Residues of endosulfan in the tissues of lactating goats

SUMMARY: The sites of tissue accumulation in lactating goats of the organochlorine insecticide endosulfan were studied. Twelve lactating goats were dosed orally with endosulfan (1 mg/kg body weight per day) for 28 days. Groups of 3 animals were killed on days 1, 8, 15, and 21 after endosulfan treatment ended and their tissues examined for the presence of endosulfan. Total residues of α and β endosulfan and endosulfan sulphate (mg/kg) were detected in kidney (0.29), gastro-intestinal tract (0.20), liver (0.12), brain (0.06), muscle and spleen (0.04), lung and heart (0.01) and milk (0.02) on the flrst sampllng day but within 15 days, concentrations had fallen to < 0.01 mg/kg in all tissues except kidney (0.20). Endosulfan could not be detected in animals 21 days after dosing had ceased. The residue in milk could only be detected on day 1 of sampling. This study indicates that kidney rather than fatty tissue should be used to monitor the presence of endosulfan in animals intended for human consumption.     

Amoxycillin as an alternative to dihydrostreptomycin sulphate for treating cattle infected with Leptospira borgpetersenii serovar hardjo

Objective To assess the effect of amoxycillin treatment on urinary excretion of leptospires from cattle infected with Leptospira borgpetersenii serovar hardjo .
Design A chemotherapy trial with controls.
Procedure Fourteen heifers serologically negative to L hardjo were inoculated with L hardjo via the conjunctival route and assessed for evidence of infection by serological, fluorescent antibody and microbiological tests. Two injections (48 h apart) of amoxycillin at a dose of 15 mg/kg were administered intramuscularly to seven heifers 6.5 weeks after infection; the remaining heifers acted as untreated controls. Later, these seven control group heifers were treated with a single dose of amoxycillin (15 mg/kg). Samples of urine were collected before and after amoxycillin treatments; kidneys were collected at slaughter, and examined by fluorescent antibody test and microbiological culture.
Results Leptospires were isolated from the urine of 11 of 14 heifers inoculated with L hardjo . After treatment of six of these with two injections of amoxycillin, leptospires were not isolated. Of the controls, four of the five initially leptospiruric heifers continued to shed leptospires; after a single injection of amoxycillin, no leptospires were detected in the kidneys of these four.
Conclusion Amoxycillin may be an acceptable alternative to dihydrostreptomycin sulphate for the treatment of cattle infected with L hardjo .     

Epidemiology of an outbreak of chronic wasting disease on elk farms in Saskatchewan

An outbreak of chronic wasting disease (CWD) in farmed elk in Saskatchewan from 1996 to 2002 was reviewed to 1, determine the progression of CWD from infection to death in farmed elk; 2, assess animal risk factors for CWD infection in farmed elk; 3, assess farm management and exposure risk factors for within herd CWD transmission; and 4, assess the suitability of the Canadian Food Inspection Agency's (CFIA) current disease control policy for CWD in light of the findings. The results from animal movement tracing, animal testing, and a farm management questionnaire were used. The duration of CWD (time from exposure to death of a CWD test-positive animal) was between a mean minimum of 19 months and a mean maximum of 40 months. Age and sex were not associated with CWD infection, except that adult elk (> or = 2 y) were more likely to be infected than young elk (< 18 mo) (RR = 2.3, 95% CI 1.6-3.5). Elk calves born in the last 18 mo prior to the death or diagnosis of their dam were at higher risk if their dams died of CWD (RR = 4.1, 95% CI 1.5-11.4) or exhibited clinical signs of CWD (RR = 8.3, 95% CI 2.7-25.7). Significant risk factors for transmission of CWD on elk farms were the introduction from an infected farm of trace-in elk that died of CWD (RR = 13.5, 95% CI 2.0-91) or developed clinical signs of CWD (RR = 7.1, 95% CI 0.93-54) and the elapsed time in years since the incursion of CWD (OR = 5.6, 95% CI 1.8-17.4). The assumptions on which CFIA's disease control policies were based were validated, but based on this new information, quarantine in cases where exposure to preclinical elk has occurred could be considered as an alternative to whole herd eradication.     

Observer variation in the histological diagnosis of plasmacytoid leukemia (marine anemia).

The reliability of past histological criteria for the diagnosis of plasmacytoid leukemia was investigated by studying observer variation in the diagnosis of the disease. Participants blindly evaluated a series of histological samples and classified them as positive, negative or questionable cases of the disease. Intra- and interpathologist agreement were used to assess reliability and were determined by calculating the observed agreement in diagnosis and the kappa statistic. There was poor overall agreement for the classification of sample cases. Questionable cases were most frequently misclassified but marked disagreement also existed for positive and negative samples. Access to historical information prior to histological examination influenced agreement. The results show that previously described histological criteria alone were insufficient for establishing the diagnosis of plasmacytoid leukemia.     

The usefulness of pelvic area measurements as an on-farm test for predicting calving difficulty in beef heifers

Data collected from 197 replacement heifers in four beef cow herds in Saskatchewan were analyzed to determine the usefulness of pelvic area measurements as an on-farm test for predicting calving difficulty.

The prevalence of calving difficulty in these herds ranged from 15-34%. Pelvic area measurements prior to the breeding season and at the time of pregnancy examination had poor positive predictive values and sensitivities in each herd. These findings were consistent whether the measurement used as a cut-off point to distinguish between a large and a small pelvic area was the lower 25th percentile, the mean, or the common standard. Standard pelvic area and calf birth weight ratios were not useful in estimating deliverable calf birth weight.

Based on these results, pelvic area measurements prior to the breeding season and at the time of pregnancy examination are poor tests for predicting calving difficulty.

     

The relationship between the presence of Helicobacter pylori, Clostridium perfringens type A, Campylobacter spp, or fungi and fatal abomasal ulcers in unweaned beef calves.

A case-control study involving 30 unweaned beef calves was conducted to determine whether specific species of bacteria or fungi were associated with fatal abomasal ulcer formation. Special microbiological and histological techniques were used to detect Clostridium perfringens type A, Helicobacter pylori, or Campylobacter spp. It has been speculated that these bacteria are potential ulcerogenic agents of unweaned beef calves. Calves were recruited for the study at necropsy, with those dying of either a perforating or a hemorrhagic ulcer representing the cases, and calves of a similar age dying of a disease unrelated to the abomasum representing the controls. Helicobacter pylori was not visualized in or cultured from any of the abomasal tissue samples. Clostridium perfringens type A was isolated from 78.6% of the cases and 75% of the controls. These isolates were further dichotomized into "heavy" and "light" growth; no significant association was found between ulcers and the amount of growth. A light growth of Campylobacter spp. was recovered from 3 cases and 3 controls. There was no compelling evidence to suggest that Clostridium perfringens type A, Helicobacter pylori, or Campylobacter spp. were involved in ulcer formation.