Congenital chondrodystrophy of unknown origin in beef herds.

Congenital chondrodystrophy of unknown origin (CCUO), often referred to as 'acorn calf disease' or congenital joint laxity and dwarfism (CJLD), has been reported in beef cattle in Canada, the United States, Europe, South Africa, New Zealand and Australia. An association of CCUO with grazing drought-affected pastures, feeding hay-only or silage-only diets or supplementation with apple pulp suggests a nutritional cause such as a mineral deficiency. This review compares published reports on CCUO in order to identify common features among outbreaks and to provide a basis for future research into the condition. A protocol for investigation of outbreaks is provided to improve the outcome of future comparisons.

Breed differences in plasma calcium, phosphorus and magnesium concentrations of Merino, Dohne Merino and S.A. Mutton Merino sheep with relation to the bent-leg syndrome.

Plasma calcium, phosphorus and magnesium concentrations were determined in ewes and their single and twin lambs from birth for 120 days in Merino, Dohne Merino and South African Mutton Merino sheep. Mineral concentrations as well as the plasma calcium: phosphorus ratio were compared between breeds. Throughout the experimental period, plasma calcium and phosphorus concentrations were higher in both single and twin lambs than in the ewes of all 3 breeds. No breed differences in plasma calcium concentrations were found. Animals of the S.A. Mutton Merino breed had significantly higher (P less than 0.05) plasma phosphorus concentrations than the other 2 breeds. The plasma Ca:P ratio in the Merino and Dohne Merino ram lambs was approximately 1.1:1 and in the S.A. Mutton Merino 0.9:1. This converse plasma Ca:P ratio found in both the S.A. Mutton Merino ewes and lambs is believed to result in an induced plasma ionised calcium deficiency which leads to improper calcification of bone. This is believed to be a contributing factor in the bent-leg syndrome. No difference was recorded in body mass between ram lambs suffering from the bent-leg syndrome and unaffected ram lambs. Plasma magnesium concentrations were not affected by breed or age of the animals.

Zinc deficiency in pheasant chicks fed practical diets.

A disease syndrome characterized by abnormal feathering and varus deviation of the tarsometatarsus spontaneously occurred in pheasant chicks fed a practical commercially prepared diet. The addition of supplemental Zn to the commercial diet was effective in alleviating the clinical signs, even though the commercial mix had Zn levels that met the published pheasant chick requirement. Supplemental arginine was ineffective in reducing the severity of the clinical signs. Also, when the diet was mixed in a laboratory setting, pheasant chicks did not develop abnormal feathering and leg bones. Clinical signs caused by feeding the commercial mix were not reproduced by altering dietary calcium and phosphorus levels in the laboratory mix. Neither adding a pellet binder nor removing supplemental Zn from the lab mix produced as severe leg and feather deformities as the commercial mix. Thus, unidentified dietary factors are capable of causing a Zn-deficiency syndrome in pheasant chicks fed practical diets with analyzed Zn levels meeting the required levels.

The effects of manganese, biotin, and choline on hexosamine and hydroxyproline content as related to leg weakness.

Three experiments were conducted with day-old broiler chicks to determine the effects of dietary choline, biotin, and manganese on cartilage hexosamine and hydroxyproline content. The incidence of leg weakness was 75% or higher on all basal diets. The levels of supplementation found to minimize leg weakness were 1540 mg choline chloride/kg diet, .2 mg biotin/kg diet, and 100 mg manganese/kg diet. The levels required to maintain normal epiphyseal cartilage hexosamine content were 385 mg of choline chloride, .05 mg of biotin, and 25 mg of manganese/kg of diet. Substantially higher levels of nutrients were needed to reduce the incidence of leg weakness. Only with manganese supplementation was the incidence of leg weakness significantly reduced at the level of supplementation required for normal hexosamine content. Hydroxyproline content was not affected by varying the levels of supplemental choline, biotin, or manganese.

Influence of high levels of pyridoxine on twisted legs in broilers.

Three experiments were conducted using commercially available broiler chicks to study the influence of high levels of pyridoxine on incidence of twisted legs. Chicks were grown in wire floored battery brooders to two weeks of age when they were weighed and visually scored for twisted legs. Supplementation of a diet containing 2.2 mg synthetic vitamin B6/kg with 10 and 20 mg/kg pyridoxine resulted in a significant decrease (P less than or equal to .05) in incidence of twisted legs in Experiment 1. In Experiment 2, supplementation with 30, 60, or 100 mg/kg numerically reduced incidence, but the differences were not statistically significant. Incidence of twisted legs was significantly increased by injecting chicks with .5 ml physiological saline at 1 and 7 days of age in comparison to noninjected controls. Including 10 mg pyridoxine HCl in the saline reduced the incidence but it was still numerically higher than the noninjected controls. Factors other than vitamin B6 nutrition appear to play a more important role in the etiology of twisted legs in broiler chicks.

Ascorbic acid deficiency and hypertrophic osteodystrophy in the dog: a rebuttal.

Plasma ascorbic acid (PAA) in normal Labrador Retriever dogs less than one year of age averaged 1.22 +/- 0.05 mg/dl (x +/- sem) and was significantly higher than the value of 0.89 +/- 0.03, for Labrador Retrievers two years of age and older. No significant diurnal variation in PAA was observed. Oral or intravenous administration of 0.5 or 1.0 g of ascorbic acid (AA) elevated PAA for less than 8 hours. Injection of ACTH caused a significant decline in PAA for the initial 2 days, with variable results thereafter. Labrador Retriever puppies fed a ration high in protein, energy and calcium developed the typical skeletal diseases of overnutrition, including hypertrophic osteodystrophy (HOD). The addition or oral AA (0.5 g twice daily) had no ameliorating effect on the skeletal lesions. Instead AA supplementation resulted in relatively higher serum calcium values which, presumably by enhanced hypercalcitoninism, decreased bone resorption. Thus, AA treatment of dogs with HOD is contraindicated, as it can only aggravate the osseous lesions of HOD. The decreased PAA reported in dogs with HOD is interpreted to be the result of stress from pain.

Bent-limb syndrome in lambs raised in total confinement.

A bent-limb syndrome in lambs raised in total confinement was characterized by curvature of the forelimbs. Radiographic findings included flaring of the affected long bone and thinning of the growth plate. The main histologic change was endochondral dysplasia of the long bone. In feed samples, all trace minerals analyzed were within recommended concentrations except iron, which was much higher (400 ppm dry matter) than the normal requirement of lambs (70 ppm). All mineral concentrations in serum were normal except those of inorganic phosphorus and iron, which were higher. Results of soft tissue and bone mineral analyses were normal. Altering the ratio of calcium and phosphorus did not affect the incidence of disease, but intramuscular administration of massive doses of vitamin D3 and reducing the amount of dietary iron had a prophylactic effect. The increase in serum phosphorus was probably related to the dietary excess of iron, which probably decreased vitamin D metabolite formation in the kidney, which in turn could be prevented by massive doses of vitamin D3.

Twisted legs in broilers.

The effect of various factors on the incidence of leg abnormalities, with particular reference to twisted leg, in broilers was studied. The incidence of twisted legs was influenced by strain and for males was twice that for females. There was also a higher incidence in cages than on litter with the type of cage floor having an effect: broilers reared on floors of metal wire and perforated sheets had more leg problems than those reared on plastic mats and plastic-covered wire. Although vitamin and mineral supplementation had no effect on caged broilers, a restriction of metabolisable energy (ME) intake during the first 14 d after hatching halved the frequency of leg abnormalities compared with those fed ad libitum. Studies of cage size and location of water suggested that a lack of exercise increases the incidence of leg abnormalities.

Investigations of leg abnormalities in chicks consuming high tannin sorghum grain diets.

Studies were conducted into the etiology of leg abnormalities noted in chicks fed high tannin sorghum grain diets. These anomalies were characterized by a bowing of the legs with a swelling of the hock joints. The incidence of these leg problems was found to be markedly higher when the amino acids in the diet provided by soybean meal were replaced by crystalline amino acids. Supplemental vitamins and minerals had no alleviating effect on the leg problem. Bone mineralization was apparently not influenced by tannins as demonstrated by similar bone ash values for chicks fed high or low tannin sorghums. A possible alteration caused by tannin in the organic matrix of bone is discussed. High tannin sorghum depressed chick growth and feed conversion when compared with low tannin sorghum in both sorghum-soybean meal and sorghum-amino acid rations. This growth depression was overcome by supplementing the high tannin sorghum-soybean meal diet with .15% DL-methionine, but no growth response was observed from a similar supplementation of a high tannin sorghum-amino acid diet.

Manganese levels and the morphology of the epiphyseal plate in broilers with slipped tendons.

Manganese deficiency in chickens results in perosis and a higher incidence of slipped tendon. Perosis is associated with a disorganization of the epiphyseal growth plates and changes in the chemical composition of the cartilage matrix. Male broilers with slipped tendons were selected from a commercial broiler farm over a 9 week growing period. Their growth rates, epiphyseal cartilage histology and tissue manganese concentrations were examined and compared with (a) normal broilers from the same farm, and (b) similar broilers raised on control and manganese deficient diets. Field broilers with slipped tendons showed no evidence of abnormality in the histological appearance of the proximal tibial growth plate at any of the ages examined. The manganese content of liver and epiphyseal cartilage from field broilers showing slipped tendon was comparable with that present in tissue from normal broilers wither from the field or raised on a chemically defined diey supplemented with managese. The slightly retared growth rate seen in the field broilers was attributed to feeding problems associated with the lameness condition. These results provide conclusive evidence that slipped tendon in field broilers is not dur to a manganese deficiency in the tissues, nor does it appear to be associated with abnormal proliferation of the chondrocytes in the epiphyseal plate.

Nutrition and bone disease in the dog and cat.

The most commonly encountered nutritional bone disease is nutritional secondary hyperparathyroidism. This is primarily of importance in the dog but is occasionally seen in kittens, particularly of the Siamese breed, and is often associated with the feeding of owner compiled, meat-rich diets. Classic rickets is now a rare clinical entity. Hypertrophic osteodystrophy is regularly seen in the larger breeds of dog and the aetiology remains obscure. Hypervitaminosis A associated with liver-rich diets is often encountered in the cat. Hypovitaminosis A has been described but its true clinical significance is unknown.

Abnormal bone development and lameness associated with secondary copper deficiency in young cattle.

Lameness in a group of 5- to 12-month-old calves was found to be clinically, radiographically, and pathologically associated with abnormal bone development of the distal growth plates of the metacarpus and metatarsus. Copper concentrations in serum and liver were low. Serum calcium, phosphorus, and alkaline phosphatase values were normal. In pasture forage samples, sulfate, zinc, and molybdenum concentrations were high, whereas copper, calcium, and phosphorus concentrations were normal. Red blood cell (RBC) counts and hemoglobin values were within normal limits. Radiographic findings included a widened zone of cartilage and lipping of the medial and lateral areas of the physeal plate. Histologic findings included focal widenings of the growth plate consisting of tongues of uncalcified cartilage.