The Journal of Agricultural Science

Research Article

The utilization of dietary energy by steers during periods of restricted food intake and subsequent realimentation

2. The comparative energy requirements of penned and exercised steers for long term maintenance at constant live weight

H. P. Ledgera1 p1

a1 East African Agriculture and Forestry Research Organization, Muguga

SUMMARY

An investigation was carried out to determine the daily energy intakes necessary to maintain, the live weights of ‘maintenance-stabilized’ steers (i.e. those held at constant live weight in pens for not less than 15 weeks) when walked at 5 km/h for distances of 5, 10 and 15 km/day.

The experiment utilized groups of Boran Zebu and Hereford × Boran Zebu steers at live weights of 275 and 450 kg.

Fed a standard diet of energy concentration 10·477 MJ metabolizable energy (ME)/kg D.M. it was found that the Hereford × Boran steers required significantly less food per day, at both live weights, than did the Borans to maintain live weight when walking distances of 15 km/day.

Based on the data relating to the total distance walked of 1120 km in 133 days it was calculated that the additional energy cost of maintaining live weight when walking was close to 4·184 kJ ME/kg/km walked. The efficiency of conversion of ME for walking was 50%.

For ‘maintenance-stabilized’ steers it was calculated that the 275 kg steers required 24, 49 and 73% more daily D.M. intake and the 450 kg steers 34, 69 and 97% more daily D.M. intake when walked 5, 10 and 15 km/day respectively than would have been the case if they had been kept inactive in pens.

(Received April 09 1976)

Correspondence:

p1 Presently at the Department of Agriculture and Forestry, Melbourne University, Victoria, Australia.

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