Management of Acyrthosiphon kondoi Shinji, blue-green aphid, and Therioaphis trifolii (Monell) f. maculata, spotted alfalfa aphid, by grazing and cutting lucerne

1980 ◽  
Vol 20 (107) ◽  
pp. 710 ◽  
Author(s):  
AL Bishop ◽  
LR Greenup ◽  
RH Holtkamp
Keyword(s):  
Direct Effect ◽  
New South ◽  
New South Wales ◽  
Aphid Species ◽  
Grazing Cattle ◽  
South Wales ◽  
Light Medium

Three experiments were carried out in New South Wales to assess the effects of grazing, forage harvesting and haymaking on populations of blue-green aphid (BGA) and spotted alfalfa aphid (SAA) and some of their predators. In experiment 1, at Tamworth, grazing by sheep at light, medium and heavy intensities reduced BGA numbers after 10 days by 52%, 74% and 93%, respectively, from the ungrazed control in dryland Hunter River lucerne. Grazing had no significant effect on the numbers of SAA and had little direct effect on the small numbers of predators present. A resurgence of both aphid species resulted in numbers significantly higher on regrowth in grazed areas than in the area left ungrazed. In experiment 2, at Tocal, grazing cattle on irrigated CUF101 at light, medium and heavy rates initially reduced BGA numbers by 30%, 53% and 75%, respectively, from their untreated levels. Grazing had little direct effect on the low number of predators present. In experiment 3, forage harvesting and mowing for hay reduced BGA and its predators more than did grazing at normal rates. It was concluded that while grazing or harvesting may reduce aphid numbers and damage initially, problems may result on regrowth.

Selenium concentration in the blood of ruminants grazing in Northern New South Wales. 1. Analysis of samples collected in the National Brucellosis Eradication Scheme

1981 ◽  
Vol 32 (3) ◽  
pp. 511 ◽  
Author(s):  
JP Langlands ◽  
JF Wilkins ◽  
JE Bowles ◽  
AJ Smith ◽  
RF Webb
Keyword(s):  
New South ◽  
New South Wales ◽  
Selenium Concentration ◽  
Selenium Status ◽  
Bovine Blood ◽  
Average Standard Deviation ◽  
Grazing Cattle ◽  
South Wales ◽  
Bovine Plasma ◽  
Survey Results

Bovine blood samples collected for the Brucellosis Eradication Scheme were analysed for selenium as a means of surveying the selenium status of grazing cattle in 10 Pastures Protection Board areas of northern New South Wales. Sources of error were also examined. The average standard deviation of repeat samplings from the same farm was �0.019�g selenium ml-1 and the seasonal variation in blood selenium concentration appeared to be relatively small. Relationships were calculated for predicting the selenium concentration in bovine plasma and liver, and in ovine whole blood, plasma and liver, from the selenium concentration of bovine blood; they were used to extend the survey results to grazing sheep. Samples were collected from 794 farms, and there were significant differences between Pastures Protection Board areas. Cattle in the Glen Innes and Armidale areas had the lowest selenium status with 26 and 14% respectively of herds having blood selenium concentrations = 0.02 �g selenium ml-1.

Selenium concentration in the blood of ruminants grazing in northern New South Wales. 3. Relationship between blood concentration and the response in liveweight of grazing cattle given a selenium supplement

1989 ◽  
Vol 40 (5) ◽  
pp. 1075 ◽  
Author(s):  
JP Langlands ◽  
GE Donald ◽  
JE Bowles ◽  
AJ Smith
Keyword(s):  
Growth Rate ◽  
New England ◽  
Whole Blood ◽  
New South ◽  
New South Wales ◽  
Selenium Concentration ◽  
Grazing Cattle ◽  
South Wales ◽  
History Of ◽  
Commercial Farms

Approximately 700 yearling (Experiment 1) or unweaned (Experiment 2) cattle grazed commercial farms on the New England Tablelands of New South Wales, and were supplemented or not supplemented with selenium (Se). Whole blood and plasma Se concentrations, and liveweight gains were measured over periods of 3-7 months. In a third experiment, 96 castrated male weaned calves on a farm with a long history of unthriftiness were allocated to four groups, and were supplemented with either Se or copper in a factorial design.In Experiments 1 and 2, mean whole blood and plasma Se concentrations of unsupplemented animals on individual farms ranged from 0.004 to 0.139, and from 0.002 to 0.058 8g Se/ml respectively, but growth rates of only two of the twenty herds responded significantly to Se supplementation, and both showed diarrhoea and ill thrift at the start of the experiment. The herd in Experiment 3 also showed ill thrift, and growth rate responded to supplementation with Se, but copper depressed growth. Se concentrations in blood and plasma were generally poor indicators of responsiveness. Possible reasons are suggested.

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