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Errors associated with expressing pasture intake as dry rather than organic matter at high stocking intensities

Published online by Cambridge University Press:  27 March 2009

P. B. O'Donovan
P. B. O'Donovan
Affiliation:
An Foras Taluntais (The Agricultural Institute), Grange, Dunsany, Co. Meath, Republic ofIreland
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Summary

Following both a low and high plane of winter feeding two groups of 18 bullocks each were stocked at 2·5 (low), 4·3 (medium) and 6·2 (high) bullocks per hectare. The Hereford × Shorthorn bullocks averaging 350 kg live weight were rotationally grazed on ten plots, seven of which contained a H.I. white clover mixture and the remaining three contained permanent pasture. Pasture digestibility and intake were determined for 16 weekly periods between early April and late September. In vitro digestibility was determined on samples obtained by means of two rumen-fistulated bullocks. A gelatin capsule containing 10 g of chromic oxide was administered daily to each bullock to estimate faecal output. Digestibility, faecal output and intake were expressed on both a dry and organic-matter basis. Increasing the stocking rate resulted in a corresponding decrease in organic matter (OM) percentage of the faeces but the magnitude of the differences varied throughout the growing season. The average decline (all 16 periods) was linear, the OM percentage of faeces being 80·9, 76·8 and 72·6 for low, medium and high stocking rates, respectively. Faecal ash content of rectal samples and those taken from the pasture differed significantly only in a few instances, indicating that pasture faecal contamination may not be serious if careful sampling is practised. Higher ash intakes at high stocking intensities are reflected in herbage intake errors when results are expressed as dry matter instead of organic matter.

Type
Research Article
Information
The Journal of Agricultural Science , Volume 78 , Issue 1 , February 1972 , pp. 97 - 103
Copyright
Copyright © Cambridge University Press 1972

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References

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