Life cycle efficiency of beef production: IX. Relationship between residual feed intake of heifers and cow efficiency ratios based on harvest, carcass, and wholesale cut weight outputs

Authors: DAVIS, MICHAEL - The Ohio State University; LANCASTER, PHILLIP - Missouri State University; RUTLEDGE, JACKIE - University Of Wisconsin; Cundiff, Larry

Submitted to: Journal of Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/21/2017
Publication Date: 3/6/2018
Citation: Davis, M.E., Lancaster, P.A., Rutledge, J.J., Cundiff, L.V. 2018. Life cycle efficiency of beef production: IX. Relationship between residual feed intake of heifers and cow efficiency ratios based on harvest, carcass, and wholesale cut weight outputs. Journal of Animal Science. 96:430–443. https://doi.org/10.1093/jas/skx075.
DOI: https://doi.org/10.1093/jas/skx075

Interpretive Summary: A major goal of the beef cattle industry is to improve the efficiency of acceptable edible meat production. Residual feed intake (RFI), estimated as the difference between actual feed intake and predicted feed intake required for maintenance and observed rate of weight gain, is used in genetic improvement programs by several breeds of beef cattle. The primary objective of this study was to determine the relationship between postweaning RFI heifers from 240 days of age to first calving and subsequent life cycle or actual lifetime efficiency of cows. Data from a unique series of experiments in which lifetime feed intake was measured both on 110 cows from their birth until they weaned 3 calves by 5 years age and on their 3 progeny from birth to slaughter were used in this study. Various ratios progeny and dam weight (outputs) to feed intake of cows and their progeny (input) were used as measures of cow efficiency. Correlations of RFI with cow efficiency ratios that included harvest weight, carcass weight, or weight of trimmed wholesale cuts as measures of output ranged from –0.05 to -0.17, indicating that smaller heifers that ate less from 240 days of age to calving tended to have slightly superior cow efficiency ratios. Residual feed intake was generally not significantly correlated with postweaning feed consumption, gain, or feed efficiency of progeny, nor with harvest weights, carcass weights, trimmed wholesale cut weights, or loineye area of the progeny. Correlations of RFI with carcass grade, backfat thickness, marbling score, and kidney fat of progeny ranging from 0.11 to 0.20 indicated that heifers with superior RFI tend to produce leaner offspring.

Technical Abstract: Data were collected from 1953 through 1980 from identical and fraternal twin beef and dairy females born in 1953, 1954, 1959, 1964, and 1969, from crossbred females born as singles in 1974, and their progeny. Numbers of dams that weaned at least one calf and were included in the first analysis were 37, 45, and 56 in the 1964, 1969, and 1974 data sets, respectively. Respective numbers of dams that weaned three calves and were included in a second analysis were 6, 8, 8, 22, 33, and 33 in the 1953, 1954, 1959, 1964, 1969, and 1974 experiments. Individual feed consumption was measured at 28-d intervals from the time females were placed on the experiment at 240 d of age until three calves were weaned or the dams had reached 5 yr of age. Residual feed intake (RFI) and residual BW gain (RG) of heifers that subsequently became dams were determined based on ADG and DMI from 240 d of age to first calving. Various measures of cow efficiency were calculated on either a life cycle or actual lifetime basis using ratios of progeny and dam weight outputs to progeny and dam feed inputs. The correlation between RFI and DMI was large and positive (r = 0.67; P < 0.0001), and RG was highly correlated with ADG (r = 0.75; P < 0.0001). Correlations of RFI with cow efficiency ratios that included harvest weight, carcass weight, or weight of trimmed wholesale cuts as measures of output ranged from –0.05 (P > 0.10) to -0.17 (P < 0.10), indicating that heifers with better (i.e., more negative) RFI values tended to become slightly more efficient cows. Correlations of RG with life cycle and actual lifetime cow efficiency ratios ranged from 0.08 (P > 0.10) to 0.23 (P < 0.05), demonstrating that heifers with better (i.e., more positive) values for RG were somewhat more efficient as cows. The correlations were stronger when cow salvage value was included in the measures of cow efficiency. Correlations of DMI and mid-test metabolic BW (MMW) with life cycle cow efficiency ratios that did not include cow salvage value as output ranged from -0.15 (P < 0.10) to -0.22 (P < 0.01). Correlations of DMI and MMW with actual lifetime cow efficiency ratios varied from -0.20 (P < 0.05) to -0.36 (P < 0.001). Therefore, smaller heifers that consumed less feed had superior cow efficiency ratios. Correlations of RFI with carcass grade, backfat thickness, marbling score, and kidney fat of progeny indicated that heifers with superior RFI would tend to produce leaner offspring.