"Field rickets" in turkey poults: field observations and pathological, radiological, and serological findings.

Two field cases of field rickets in turkey poults were studied. The primary observation was lameness, and the sole necropsy finding of significance was hypomineralization of bone. This finding was confirmed radiographically; thin cortices and wide growth plates were noted. Microscopically, there was failure of osteoid mineralization, failure of orderly progression from cartilage to bone in the growth plate, the formation of bony trabeculae perpendicular to the long axis of the bone, and fibroplasia in marrow spaces. On a routine serological screen for mycoplasma and several viruses, there were no differences between affected and normal poults from the same flock.

Field rickets in turkey poults: biochemical findings.

Two clinical cases of field rickets and one of nutritional rickets in turkey poults were studied. Plasma levels of calcium, phosphorus, alkaline phosphatase, and vitamin D metabolites were determined. Concentrations of calcium, phosphorus, and alkaline phosphatase in affected poults were typical of nutritional rickets. The mean plasma calcium concentration in rachitic poults was not significantly different from that in controls. Mean values for plasma phosphorus were 1.5 to 2.4 mg/dl lower in the rachitic poults, and values for alkaline phosphatase activity were 1.3-1.7 times greater. In assays of vitamin D metabolites, mean 24, 25 dihydroxyvitamin D3 values were consistently lower in rachitic poults.

Validation of real-time ultrasound technology for predicting fat thicknesses, longissimus muscle areas, and composition of Brangus bulls from 4 months to 2 years of age.

Sixty Brangus bulls were evaluated live using two real-time ultrasound instruments and four technicians to estimate longissimus muscle area (LMA) and 12th rib fat thickness (FT) every 4 mo beginning at 4 and 12 mo of age, respectively, and continuing until 24 mo of age. Ten bulls were slaughtered every 4 mo to determine actual LMA and FT, 9-10-11th rib chemical composition, yield grade (YG) factors, and empty body weight (EBW). Live animal traits were used to predict 9-10-11th rib composition, YG, and EBW. Scanned mean FT was accurate (P less than .05) at 16 mo and was not different (P = .09) from the actual mean FT (95% of the time the error in estimation was less than or equal to .33 cm). Scanned mean LMA was accurate (P less than .05) at 12 mo (95% of the time the error in estimation was less than or equal to 20.0 cm2). Absolute differences between scanned and actual mean FT and LMA were different (P less than .05) from zero for the main effects of month, operator and(or) interpreter, and instrument. Increased level of operator skill did not improve the accuracy of FT or LMA measurements, whereas increased level of skill of the interpreter of scans did improve the accuracy of LMA estimations. There was no difference (P greater than .05) between ultrasound instruments in accuracy of estimating FT or LMA. The most accurate prediction of YG occurred at 12 mo and incorporated LW, hip height (HH), and ultrasound LMA (R2 = .95, SD = .14). The most accurate prediction of EBW occurred at 16 mo and incorporated LW, HH, and ultrasound FT (R2 = .99, SD = 6.65 kg), whereas the most accurate equation for combined slaughter periods incorporated LW, HH, and ultrasound LMA (R2 = .99, SD = 20.71 kg). We conclude that scanning of LMA at 12 mo and of FT at 12 or 16 mo were sufficiently accurate to characterize groups of bulls; however, some individual measurements were quite inaccurate. Measurements at other months should not be considered accurate for either individuals or groups of bulls. Yield grade and EBW can be accurately estimated from live animal and ultrasound measurements, which may be useful in identifying Brangus cattle with superior cutability and may eliminate the need for serial slaughter in research projects.

Free fatty acid-induced hypocalcemia in food-deprived dairy cattle.

Food deprivation in 6 dairy cows caused significant increases (P greater than F = 0.0054) in serum free fatty acid concentrations, but did not cause clinically important decreases in serum ionized calcium concentration. Several determinants, including blood pH, serum albumin, and serum bicarbonate were studied as factors that could potentially alter calcium ion concentration. Although several changes were significant, they were small and were not considered to be clinically important in the context of calcium-ion binding. It was concluded that free fatty acid binding of calcium ion did occur, but that such binding did not contribute significantly to the etiopathogenesis of calcium responsive midlactational downer cow syndrome.

Serum selenium concentrations and glutathione peroxidase activities in cattle grazing forages of various selenium concentrations.

In cows from 15 dairy herds (n = 210), serum selenium (Se) concentrations ranged from 0.021 to 0.789 microgram/ml, whereas 0.05 to 0.40 microgram/ml is the reported range for adequate serum Se concentrations in cattle. Serum Se concentrations of dairy cattle appeared to follow a geographic distribution pattern. On the basis of herd mean serum Se concentrations, adequate serum Se concentrations were found in cattle from only 1 of 5 herds grazing forage in the geographic area classified as Se deficient for cattle. Adequate mean serum Se concentrations were found in cattle from 4 of 5 herds located in geographic areas described as having variable forage Se concentrations (Se-marginal areas). Of the 10 herds from these 2 areas, there were only 2 herds in which 95% of the cattle had serum Se concentrations in the Se-adequate range (0.05 to 0.40 microgram/ml). In 2 selected neighboring farms in the Se-deficient area, cattle in 1 herd had adequate serum Se concentrations and cattle in the other herd had less than adequate serum Se concentrations (less than 0.05 microgram/ml). Therefore, more cattle are at risk of developing Se-deficiency disease than is commonly believed and forage of neighboring farms may have different Se concentrations. Serum Se concentrations (up to 0.789 microgram/ml) correlated with glutathione peroxidase enzyme activity; this serum Se concentration (0.789 microgram/ml) is approximately 6.2 times higher than previously reported in dairy cattle. Therefore, RBC glutathione peroxidase activity may be useful in determining the diagnosis of chronic Se toxicosis.

Blood concentrations of beta hydroxybutyrate in clinically normal Holstein-Friesian herds and in those with a high prevalence of clinical ketosis.

Statistical parameters necessary for the comparison of herd blood beta hydroxybutyrate (HB) concentration means with HB concentrations in the general population were determined in 11 clinically normal herds of Holstein-Friesian cows. These parameters were then used to compare clinically normal cows from 2 Holstein-Friesian herds experiencing a high prevalence of clinical ketosis with the normal population. Blood HB concentration means were compared with plasma glucose concentration means for their relative value as predictors of clinical ketosis prevalence within a herd. Blood HB concentration values were distributed approximately log normal and were directly related to amount of milk production. Herds with a high prevalence of clinical ketosis had blood HB log means higher (P less than 0.01) and glucose means lower (P less than 0.05) than did the normal population. Herd blood HB log means should be determined on 7 or more animals within specified production groups. When these means exceed the normal population log mean by more than 1 SD, susceptible cows in the herd may be at increased risk for the development of clinical ketosis. Blood HB log means may be of greater value than are plasma glucose concentration means for the prediction of herd ketosis prevalence.

Evaluation of biochemical evidence of congenital nutritional myopathy in two-week prepartum fetuses from selenium-deficient ewes.

Muscle damage attributable to selenium (Se)/vitamin E deficiencies is known to develop at birth or later in lambs. The purpose of this study was to determine whether and when muscle damage develops in utero. Thirty pregnant ewes maintained on Se-deficient forages from birth were allotted to 3 equal groups. Half of each group was given a single IM injection of 0.056 mg of Se/kg of body weight, 1 month before parturition. At 3 weeks before parturition, cesarean section-derived fetuses from Se-deficient ewes did not have evidence of muscle damage. At 2 weeks before parturition, fetuses from Se-deficient ewes had biochemical evidence of congenital nutritional myopathy, as evidenced by low blood Se concentration (P less than 0.05) and by increased plasma creatinine kinase (P less than 0.001) and lactate dehydrogenase (P less than 0.01) activities, compared with fetuses from Se-treated ewes. Thus, for optimal protection of fetuses and newborn lambs in Se-deficient areas, Se should be administered to ewes at least 1 month before parturition.

Effects of selenium-vitamin E injection on bovine polymorphonucleated leukocytes phagocytosis and killing of Staphylococcus aureus.

Phagocytosis and killing of Staphylococcus aureus by polymorphonuclear leukocytes (PMN) from 8 selenium (Se)-deficient dairy cows from Wisconsin was compared with that in 5 Se-vitamin E injected dairy cows from the same herd. There was no significant difference in the ability of the PMN to phagocytize bacteria. However, PMN of Se-vitamin E injected cows killed the phagocytized bacteria significantly (P less than 0.025) better than did PMN from Se-deficient cows. The defect in the killing capability of PMN of Se-deficient cows might be due to reduced dihydronicotinamide adenine dinucleotide phosphate concentration as a result of diminished glutathione peroxidase activity due to Se-deficiency.

Effects of 1 alpha,25-dihydroxycholecalciferol on disuse osteoporosis in the dog: a histomorphometric study.

Disuse osteoporosis was produced in dogs by immobilization of the left rear limb in a plaster cast. The trabecular bone volume of the calcaneus was then determined following treatment with 1 alpha,25-dihydroxycholecalciferol for 4 weeks with oral dosages of 60 to 240 ng/kg of body weight. The trabecular bone volume percentage of the immobilized calcaneus was in direct relation to the dosage of 1 alpha,25-dihydroxycholecalciferol.

Iodine toxicosis in six herds of dairy cattle.

Daily iodine intake estimated to range from greater than 68 to 600 mg/animal/day was associated with signs referable to iodine intoxication in adult cows in 6 herds of dairy cattle. Signs were reversed by lowering supplemental intake to less than 12 mg/animal/day. Results of biochemical tests other than those for serum and milk iodine were not diagnostic. Serum iodine concentrations were 2.6 to 6.9 times the mean iodine concentration found in 12 control cows, each receiving 12 mg of iodine/day. Milk iodine concentrations were 3.6 to 13.6 times milk iodine concentrations in the control cows.

Bioavailability of phosphorus in commercial phosphate supplements for turkeys.

Forty-seven commercial phosphorus supplements were obtained from feed manufacturers and subjected to biological phosphorus availability assay using the turkey poult. Bone ash was the response criterion. Compared to a reference source of commercial mono/ dicalcium phosphate (assigned 100), 7 other mono/ dicalcium phosphates averaged 97.1 (range 88.6 to 110.0), 20 dicalcium phosphate sources averaged 90.6 (76.3 to 104.8), and 20 defluorinated phosphate sources averaged 78.4% (68.6 to 89.6) availabilities. Combining equal parts of all sources of each type of phosphorus supplement and using purified grade calcium phosphate monobasic monohydrate as a defined standard, the commercial mono/ dicalcium phosphates, dicalcium phosphates, and defluorinated phosphates averaged (with 95% confidence limits) 93.6 +/- 7.6, 88.3 +/- 8.2, and 70.2 +/- 7.2% phosphorus availability in a slope ratio bioassay. Calculating the requirement intercepts utilizing the blended phosphorus supplements indicated apparent requirements using mono/ dicalcium phosphate, dicalcium phosphate, and defluorinated phosphate of .74, .76, and .83% total phosphorus in the diet, respectively. Considering 1) the variability in availability of the sources, 2) variation in feed mixing, 3) the National Research Council requirement of .80%, and 4) that newly hatched poults are completely dependent on one batch of prestarter feed during 0 to 10 days of life, it is suggested that in certain instances field rickets could result from deficiency of dietary phosphorus.

Effect of dietary sodium fluoride on growth and bone development in growing turkeys.

Large White male turkeys were fed rations containing 0, 12.5, 25, 50, 100, 200, 400, and 800 ppm added fluoride (F) from sodium fluoride in a corn-soybean assay diet containing tricalcium phosphate and 3 to 5 ppm F. The 800 ppm treatment was discontinued at 8 weeks because of low weight gains and a high incidence of leg disorders. Turkeys receiving defluorinated phosphate (32% calcium, 18% phosphorus) had significantly higher 4-week body weights than turkeys receiving tricalcium phosphate. Turkeys fed 0, 400, and 800 ppm F had significantly lower body weights at 8 weeks than turkeys fed 50 ppm F. A similar weight pattern was seen at 18 weeks, although the differences were not statistically significant. Based on growth response in this study, a requirement of 20 ppm F is proposed. Increasing levels of dietary F resulted in large increases in tibia F. Removal of high dietary F in certain groups at 8 weeks resulted in growth recovery and reduction in tibia F by 18 weeks. Elevated plasma alkaline phosphatase activity was observed with added dietary F of 400 and 800 ppm. At 4 weeks, tibiae from turkeys receiving high F had a trend (not statistically significant) toward lower percentage ash and a significantly lower breaking strength than controls. Compared to controls, tibiotarsi from turkeys on high F rations were significantly shorter, had thinner cortices, and had a narrower proliferative zone of proximal growth plates. A high incidence of tibial dyschondroplasia was observed, but it was not correlated with dietary treatment.

The interaction of dietary vitamin A and vitamin D related to skeletal development in the turkey poult.

Large white male turkey poults were fed diets with different levels of vitamins A and D to study the interaction of these vitamins with regard to skeletal development. Poults fed a basal diet deficient in both vitamins A and D developed severe lameness, growth depression, mortality and lesions consistent with rickets. Birds fed a diet containing the required level of vitamin D (900 ICU/kg, NRC estimated requirement) and a high level of vitamin A (400,000 IU/kg) also developed severe lameness, growth depression and a rachiticlike condition, characterized by thicker than normal proximal tibial epiphyseal plates and lower than normal bone mineral content. When fed a diet containing the required level of vitamin A (4,000 IU/kg, NRC estimated requirement) and a high level of vitamin D (900,000 ICU/kg), poults developed hypervitaminosis D as evidenced by mild growth depression and renal tubular mineralization. When poults were fed a diet containing high levels of both vitamins A and D growth rate and bone mineral content were similar to control poults fed a diet containing the required levels of vitamins A and D. In addition, lameness and renal tubular mineralization were not apparent in the poults fed a diet containing high levels of both vitamins A and D. It was concluded that there is an antagonistic interaction between vitamins A and D.

The evaluation of selenium status of sheep from the major production areas of Morocco.

In order to evaluate the selenium status of sheep in the major raising areas of Morocco, blood selenium concentration, erythrocyte glutathione peroxidase activity and feed selenium levels were determined. A total of 843 blood samples from sheep and 118 feed samples were analyzed. Results showed that 73% of sheep sampled had blood selenium concentrations below 100 ng/ml, and were deficient or marginal. Erythrocyte glutathione peroxidase activity was below 19 IU/g hemoglobin and feed selenium levels below 0.1 mg/kg on a dry matter basis. The erythrocyte glutathione peroxidase activity was highly correlated with blood selenium concentration over a wide range of selenium levels (r = 0.88, P less than 0.001, N = 622), indicating that the enzyme can be used as an indicator of the selenium status of grazing sheep.

The effect of dietary energy concentration on calf performance.

At three locations, 120 calves were fed a high fat milk replacer at 10% of birth weight from d 5 through 13. On d 14, calves were assigned randomly within sex and date of birth to a 2 x 2 factorial arrangement of treatments. Treatments were (on a DM basis) high fat milk replacer (21.6%) and high fat starter (7.3%), high fat milk replacer (21.6%) and low fat starter (3.7%), low fat milk replacer (15.6%) and high fat starter (7.3%), and low fat milk replacer (15.6%) and low fat starter (3.7%). Milk replacer was fed at 8% of birth weight/d from d 14 to 35 and at 4% of birth weight/d from d 36 to 42. High fat replacer depressed DMI before and after weaning. High fat starter depressed DMI after weaning. Before weaning, calves gained more BW when fed low fat replacer. Calves fed low fat starter gained more BW after weaning. On d 56, BW were highest for calves fed low fat replacer and starter and lowest for those fed high fat replacer and starter. Growth or health of calves was not improved by fat addition to the diet.