Lythrum hyssopifolia (lesser loosestrife) poisoning of sheep in Victoria

Objective To document an ovine disease attributed to the consumption of Lythrum hyssopifolia (lesser loosestrife). Procedures Historical and histological review of field and experimental cases. Results 1–20% mortality occurred in sheep flocks grazing paddocks where L. hyssopifolia was the predominant green vegetation. Well‐documented disease outbreaks occurred in summer on nine farms across Victoria between 1974 and 2002. Liver damage occurred in all nine outbreaks, with kidney damage in at least eight. Hepatocyte necrosis was usually zonal to midzonal (zone 2) in the liver samples from four farms and periacinar (zone 3) in those from three farms, but some livers showed only single‐cell necrosis. Multinucleate hepatocytes near necrotic areas were a feature in six cases. Proximal tubular epithelium appeared to be the primary renal target and brown granules were often present in renal tubules. Biochemical and histological evidence of liver and kidney damage was obtained from two sheep experimentally pen‐fed harvested L. hyssopifolia. Conclusion Chemicals in L. hyssopifolia are toxic to ovine hepatocytes and renal tubular epithelial cells.     

Imazethapyr aqueous photolysis, reaction quantum yield, and hydroxyl radical rate constant

The recent introduction of imidazolinone-tolerant rice varieties allow imazethapyr to be used in commercial rice. Little is known about imazethapyr photodegradation in the rice field. Laboratory studies were conducted to determine the direct and indirect photolysis rates for imazethapyr and to evaluate the photolysis of imazethapyr in three rice paddy waters. The reaction quantum yield (phi I) for imazethapyr was determined to be 0.023 +/- 0.002, while the hydroxyl radical rate constant (K(I)*OH) was 2.8 x 10(13) M(-1) h(-1). These results show that imazethapyr is susceptible to both direct and indirect photolysis reactions in water. The results also show that imazethapyr photolysis in paddy water will be affected by turbidity because of its impact on the availability of sunlight to drive direct and indirect photolysis reactions.     

Cooling of broiler hatching eggs during incubation

1. Broiler hatching eggs were cooled to 22°C for periods of 8 or 24 h on day 16 of incubation. Cooling had no significant effects on hatchability or chick quality compared with controls.

2. Cooling to 22°C for 24 h on days 14, 15, 16, 17 or 18 yielded similar results but cooling on day 13 increased late embryonic mortality.

3. When eggs were cooled to 22°C on day 16 of incubation there were no major differences in hatchability up to 48 h of cooling but chick quality deteriorated rapidly after 30 h and the limit for embryonic survival at this temperature was about 72 h.

4. There were no significant differences when eggs were cooled on day 16 and held for 24 h at 21.1, 23.9 or 26.7°C but hatchability and late deaths were significantly affected by cooling to 18.3°C.