Influence of Residual Feed Intake and Cow Age on Dry Matter Intake Post-Weaning and Peak Lactation of Black Angus Cows.

Cory T. Parsons,Julia M. Dafoe,Timothy DelCurto,Darrin L. Boss,Samuel A. Wyffels

doi:10.3390/ani11061822

Abstract

Simple SummarySupplemental nutrition for cattle is the greatest operating cost for cow-calf producers, accounting for 65% of the annual expenses. In addition, residual feed intake (RFI) is being used as a selection tool for purchasing and retaining heifers, as well as selecting bulls with the goal of improving feed efficiency and/or reducing supplemental inputs. However, the use and relevance of RFI as a selection tool for the cow-calf industry needs additional research. In our studies, heifer post-weaning RFI did not influence mature cow dry matter intake and intake behavior for both lactating and non-lactating beef cows. In contrast, cow age did correspond to increases of intake and intake rates of mature cows. However, when intake was expressed as g/kg body weight−1, no differences were observed with respect to cow age for lactating and non-lactating cows. Milk production was influenced by heifer post-weaning RFI in 5–6- and 8–9-year-old cows, however, did not influence 9–10-year-old cows. Therefore, our research suggests that cow age has greater impacts on dry matter intake than RFI, however, the relationship between RFI of heifers and subsequent mature cow milk production warrants further investigation.We evaluated heifer post-weaning residual feed intake (RFI) classification and cow age on dry matter intake (DMI) at two stages of production. Fifty-nine non-lactating, pregnant, (Study 1) and fifty-four lactating, non-pregnant (Study 2) commercial black Angus beef cows were grouped by age and RFI. Free-choice, hay pellets were fed in a GrowSafe feeding system. In Study 1, cow DMI (kg/d) and intake rate (g/min) displayed a cow age effect (p < 0.01) with an increase in DMI and intake rate with increasing cow age. In Study 2, cow DMI (kg/d) and intake rate (g/min) displayed a cow age effect (p < 0.02) with an increase in DMI and intake rate with increasing cow age. Milk production displayed a cow age × RFI interaction (p < 0.01) where both 5–6-year-old and 8–9-year-old low RFI cows produced more milk than high RFI cows. For both studies, intake and intake behavior were not influenced by RFI (p ≥ 0.16) or cow age × RFI interaction (p ≥ 0.21). In summary, heifer’s post-weaning RFI had minimal effects on beef cattle DMI or intake behavior, however, some differences were observed in milk production.

Highlights

Supplemental nutrition for cattle is the greatest operating cost for cow-calf producers, accounting for 65% of the annual expenses [1,2,3]
Neither dry matter intake (DMI) (g/kg of body weights (BW)), intake variation (% CV), or time spent at the feeder were affected by cow age or Residual feed intake (RFI) (p ≥ 0.16), averaging 28.8 g/kg of BW, 19.0% CV, and 107.5 min/d, respectively
Neither DMI intake (g/kg of BW), % CV, nor time spent at the feeder were affected by cow age, or RFI, averaging 21.7 g/kg of BW, 11.7% CV, and 149.7 min/d, respectively

Summary

Introduction

Supplemental nutrition for cattle is the greatest operating cost for cow-calf producers, accounting for 65% of the annual expenses [1,2,3]. Most studies have used steers and terminal heifers when evaluating RFI impact on various aspects of beef cattle production [4,5,6]. The use and relevance of RFI as a selection tool for the cow-calf industry needs additional research [7,8,9]. Research pertaining to RFI of cattle offered forage-based diets is limited [11], with even less data available related to beef cattle foragebased production systems [3,7,12,13]. More research is needed to evaluate the utility of RFI estimates on beef cattle production systems in extensive forage-based environments [8,12,14]

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Conclusion