Age, geographic, and temporal distribution of fecal shedding of Cryptosporidium parvum oocysts in cow-calf herds

OBJECTIVE: To evaluate fecal shedding of Cryptosporidium parvum from California cow-calf herds with respect to age, geographic region, temporal effects, and association with watery feces. ANIMALS: Cows and calves from 38 beef cow-calf operations. PROCEDURE: Fecal specimens were collected and examined for C parvum oocysts, using immunofluorescent microscopy. Associations between age, geographic region, month of collection, watery feces, and likelihood of shedding C parvum were evaluated. RESULTS: 3.9% of cattle were shedding C parvum oocysts. Prevalence of shedding among calves ranged from 0 to 13%, and was 0.6% among cattle > or = 12 months old. The odds of shedding C parvum among 2-month-old calves were 41 times greater than among cattle > 4 months old. The odds of shedding C parvum among cattle tested in May were 8.7 times greater than among cattle tested during June, July, or August. The odds of infected individuals having watery feces were 3 to 4 times greater than for noninfected individuals, but the etiologic fraction was only 8 to 9%. CONCLUSIONS AND CLINICAL RELEVANCE: Substantial fecal shedding of C parvum by cow-calf herds was limited to calves 1 to 4 months old, with low prevalence detected in older animals. Risk of contamination of watersheds with C parvum was limited to those periods when young calves were in the herd. Although the odds of having watery feces were greater for animals infected with C parvum than for noninfected animals, the low etiologic fraction suggests that most calves with watery feces were not infected with C parvum.     

Evaluation of clinical characteristics, diagnostic test results, and outcome in horses with internal infection caused by Corynebacterium pseudotuberculosis: 30 cases (1995-2003)

OBJECTIVE: To determine clinical signs, results of diagnostic testing, and outcome in horses with internal Corynebacterium pseudotuberculosis infection. DESIGN: Retrospective study. ANIMALS: 30 horses. PROCEDURE: Information pertaining to clinical data, results of diagnostic tests, and costs of hospitalization and treatment was extracted from medical records of affected horses. RESULTS: Internal C. pseudotuberculosis infection was diagnosed on the basis of clinical signs, diagnostic imaging, and clinicopathologic data, including results of serologic tests and bacterial culture. The most common clinical signs were concurrent external abscesses, anorexia, fever, lethargy, weight loss, and signs of respiratory tract disease or abdominal pain. Clinicopathologic abnormalities included a geometric mean reciprocal serum synergistic hemolysin inhibition titer > or = 512, leukocytosis with neutrophilia, hyperglobulinemia, hyperfibrinogenemia, and anemia. Specific organ involvement was diagnosed in 27 of 30 horses. Affected organs included the liver (18 horses), lungs (12), kidneys (7), and spleen (3); multiple organs were affected in 10 horses. Treatment with antimicrobials for a median of 36 days (range, 7 to 97 days) was usually successful, yielding an overall survival rate of 71%. CONCLUSIONS AND CLINICAL RELEVANCE: Early diagnosis and long-term antimicrobial treatment were important for a successful outcome in horses with internal C. pseudotuberculosis infection. Ultrasonographic imaging was an important technique for identifying specific organs affected, aiding in obtaining samples for a definitive diagnosis, and monitoring response to treatment. Pregnant mares with internal infections are at risk for fetal loss. Preexisting chronic organ disease may be associated with a poor prognosis.     

Repeatability of 2 methods for assessment of insulin sensitivity and glucose dynamics in horses

Both the euglycemic-hyperinsulinemic clamp (EHC) and minimal model analysis of the frequently sampled intravenous glucose tolerance test (FSIGT) have been applied for measurement of insulin sensitivity in horses. However, no published data are available on the reproducibility of these methods. Therefore, the objective of this study was to evaluate the variation and repeatability of measures of glucose dynamics and insulin sensitivity in horses derived from minimal model analysis of the FSIGT and from the EHC method. Six healthy horses underwent both the FSIGT and EHC on 2 occasions over a 4-week period, with a minimum of 5 days between tests. Coefficient of variation (CV) and intraclass correlation coefficient (ICC) were calculated for measures of glucose metabolism and insulin sensitivity derived from each test. In the EHC, insulin sensitivity, expressed as the amount of metabolized glucose (M) per unit of serum insulin (I) (M/I ratio), averaged 0.19 +/- 0.06 x 10(-4) mmol/kg/min x (pmol/L)(-1) with an average interday CV of 14.1 +/- 5.7% (range, 7-20%) and ICC of 0.74. Minimal model analysis of the FSIGT demonstrated mean insulin sensitivity (Si) of 0.49 +/- 0.17 x 10(-4)/min x (pmol/L)(-1) with an average interday CV of 23.7 +/- 11.2% (range, 9-35%) and ICC of 0.33. Mean CV and ICC for minimal model glucose effectiveness (Sg) and acute insulin response (AIRg) were, respectively, 26.4 +/- 11.2% (range 13-40%) and 0.10 and 11.7 +/- 6.5% (range 7-21%) and 0.98. Insulin sensitivity measured by the EHC has lower interday variation when compared with the minimal model estimate derived from the FSIGT.     

The Longevity of Resting Sporangia of Synchytrium endobioticum (Schilb.) Perc. in Soil1)

Resting sporangia of the potato wart disease pathogen Synchytrium endobioticum (Schilb.) Perc. which persist in soil can be extracted from soil by a wet-sieving and chloroform centrifugation method and counted. Soils from the sites of old wart outbreaks have been checked for resting sporangia. Sampling procedures, patterns and errors are being assessed.     

Escherichia coli dihydrodipicolinate synthase and dihydrodipicolinate reductase: kinetic and inhibition studies of two putative herbicide targets

Dihydrodipicolinate synthase (DHDPS) (EC 4.2.1.52) and dihydrodipicolinate reductase (DHDPR) (EC 1.3.1.26) have attracted much recent attention as potential herbicide targets. DHDPS was feedback-inhibited by (S)-lysine; inhibition was reversible and uncompetitive with respect to both (S)-ASA and pyruvate. Homoserine lactone was a reversible non-competitive inhibitor of DHDPS with respect to both (S)-ASA and pyruvate. (R)-Cysteine sulfinic acid and (S)-glutamic acid were reversible uncompetitive inhibitors of DHDPS with respect to (S)-ASA. (S)-Aspartic acid was a reversible mixed-type inhibitor. Dipicolinic acid was a reversible competitive inhibitor of DHDPR with respect to the substrate (4S)-4-hydroxy-2,3,4,5-tetrahydro-(2S)-dipicolinic acid, as was isophthalic acid. Δ³-Tetrahydroisophthalic acid was a moderate inhibitor of both DHDPS and DHDPR. These compounds represent possible leads in the development of novel herbicides. © 1999 Society of Chemical Industry     

Demographic analysis of trade-offs with deliberate fragmentation of streams: Control of invasive species versus protection of native species

Tools restricting the movements of invasive species (e.g. barriers) and reducing habitat fragmentation for native species (e.g. corridors, fishways) provide examples where actions taken to address one environmental concern can hinder efforts to address another environmental concern. We used perturbation analysis of stage-structured projection matrices to evaluate the efficacy of seasonally operated barriers and fishways for controlling non-native sea lamprey (Petromyzon marinus) in the Laurentian Great Lakes while minimizing effects on non-target fishes. For non-jumping fishes migrating in spring, seasonally operated barriers without a fishway will not balance the management objectives satisfactorily. Migration phenologies of the seven common non-target fishes considered in our analyses overlapped considerably with the migration phenology of sea lamprey, with peaks in migration typically being 7–43 days (median 12) from the peak in the sea lamprey migration. Consequently, across species, years, and tributaries, 44–100% of the migratory runs of non-target fishes would be blocked under the 75-day operation period required to block 99% of the sea lamprey spawning run, on average. Reductions in the production of non-target fishes due to blocking were also projected to be similar in magnitude to reductions projected in the production of sea lamprey, unless density-dependent compensation was strong or overlap in migration phenologies between a non-target species and sea lamprey was low. Even under density-dependent compensation, providing a fishway is advisable and passage of non-target fishes may have to be highly effective to avoid population declines in non-jumping species that migrate between a Great Lake and its tributaries.     

Radioactive gold-198 seeds for the treatment of squamous cell carcinoma in the eyelid of a cat

A 19-year-old, speyed, domestic short-hair cat was presented with an eyelid tumour of 3 months duration. Ophthalmic examination revealed a large, raised, ulcerated and bleeding mass affecting the left lower eyelid. The mass was 12 mm x 10 mm in size, extended to the medial canthus and had eroded 10 mm of eyelid margin. Mandibular lymph nodes were not palpably enlarged. A diagnosis of squamous cell carcinoma was confirmed by histologic examination. Due to involvement of more than half the lower eyelid, it was decided that treatment with radioactive gold-198 seeds was appropriate. Nine radioactive gold-198 seeds were implanted, delivering a minimum tumour dose of 65 Gy. Three weeks postoperatively the mass had resolved, with only a small scab remaining. After a further 3 weeks, there was no evidence of the eyelid tumour. Although approximately 7 mm of eyelid margin was absent, this did not cause any clinical signs other than mild conjunctivitis. There was no evidence of the tumour 10 months postoperatively, when the cat was euthanased for unrelated disease.     

Improving the Reproductive Efficiency by Zoo-Technical Methods at a Dairy Farm

This trial was conducted on a Hungarian dairy farm between July 2001 and December 2004. The objective of this work was to improve the reproductive efficiency with relatively high milk production. At the beginning of this trial blood and fodder samples were taken for checking the metabolic status of the animals in order to determine their health condition. The nutritive value of the daily ration for all groups met with the requirements of the Hungarian National Standard and almost all serum metabolic parameters differed between the milking and pregnant animals. Early pregnancy detection (by ultrasound) and ovulation synchronizing methods were introduced to optimize reproductive performance. The oestrus cycle was also checked by ultrasound and open cows were treated by the appropriate method in order to inseminate them as soon as possible. Efficiency of artificial insemination (AI) followed by a single prostaglandin F2alpha (PGF2alpha) and Ovsynch treatment was similar (30.8% and 29%) and less effective than AI after natural heat detection (37.1%). Provsynch (Pre-synch followed by Ovsynch) was the most effective ovulation synchronization method (conception rate=42.6%; p<0.01). Although milk production increased between 2002 and 2004 by approximately 600 kg per cow, the calving period decreased by 20 days and the number of AIs per pregnancy was also improved (0.8 AI per conception). These findings are really beneficial economically because the decrease in the calving interval returns profit for the dairy farms; one open day costs euro2.5/cow. Economical analysis showed a high profit ratio from the reproductive 'investment' on this farm. Every invested euro yielded approximately euro10.