Abstract
Our long-term objective is to develop breeding strategies
for improving feed efficiency in dairy cattle. In
this study, phenotypic data were pooled across multiple
research stations to facilitate investigation of the genetic
and nongenetic components of feed efficiency in
Holstein cattle. Specifically, the heritability of residual
feed intake (RFI) was estimated and heterogeneous
relationships between RFI and traits relating to energy
utilization were characterized across research stations.
Milk, fat, protein, and lactose production converted
to megacalories (milk energy; MilkE), dry matter intakes
(DMI), and body weights (BW) were collected
on 6,824 lactations from 4,893 Holstein cows from research
stations in Scotland, the Netherlands, and the
United States. Weekly DMI, recorded between 50 to
200 d in milk, was fitted as a linear function of MilkE,
BW0.75, and change in BW (ΔBW), along with parity,
a fifth-order polynomial on days in milk (DIM), and
the interaction between this polynomial and parity in
a first-stage model. The residuals from this analysis
were considered to be a phenotypic measure of RFI.
Estimated partial regression coefficients of DMI on
MilkE and on BW0.75 ranged from 0.29 to 0.47 kg/Mcal
for MilkE across research stations, whereas estimated
partial regression coefficients on BW0.75 ranged from
0.06 to 0.16kg/kg0.75. Estimated partial regression
coefficients on ΔBW ranged from 0.06 to 0.39 across
stations. Heritabilities for country-specific RFI were
based on fitting second-stage random regression models
and ranged from 0.06 to 0.24 depending on DIM. The
overall heritability estimate across all research stations
and all DIM was 0.15 ± 0.02, whereas an alternative
analysis based on combining the first- and second-stage
model as 1 model led to an overall heritability estimate
of 0.18 ± 0.02. Hence future genomic selection
programs on feed efficiency appear to be promising;
nevertheless, care should be taken to allow for potentially
heterogeneous variance components and partial
relationships between DMI and other energy
Original language | English |
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Pages (from-to) | 2013 - 2026 |
Number of pages | 14 |
Journal | Journal of Dairy Science |
Volume | 98 |
Issue number | 3 |
Early online date | 9 Jan 2015 |
DOIs | |
Publication status | Print publication - 1 Mar 2015 |
Bibliographical note
1023378Keywords
- Heritability
- International study
- Random regression model
- Residual feed intake