A Potential Practical System to Estimate Pasture Intake of Individual Animals

Pasture feed intake of individual animals is very difficult to estimate. A practical measurement system would better enable the selection of livestock for pasture feed use efficiency and lower maintenance requirements, which are very important biological and economic traits. A prototype (Proway-CottleDove) feed bin system was trialed by comparing chaff intakes by cattle in a feedlot measured by a race fed autofeeder with intakes estimated by marker analysis of faecal and feed samples following the controlled daily consumption of wax labeled supplement. Intake of a native pasture was also estimated by use of the bin. Autofeeder-recorded daily chaff intakes were very variable and unreliable and so the accuracy of the bin system in estimating intake could not be determined. The repeatabilities of chaff intakes estimated from marker concentrations from sequential faecal samples were 0.2-0.3. Chaff intake predictions were in a feasible range, based on cattle liveweight. When the pasture grasses were combined in analyses, following a principal component analysis of markers, the diet composition, digestibility and daily intake of pasture plus supplement estimates, on average, were consistent with the prediction of intake from liveweight and liveweight gain. The average total intakes estimated from days 5, 7 and 10 faeces marker concentrations were 7.8kg, 6.9kg and 9.7kg/head respectively. The bin system used in this trial would estimate pasture intake at an approx. cost of $122/head. Multi-bin systems using Sapien Technology components and databases are being developed for further testing.