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ARS Home » Plains Area » Clay Center, Nebraska » U.S. Meat Animal Research Center » Genetics and Animal Breeding » Research » Publications at this Location » Publication #335400
Title: Life cycle efficiency of beef production: VIII. Relationship between residual feed intake of heifers and subsequent cow efficiency ratios

Author
item DAVIS, MICHAEL - The Ohio State University
item LANCASTER, PHILLIP - Missouri State University
item RUTLEDGE, JACK - University Of Wisconsin
item Cundiff, Larry

Submitted to: Journal of Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/29/2016
Publication Date: N/A
Citation: N/A

Interpretive Summary: Improvement in efficiency of energy utilization by cows could greatly reduce costs of beef production. A measure of feed efficiency used in several beef cattle genetic improvement programs is residual feed intake (RFI) estimated as the difference between actual feed intake and predicted feed intake required for maintenance of live weight and observed rate of weight gain. A primary objective of this study was to determine the relationship of RFI estimated in heifers from 8 months of age to first calving with their subsequent efficiency as cows, as well as the relationships of RFI with various output and input component traits of cow lifetime efficiency. Individual feed consumption was measured at 28-d intervals from the time females were about 8 months of age until 3 calves were weaned or the dams had reached 5 yr of age. Various measures of cow efficiency were calculated on an actual lifetime or lifecycle basis using ratios of progeny and dam weight outputs to progeny and dam feed inputs. Correlations indicated that heifers that ate less and had smaller metabolic midweights from 240 d of age to first calving had superior efficiency ratios as cows. Residual feed intake of heifers from 8 months of age to first calving was lowly but favorably correlated with estimates of lifetime efficiency. However, RFI of heifers from 240 d of age to first calving was not correlated with feed intake of cows at subsequent ages through 5 years of age. Nor was RFI at young ages significantly correlated with age at puberty, age at calving, milk production or feed intake of cows at subsequent ages. Results of this study do not indicate any serious antagonisms of postweaning heifer RFI with subsequent cow and progeny performance traits or with estimates of life time efficiency.

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, and from crossbred females born as singles in 1974, and their progeny. Numbers of dams that weaned at least 1 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 3 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 until 3 calves were weaned or the dams had reached 5 yr of age. Residual feed intake (RFI) and residual gain (RG) of the heifers that subsequently became the dams in this study 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. Residual feed intake was phenotypically independent of ADG and metabolic midweight (MMW), whereas the correlation between RFI and DMI was positive and highly significant (r = 0.67; P < 0.0001). Residual gain was highly correlated with ADG (r = 0.75; P < 0.0001) and had near 0 correlations with DMI and MMW. Correlations indicated that heifers that ate less and had smaller metabolic midweights from 240 d of age to first calving had superior efficiency ratios as cows. Residual feed intake was not significantly correlated with age at puberty, age at calving, or milk production. Results of this study do not indicate any serious antagonisms of postweaning heifer RFI with subsequent cow and progeny performance traits or with life cycle or actual lifetime cow efficiency. In addition, selection for increased RG would result in earlier ages at calving, but would also tend to result in taller and heavier cows.