Influence of supplementary fibrolytic enzymes on the fermentation of corn and grass silages by mixed ruminal microorganisms in vitro

This study was done to determine the effectiveness of supplementary enzymes at increasing the fiber digestion by ruminal microorganisms and to assess whether enzyme activity limits the rate of fiber digestion in ruminal digesta. In vitro comparisons of enzyme activities in two feed enzyme preparations (A and B) with enzyme activities extracted from ruminal fluid indicated that the addition of fibrolytic enzymes at the application rates recommended by the manufacturers would not be expected to increase significantly glycanase and polysaccharidase activities in ruminal fluid. Preparations A and B both increased (P < 0.001) the rate of gas production from freeze-dried corn and grass silages in in vitro incubations with ruminal fluid, but only at concentrations much higher than recommended application rates. Autoclaved controls had little or no effect. Ultrafiltration of enzyme B indicated that most stimulation was due to components >100 kDa, which is consistent with the cause of the stimulation being enzyme activity. Fibrolytic enzymes from other sources were also able to stimulate gas production: increased rates of gas production were observed in seven out of eight combinations of "cellulase" and corn or grass silage (P < 0.05). The comparison of glycanase and polysaccharidase activities with gas-stimulatory activity in the different enzyme preparations indicated that the highest correlation was between increased gas production and enzyme activity against microgranular cellulose (P < 0.05). In a wider range of fibrolytic enzyme preparations, those with endo-(beta-1,4)- or exo-(beta-1,4)-xylanase activity equal to that of preparation A did not produce similar increased rates of fermentation of corn silage when glucanase activity was low (P > 0.05). In contrast, preparations with glucanase activity similar to enzyme A gave at least as great (P < 0.05) an improvement in gas production than enzyme A, irrespective of xylanase activity. It was concluded that enzyme activity, probably a type of endo-(beta-1,4)-glucanase activity, limits the rate of fermentation of corn and grass silage in the rumen. Enzyme supplements of the type used in these experiments are unlikely to possess sufficient activity to overcome this limitation by direct application to ruminal digesta, implying that treatment of the ration prefeeding will be key to harnessing the potential of exogenous fibrolytic enzymes in ruminant nutrition.     

Identification of focal adenomyosis as a uterine lesion in two dogs

A focal uterine adenomyosis is described in two bitches. In both cases, the uterus showed knobbly enlargements of 4 to 8 cm in diameter, which resulted in distinct clinical symptoms. Other pathological changes of the uterus were not present. One bitch was presented because of a history of vaginal discharge of several months' duration. Radiographs, as well as ultrasonography, revealed a soft tissue lesion at the cervix. The other bitch showed a marked reduction in its general condition and a sudden onset of a tense abdomen. Radiologically, a lesion of soft tissue opacity was observed in the mid-abdomen and was seen to originate from the left uterine horn during exploratory laparotomy. A torsion of the lesion was present, which explained the clinical signs in this second case.     

Multifactorial mortality in bongos and other wild ungulates in the north of the Congo Republic

Wildlife mortality involving bongos, Tragelaphus eurycerus, and other ungulates was investigated in the north of the Congo Republic in 1997. Four bongos, one forest buffalo, Syncerus caffer nanus, and one domestic sheep were examined and sampled. Although an outbreak of rinderpest had been suspected, it was found that the animals, which had been weakened by an Elaeophora sagitta infection and possibly also by adverse climatic conditions, had been exsanguinated and driven to exhaustion by an unusual plague of Stomoxys omega.     

Culicoides antigen extract stimulates equine blood mononuclear (BMN) cell proliferation and the release of eosinophil adherence-inducing factor(s)

Intradermal injection of a Culicoides antigen extract (CAgX) induces T lymphocyte and eosinophil accumulation in the skin of horses with sweet itch. Blood mononuclear (BMN) cells from normal ponies proliferate when stimulated by mitogen (phytohaemagglutinin, PHA) or antigen (tetanus toxoid, TT) and, as shown here, release soluble factor(s) that induce eosinophil adherence. CAgX also caused concentration dependent proliferation of BMN cells from sweet itch and normal ponies [stimulation index: 29 (13) and 17 (7) for BMN cells from sweet itch and normal ponies, respectively during the active phase of disease; 4 microg protein ml(-1)CAgX; 168 h]. A heat labile factor(s) which caused eosinophil adherence was also released [sweet itch ponies: 6.0 (1.6) per cent adherence versus 1.3 (0.4) per cent; normal ponies: 6.6 (0.5) per cent adherence versus 0.9 (0.1) per cent for supernatants from CAgX (4 microg protein ml(-1); 48 hours) stimulated versus unstimulated BMN cells, respectively]. These results suggest that soluble proteins released from T lymphocytes could affect eosinophil function in the lesional skin of sweet itch horses.     

Prevalence of chronic wasting in Dutch dairy herds with a history of chronic health problems

The prevalence of chronic wasting in cattle in March and April 2000 was studied on 218 dairy farms with a history of health problems accompanied by wasting, following reports in the media suggesting that chronic wasting was a substantial problem on Dutch dairy farms. A telephone call revealed that the health problems had resolved on 41 farms; 16 of these farms had culled all cattle. Two farmers refused co-operation. On the remaining 175 farms the animals were inspected and was completed a questionnaire. A high percentage of culling for of health reasons (on average 18.1% of young stock and adult cattle) and an increased mortality rate (4.8%) were reported on the farms visited. In only two of the 175 inspected herds, more than 20 percent of cattle were found showing signs of wasting. These two herds were identified as 'chronic wasting herds'. The prevalence of such herds was low in this study. Consequently, it is likely that there were very few 'chronic wasting herds' among the whole Dutch dairy population in March/April 2000.     

Effect of different methods of administration of ivermectin on its efficacy against the shedding of gastrointestinal nematode eggs by gazelles

Seven different methods of administering ivermectin to gazelles were compared: subcutaneous injection, direct oral administration, administration in individual feeds, administration in a herd feed, direct oral administration of a second ivermectin formulation, administration in individual water supplies, and administration in the herd's water supply. The first five treatments were effective, as monitored by faecal egg count reduction tests, and administration in individual feeds or in a herd feed avoided the need to capture the animals, with the attendant risk of mortality. Of the factors associated with the recipients (species, sex, age and inbreeding coefficient) age was the only significant factor for the efficacy of the treatment. Oral or subcutaneous, individual or collective, and direct or indirect administrations were equally satisfactory for the treatment of all the parasite groups studied. Only when parasitic problems were due to Nematodirus species did direct administration to individual animals appear to be preferable.