Influence of residual feed intake and cow age on dry matter intake postweaning and peak lactation

Abstract

Supplemental nutrition for cattle is the greatest operating cost for cow-calf producers, accounting for 65% of the annual expenses (Meyer et al., 2008). Therefore, selection pressure for efficient animals that have lower feed intake but maintain production, or average intake with higher production, could have positive impacts on cow–calf profitability (Meyer et al., 2008). Thus, improving feed efficiency through genetic selection holds significant opportunity for the beef industry. Residual feed intake (RFI) is currently being used as a selection tool for purchasing and retaining heifers and for selecting bulls and semen. Most studies have used steers and terminal heifers when evaluating RFI impact on various aspects of beef cattle production (Kelly et al., 2010). Additionally, the majority of RFI studies have included energy-dense diets and rations focusing on feedlot performance (Lawrence et al., 2011). However, the use and relevance of RFI as a selection tool for the commercial cow–calf industry needs further research (Manafiazar et al., 2015). Research pertaining to RFI of cattle offered forage-based diets is limited (Arthur et al., 2005), with even fewer data available related to beef cattle forage-based production systems (Meyer et al., 2008). As a result, more research is needed to evaluate the utility of RFI estimates on the beef production in extensive forage base systems (Kenny et al., 2018). Therefore, the objectives of this study were to evaluate the influence of heifer postweaning RFI and cow age on dry matter intake (DMI), intake behavior, as well as milk production of dry-lotted black Angus beef cows. We hypothesized that heifers identified as low RFI eat less and the influence of RFI may interact with cow age.