Howard H. Casper

The effect of grain storage conditions on the viability of Fusarium and deoxynivalenol production in infested malting barley.

A continuing outbreak of Fusarium head blight occurred on barley in the upper Midwest from 1993 to 1995. This resulted in barley with levels of the mycotoxin deoxynivalenol (DON) reaching levels of concern for maltsters and brewers. This study evaluated the effect of 7 months of storage under different conditions (ambient outdoor temperature from October to April), -20 degrees C, 4 degrees C, 24 degrees C with quiescent air, and 24 degrees C with forced air) on the viability of Fusarium and Alternaria infesting stored grain. Additionally, the ability of Fusarium to produce DON after storage and during malting was evaluated. Initial levels of infestation of barley by Fusarium and Alternaria were 85 and 75%, respectively. All storage condition reduced the viability of both molds slightly and significantly for Fusarium. Forced air ventilation at 24 degrees C was the type of storage most effective in reducing the viability of Fusarium, dropping the percentage of infected kernels to 66%. DON levels did not change after 7 months with respect to storage conditions. However, DON levels were lower in malt produced from barley stored at 24 degrees C with or without aeration. On-farm storage of infected barley at elevated temperatures may provide a means to reduce the level of DON in finished malts.

Copper Toxicosis in Suckling Beef Calves Associated with Improper Administration of Copper Oxide Boluses

chronic copper poisoning in 4to 12-week-old single-suckled calves. Agri-Pract 17:36–40. 14. Sullivan JM, Janovitz EB, Robinson FR: 1991, Copper toxicosis in veal calves. J Vet Diagn Invest 3:161–164. 15. Suttle NF: 1981, Effectiveness of orally administered cupric oxide needles in alleviating hypocupraemia in sheep and cattle. Vet Rec 108:417–420. 16. Suttle NF: 1987, Safety and effectiveness of cupric oxide particles for increasing liver copper stores in cattle. Res Vet Sci 42:224–227. 17. Suttle NF, Valente E: 1981, Species differences in the retention of orally administered cupric oxide ‘needles’ in the alimentary tract. Proc Nutr Soc 40 (2):70A. 18. Viejo RE, Casaro AP: 1993, Suplementacion parenteral con cobre en vacas gestantes. Arch Med Vet 25:89–94. 19. Whitelaw A, Fawcett AR, Macdonald AJ: 1984, Cupric oxide needles in the prevention of bovine hypocuprosis. Vet Rec 115: 357.

Effect of delayed harvest on contamination of pearl millet grain with mycotoxin-producing fungi and mycotoxins

The response to delayed harvest of fungal and mycotoxin contamination of grain of the pearl millet hybrid HGM 100 was examined in 1992 and 1993. Samples of grain were assayed from seven plantings at locations near Tifton, Georgia, USA. Grain was harvested at 30, 40, and 50 days after anthesis and evaluated for infection byFusarium species andAspergillus flavus, and mycotoxin contamination. Mean isolation frequencies ofF. semitectum (35.6%) andF. chlamydosporum (17.2%) increased linearly with delayed harvest.Fusarium moniliforme andF. equisiti were infrequently isolated (<0.5%) and did not increase in the grain when harvest was delayed. Low mean concentrations of zearalenone (0.17 ppm), nivalenol (0.42 ppm), and deoxynivalenol (0.01 ppm) were detected but were not affected by delayed harvest. Isolation frequencies ofF. chlamydosporum andF. equiseti were correlated (P=0.07) with levels of nivalenol.Aspergillus flavus was not isolated from the grain, and aflatoxin concentrations averaged 1.9 ppb.

Dicoumarol concentrations in sweetclover hay treated with preservatives and in spoiled hay of high- and low-coumarin cultivars of sweetclover

Three methods for preventing the occurrence of toxic dicoumarol concentrations [> 20 mg kg−1 dry matter (DM)] in sweetclover [Melilotus officinalis (L.) Lam. and M. alba Desr.] hay were tested. In Method 1, the high coumarin (HC) cultivars ‘Madrid’, ‘Goldtop’, ‘Yukon’ and ‘Arctic’ and the low-coumarin (LC) cultivars ‘Norgold’ and ‘Denta’ were evaluated for dicoumarol production in artificially spoiled hay in 1982 and for DM yield in 1981 and 1982. The HC cultivars averaged 4567 kg DM ha−1 over the 2 years, while LC cultivars averaged 3996 kg DM ha−1. Spoiled hay from HC cultivars averaged 91 mg dicoumarol kg−1 DM, while spoiled hay from LC cultivars had only 5 mg kg−1. In Method 2, propionic acid (PA), sodium diacetate (SD), NaCl and Hay Treet (HT; a commercial preservative) were compared in two trials as preservatives of sweetclover hay at 266 g kg−1 moisture concentration. Hay Treet was also compared as a preservative of sweetclover hay re-wetted to 400 g kg−1 moisture concentration in a third trial. Propionic acid prevented dicoumarol formation and heating in re-wetted hay while SD, NaCl and HT did not. Hay Treet at 100 g kg−1 prevented heating and dicoumarol formation in hay re-wetted to 400 g kg−1 moisture, but HT at 3 and 10 g kg−1 did not. In the last experiment, sweetclover hay was treated with NH4OH or anhydrous ammonia in an attempt to de-toxify the hay. Neither treatment significantly reduced dicoumarol concentrations.

Properties of a 4-ene-3-ketosteroid-5α-reductase in cell extracts of the intestinal anaerobe, Eubacterium sp. strain 144 ☆

When Eubacterium sp. 144 was grown in the presence of progesterone, extracts of these cells contained a 4-ene-3-ketosteroid-5 alpha-reductase (5 alpha-reductase). No evidence for the presence of a 5 beta-steroid-reductase or a 5 alpha to 5 beta-steroid-isomerase was found. 5 alpha-Reductase activity was dependent on reduced methyl viologen as the electron donor and this could be generated biologically by adding pyruvate or H2 to cell extracts or chemically by adding sodium dithionite. NADH or NADPH with or without flavin nucleotides were not electron donors for 5 alpha-reductase. Most of the 5 alpha-reductase activity (60-65%) of crude extracts was located in the membrane fraction and the enzyme was solubilized by treatment with 1% Triton X-100. Optimum 5 alpha-reductase activity occurred at pH 7.0-7.5 in potassium phosphate buffer but was stimulated by Tris-HCl buffer (pH 8.0-9.0). 5 alpha-Reductase activity was highest at 10% (v/v) methanol and was progressively inhibited by higher methanol concentrations. Sulfhydryl reagents strongly inhibited 5 alpha-reductase but the enzyme was not affected by other metabolic inhibitors. Extracts prepared from cells induced with 16-dehydroprogesterone and grown without hemin contained 5 alpha-reductase and 16-dehydroprogesterone-reductase activities equivalent to those found in extracts of induced cells grown with hemin. This indicates that hemin is not required for the synthesis of active steroid double bond-reductases in strain 144.

Evaluation of Vitamin K3 Feed Additive for Prevention of Sweet Clover Disease

Sweet clover poisoning in cattle is caused by an anticoagulant (dicumarol) that is formed in moldy sweet clover hay. Previous experiments with vitamin K3 and vitamin K3 in therapy trials indicated that vitamin K3 was effective in reducing prothrombin times but vitamin K3 was not. As a possible alternative in the use of toxic sweet clover hays, vitamin K3 was evaluated to see if it would prevent hemorrhagic crises when fed to cattle consuming toxic sweet clover hay. Vitamin K3 levels of 0, 0.45, 4.5, 11, and 45 mg/kg body weight/day were fed to 173-235-kg steers consuming toxic (40–50 ppm dicumarol) sweet clover. The 45-mg K3/kg/day supplement was not palatable and had to be discontinued. The 0.45, 4.5, and 11-mg K3/kg/day supplements did not significantly reduce the prothrombin times as compared to the 0-mg K3/kg/day group.

Lupin Bean Meal Toxicosis in Swine

3. Clifton-Hadley FA, Alexander TJL, Enright MR: 1986, The 11. Murray BE, Medersky-Samaroj B: 1983, Transferable s-lacepidemiology, diagnosis, treatment and control of Streptococcus tamase. A new mechanism for in vitro penicillin resistance in suis type 2 infection. Proc Am Assoc Swine Pratt, Minneapolis, Streptococcus faecalis. J Clin Invest 72: 1168-1171. Minnesota, pp. 473-491. 12. Naraqi S, Kirkpatrick GP, Kabins S: 1974, Relapsin pneu4. Fontana R, Canepari P, Lleb MM, Satta G: 1990, Mechanisms mococcal meningitis: isolation of an organism with decreased of resistance of enterococci to beta-lactam antibiotics. Eur J susceptibility to penicillin G. J Pediatr 85:671-673. Clin Microbiol Infect Dis 9: 103-105. 13. Patterson JE, Zervos MJ: 1989, Susceptibility and bactericidal 5. Gottschalk M, Higgins R, Beaudoin B: 1990, Distribution of activity studies of four s-lactamase-producing enterococci. AnStreptococcus suis capsular types 9 to 22 according to the site timicrob Agents Chemother 33:251-253. of isolation. Can Vet J 31:393. 14. Sanford SE, Tilker AME: 1989, Streptococcus suis antimicro6. Gottschalk M, Higgins R, Jacques M, et al.: 1989, Description bial susceptibility. Can Vet J 30:679-680. of 14 new capsular types of Streptococcus suis. J Clin Microbiol 15. Schultz RA: 1984, Treatment of pneumonia in swine. Proc Am 27:2633-2636. Assoc Swine Pratt, Kansas City, MO., pp. 142-146. 7. Gottschalk M, Higgins R, Jacques M, et al.: 1991, Isolation 16. Shneerson JM, Chattopadhyay B, Murphy MFG, Fawcett IW: and characterization of Streptococcus suis capsular types 9-22. 1980, Permanent perceptive deafness due to Streptococcus suis J Vet Diagn Invest 3:60-65. type II infection. J Laryngol Otol 94:425-427. 8. Higgins R, Gottschalk M, Fecteau G, et al.: 1990, Isolation of 17. Touil F, Higgins R, Nadeau M: 1988, Isolation of Streptococcus Streptococcus suis from cattle. Can Vet J 31:529. suis from diseased pigs in Canada. Vet Microbiol 17: 171-177. 9. Higgins R, Gottschalk M, Mittal K, Beaudoin M: 1990, Strep18. Ward J: 1981, Antibiotic-resistant Streptococcus pneumoniae: tococcus suis infections in swine. A 16-month study. Can J Vet clinical and epidemiologic aspects. Rev Infect Dis 3:254-265. Res 54:170-173. 19. Woo J, Li EK: 1987, Streptococcus suis meningitis requires 10. Hoffman LJ, Henderson LM: 1985, The significance of Strepprolonged treatment with penicillin. Infection 15: 129-130. tococcus suis in swine disease: clinical, pathologic and bacteriological data from a two year study. Proc Annu Meet Am Assoc Vet Lab Diagn 28:201-210.