Coopworths
No 1 FLOCK

ESTABLISHMENT

In the late 1950's the Coopworth sheep was developed by Prof. Ian Coop because of reluctance by traditional breed societies to recognise the importance of selection based on performance to improve profitability of sheep farming and because of difficulty in maintaining sources of first cross ewes in sheep systems at that time. In 1958-60 Border Leicester rams were mated to Romney ewes and from 1960 interbreeding of Border Leicester x Romney ewes and rams commenced. This formed the basis the Lincoln University (then Lincoln College) registered Coopworth flock.

ROLE IN COOPWORTH BREED

Lincoln's flock is number one in the Coopworth flock book, and during the establishment of the breed has been regarded as the leading flock technically. It is the one of the three flocks regarded as foundation flocks of the breed.

Breeding History Important events genetically in the flock's history are:

1958 -60	Crossbreeding Border Leicester x Romney
1960	Interbreeding began
1984,1985	20 industry and 20 Lincoln-bred rams used to test genetic sources
1986	Selection lines established.
2001 - Present	Control line maintained. Intensive selection based on SIL DPO Index to allow genetic evaluation of selection responses

PEDIGREE AND PERFORMANCE RECORDING

Following the initial matings the Lincoln Coopworth flock was and still is fully recorded for pedigree, reproductive rate, weaning weights, hogget live weights and hogget fleece weights. Performance records are available for thousands of animals from 1960 till the present day.

In more recent times additional objective information has been recorded, analysed and used in the selection of Sires and replacement female stock. This additional information has included muscle and fat depths, CAT SCAN measurements, fleece micron, fleece yield, fleece colour.

SELECTION OBJECTIVES

Until 1986 the flock was selected to improve the following characters simultaneously:

— number of lambs born

— survival

— fleece weight

— fleece quality

— weaning weight

— hogget liveweight

In 1986 the flock comprised about 1000 breeding ewes. These were allocated to four lines, control (12.5%) lean tissue growth (25%) fleece weight (25%) production index (37.5%).

Each line had the following objectives:

Control

This line is closed to outside animals and has the aim of not changing genetically, ie. genetically it is the same as in 1986. Divergence in performance between this line and other (selected) lines represents genetic change in the selected line. It has the same age structure as the other flocks and replacement rams and ewes are selected based on their production index values post-weaning. The mean value of males and females selected is 0, and their standard deviation equals that of the unselected control population each year.

Lean Tissue Growth

This line was closed and was selected to improve rates of lean growth. Measurements of liveweight, muscle and fat depth were combined into a selection index . At any liveweight, selected animals are expected to be heavier with less fat and more muscle; at any given age.

Fleece Weight

This line is closed and is selected to improve fleece weight.

Selection was based on high animal performance for hogget fleece production. Ram fleeces are measured for percent clean yield, clean fleece weight is calculated, and selection based on clean weight. Replacement ewe selection was also based on clean fleece weight.

Production Index

This line uses two reference rams from NZOSR each year and 6 'home-bred' 19 month rams (one son from each of 6 highest-performing sire groups).

The aim of this line was to be representative of industry with regard to 'selection procedures'. Rate of genetic gain in fleece weight when incorporated in a production index could be compared with that in the fleece weight line (single trait selection). Similarly rate of genetic gain in growth rate could be compared with that in the lean growth rate line in which growth rate is expected to be a major component of improvement.

Traits incorporated in the production index (and the criteria of breeding value prediction) are:

— Number of lambs born

— Weaning weight

— Hogget weight

— Hogget fleece weight

The breeding values of the individual traits are combined into an index using rev's determined by the New Zealand Coopworth Sheep Society.

ANALYSIS OF GENETIC VALUE IN COOPWORTH FLOCK

In 1996 Phil Beatson estimated genetic values in the flock for animals born 1979-94, These analyses fitted sophisticated models using REML and BLUP routines and papers describing parameter estimates and genetic trend are published (authors Beatson and Lewis). '

— for each trait, the lines were of very similar genetic value in 1986 (i.e. base populations for the selection lines were very similar).

— the expected genetic value (estimated breeding values) in the control line have not changed markedly for the traits.

— selection has seen the selection lines diverge from the control for the respective traits.

— there has been a correlated response in hogget liveweight when selection has been for improved fleece weight, but not in fleece weight when selection for improved lean tissue caused an increase in hogget liveweight.

— there has been nearly linear response to selection with no obvious 'screening' effect.

THE IMPORTANCE OF THE LINCOLN COOPWORTH FLOCK

We believe that this flock is an internationally unique and valuable genetic resource.

— the flock is recorded since 1958.

— the background of each of the four selection lines is identical due to the method of line establishment.

— genetic diversity between the four selection lines was due to selection rather than initial screening responses, or initial differences in genotype.

— the lean tissue growth and fleece weight lines will provide important information for direct and correlated responses to selection.

— the production index line is representative of industry flocks as it is referenced.

— responses for single trait versus production index selection can be quantified for fleece weight.

— responses in lean tissue growth and its components in the lean growth line can be compared to those in the production index line.

— the control line has not changed for the traits analysed in sophisticated analysis models.

— future full comparisons of performance levels in control hoggets vs selection line hoggets will allow quantification of the expected genetic change predicted by these genetic models.

— the control line controls not only the Lincoln selection lines, but all flocks in the NZ Ovine Sire Reference due to the production index line being referenced.

CURRENT STATUS OF THE LINCOLN COOPWORTH FLOCK

The Lincoln Coopworth flock currently comprises 380 registered ewes (60 in control line). The remaining 320 ewes have been selected based on the SIL Dual Purpose Overall Index following the conclusion of the selection line program (15 years duration 1986-2001).

Reference rams from NZOSR and APEX have been used in the 2002 mating.

All Ram and Ewe hoggets are carried through to post hogget shearing to allow the collection of complete data sets for valid genetic analysis through Sheep Improvement Ltd (SIL)

The current policy is to continue to maintain the control line as this line not only controls the Lincoln flock but all flocks that are linked by sire referencing to the Lincoln flock. We believe this control flock while costly to maintain is an internationally unique and valuable genetic resource.

The remainder of the flock will be selected on the SIL Dual Purpose Overall Index with little or no account taken of family lines. This will demonstrate to the industry the genetic gains possible and associated production increases.

Measure taken on all progeny include:

Reproductive Rate
Survival
Weaning Weight
Hogget Liveweight
Hogget Fleece Weight
Fleece micron
Ultrasonic Muscle Depth
Ultrasonic Fat Depth
CAT Scan measurements (muscle, fat, bone ratios)
Genetic Trends Graphs

PURCHASE OF RAMS

Availability

There are currently 120 two-tooth Coopworth for sale for the 2004 mating. These rams are all well above average for individual traits or for overall production, and have been selected for sale from the top 25% of ram lambs born in 2002

There are currently confirmed orders for 75 of these rams across all price brackets.

The fertility index (no lambs scanned 212% / ave ewe mating wt 62.5kg) of the University Coopworth flock in 2003 was 3.39

The rams this season are in exceptional order and having recently attended some sheep sales early indications locally and nationally suggest a strong demand for quality Coopworth rams this year.

The University Coopworth flock is based at the Ashley Dene property (355ha) which is situated some 10 kilometres from the main University campus. If you wish to, you are invited, at the time of your visit, to have a tour of the Ashley Dene property and view other livestock and research programmes currently being undertaken.

We continue to be extremely confident in the fact that the genetics of the Lincoln flock have continued to improve. In an across flock analysis, generated through the Sheep Improvement Ltd (SIL) system, for NZOSR in December 2001, this analysis contained 20 flocks and 447 proven sires involved in the NZOSR Sire Reference scheme. Lincoln had six of the top seven sires.

The short list of rams to be selected as reference rams for the 2003 mating season, using the SIL across flock analysis, included five Lincoln bred rams.

COMMERCIAL FARMERS BUYING LINCOLN RAMS CAN TAP INTO THIS GENETIC POTENTIAL AT NO ADDITIONAL COST TO THE NORMAL RAM PRICE.

NO ADDITIONAL COST - ALL PROFIT

Ram Price Structure for 2008/2009

Top 5% based on DPO Index	$650
Next 25% based on DPO Index	$550
Next 50% based on DPO Index	$450
Next 20% based on DPO Index	$350

CONTACTS

For further information, queries or personnal assistance please contact:

Chris Logan                                                             Colin Pettigrew
C/- Animal Science                                                 Manager Ashley Dene
P.O Box 84                                                               R.D 5
Lincoln University                                                  Christchurch

Ph: (03) 325-3838 extn 8620 Ph: (03) 329-5582
Ah: (03) 347-3042 Mobile: (027) 287-7173
Fax: (03) 325-3618
Mobile: (027) 604-8450

e-mail: logan@lincoln.ac.nz email: pettigrc@lincoln.ac.nz