Summary
This five-year field trial evaluated 106 Hays Converter beef heifers to determine whether feed utilisation efficiency (measured as RFI) confers differential weather resilience during intensive feeding. Low-RFI heifers consumed 6.51 kg DMI/d versus 7.59 kg for high-RFI heifers (P < 0.001) and achieved superior feed conversion (0.182 vs 0.144 kg/kg), yet showed comparable resilience to perturbations in feed intake across varying environmental conditions. The study found that perturbation frequency and severity were primarily driven by climatic thermal risk (CETI) rather than inherent feed efficiency phenotype.
Regional applicability
These findings have moderate transferability to United Kingdom beef production, particularly in housed intensive systems; however, UK climate differs significantly from Western Canadian conditions, which limits direct application of CETI thresholds. The methodology for assessing resilience to feed intake perturbations and the relationship between RFI and environmental stability may inform genetic selection strategies in UK beef breeding programmes, though validation under UK climatic and management conditions would be required.
Key measures
Residual feed intake (RFI), dry matter intake (DMI), average daily gain (ADG), gain-to-feed ratio (G:F), cumulative feed intake (CFI), current effective temperature index (CETI), intake perturbations (shortfalls and increases), deviation variance
Outcomes reported
The study assessed whether residual feed intake (RFI) classification affects heifer resilience to environmental perturbations in feed intake during intensive feeding trials. Environmental conditions significantly affected performance parameters, with low-RFI heifers demonstrating superior feed conversion efficiency but comparable resilience to feed intake disruptions across weather conditions.
Topic tags
Dig deeper with Pulse AI.
Ask about this record, its theme or its relevance to UK farming and policy. Pulse AI uses selected catalogue evidence and cites the sources it draws on.