Interrelationships among Production and Clinical Disease in Dairy Cattle: A Review

Epidemiological evidence is presented in order to answer two questions. The first question is: “Does high milk production put a cow at increased risk of disease?” The answer to this question seems to be “maybe” for milk fever, but “no” for most other common diseases (veterinary-assisted dystocia, retained placenta, metritis, cystic ovary, ketosis, left displaced abomasum, and mastitis). The second question is: “Is low milk production a consequence of disease?” For most diseases the answer is a cautious “yes”.     

The ability of biochemical and haematological tests to predict recovery in periparturient recumbent cows

Blood samples from 433 periparturient recumbent cows submitted by veterinary practitioners to Ruakura Animal Health Laboratory during 1983 and 1984 were analysed and results related to whether cows recovered, died or were euthanased. Generally cows were sampled only once and the time varied from 15 minutes to 20 days after becoming recumbent. During 1983 serum calcium, magnesium, phosphorus, creatine phosphokinase (CK), aspartate amino transferase (AST), glutamate dehydrogenase (GDH), gamma glutamyl transferase (GGT) were analysed. In 1984 serum urea, creatinine, fibrinogen and haematological examination (haemoglobin, haematocrit, total and differential white cell counts) were added to the panel. Overall 39% of cows recovered, 30% died and 32% were destroyed. Precalving cows had 111% more deaths and 7% less survivors than postcalving recumbent cows (P<0.1). There was little difference (3%) in euthanasia prevalence. Tests that were most useful in predicting a lack of recovery were serum urea and muscle enzymes. Using these tests and duration of recumbency when sampled a model was produced to predict the probability of recovery from 254 cases.     

Suspected selenium poisoning in a horse

A case of selenium poisoning was suspected following the administration of 325 micromol selenium a day as sodium selenate (25 mg Se) for five consecutive days. The main signs were confined to changes in the integument which were loss of hair from the mane and tail, disintegration of the skin of the anus, lips, prepuce and scrotum, and separation of the hooves from the coronary corium. Periodic analyses of blood, hair and hoof parings from the sole correlated strongly with blood and identified horn and hair as important additional routes of excretion.     

The effects of nutrient solution sterilization on the growth and yield of hydroponically grown lettuce

Two methods of removing bacteria from hydroponic nutrient solution [ultraviolet (UV) radiation and submicronic filter] were evaluated for efficiency and for their effects on lettuce (Lactuca sativa L.) production. Both methods were effective in removing bacteria; but, at high intensity, the ultraviolet sterilizer significantly inhibited the production of plants grown in the treated solution. Bacterial removal by lower intensity UV or a submicronic filter seemed to promote plant growth slightly, but showed no consistent, statistically significant effect.     

The kinetics-based enzyme-linked immunosorbent assay for coronavirus antibodies in cats: calibration to the indirect immunofluorescence assay and computerized standardization of results through normalization to control values.

The computer-assisted, kinetics-based enzyme-linked immunosorbent assay for coronavirus antibodies in cats was calibrated to the conventional indirect immunofluorescence assay by linear regression analysis and computerized interpolation (generation of "immunofluorescence assay-equivalent" titers). Procedures were developed for normalization and standardization of kinetics-based enzyme-linked immunosorbent assay results through incorporation of five different control sera of predetermined ("expected") titer in daily runs. When used with such sera and with computer assistance, the kinetics-based enzyme-linked immunosorbent assay minimized both within-run and between-run variability while allowing also for efficient data reduction and statistical analysis and reporting of results.