Energy for maintaining liveweight: an indicator of adaptive abilities of beef cows?
Productivity of low input livestock systems partly relies on animals’ ability to cope with changing environments while achieving productive and reproductive performances. In such conditions, individuals’ robustness could be estimated by indicators of animal adaptive abilities which account for energy variations across the productive cycle. In mature suckler cows, the net energy requirements for production are low (30%) compared to those for maintenance (70%) which complicates the evaluation of adaptive abilities. The later could be approached by estimating the net energy required for maintaining liveweight constant (Em). The objective of this study was to (1) estimate in beef cows having different body reserves at calving the partition of net energy between net energy outputs (Em, Emilk) and net energy inputs (Eintake + Etissues) and (2) test the relevance of Em as an indicator of adaptive abilities of beef cows.
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