Fly ash, basic slag and Glenbrook slag toxicity in cattle
作者:
H.F. Dewes,
L.M. McLeay,
C.G. Harfoot,
期刊:
New Zealand Veterinary Journal
(Taylor Available online 1995)
卷期:
Volume 43,
issue 3
页码: 104-109
ISSN:0048-0169
年代: 1995
DOI:10.1080/00480169.1995.35864
出版商: Taylor & Francis Group
数据来源: Taylor
摘要:
In case studies of two herds of dairy cattle, a herd of 270 Friesian cows and heifers and a herd of 256 Jersey cows and heifers experienced high death rates and a protracted course of illness when fly ash was broadcast as a fertiliser over the farms at a rate of about 1 tonne per hectare. The onset of weakness, lassitude and diarrhoea in the cattle first appeared within 4–5 days and both fertility and milk fat production fell off dramatically. In the following 7 months, 51 animals died in the Friesian herd and a similar death rate and performance losses occurred in the Jersey herd. Emaciation and hepatic fibrosis were consistently reported from autopsies. Heavy metal poisoning was eliminated from the possible diagnosis. The slags and fly ash used as fertiliser had several features in common. They contained 29–40% calcium as calcium oxide, 15–35 grams of iron per kg, they were all extremely alkaline and concentrations of lead and arsenic were low. The effect of adding fly ash to rumen contentsin vitrowas to raise the pH to greater than 7.2, at which point fermentation was markedly reduced.
点击下载:
PDF (762KB)
返 回