August Holstein Association USA Indexing Revisions – Will these changes to TPI do it for dairy breeders?


When The Bullvine reviewed the recently announced HAUSA decision to revise their UDC, FLC and TPI genetic indexes, we decided to do go beyond simply reporting the changes that will be made in August to the formulae. The critical matter for Holstein breeders will be whether the new information will assist breeders in achieving their breeding objectives. The usefulness of the changes will apply to breeders around the world as HAUSA indexes are used, or at least known, in all major Holstein breeding countries.

Successful dairy breeders only use genetic indexes to the extent that they find them effective in breeding productive, profitable dairy cattle. Sometimes they wonder if breed association hear their questions, positions, and concerns about the accuracy of the indexes. Well, the good news is that the Genetic Advancement Committee (GAC) and research staff of Holstein Association USA (HAUSA) heard and worked on why udder composite (UDC) and feet and leg composite (FLC) genetic indexes for sires are so closely tied to a sire’s stature index.

Studied and Revised UDC and FLC

In a perfect world, every body part would be evaluated independently and then a final assessment would be arrived at for an animal’s conformation compared to our idealized view of a cow’s conformation. However, classifiers, just like all the rest of us cattle breeders and judges, let an animal’s outstanding or most limiting body feature unduly influence the decision made on other parts. This has been found to be true for both udder composite and feet and leg composite. Tall cows get over evaluated and short cows get under evaluated for UDC and FLC.

Breeders have been noticing this some time. It comes to the forefront now because many trend setting lifetime profit focused breeders have publicly stated they are breeding for decreased stature. They have found udders and legs on their desired shorter cows are being under indexed.

In studying this situation, HAUSA found that this was a relevant concern. As a result, an adjustment (+ or -) will be made to UDC and FLC for the stature of a bull’s daughters. The adjustment is a straightforward addition for short and a subtraction for tall. Of course, it will take a while for breeders to assess if these changes improve the accuracy of UDC and FLC.

Revised Formulae

UDC =  – 0.03 + [ .16 x FU + .23 x RUH + .19 x RUW + .08 x UDC + .20 x UD + .04 x FTP + .05 x RTP(optimum) +.05 x TL (optimum) – .20 x Stature ]  x 1.16

FLC =  0.02 + [ .09 x Foot Angle + .21 x Rear Legs Rear View + .70 x Feet & Leg Score – .20 x Stature ] x 1.09

Stature receives 16.7% of the weighting in both UDC and FLC. A surprising significant percentage.

What about Decreasing the Stature of Holsteins

As an aside but also somewhat related note, many leading breeders focused on high yield, high fertility, high health and long-lived cows are advertising bulls and heifers with negative stature numbers. When reading stature numbers remember that a zero animal will not genetically decrease stature. It will likely take a bull below -0.50 to -1.00 to result in progeny with less stature. A quick study of the current top twenty TPI daughter proven sires shows that they, on average, are +1.03 for stature. Therefore, using the top TPI sires does not decrease stature.

For the new TPI, which we will cover in the next section of this article, the top twenty proven TPI sires (using their April ’17 proofs) average +0.55 for stature.  The result of this proactive move by HAUSA is fewer top sires with higher stature indexes. For more on stature read the following Bullvine articles (Read more: Does Size Matter?, Are Today’s Holstein Cows Too Tall? and 15 Strength Sires That Will Still Fit In Your Stalls.

A question that one of my associates, an animal science researcher, recently asked was “Do we still need to measure stature in Holsteins?”. That is an excellent question given that most breeders are of the opinion that Holsteins do not need to increase in stature and that stature can bias the assessment for other traits. The latest correlations between stature and productive life and milk, fat and protein yields are in the range 0.04 to 0.13. So, is measuring stature helping or hindering in the breeding of better Holsteins?

Changes to TPI

It was two years ago (2015) that HAUSA last made changes to the TPI formula. Given the rapid pace of breed improvement, the increased number of traits evaluated, the decreased generation intervals and the more emphasis on health and fertility traits, changes in the TPI formula is an ongoing necessity.

The 2017 TPI formula will have some traits emphasis changes (see table 1). And beyond the changes that will be made in UDC and FLC, FE (feed efficiency) will have a revised formula that looks at body size differently than in the past and LIV (livability of cows generated by CDCB) will be added.

Table 1 – Trait Emphasis in TPI Formula

Trait 2015 2017
                 (%)               (%)
Milk Yield 0 0
Fat Yield 16 17
Protein Yield 27 21
FE (Feed Efficiency) 3 8
PTAT 8 8
Dairy Form -1 -1
Udder Composite  11 11
Feet & Leg Comp. 6 6
PL 7 4
LIV 0 3
SCS -5 -5
FI (Fertility Index) 13 13
DCE -2 -2
DSB -1 -1
Summary    
Production 46 46
Conformation 26 26
Health, Fert., Longevity 28 28

Note: Major changes are the increased emphasis on FE in place of protein and the addition of LIV

The inclusion of LIV in TPI is a good addition. The FE index was first published by HAUSA a couple of years ago and is based on opinion not science based research. However, breeders can expect, within the year, to be reading more from the international scientific study on the genetics ability of a sire’s daughter for feed efficiency.

HAUSA Revised Formula

FE  =  – 0.0187 x Milk Yield  +  1.28 x Fat Yield  +  1.95 x Protein Yield  –  12.4 x Body Weight Composite

Breeders using TPI must always remember that a constant value of 2187 is added to the values calculated in the TPI formula. In other words, if an animal has a TPI number below 2187 then that animal is below breed average.

Table 2 – Averages and Standard Deviations for Production Traits (Bulls) 

Trait Active A.I. Proven Genomic Evaluated
  Average Proof STD DEV Average index STD DEV
Milk Yield 717 (+/-) 772 1125 (+/-) 638
Fat Yield 33 (+/-) 29 59 (+/-) 22
Protein Yield 26 (+/-) 21 43 (+/-) 16

Explanation – Of active A.I. proven sires 66% are between -55 and 1489 lbs of milk and 95% are between -827 and 2261 lbs of milk
Data Source – CDCB

Table 3 – Average STA* of Available US Holstein Bull Population (April ’17)

Trait Average Direction
Stature 1.09     Tall
Strength 0.62     Strong
Body Depth 0.56     Deep
Dairy Form 1     Open
Rump Angle** 0.06     Sloped
Rump Width 0.82     Wide
RLSV** 0.22     Curved
RLRV 1.17     Straight
Foot Angle 1.19     Steep
F & L Score 1.26     High
FU Attach 1.81     Strong
RU Height 2.31     High
RU Width 2.13     Wide
Udder Cleft 1.01     Strong
Udder Depth 1.4     Shallow
F Teat Place 0.83     Close
R Teat Place 0.79      Close
Teat Length*** 0.29     Short
Udder Composite 1.49     High
F&L Composite 1.15     High

* STA – standard transmitting abilities
** Trait optimum scored from one extreme to other extreme
*** Trait does not have a wide variation in Holsteins
Data Source – Holstein Association USA

Top TPI Bulls – Much Change?

Of course, with a new TPI formula there will be some change in which bulls make the top listings.  However, overall, do not expect to see major changes to bull TPI’s. The top twenty current proven TPI sires increase 14 TPI points from their April ’17 TPI’s using the TPI formula to be implemented in August. This is not much change, considering that these sires range from 2517 to 2761 in TPI

Bulls with high-fat yield, high LIV and moderate size will gain. Bulls leaving tall, large framed daughters with low LIV will drop down the TPI ranking list. Remember this latter group will have their UDC and FLC reduced by the new formulae for those traits.

Although Robust is no longer producing semen and has not appeared on the active proven sire list for a while now, he would rank 20th for all sires that are 85% REL or higher on the new TPI. Gaining even more will be his son, Cabriolet, a sire that has good numbers for PL, LIV, FI and for stature is -1.20 and for strength is -1.02. These are traits that commercial dairy farmers are saying are important to them. Other bulls increasing in TPI because of the new formula include: Monty, Racket, Altacr, Tetris, and Donatello.

Points Not to be Overlooked

Sire selection is extremely important with respect to herd improvement. In herds not using ET and sexed semen, sire selection counts for 90% of herd improvement.

Some points not to be overlooked when it comes to sire selection include:

  • TPI places considerable emphasis on breed ideal type but not necessarily on the most functional conformation especially as it relates to frame, stature, strength in young first calvers, up-hill-run and depth of body.
  • Breeders should have a genetic improvement plan for their herd or for portions of their herd. (Read more: Flukes and Pukes – What Happens When You Don’t Have a Plan, What’s the plan? and Pick The Right Bull – Your Future Depends on The Decisions You Make Today!) With sexed semen, heavy use of genomic sires and majority of the flushing being done of heifers, it is important for breeding plans to be visionary and dynamic.
  • For more on what selection index best suits individual breeder’s need go to (Read more: Everything You Need To Know About TPI and LPI and TPI™ and LPI – Marketing or Mating tools?)
  • For many breeders, it may be more beneficial to use the genetic indexes on descriptive traits instead of UDC and FLC. Traits like udder depth and rear legs rear view have higher correlations with productive life than UDC and FLC have.
  • It is possible that HAUSA’s actions in addressing the ever-increasing stature of the breed may be too little and too late.
  • The TPI formula does not include other soon to be important traits: Beta Caesin; Kappa Caesin; inbreeding; polled; gestation length; and fitness / wellness (Read more: 12 Things You Need to Know About A2 Milk, Breeding for Kappa Casein to Increase Cheese Yield, The Truth about Inbreeding, Is Polled Worth It?, Gestation Length: In-depth Review and The Complete Guide to Understanding Zoetis’ New Wellness Traits – CLARIFIDE® Plus)
  • HAUSA needs to be researching how to include these and other traits in order for TPI to remain relevant in the future. With the emphasis on protein yield exceeding the emphasis on fat yield, TPI may be assisting with cheese yield but not with the excess of milk powder on the world scene which leads to lower farm gate milk prices.
  • With many breeding companies generating total merit indexes and with many breeders having their own customized total genetic merit indexes, the universal TPI index may not survive.
  • TPI is a relative trait emphasis formula. However new total merit indexes are using outcome formula based results instead of relative emphasis formula. CDN’s Pro$ index is an outcome based index.
  • Always remember that TPI is a relative animal genetic merit ranking system. Mating a top TPI sire to a top TPI dam will not necessarily get a breeder a top TPI progeny. Breeders need to use corrective mating to have the possibility of an improved progeny. This means that the values for the traits in TPI must be considered.
  • Breeders should not get caught up in the marketing hype of indexes like TPI when buying semen and embryos.
  • For fast genetic improvement for a trait, use sires that are, at least, one standard deviation above average for that trait. Tables 2 and 3 contain the standardized measures for some traits.

The Bullvine Bottom Line

Will these changes to TPI do it for dairy breeders? The changes are not major and time will tell if they have an impact on Holstein breeding. Holstein breeders using TPI need to delve deeper than the TPI number. TPI is however, useful as a first sort of sire lists.

For The Bullvine – “The HAUSA August index changes are an attempt to maintain relevance to Holstein breeders’ needs”.  It is clear that 95%, maybe even 99%, of tomorrow’s breeders will not be selling breeding stock and will only be buying semen and/or embryos. Therefore, the marketing aspects of TPI will not matter to them.

Much more needs to be studied and implemented by HAUSA, when it comes to its animal genetic ranking systems including the TPI formula. Breed improvement committees and those responsible for sire selection will need to base their decisions on a combination of what science and field data show them as what will be best for genetic advancement.

 

 

 

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