The Dulverton Value Determing Trait Index, The Traits, The Weightings The Outcomes

Author Stephanie ChappellPosted on Comments [ 0 ]

PREAMBLE

Dulverton has elected to engage The Igenity Beef Profile to assist select for Genetic superiority amongst the traits considered all important in determining VALUE, Value across a range of Beef production systems. Four of these traits Stayability (Stay), Carcass Marbling (Marb), Residual Feed Intake (RFI) and Tenderness (TDR) aren’t adequately evaluated by Breedplan. Two of the major profit drivers for beef production systems are Stay and RFI. The Angus Breed has plenty of work to do to improve that breeds performance for these two major PROFIT drivers.

DEFINITIONS

Stayability (Stay): The chance a heifer will remain in the herd as a productive cow unit until at least six (6) years of age. The higher Igenity score will indicate a greater percentage increase in Stay. Please recognise Stay is a complex maternal trait and is influenced by a number of factors and interrelated traits e.g. environment, fertility, calving ease, temperament, structural soundness. Improving Stay should hopefully assist Dulverton Bulls Stay longer in the herds of valued clients.

Residual Feed Intake (RFI): An indicator of Feed Efficiency. It is the difference in animal’s daily consumption of feed to achieve the same level of gain. Lower RFI equals greater feed efficiency.

Note the very poor relationship NFI-F with RFI. Dulverton has been selecting for NFI-F since the inclusion of the Trait into Breedplan and can boast quite adequate genetic performance for the trait, yet The Dulverton Performance for RFI, as is the case with the greater majority of Angus in the IGS/Igenity combined seven (7) Taurus Breed Database, is poor. It seems Feed Efficiency, a trait of paramount importance in improving Industry Profitability (Feeder cattle performance in Feedlots, Cow, Cow/calf performance at pasture), needs major attention. The Biology, to better understand the intricacies of feed efficiency needs closer scrutiny, as do the measurement procedures of this important complex biological phenomenon. It is impossible to assign genetic measures until the above have been undertaken. In the meantime Dulverton is committed to presenting both NFI-F and RFI data for the clients consideration.

The complete set of Traits used to compile The Dulverton Value Determining Traits Index include-:

  • CALVING EASE MATERNAL
  • STAYABILITY (STAY)
  • RESIDUAL FEED INTAKE
  • TENDERNESS EATING QUALITY   
  • MARBLING
  • RIB EYE AREA (REA) BEEF YIELD
  • CARCASS WEIGHT

Consider the following worked examples for two Calving Ease Maternal Bulls in the sale, Lot 1 U025 and Lot 71 U197. The Dulverton Team suggests both bulls are Calving Ease prospects, not only do they score well for CEM but they are also adequate for both BW and CED. LOT 1 U025 registers 4 for BW and 7 for CED while Lot 71 U197 scores 5 for BW and 8 for CED.

Value Determing Trait Index, worked examples

TRAITTRAIT WTRaw Scores U025Trait WeightedRaw Scores U197Trait Weighted
CEM10%7788
STAY25%615820
RFI15%6666
TENDER10%101077
Eating Quality MARB20%918918
REA5%73.563
Beef Yield CW15%812812
VALUE DETERMINING TRAIT INDEX71.574

USING THE VALUE DETERMINING INDEX (VDT Index)

Background

Genetic progress is neither an easy concept to grasp nor is it easy to make, genetic progress. Put simply the more traits included in the suite of traits being selected for then the slower the genetic progress for any one of the traits in the suite. Unfortunately beef production is more complicated than sitting down and identifying one trait to select for and going for it. Be aware Breedplan and IBP both record on in excess of fifteen traits and when an additional set of traits such as those involved with structural soundness are included the total suite of traits to be considered soon jumps to in excess of twenty.

Dulverton, has been conscious of the complexities involved with sorting the sets of genetic data available to Beef producers interested in purchasing herd improvers, for quite sometime now. To assist point commercial bull purchasers toward those bulls in the Dulverton draft that could suit their needs Dulverton has developed The Value Determining Index. The Index has taken into consideration the fact that there are a set of needs to be satisfied by a range of Industry Stakeholders when investigating dollar value. In addition Dulverton has been convinced “There is only one reason to produce Beef and that is to satisfy the Eating Quality expectations of The Consumer both consistently and Price Competitively”.

The VDT Index comprises-:

  • The On-Farm component, the traits being Calving Ease Maternal (CEM), Stayability (STAY), RFI (Feed Efficiency) and Carcass Weight, the On Farm implication being Genetic Growth. Note the importance of The Maternal components some of which aren’t all that highly heritable. Take fertility, a contributor to the complex trait STAY, as an example, fertility has a Heritability estimate of only about 10% implying genetic progress for the trait is slow. Optimum pregnancy check results are achieved by correct management of the environment (Leptospirosis, Vibriosis etc vaccinations, increasing plane of nutrition at time of joining etc), plus consideration of the genetic effect. While Fertility is lowly heritable Infertility is highly heritable so guarding against the likely causes for infertility are a must. For example potential sires with testicle measurements below 36cm, retaining and breeding females  who fail to conceive during the breeding season etc.
  • The Down Chain component, the traits being those contributing to Eating Quality eg Tenderness and Marbling, both moderately to highly heritable. Adequate expression of Tenderness implies a consideration for genetic Growth consider the concept of Ossification where optimum ossification is expressed by achieving even and adequate lifetime growth rates. The other Down Chain component is that of Beef Yield where the genetic contributors are identified as REA (muscling) and Carcass Weight. Carcass weight is again a genetic growth function.

The VDT Index, How it may help Select a Herd Improver

Dulverton is suggesting The VDT Index be used as a “Pointer”, a Tool to help identify a potential sire with herd improving capabilities. Consider the following procedure-:

  • Start by locating the set of Bulls in the Draft with a VDT Index of sixty (60) plus. The Dulverton goal is to present a catalogue of eighty (80) plus sires with VDT Indexes of sixty (60) plus. There are thirty seven (37) bulls with an Index of sixty (60) plus, not enough but this will change as Dulverton can apply more selection pressure on their females, especially for STAY and RFI.
  • Be sure to peruse the other traits included in the IBP Suite that maybe of interest, be satisfied they are adequate.
  • Investigate the GTS Structural Soundness data as provided by Dick Whale, not much point purchasing a Genetic Powerhouse should that individual be “unsound”.
  • Go look at the Bull be sure he satisfies the overall expectations
    Many may wish to reverse this “Order”, be happy with the bull first then be sure ‘The Profile” suites.
  • Most Bull purchasing personnel will be aware that combining Genetic superiority as described by platforms such as Breedplan, Igenity Beef Profile etc. with superior Structural soundness, is not easy. Take this Dulverton Draft for example, there are no fewer than fourteen (14) Grade 7’s and twenty two (22) Grade 6’s that are below sixty (60) for the VDT Index. Dulverton is keen for clients to consider these Structure improvers investigate what traits they perform at or above average for. It’s taken Dulverton forty three years to put together a catalogue with twenty three Grade 7’s in it, don’t “Throw the Baby out with the bath water”. 

There’s still a long, long way to go eh? Hang in there and together we will make genetic progress for the Traits that determine Value while maintaining and improving structural soundness. Dulverton will produce more like this fella D. Think Big T200, he scores 72 for the VDT Index including a 7 for STAY and a 5 for RFI, he is a Grade 6.

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