GEM and the UW Silage Breeding Project

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GEM and the UW Silage Breeding Project

• J.G. Coors
• D. Majee
• D.T. Eilert
• P.J. Flannery
• Department of Agronomy
• University of Wisconsin
• with acknowledgements to
• J.G. Lauer
• UW Department of Agronomy
• R.D. Shaver
• UW Department of Dairy Science

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• Outline
• Silage quality what is it?
• UW silage breeding system
• GEM contributions silage germplasm
• GEM contributions starch degradability
• Summary

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Dry Matter
Protein
Carbohydrate
Sugars starch
Cell wall
Degradable protein
Bound
Unavailable starch
Sugar and Starch Bugs
Bound with Lignin
Undegradable protein
Fiber Bugs
Digestible energy protein
Absorbed
Metabolizable energy protein
Maintenance
Lactation
Pregnancy
Growth
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Milk2000
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Processed
Unprocessed
Adapted from Schwab and Shaver, unpublished.
Based on data of Bal et al., 2000 Dhiman et
al., 2000 Rojas-Bourrillon et al., 1987
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GEM Contributions Silage Germplasm
Phase I Silage evaluation of elite GEM topcrosses
(15-25) that were identified in prior years by
other GEM cooperators as having high grain yield
and suitable maturity for Wisconsin (lt120RM).
Phase 2 For those topcrosses with high forage
yield and good nutritional quality in Phase 1
trials, the respective GEM breeding population is
included in the UW inbred development nursery for
further inbreeding and selection Phase 3 Inbred
development testcrosses at S2 to S6 generations
using two to four inbred testers
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2004 UW GEM Program
Phase I 17 breeding populations or early
generation GEM inbred families crossed to LH185,
LH198, LH200, LH244, or LH287 were evaluated for
silage potential (GEMNEW). Phase 2 Gem
inbreeding nursery included 400 inbred families
from 10 breeding populations. Most inbred
families (170) were derived from CUBA164
background. Phase 3 160 advanced generation
inbreds from six populations were crossed to two
testers each for evaluation in 2005. Evaluated
50 S3 families topcrosses to two testers
(GEM198, GEM244). 27 promising S4 families
evaluated in topcrossed to two to four testers
each (GEMADV).
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Forage yield for GEMNEW trial in 2004 Entries
marked with will be analyzed for nutritional
quality
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2004 UW GEM Program
Phase I 17 breeding populations or early
generation GEM inbred families crossed to LH185,
LH198, LH200, LH244, or LH287 were evaluated for
silage potential (GEMNEW). Phase 2 Gem
inbreeding nursery included 400 inbred families
from 10 breeding populations. Most inbred
families (170) were derived from CUBA164
background. Phase 3 160 advanced generation
inbreds from six populations were crossed to two
testers each for evaluation in 2005. Evaluated
50 S3 families topcrosses to two testers
(GEM198, GEM244). 27 promising S4 families
evaluated in topcrossed to two to four testers
each (GEMADV).
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2004 UW GEM Program
Phase I 17 breeding populations or early
generation GEM inbred families crossed to LH185,
LH198, LH200, LH244, or LH287 were evaluated for
silage potential (GEMNEW). Phase 2 Gem
inbreeding nursery included 400 inbred families
from 10 breeding populations. Most inbred
families (170) were derived from CUBA164
background. Phase 3 160 advanced generation
inbreds from six populations were crossed to two
testers each for evaluation in 2005. Evaluated
50 S3 families topcrosses to two testers
(GEM198, GEM244). 27 promising S4 families
evaluated in topcrosses to two or four testers
each (GEMADV).
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Forage yield for GEM198 and GEM244 trials in 2004
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Forage yield for GEMADV trial in 2004
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Components of GEM Quality Synthetic (GQS) 2003
trial, LH279 topcrosses
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GEM Contributions Starch Degradability
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Rumen Degradability of Starch
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Starch Degradability
Oh43 o2
CHO5015N12-387-1-B
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Correa et al., 2002
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Starch Degradability Studies
Objectives

• Determine whether there is genetic variation for
  starch
• degradability
• Determine the extent to which kernel vitreousness
  is related
• to starch degradability

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Starch Study
Entries
32 inbred lines and 1 population (2002) 19
hybrids (2003)
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Procedure Two-Stage Starch Digestion
(Pioneer Hi-Bred International, Inc.)

• STAGE 1 - in-situ ruminal incubation
• Two steers with ruminal cannula 2 wk
  adaptation to 70 (DMB) corn silage diet
• In-situ procedure
• Corn kernels ground with Wiley Mill (6mm
  screen)
• 1.5g ground material placed in 5 x 5 cm dacron
  bag
• Eight replicate bags incubated for each sample
• Placed in rumen for 0 and 14 h,
• Removed, rinsed and dried at 62oC for 24 h
• STAGE 2 - post-ruminal in-vitro incubation
• 14-h ruminal residue subjected to 8 h
  incubation
• intestinal enzymatic cocktail (pepsin
  pancreatic enzymes)
• Removed, rinsed and dried at 62oC for 24 h
• Final Action
• Eight replicates for DM disappearance
• Eight replicated bags composited for a single
  starch analysis

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½ milk-line stage
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Black layer stage
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Black layer stage hybrids
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Summary
GEM has contributed greatly to the UW silage
breeding program by providing 1) Superior and
unique germplasm 2) Better understanding of
nutritional properties of silage
http//silagebreeding.agronomy.wisc.edu