The 2005 Romney lambing and weaning data were received at the genetic evaluation center on September 17, 2005.  EPD's were returned to the data coordinator on October 17, giving a processing time that was consistent with our target turn-around time of 37 days.   

EPD Reports

Each Romney breeder will receive a spreadsheet containing EPDs for all animals in the flock.  Animals in the spreadsheet will be listed in the following order: 

·         Breeding ewes

·         Ewe lambs

·         Breeding rams

·         Ram lambs

 The listing should contain all breeding animals listed on the preprinted data entry spreadsheet, and all surviving lambs from the current lamb crop. Animals that were culled or died will be identified; EPDs will be provided for these animals, but they will not appear on next year's spreadsheet.

The EPDs reported for each flock are shown below. 

 

1. The 60-Day Weaning Weight EPD provides an estimate of preweaning growth potential.

 

2. The Maternal Milk EPD provides an indication of the genetic merit for mothering ability.  This EPD

primarily reflects genetic differences in ewe milk production potential as realized in her lambs. 

The maternal milk EPD is thus expressed in pounds of lamb weaned, not pounds of milk

produced.  It is derived by evaluating if individual ewes produce lambs that do better or worse

than expected based on the weaning weight EPDs of the parents.  Ewes whose lambs grow faster

to weaning than predicted are assumed to be better milk producers whereas ewes whose lambs

grow more slowly than predicted to weaning are assumed to produce less milk.  This relationship

between maternal milk EPD and actual milk production has been validated in beef cattle and is

assumed to be similar in sheep, although other elements of maternal behavior may also be

included in the maternal milk EPD.  Selection for high maternal milk EPDs is anticipated to

improve milk production and mothering ability in the flock.

 

3. The Milk plus Growth EPD combines information on weaning weight and maternal milk EPDs to provide an index of the total anticipated contribution of an animal's daughters to lamb weaning weight.  The milk plus growth EPD is calculated as the sum of the maternal milk EPD plus one half the weaning weight EPD.  It recognizes that the genetic contribution of a ewe to the weaning     weight of her lambs combines the effects of her milk production (measured by the maternal milk EPD) and a sample one half of her genes for preweaning growth potential (measured by the weaning weight EPD).  Because the milk plus growth EPD is calculated from two other EPDs, an accuracy value is not reported for this EPD.

 

4. The Fleece Weight EPD provides an estimate of the animal's genetic potential for wool production.  It is based primarily on yearling wool production, although some records on older animals have also been used to derive the fleece weight EPD.

 

5.  The Number Born, or Percent Lamb Crop, EPD evaluates genetic potential for prolificacy.  This EPD is expressed as numbers of lambs born per 100 ewes lambing.  An EPD of +5.0 for percent lamb crop thus indicates that an animal is expected to produce daughters who will have an average of .05 more lambs at each lambing, or 5.0 more lambs per 100 lambings, than an average ewe.  Selection on percent lamb crop EPD is expected to increase prolificacy in the flock.

 

Note that calculation of the 60-day weaning weight EPD requires that animals be weighted at between 30 and 90 days of age, and NSIP strongly recommends that this age window be further narrowed to between 45 and 90 days of age.  Even if lambs are not weaned until later, breeders are encouraged to take a preweaning weight at around 60 days and to report this weight.   Remember, up to three weights can be reported for each animal, so it will still be easy to report later weaning or postweaning weighs.

 

For this year, fleece weight was the only wool trait evaluated.  NSIP has the capability to also process fiber diameter and staple length records, but the number of records reported for these traits was too small to permit calculation of EPDs.  NSIP will be glad to work with participating Romney breeders to identify the wool traits of importance to the breed and to incorporate these wool traits into the EPD system.

 

Each EPD is accompanied by a "prediction error" to indicate the accuracy of the EPD.  A detailed discussion of the properties and use of the prediction error will be provided in a separate document.  

 

 Submitting Data for the 2006 Lamb Crop

 Later this year, each NSIP Romney breeder will receive a new, preprinted data entry spreadsheet for reporting data from the 2006 lamb crop.  All active animals in each flock, including breeding ewes, ewe lambs, breeding rams, and ram lambs will be listed in a single spreadsheet.  The spreadsheet will be arranged in sections corresponding to the different classes of animals.

 

Use of the preprinted spreadsheet to report data is mandatory.  Errors in animal identification (birth dates, tags, registration numbers, parents) can be corrected as needed, missing data can be added, and newly registered animals can have their registration numbers reported.  The objective is to avoid recopying animal identification information from year to year.  In this way, we will know that reported changes in animal identification information do represent corrections made by the producers.  Newly purchased animals can be added at the bottom of the spreadsheet with identification information and performance records.  There is still substantial missing pedigree information on the spreadsheets.  It is critical that missing registration numbers and birth dates be added whenever possible.

 

The preprinted data entry spreadsheet for next year will be divided into the following four sections.

 

Section 1:  Breeding Ewes.  The breeding ewe section will include all active, adult ewes.  An active, adult ewe is defined as a ewe that appeared on the 2005 data entry spreadsheet and was not identified on that spreadsheet as having been culled or having died.  This section should include the complete adult ewe inventory for the flock on the date you submitted your records for the 2005 lamb crop.

 

Section 2: Ewe Lambs.  This section will include all ewe lambs from the 2005 data entry spreadsheet that were not listed as sold or died on that spreadsheet.  This section should thus include all your replacement ewe lambs from 2005 as well as ewe lambs that had not yet been marketed at the time you submitted your records.  It is important that you report accurate disposal codes for these ewe lambs.  First, it will ensure that ewe lambs that have died or been sold are removed from inventory.  Second, it will allow us to add your replacement ewe lambs to your active breeding ewe inventory. Also, it is important that you take this opportunity to update registration information on ewe lambs, including both those you kept and those you sold for breeding.  Many of the 2005 lambs were not yet registered when their records were sent to NSIP.  Registration information is critical to the across-flock analysis, both to provide accurate animal identification within flocks and to document the genetic ties between flocks that are necessary for the across-flock analysis.  Therefore be sure to always add new registration information to the data entry spreadsheets. 

 

Section 3: Breeding Rams.  This section will list all rams on your inventory that produced lambs in the 2005 data or that had daughters in your active breeding flock.

 

The identification of “active” rams is more difficult than the identification of active ewes.  We require that all rams used to produce lambs on your farm be placed on your inventory, but in some cases (borrowed or leased rams, AI) that ram may not be physically located on your farm.  If you remove him from inventory, you will no longer get EPDs for that ram on your flock EPD reports.  So we have instituted the following guideline for defining an “active” breeding ram.  If you want to continue to have EPDs listed for a given ram, even if he is not physically located on you farm, leave him as an active breeding animal (that is, do not enter a disposal code) on the data entry spreadsheet.  If, at some point in the future, you are no longer interested in getting EPDs on a ram, then insert a disposal code and he will no longer appear on your flock EPD list.  The 2006 data entry spreadsheet will likely contain several rams that you no longer care about, and may have some rams missing that you do want EPDs on.  So next year, be sure to add missing rams to inventory, and put in a disposal code for rams that you no longer care about.

 

Section 4: Ram Lambs.  This section will include all ram lambs from the 2005 data entry spreadsheet that were not listed as sold or died on that spreadsheet.  This section should thus include all your replacement ram lambs from the 2005 lamb crop as well as ram lambs that had not yet been marketed at the time you reported records on the 2005 lamb crop.  As for the ewe lambs, it is important that you report accurate disposal codes and update registration information for these ram lambs.  As for the breeding rams, if you want to continue to see EPDs on a ram lamb that you sold or own in partnership, just leave him as active on the spreadsheet.