3 foals < 48 hours old, and at 11 to 14 days of age in 4 foals, 21 to 22 days of age in 3 foals, and 31 to 42 days of age in 4 foals. Each foal was tested only once, to avoid any effects of CSF sample collection on subsequent analysis. Regression analysis confirmed age-related effects on CSF glucose, protein, and magnesium concentrations, but did not indicate an effect of age on CSF sodium and potassium concentrations or cell counts. Results indicate that CSF glucose concentration decreases with age; foals < 2 days old had the highest CSF glucose values, 98.8 +/- 12.0 mg/dl (mean +/- 1 SD). In foals 10 to 14 days old, CSF glucose concentration was 67.3 +/- 12.0 mg/ dl, was 65.3 +/- 4.5 mg/dl in foals 21 to 22 days old, was 70.0 +/- 5.4 mg/dl in foals 31 to 42 days old, and was 51.1 +/- 2.5 mg/dl in adults. Protein values in CSF also decreased with age: 109.0 +/- 9.7 mg/dl in foals < 2 days old, 81.0 +/- 22.8 mg/dl in foals 10 to 14 days old, 60.5 +/- 22.4 mg/dl in foals 21 to 22 days old, and 58.5 +/- 17.0 mg/di in foals 31 to 42 days old. The CSF protein concentration was 60.3 +/- 10.8 mg/dl in adult horses. Magnesium concentration in CSF increased slightly with age, then decreased after 22 days of life. In foals < 2 days old, the value was 2.43 +/- 0.16 mg/dl. Values in older foals and horses were: 2.51 +/- 0.08 mg/dl in foals 10 to 14 days old, 2.65 +/- 0.05 mg/dl in 21- to 22-day-old foals, 2.55 +/- 0.05 mg/dl in 31- to 42-day-old foals, and 2.35 +/- 0.09 mg/dl in adult horses. Mean CSF sodium and potassium concentrations were 151.7 +/- 3.7 mmol/L and 3.14 +/- 0.54 mmol/L, respectively, for all ages. There was no effect of age on these analytes. Values for CSF enzymes were considered invalid for the assay technique used and were not further analyzed.

Mean phosphorus (P) content in bovine rib bone was 102.9, 108.3, and 182.7 mg/g of bone on fresh, dry, and ash weight bases, respectively. Values for calcium (Ca) were 194.3, 203.7, and 344.6 mg/g, respectively, and for magnesium (Mg) were 5.3, 5.5, and 9.4 mg/g, respectively. Mean percentage of ash in rib bone was 59.12%. Expected concentrations of Ca, P, and Mg were determined on fresh, dry, and ash weight bases and for 3 age groups, 3 breeds, and bulls, females, and steers. On an ash weight basis, cattle 6 to 18 months old had 185.74 mg of P/g, 372.52 mg of Ca/g, and 12.37 mg of Mg/g. Those 19 to 36 months old had 182.02 mg of P/g, 322.35 mg of P/g, and 8.09 mg of Mg/g. Those > 36 months old had 174.80 mg of P/g, 340.36 mg of Ca/g, and 6.62 mg of Mg/g. Steers had 183.93 mg of P/g, 352.73 mg of Ca/g, and 10.15 mg of Mg/g. Females had 178.47 mg of P/g, 320.28 mg of Ca/g, and 6.5 mg of Mg/g. Males had 176.15 mg of P/g, aH on an ash weight basis. Dairy breeds were found to have 186.08 mg of P/g, 351.25 mg of Ca/g, and 10.47 mg of Mg/g. Cattle of mixed breeding had 177.42 mg of P/g, 341.28 mg of Ca/g, and 6.54 mg of Mg/g. The Africander breed of beef cattle had 167.07 mg of P/g, all on an ash weight basis.