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.

Biplanar radiography was used to study normal growth of the left and right radius in 5 Beagles and growth of the left radius alone in 15 additional Beagles. We explored the applicability of this radiographic method in veterinary medicine by measuring the contribution to total radius length from each growth plate. Spherical tantalum markers (0.5 mm) were embedded in the proximal epiphysis, diaphysis, and distal epiphysis of each dog's radius at 10 weeks of age. Simultaneous biplanar radiographic views were obtained every 4 weeks until skeletal maturity was documented. A three-dimensional coordinate system was constructed allowing for measurement of growth (in millimeters). Resolution of the measuring system was 0.074 mm. Mean +/- SEM length of the skeletally mature Beagle's radius, as measured from proximal epiphyseal bead to distal epiphyseal bead, was 95.33 +/- 1.07 mm. The percentage of contribution to the total radius length from the proximal and distal growth plates was 36.76 and 64.73%, respectively, with 95% confidence interval of 2.29%. The percentage of contribution to radius length from the distal radial growth plate increased for each consecutive time segment, with the distal radial physis contributing 61.75% from 10 to 14 weeks of age and increasing to 70.22% from 22 to 26 weeks of age. Significant growth was not observed after 26 weeks of age. The period of most rapid growth was between 10 and 14 weeks of age. Biplanar radiography was accurate and precise in quantifying the relative contribution of the proximal and distal growth plate to radius length in Beagles. The method is applicable in veterinary research or clinical medicine for monitoring of axial and angular growth: physiologic, iatrogenic, or pathologic.

Association between individual cumulative milk yield and various reproductive disorders in 56,772 Finnish Ayrshire cows belonging to 5,912 herds in 80 communities was studied. All cows delivered calves between September 1985 and September 1986. Five logistic regression models were fitted, 1 for each outcome disorder of interest: early metritis, late metritis, silent heat, ovarian cyst, and other infertility. Cumulative individual 37-day milk yield was used in the early metritis model, and cumulative individual 60-day milk yield was used in the other models, on the basis of median days in milk when these disorders developed. Cumulative 305-day herd milk yield, parity, calving season, presence or absence of other disorders, and community were also included in the models. Point estimates from the models represented odds ratios for the likelihood of having the outcome disorder.Lactational incidence risks for the 5 reproductive disorders studied were: early metritis (2.4%), late metritis (1.1%), silent heat (5.4%), ovarian cyst (6.6%), and other infertility (2.1%). The risk of early metritis decreased with increasing 37-day milk yield. The risk of silent heat, ovarian cyst, and other infertility increased with increasing 60-day milk yield; 60-day milk yield had no effect on late metritis. The 305-day herd milk yield increased the risk of early metritis, ovarian cyst, and other infertility; it had no effect on late metritis or silent heat. Parity had an effect on all disorders, except late metritis. Cows that delivered calves during the colder, darker seasons of the year had a higher risk of reproductive disorders than did those that delivered calves at other times of the year. A number of other disorders, reproductive and otherwise, were significant predictors of development of the outcome disorders.