A comparison of crossbred and straightbred cow-calf pairs. I. Heterosis effects on total feed efficiency

Records of 104 crossbred and 33 straightbred individually fed cow-calf units were used to study the effects of heterosis on total cow-calf feed efficiency in the production of weight of calf at weaning, 168 d postweaning, slaughter and in the carcass. The cows were Angus, Hereford, Charolais and reciprocal crosses of these breeds. The calves were straightbred and all possible two-breed backcrosses and three-breed crosses produced from first cross cows. The efficiency of the cow-calf unit was defined as kg of calf produced per kg of total TDN (total digestible nutrients) consumed by the cow-calf pair. Total feed consumed by the cows was for an average period of 315 d, from approximately November 21 to October 2. Total calf TDN consisted of creep to weaning and feed during the postweaning fattening period to slaughter. For all measures of cow-calf unit efficiency studied, the heterosis estimates were small but generally positive, ranging from -.8 to 2.1%. The average advantage of all crosses over the straightbred parents for the conversion of total feed consumed by cow-calf pair to calf weight at weaning was 2%. Heterosis effects, individual and maternal combined, on the average, among two-breed backcrosses and the three-breed crosses were essentially the same. Among the three groups of first-cross cows compared, the study indicated that a slight advantage in total cow-calf efficiency was exhibited by the Angus X Hereford cross.(ABSTRACT TRUNCATED AT 250 WORDS)     

Serum sialic acid levels increased in tumor-bearing dogs

Serum concentrations of lipid-soluble (glycolipid) sialic acid were determined for 96 client-owned dogs, of which 24 were diagnosed as bearing tumors. A markedly increased concentration of lipid-soluble serum sialic acid was found in 22 of 24 tumor-bearing dogs (92%) compared with 17 of 72 dogs with other definitely false-positive, based on necropsy and follow-up work. Almost all others had acute infections or terminal congestive disorders and were potential tumor bearers. The values obtained appeared to be independent of the sex or age (or both) of the dogs. Based on the analysis of a single biochemical variable, the procedure may permit cancer detection applicable to a wide range of tumor types in dogs if evaluated in terms of the general health status of the animal.     

Central nervous system depression associated with glucocorticoid ingestion in a dog

Signs of a central nervous system disorder were observed following 2 instances of accidental ingestion of glucocorticoid in a young female Doberman Pinscher. The signs included transient aggressive and paranoid behavior, amaurosis, disorientation, ataxia with circling backward, and depression. Vomiting, weight loss, and abnormal drinking behavior persisted for several weeks following recovery from the acute illness.     

Cisplatin chemotherapy for metastatic squamous cell carcinoma in two dogs

Cisplatin was used successfully to treat 2 dogs with metastatic squamous cell carcinoma. One dog was observed to have a complete remission and died of unrelated causes 23 months later. The other dog had a partial remission of the tumor, but relapsed and was euthanatized 4 1/2 months after the beginning of treatment. Both dogs tolerated the treatment well.     

Nasal obstruction caused by cystic nasal conchae in cattle

Four Holstein heifers were found to have partial nasal obstruction caused by bilateral cystic conchae. Three of the heifers (age range, 4 to 6 months) had a history of progressive nasal obstruction since near birth, were affected severely, and required surgical management. Each of 2 surgical procedures, a bilateral dorsolateral nasal flap approach and a dorsal nasal flap approach, was used successfully. The fourth heifer, which was 15 months old, had signs of nasal obstruction since shortly after birth, but was affected only mildly and was not treated. Follow-up information obtained 10 to 37 months later revealed that all cattle were considered normal and had no signs of nasal obstruction. In each case, a developmental problem or malformation of the ventral nasal concha resulting in cystic enlargement was suspected. The onset of clinical signs early in life and the bilateral nature suggested that the defect was of congenital origin.     

Effects of enrofloxacin and magnesium deficiency on matrix metabolism in equine articular cartilage

OBJECTIVE: To investigate the effects of enrofloxacin and magnesium deficiency on explants of equine articular cartilage. SAMPLE POPULATION: Articular cartilage explants and cultured chondrocytes obtained from adult and neonatal horses. PROCEDURE: Full-thickness explants and cultured chondrocytes were incubated in complete or magnesium-deficient media containing enrofloxacin at concentrations of 0, 1, 5, 25, 100, and 500 microg/ml. Incorporation and release of sulfate 35S over 24 hours were used to assess glycosaminoglycan (GAG) synthesis and degradation. An assay that measured binding of dimethylmethylene blue dye was used to compare total GAG content between groups. Northern blots of RNA from cultured chondrocytes were probed with equine cDNA of aggrecan, type-II collagen, biglycan, decorin, link protein, matrix metalloproteinases 1, 3, and 13, and tissue inhibitor of metalloproteinase 1. RESULTS: A dose-dependent suppression of 35S incorporation was observed. In cartilage of neonates, 35S incorporation was substantially decreased at enrofloxacin concentrations of 25 mg/ml. In cartilage of adult horses, 35S incorporation was decreased only at enrofloxacin concentrations of > or =100 microg/ml. Magnesium deficiency caused suppression of 35S incorporation. Enrofloxacin or magnesium deficiency did not affect GAG degradation or endogenous GAG content. Specific effects of enrofloxacin on steady-state mRNA for the various genes were not observed. CONCLUSION AND CLINICAL RELEVANCE: Enrofloxacin may have a detrimental effect on cartilage metabolism in horses, especially in neonates.     

Persistent isolated hypocortisolism following brief treatment with trilostane

A 12‐year‐old male neutered Miniature Poodle with confirmed pituitary‐dependent hyperadrenocorticism was treated with trilostane. After three doses, it developed clinical and laboratory changes suggestive of isolated hypocortisolism (‘atypical hypoadrenocorticism’), which persisted and progressed for more than 3 months despite immediate withdrawal of the trilostane. The clinical signs of hyperadrenocorticism resolved without further trilostane. After 3 months, prednisolone treatment was started and the clinical signs of hypocortisolism resolved. Prednisolone therapy was required for more than 1 year. Ultrasonography initially demonstrated large hypoechoic adrenal cortices, typical of dogs with hyperadrenocorticism, which then became small and heteroechoic, consistent with the development of adrenal necrosis. Persistent isolated hypocortisolism has not been reported previously as a complication of trilostane therapy. The case is also remarkable for the very short duration of trilostane therapy that elicited this complication. Clinicians should be aware that trilostane therapy may result in adrenal necrosis, even in the very earliest stages of therapy, but prompt action can prevent a life‐threatening situation.