REDUCING COST OF EFFICIENT BEEF PRODUCTION
Location: Range and Livestock Research
Project Number: 5434-31000-016-00
Start Date: Jan 14, 2008
End Date: Oct 22, 2012
1: Characterize rumen microbial populations, including cellulolytic microbes, and
elucidate dynamics of these populations through the use of metagenomic approaches.
2: Determine rumen microbial and host genetic effects associated with differences
in measures of efficiency of heifers developed under divergent planes of nutrition
or different diets.
3: Determine phenotypic and genetic relationships of early-in-life measures of feed
consumption, growth and body composition, with subsequent reproduction and lifetime
4: Determine if the level of nutrition in utero and prior to puberty results in
epigenetic effects on traits associated with production efficiency at later stages
5: Develop and validate appropriate phenotypes for measuring fertility in cattle in
order to determine interactions between variation in cow feed efficiency and
6: Identify and fine map quantitative trait loci (QTL) affecting feed intake,
growth and reproduction.
Line 1 Hereford, an intercross (CGC) of Charolais (25%), Red Angus (50%) and
Tarentaise (25%), and two predominantly Hereford-Angus crossbred herds are used.
Line 1 Hereford cattle are ~30% inbred, with consequently reduced fitness, and have
close ties to the bovine genome sequence. Two distinct nutritional environments
will be imposed on the CGC population to challenge the nutrition-reproduction axis.
One Hereford-Angus cowherd provides donor and recipient females for studies using
embryo transfer. The other Hereford-Angus cowherd calves in two seasons and thus
has differential synchrony between nutritional value of range forage and nutrient
requirements of the cows.
1: Identify new species of rumen microbes through whole genome shotgun sequencing
of rumen microbial milieu. Compare rumen bacterial species diversity responses to
2: Evaluate rumen microbial diversity and host animal gene expression in samples of
animals expressing extreme differences in feed efficiency.
3: Estimate genetic and phenotypic variances and covariances of longevity,
stayability, number of calves produced, and cumulative production of beef cows with
early-in-life measures of growth rate, feed consumption, and indicators of body
composition. Determine effects of phenotypes measured early-in-life on subsequent
fertility of bulls.
4: Determine effects of feed intake prior to puberty and level of supplementation during mid to late gestation on genetic (co)variance and gene expression of the
treated animals and their progeny. Determine effects of nutrient intake during
gestation on phenotypes of treated animals and their progeny.
5: Determine factors controlling establishment and maintenance of pregnancy in cows
induced to ovulate different sized follicles. Establish relationships between
previous nutrition, time post-partum, resumption of estrus, and energetic
efficiency in young postpartum beef cows.
6: Identify QTL affecting growth and reproduction in an advanced intercross of Red
Angus, Charolais, and Tarentaise. Identify QTL with over-dominance effects on
fitness. Identify genes expressed in tissues of cattle.