Effect of mycotoxin contaminated feed on production parameters of dairy cows

Based on a feeding trial using 27 lactating "Simmental-cows" the effect of naturally contaminated feed with deoxynivalenol (DON) as well as zearalenone (ZON) regarding production parameters was examined. 3 groups of cows according to lactation number, milk yield (kg ECM) and body mass were used. The average daily intake of DON in group K was 12.4 mg, in group T 14.1 mg and in group M 14.3 mg and ZON in group K was 12.4 mg, in group T 0.67 mg and in group M 0.68 mg respectively. The feed of animals of group M was supplemented with "Mycofix Plus" as mycotoxin inactivator. The red and white blood picture including the thrombocytes were in all groups within the normal range. Concerning enzymes (GGT, AP) and metabolites (GLUC, TBIL, UREA, CREA) the mean values of the 3 groups were in the normal range. Slightly increased were the mean values of all groups in respect to the AST- and GLDH-activities. Volatile fatty acids of the rumen content were significantly highest in group M, also the number of dead rumen infusoria was significantly decreased, but the counts of small sized infusoria increased. The study has shown that "Mycofix Plus" might be able to enhance the activity of rumen flora concerning detoxification of mycotoxins in feed of dairy cows.     

III. Buchbesprechungen

Ohne Zusammenfassung     

Development of qualitative and semiquantitative immunoassay-based rapid strip tests for the detection of T-2 toxin in wheat and oat

Novel qualitative as well as semiquantitative rapid strip tests for screening of T-2 mycotoxin in agricultural commodities were developed. Colloidal gold particles were coated with monoclonal anti-T-2 antibodies and used as detector reagent, indicating the strip test results by formation of up to two colored lines in a competitive assay format. The test line comprises a protein conjugate of the T-2 mycotoxin and the control line an antispecies-specific antibody to confirm the correct test development. To perform the test, 5 g of sample was extracted in a ratio of 1:5 with methanol/water (70:30) by shaking for 3 min and the extract directly used without further cleanup steps. The T-2 toxin lateral flow device (LFD) presented has a cutoff level around 100 microg/kg for naturally contaminated wheat and oat. The semiquantitative test may be used in the lower micrograms per kilogram range and allows for rapid semiquantitative photometric classification of the level of sample contamination. For both tests, results were obtained within 4 min. The developed LFDs therefore allow for the first time fast and on-site screening for the determination of T-2 toxin in cereals.     

Comparative measurements on ruminal pH-value in cattle

Subacute rumen acidosis (SARA) of ruminants is an important factor in terms of animal health, especially in high yielding cattle. In order to find an accurate method to determine the ruminal pH-value, three methods using eight rumen cannulated cattle were compared. An indwelling measuring unit (sensor) was used for continuous measurement of the ruminal pH-value. These results were compared to the pH-values of samplings via rumen fistula and to the results of samplings via oral stomach tube. Due to the different rations, mean pH-value of trial 1 (average of all methods) was 6.64 +/- 0.37 (hay ad lib., 2 kg concentrate/ animal) and 6.24 +/- 0.36 for trial 2 (75% maize silage, 1 kg hay, 2 kg soybean meal). In trial 1 no statistically significant differences between all methods could be observed. Under more acidic ruminal conditions of trial 2 all methods differed significantly (p < 0.05). In the lower pH-range of trial 2, a difference of 0.32 that data can be collected continuously. The sensor system was evaluated by a comparison with standardized pH-dilutions (pH 4, pH 7). The sensor system has proven to be an accurate and reliable instrument (r = 0.9984) and it represents an innovative system for answering scientific questions in terms of rumen physiology and rumen pathology.     

Impact of Mononychellus progresivus and Oligonychus gossypii (Acari: Tetranychidae) on cassava growth and yield in Central Africa

Growth of cassava was investigated in Central Africa (Congo) on crops attacked by two phytophagous mites: Mononychellus progresivus and Oligonychus gossypii. Change and distribution of dry matter in leaves, stems and roots were monitored for the 24 month crop cycle on infested and mite-free plants. Leaf dry matter increased during the rainy season and decreased during the dry season. Stems contain the reserves used for initiating plant growth after the dry season. Dry matter increased in the roots which form true storage organs. At the start of the second year of cultivation, one third of the root biomass was used to support the recovery of plant growth and development. Mite densities fewer than 50 mobile forms per leaf (maximum number of mites) were not sufficient to cause significant loss of leaf, stem and root dry matter. Nevertheless the mites diverted part of the biomass allocated to the roots thereby reducing the efficiency of storage root production in the infested plot.     

Evaluation of basic feed in dairy cow nutrition]

The basic feeds hay, grass silage and corn silage out of 70 dairy farms were investigated for the correct evaluation of their concentration of raw protein (RP) and gross energy (NEL) lactation. Three different kinds of rations were grouped: type A (estimated feed mass, table data contents), type B (weighed feed mass, table data contents), type C (weighed feed mass, analysed contents). Concerning gross energy lactation significant differences between C and A and C and B could be detected. Calculations of the expected milk yield (Milk Yield Potential, MYP) out of gross energy lactation and of raw protein were carried through and compared, using each, analysis data and table standards. MYP out of raw protein in basic feeds significantly exceeds the possible milk yield out of gross energy concentration, referring to table standards and analysis data as well. Raw protein-MYP of analysed data was significantly higher than of table standards, whereas gross energy MYP calculated with analysed data did not agree with table standards.     

Partial antagonization of midazolam-medetomidine-ketamine in cats--atipamezole versus combined atipamezole and flumazenil

Two different methods, administered both subcutaneously and intravenously, to reverse intramuscular midazolam-medetomidine-ketamine, are evaluated. Eighteen cats were anaesthetized twice each 5 min after premedication with atropine 0.04 mg/kg using midazolam 0.5 mg/kg, medetomidine 0.02 mg/kg and ketamine 2.0 mg/kg intramuscularly in one syringe. Because this study was conducted in co-operation with a dental prophylaxis project, cats had to be immobilized for approximately 1 h. Therefore, anaesthesia was prolonged with propofol to effect, if necessary. After 68+/-11 min on average, immobilization was partially reversed by either atipamezole 0.05 mg/kg subcutaneously (group A/SC, n=7) or intravenously (group A/IV, n=10), or by atipamezole 0.05 mg/kg and flumazenil 0.05 mg/kg subcutaneously (group AF/SC, n=10) or intravenously (group AF/IV, n=9), respectively. These four groups were additionally compared with a non-reversed group. Recovery time and total time of immobilization (until cats regained a standing position) were not significantly shortened using the antagonists. However, unconsciousness and sedation (expressed through parameters like the time taken to head lifting, crawling, sitting and the return of righting reflex) were significantly shortened by the antagonists, especially if administered intravenously. Abnormal behaviour, such as vocalization, licking, hyperaesthesia, restlessness or salivation, was observed in all groups. However, excitation and hyperaesthesia were not observed in group AF/IV, whereas in this group only intensified salivation occurred. The addition of flumazenil showed no significant difference to atipamezole alone, but subcutaneous administration of atipamezole alone was not sufficient in the dosage used to show an advantage compared to non-reversed cats.     

Vagococcus salmoninarum I—A chronic coldwater streptococcosis in broodstock brook trout (Salvelinus fontinalis) in Wisconsin,USA

In 2018, Vagococcus salmoninarum was isolated from two lots of broodstock “coaster” brook trout (Salvelinus fontinalis) containing ~1,500 fish at the Iron River National Fish Hatchery, at which time it was identified as the causative agent of a chronic coldwater streptococcosis epizootic. Clinical signs included exophthalmia, lethargy, erratic swimming and loss of equilibrium. Female fish experienced disproportionately higher morbidity and mortality than male co-inhabitants, and routinely retained eggs following spawning. The most consistent gross clinical sign was heart pallor and turbid pericardial effusion. An attempted treatment using florfenicol was ineffective at halting the epizootic, which spanned more than a year and resulted in >50% mortality before remaining fish were culled. As there is no previous documentation of V. salmoninarum at this hatchery or in this species, it is still unclear what circumstances led to this epizootic. The inability to treat this chronic disease led to the loss of valuable broodstock, hampering ongoing fishery conservation efforts in the Great Lakes Basin.