Columbia
NSIP Notebook
November 2, 2006 Number
6
David Notter and
Randy Borg
Department of
Animal and Poultry Sciences
Virginia Tech
The 2005 Columbia National Genetic Evaluation
Introduction
The 2005 NSIP Columbia national genetic evaluation is now
complete, and EPD have been delivered to the data coordinator. Genetic trends have been updated and are
again provided as a way to track genetic improvement in the breed.
The 2005
Columbia NSIP Data
Data for 2005 were received from four Montana flocks and included
records on 188 breeding ewes that produced 280 live lambs. The lambs were
offspring of 18 Columbia rams.
Following editing, valid records were received for 2005 on 55 60-day
weaning weights, 155 120-day weaning weights, 21 fleece weights, 8 staple
lengths, 18 fiber diameter (fleece grade) measurements, and 236 litter
sizes. The entire NSIP Columbia data
base now contains records on 3,758 60-day weaning weights, 2,960 120-day
weaning weights, 551 postweaning (60- to 120-day) gains, 1,473 fleece weights,
1,468 staple lengths, 789 fiber diameter measurements, and 3,995 litter
sizes.
Means for each trait are shown below. Weaning weights were adjusted to a single birth and rearing,
adult dam, and ewe lamb basis.
Postweaning gains were not adjusted, but male and female lambs were
placed in different contemporary groups.
Yearling fleece weights and staple length were adjusted to an age of 365
days. Fleece weights and staple lengths
for older animals were adjusted to an adult animal and 365-day shearing
interval basis. Fleece grades for
yearlings did not receive any adjustments.
Fleece grades for older animals were adjusted to an adult animal basis. For fleece traits, yearling and older
animals, and males and females were placed in different contemporary
groups. Litter sizes were adjusted to
an adult ewe basis.
Trait Mean
60-day
adjusted weaning weight 61.8 lb
120-day
adjusted weaning weight 105.8
lb
postweaning
(60- to 120-day) gain .73 lb/day
fleece weight 11.1lb
staple length 3.67 in
fiber
diameter 25.5 microns
litter
size 1.85 lambs
EPDs were calculated for a total of 8,259 animals, including 2,420
breeding ewes and 448 sires.
As for last year, EPDs are listed for weaning weight, maternal
milk, and milk plus growth at both 60- and 120-day weaning ages. EPDs based on 60- or 120-d weaning are very
similar, providing essentially the same information about preweaning growth
potential. Fleece weight, staple
length, and fiber diameter EPDs were calculated for all animals, but will be
very close to zero for the flocks that do not report fleece data.
Breeders who
have already decided which of the EPDs they wish to concentrate on in their
flock may wish to delete extraneous columns from the EPD spreadsheet to better
focus on the traits that they find most useful.
The 2005 Columbia data were received at the genetic evaluation
center on September 20, 2006. The EPDs
were returned to the data coordinator on October 31, giving a processing time
of 41 days.
EPD Reports
Each Columbia breeder will again receive a single spreadsheet
containing animal identification and EPDs for all animals in the flock. Animals in the spreadsheet will be listed in
the following order:
·
Breeding ewes
·
Yearling ewes
·
Breeding rams
·
Yearling rams
2005 Columbia
Sire Summary
The 2005 NSIP Columbia Sire Summary is also now available for
distribution to breeders and other interested parties. In order to be eligible for the Sire Summary,
a ram must have a PE of less than 0.9 for 60-d weaning weight, less than 1.7
for 120-day weaning weight, less than 2.65 for 120-d postweaning weight, or
less than 1.15 for 60-day maternal milk.
The ram must also have a minimum of five offspring with weaning weight
records or a minimum of 10 daughters with litter size records. This year's Columbia sire summary contains
EPDs for 41 rams born after January 1, 1997.
Submitting Data
for the 2006 Lamb Crop
No major changes are
anticipated in submitting data for 2006.
Each NSIP Columbia breeder will receive a new preprinted data entry
spreadsheet for reporting data on the 2006 lamb crop. All active animals from the flock, including breeding ewes, ewe
lambs, breeding rams, and ram lambs will be listed in a single spreadsheet
arranged in sections corresponding to the different classes of animals.
Use of the preprinted spreadsheet is mandatory. Errors in animal identification (birth
dates, tags, registration numbers, parents) can be corrected as needed and
newly registered animals can have their registration numbers added. Newly purchased animals can be added at the
bottom of the spreadsheet with identification information and performance
records.
Genetic Trends
in the Columbia Breed
Genetic trends in EPDs are shown below, and document the traits
that have received emphasis in NSIP Columbia flocks. Each point represents the average EPD of all animals born in each
year. Estimates of genetic trends
before 1990 were highly variable because of limited numbers of observations,
with less than 30 observations per year before 1990 compared to averages of 385
observations per year between 1990 and 1999 and over 450 observations per year
between 2000 and 2004. Changes in
performance since 1990 have been more consistent, with modest, but significant,
positive changes in weaning weight, maternal milk, milk + growth, 120-day
postweaning weight, and staple length and a significant decline in fiber
diameter. Percent lamb crop and fleece
weight changed little over the period.
Apparent declines in EPDs for maternal milk, milk + growth, percent lamb
crop, fleece weight, and staple length in 2005 lambs merit monitoring in the
future, but may be artifacts of the reduced number of participating flocks and
the very limited amount of wool data reported for the 2005 lamb crop.
Figure 1. Genetic Trends for Weaning Traits in NSIP
Columbia Flocks
Figure 2. Genetic Trends for Postweaning Weight and Percent Lamb Crop
In NSIP Columbia Flocks
Figure 3. Genetic Trends for Fleece Traits in NSIP
Columbia Flocks
