Publication Date
1989
Location
Nice France
Description
Herbage intake in grazing animals is commonly estimated from faecal dry matter output, calculated from the dilution of orally-administered chromium sesquioxide (Cr203), and an in�� vitro estimate of herbage digestibility (e.g., Freer et al. 1988). A major disadvantage of this approach is that a single digestibility value is ultimately applied to all the animals in a group, despite the fact that both the level of intake of individual animals and the consumption of supplement can alter herbage digestibility (Waite et al. 1964). More recently, Mayes et al.(1986) obtained accrurate estimates of known herbage, from a combination of the faecal levels of the n-hydrocarbons (alkanes) of plant cuticular waxes (predominantly oddnumbered carbon chain length) and those of orally-administered synthetic alkanes (even-numbered chain lengths). Neither type of alkane is wholly indigestible but, since alkanes of adjacent chain length have very similar faecal recoveries, the errors arising from incomplete recoveries cancel out in the calculcation of intake (Mayes et al. 1986). A major advantage of this method is that it reflects the digestibility in individual animals. It is thus well suited to grazing situations where levels of intake may differ between treatments or where supplements are used in some treatments. In this paper, we report the results of a comparison of these two methods for estimating herbage intake, conducted with grazing ewes.
Citation
Dove, H; Foot, J Z.; and Freer, M, "Estimation of Pasture Intake in Grazing Ewes, Using the Alkanes of Plant Cuticular Waxes" (1989). IGC Proceedings (1985-2023). 40.
(URL: https://uknowledge.uky.edu/igc/1989/session9/40)
Included in
Agricultural Science Commons, Agronomy and Crop Sciences Commons, Plant Biology Commons, Plant Pathology Commons, Soil Science Commons, Weed Science Commons
Estimation of Pasture Intake in Grazing Ewes, Using the Alkanes of Plant Cuticular Waxes
Nice France
Herbage intake in grazing animals is commonly estimated from faecal dry matter output, calculated from the dilution of orally-administered chromium sesquioxide (Cr203), and an in�� vitro estimate of herbage digestibility (e.g., Freer et al. 1988). A major disadvantage of this approach is that a single digestibility value is ultimately applied to all the animals in a group, despite the fact that both the level of intake of individual animals and the consumption of supplement can alter herbage digestibility (Waite et al. 1964). More recently, Mayes et al.(1986) obtained accrurate estimates of known herbage, from a combination of the faecal levels of the n-hydrocarbons (alkanes) of plant cuticular waxes (predominantly oddnumbered carbon chain length) and those of orally-administered synthetic alkanes (even-numbered chain lengths). Neither type of alkane is wholly indigestible but, since alkanes of adjacent chain length have very similar faecal recoveries, the errors arising from incomplete recoveries cancel out in the calculcation of intake (Mayes et al. 1986). A major advantage of this method is that it reflects the digestibility in individual animals. It is thus well suited to grazing situations where levels of intake may differ between treatments or where supplements are used in some treatments. In this paper, we report the results of a comparison of these two methods for estimating herbage intake, conducted with grazing ewes.
