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US Genetic Evaluation Changes: Are You Keeping Up?

Tuesday, October 21st, 2014

There is an old saying about “Keeping up with the Joneses”. The term is often attached to things that happen in high society, but it can also be attached to the purchase of material things. Three decades ago it was installing a home swimming pool. Ten to fifteen years ago it was making sure that your children were introduced to the use of a computer. Recently it has been joining Facebook? Well, dairy cattle breeding is not exempt from change. Today The Bullvine wishes to overview and provide some comments about keeping up with the changes in genetic indexes for December 2014 recently announced by the Council On Dairy Cattle Breeding (CDCB). For readers interested in exact details, they can go to https://www.cdcb.us/New/News.htm.

Weekly Genomic Evaluations

The first thing to take note of is that genomic indexes will be available every Tuesday (8 am Eastern Time) for animals that have had their analysis completed in the past week. These weekly released indexes will be approximate as they will not be a full run of the evaluation system. Then once a month the full evaluation will be done and released on the first Tuesday of the month. Some breeders will ask ‘Why do an approximation? Just release the results monthly’. There are two reasons for this move: 1) The work flow at the analysis lab can be evened out throughout the month; and 2) Breeders can select, sell or cull animals (or embryos) earlier thereby minimizing the expense of raising calves.

Be Clear About the Release Date

For buyers, using genomic evaluation results, it will be important that they ask for the date of release of the results. It is entirely likely that this change to weekly genomic releases will create confusion until breeders are aware that weekly releases are approximations and until CDCB irons out any wrinkles there may be at the start. As well buyers interested in knowing how close to the top of an elite list that an animal is will need to do extra checking. I think we all knew that in time there would be more and more frequent reporting of animal’s genetic indexes. Dairy cattle breeding is faster every year that’s what happens when genetic advancement is rapid. Breeders need to make sure that they ask if an animal tops the list at the time of the official releases in Dec, April or August, or at the time of the nine other monthly releases, or on a weekly release. Make sure you ask for the release date.

Base Roll

Every five years the base to which all animals are compared is updated. In December, the base will change to all cows born in 2010 from all cows born in 2005. On the CDCB website, the changes for all traits and all breeds are listed. Table 1 lists are some of the changes in indexes breeders can expect for Holsteins and Jerseys both of which have made significant genetic improvement from 2005 to 2010.

Table 1 – Index Changes That Will Occur in December 2014

	Holstein	Jersey
Net Merit $	-184	-124
Protein (lbs)	-12	-12
Fat (lbs)	-17	-19
Milk (lbs)	-382	-327
Productive Life (months)	-1	-0.8
SCS	0.07	-0.04
DPR	-0.2	0
CE	0.4	n/a
DCE	1.6	n/a
UDC	-0.92	-0.33
FLC	-0.78	-0.15
BDC	-0.61	-0.15
Final Score	-0.99	-0.53

Breeders can expect that bulls and cows will have their genetic indexes lowered. The relative rank of animals, of course, will not change. All animals will be affected to the same degree. Bulls that were $700 NM will now be $516 NM. A base change time is an excellent time for breeders to re-evaluate the minimum values they will require bulls or replacement females to meet.

NM$ Index

Based on the up-to-date facts on genetic merit of the USA dairy populations and the economics of dairy farming in the USA, researchers at USDA-AIPL have fine-tuned the Net Merit index formula. Table 2 provides a comparison of the traits included and their weights for the formula used from 2010 to 2014 and the new formula for 2015.

Table 2 – Traits and Weights * in NM$

	2010	2015**
Milk	0	-1
Fat	19	22
Protein	16	20
PL	22	19
SCS	-10	-7
UDC	7	8
FLC	4	3
BDC	-6	-5
DPR	11	7
CCR	0	2
HCR	0	1
CA$	5	5

* A negative value indicates that a higher rated animal impacts negatively on NM$
** Indexes that will be issued on December 02, 2014

The changes may not seem major, but it should be noted that the emphasis on production traits are increasing from 35% to 43%. This is similar to the change in emphasis that will occur in TPI in December (link to MSH’s article on changes for TPI). Breeders can expect that there will be re-ranking of bulls for NM$ especially for bulls that either excel or are below average for their production traits indexes. Animals that excelled for SCS, PL and DPR, can be expected to fall back relative to other animals in the breeding population. Breeders should take time to go through the new rankings in December before ordering semen, purchasing embryos or replacement females.

A New Grazing Index

Based on breeder requests, CDCB will be producing a fourth total merit index called Grazing Merit (GM$). The three previous total merit indexes, Net, Cheese and Fluid will remain in place. GM$ will take into account the needs of grazing herds and reflect the need in those herds for high fertility and seasonal calving cycles. With the move, in some regions or countries, to have the cows harvest their own forage and the production of milk during the growing season, this index is sure to get serious consideration.

Fertility Indexes

As noted in Table 2 heifer and cow conception rate genetic indexes are now included in the NM$ formula. The rationale is, of course that a conception must take place before there is a pregnancy. Fertility will no longer be solely DPR. As well the methodology for determining DPR will change with more information incorporated into the calculation. Breeders can expect that for some sires, there may be changes in their DPR as the correlation between the previous and the December DPR proofs is only 0.97.

New Genetic Evaluation Software

The new software has been used for calculating all fertility indexes since December 2013. This change in software will not be as obvious to breeders. The software in use previously was implemented in 1989. Since then, computational strategies and methodologies have been significantly enhanced. Extensive comparisons have shown that, for the daughter proven sires, the correlation between the evaluation results for the new and old software is 0.995. That is very high. However for cows and genomically and parent average evaluated animals, there may be some changes due to a software change.

Sign Up to Learn More

Holstein USA wants all breeders, regardless of which breeds they have in their herd, to have the latest details before December 02. They will be doing that by hosting a webinar on November 13 at 1 pm Eastern Time. Details on the webinar can be found by going to http://www.holsteinusa.com and on the home page will be found a link to the webinar. Click on the link – people wishing to participate in the webinar will need to register. Interested people should register early.

The Bullvine Bottom Line

It is recommended that breeders take the time after the indexes are released on December 02 to go through the official listings with the goal of objectively selecting the animals, especially sires, which best meet their breeding plan. (Read more: What’s the plan?). We say objectively because it could well be that a sire you were using this fall no longer ranks high enough for you to continue to use him. However, it is not only sires that we must be objective about. Some previously high donor females may also drop. However, there will also be animals that go up in their rank position in their breed.

Even though our first reaction may be to say that the new index is wrong, we must remember that the researchers have worked hard to bring the industry more accurate information so dairy breeders can continue to move their herds forward genetically — as rapidly as possible! Making it possible to keep up with the Joneses!!