Many breeders who are pursuing high Genomic rank
matings for AI and embryo markets are starting to question the type and
physical proportions of many resulting heifers. The phenotype of heifers (and their full
brothers who often go into AI) seems to be like this:
Around
one third are too coarse (bully in front, narrow in rear) to milk well.
Another third are too frail (narrow throughout, very fine boned) to
compete.
That
leaves roughly one third that still look like a functional “dairy type” animal.
(Yet
we are assigning 50% Rel in Brown Swiss, 60% Rel in Jerseys, 70% Rel in
Holsteins to these calves)
In the beginnings of scientific
(mathematical) genetic evaluation, we compared a bull’s daughters to their
dams, to see if the bull could improve on his mates. The comparisons were made both for type and
for production. This approach resulted
in development of “mature equivalent” (ME) factors to recognize that a
young cow (first lactation bull daughter) was too immature to compete directly
with a matured cow (third or later lactation dam).
This was known as “intergenerational
comparison”—what changed from one generation to the next?
We still use intergenerational
concepts in qualitative analysis (aAa or DMS), to predict results from
possible mating choices.
But geneticists from early on
preferred to seek the genotype (genetic potential) over the phenotype
(realized result) believing that the phenotype was “too influenced by
environment”. Their first step was to
convert sire evaluation to “daughters versus herdmates”, still using ME
factors, and they called that result a “Predicted Difference” (PD). This is “intragenerational”
comparison—looking at all cows in the same generation, which logically led to
the concept of “parity” (only compare daughters of our bull against other cows
born the same season of the same year).
The next step was the inclusion of the
averages of the ancestors—first by “Pedigree Index” (1/2 sire PD plus ¼
maternal grandsire PD) which was assigned to both daughters and their
contemporaries, so any deviations could be put in a “genetic” [pedigree rank]
relevance. By the time the “Animal Model” is
inaugurated (pulling in Parent Averages for all animal pedigree relationships)
we called the result the “Predicted Transmitting Ability” (PTA) [actual deviation was only part of the
total weighted data].
The industry was quite aggressive in
promoting these indexes, which led to the composite ranking index ($Net
Merit, TPI, JPI in the USA, LPI in Canada, BW in New Zealand,
RWZ in Germany, etc). All
these indexes were designed to promote that nation’s genetics into any export
market they could reach.
Now we have Genomics which
looks at the DNA, but condenses the genotype to 64,000 “marker genes” that were
possessed in common by animals who ranked for any measured trait in the
historical reference list for each breed. Now all we need to have a “ranking” animal
currently is to find 7% or more of the markers in the DNA of your calf plus
the pedigree ancestors to reinforce the assumptions (60% DNA vs 40% pedigree)
to impute a high index. We no longer
“need” any progeny to get an elite ranking.
This might explain why there is so
much physical variation in the individual high-ranked bull or heifer.
You do not need a “complete” or
physically “balanced” physique to have the right “marker genes” to produce a
high Genomic ranking value. This is
reductionist theory taken to its most extreme point.
How to still breed good cows for your environment
Not all Genomic sires are “the same”. Some still actually have dams with scores
and completed lactations. Some
actually have multi generation maternal performance to give us confidence
beyond the mathematical assumptions.
And—as large expansion herdsmen are learning, type
is still important. Cows with a
defective physique still leave herds faster than cows who have good physical
adaptation to the environment. The only
issue with “type” is the basis on which you plan matings.
This heifer matured into a cow who made a lifetime
yield three times that of the average commercial dairy cow (which at last
count calves twice and milks less than 30 months).
She has the sharp shoulder and wide chest of the
“sturdy” dairy cow, the deep and well sprung rib of the “ruminant capacity”
dairy cow, the even proportioned udder with teat positioned central to each
quarter on an udder with a level floor, and a rear leg position that fully
supports her rear end weight, with springy joints, standing on substantial feet
requiring minimal hoof trimming. If you
could add some more open space between her pins, she could have a more roomy
rear udder (and likely calve easier) but this is a cow that will fit easily
into any free stall space.
Mating should be on the physical, rather than a
theoretical genetic, level if you wish to make cows like this one consistently. Too many cows today are narrow, clumsy in
their tallness, not able to maintain body condition, slow to breed, hard to
calve. Again, bulls do not need
“balanced” physiques to receive a high genetic ranking. The list of traits which add up to a high
index is a short list that mostly ignores the physique.
This is why we continue to bug you about considering
the “aAa” method for planning matings that produce physiques capable of
actually harvesting all that theoretical value the indexes promise (but are
only able to deliver about one third of the time).
Some
current favorites from
newer sires:
Two high production sires (progeny verified) who can
safely calve your heifers:
99HO7070 Jehosaphat
(aAa 342156) 151HO 569 Pavethe way
(aAa 534126)
Use him on the smaller framed
heifers Use him on the
taller, narrower heifers
Calving ease: 5.9%
(5.8% maternal)
Calving ease: 5.7% (7.4% maternal)
+1060m -02%
+35bf -01% +30pr +1242m -01%
+41bf -01% +36pr
Carries the desired A2A2 Beta
casein gene Carries the
desired A2A2 Beta casein gene
+4.1 Productive Life +0.2 Dtr PG rate +6.1 Productive Life +1.1 Dtr PG rate
It is highly unusual to find sires
(as these two are) who are still “plus” DPR above +1000m PTA
“Planet” son from a “Shottle” dam “Planet” son from a “O Man” dam
Used within an aAa-directed mating plan, you can harvest
the above genetic potential while also having a properly balanced cow physique
that is capable of a full productive life without high maintenance cost.
Balancing the mating realizes
more successful heifers than agonizing over linear profiles. If you are afraid to use any bull without a
“perfect” linear, you will end up producing tall, narrow, shallow cows—what
linear classification techniques favor.
Think about that before you pass up any bull who has the production
and daughter fertility and calving ease and developed maternal line gene
support you need to change the “high maintenance” cow experiences you may have
been getting.
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