Faecal specimens from 200 market swine (115 feeder pigs and 85 butcher hogs) offered for sale at a southern California livestock auction yard during a three-month period, were examined for cryptosporidium oocysts. Of the 10 pigs (5 per cent) found to be excreting the parasite, seven were feeder pigs and three were butcher hogs. Of the feeder pigs four (4.1 per cent) came from the 98 non-diarrhoeic pigs and three (17.6 per cent) from 17 diarrhoeic pigs. The 85 butcher hogs were all apparently healthy.

The reduction of mercury in samples of dairy cattle and chicken feed rations and manures prepared by acid digestion for determination by flameless atomic absorption is rapidly, smoothly, and quantitatively effected by sodium hypophosphite. The reducing agent is air-stable, is effective over a wide range of mercury concentrations, and is useful in the presence of many mineral acids commonly used for wet digestion of these matrices. The accuracy and precision obtained in determinations with this reagent are equivalent to those obtained using stannous chloride at the same conditions. Recovery efficiencies for the total analytical procedure were studied using cattle manure and feed rations spiked to 0.6 ppm Hg as phenylmercuric nitrate; the range of recoveries varied from 93 to 102% (97% average). The absolute detection limit of the method is 10 ng Hg, and the precision varies in the range of 2.2-6% for samples containing 3 ppt-10 ppm Hg. The advantages of sodium hypophosphite lie in the elimination of premature reduction of mercury caused by traces of stannous chloride adhering to the walls of the reaction vessel, the elimination of several wash steps in the determination, and the long shelf life of the reagent.

No abstract

Beef cattle manures have been converted to a water slurry and subjected to centrifugation, flocculution and drying to produce a silage replacement product (CI), a 20% protein powder from the centrifuge supernatant fluid (CII) and a soil amendment product (CIII). These products and the manure slurry were analyzed for their As, Cd, Cr, Cu, Fe, Hg, Mn, Ni, Pb and Zn content by atomic absorption spectrophotometry. Different sample mineralization techniques, metal recovery efficiencies and matrix effects were investigated. Metal concentrations increased in the products in the order of silage replacement, protein and soil amendment. Except for a high iron concentration, the silage replacement product (CI) had concentrations of these metals comparable to those for typical feedlot rations, and metal concentration in the protein fraction (CII) was three to six times higher as compared to the range of metal levels in CI; the soil amendment product (CIII) showed metal concentrations comparable to reported manure values. The effects of these metal concentrations on utility of the silage replacement and protein products as feed ingredients for animal feed rations is discussed.