Genetic indexing is based in the
commodity definition of milk value, not in specialized genotypes that
optimize our ability to capitalize on premium milk markets. This needs to be recognized by dairymen, as
soon as they pursue specialty milk markets that increasingly include
specialized land, feeding, animal, and processing protocols.
Thus, while Genomics has been
all about condensing the selection mechanisms to a reductionist scan of the DNA
for marker genes specific to commodity value production and only imputes index
estimates for the AI sire selection process, dairymen increasingly are seeking
information that goes beyond the basics of additive trait statistics.
Dairymen have tried crossbreeding
as well as linebreeding. They
have limited their sire selection to sources with similar farm management (as
in graziers only using New Zealand grassland bred sires). These are all a reaction to the
inefficiency of the selection (“ranking”) index to produce the cows needed to
meet your goals. Over time,
all indexes have this weakness, mating “likes” to “like”.
There may be a specific gene, as with polled
heads or A2 Beta Casein or specific selection traits, as with plus
butterfat% and protein% deviations or plus Productive Life that
become absolute requirements. In each
of these cases, there is a relationship to the milk market and to farm
management parameters that dictates these genes as more important than the
composite index the AI industry uses to “keep score”.
Matrix selection makes more
sense (than index rank) for any specialized management or market.
A “matrix” is basically a list of
“absolute” traits and qualities you wish each mating sire to possess. If it is a longer list, you may settle for
sires who possess 75% of the desired characteristics. But the point is that rather than trust a
composite index that “averages” the good with the bad to create a ranking
biased by an external view of what is important, you work with bulls who avoid
faults you wish to eliminate from your herd while providing the traits you need
for your market and future market.
If you are seeking to participate in
any direct milk marketing or specialty milk classification, genetic ranking as
we currently practice it no longer applies to your situation.
Why do we continue to produce “frail” heifers in spite of culling “frail” cows ?
This is another aspect of index dependence. The more generations you follow a single
index, the more “inbred to the index” your herd becomes. In the case of TPI, LPI and $NM, it is in
physical aspects of the animals that we create limitations for health and productivity
even as the indexes are formulated to include trait measurements in favor of
health and herd survival.
The conclusion of many of us is quite simple: the
heritability of qualitative physical characteristics is clearly greater than
the heritability of trait measures for health, fertility and herdlife. While you are adding up pedigrees full of
PL, you are raising physiques that are too fine boned, shallow and narrow to
function as they reach maturity.
Thus we continue to cull more cows in third lactation than we did in
first and second lactations, leaving so many of us needing every heifer we
raise to maintain herd size.
“aAa” will better explain why matings to highly
ranked sires do not produce longer herdlife cows.
Are you ready for what could come your way in the
milk market?
First it was component pricing, which made selection
for +bf% and pr% more important.
Recently it was a lowered SCC standard, which makes
selection on SCS more important.
Next, to be proactive in the face of consumer activism,
but more importantly for impacts on calf growth and labor efficiency, selection
for polled heads has become important.
What is next?
It could be A2 Beta Casein. Just as was true for the earlier evolutions
in dairy breeding, we are prepared with knowledge to advise on this potential
premium milk market. The desired trait
can be found in a useful cross section of the major dairy breeds already, thus
the usual arguments “but this interferes with genetic progress” will be
as meaningless as they were for all prior issues that changed the direction of
mating selection.
Our breeding program has two focuses: (1) mate
cows for more adaptable replacements, (2)
select on traits that enhance current profitability and future
marketability. Thus it is NOT a
commodity “one size fits all” breeding philosophy or sire list.
Mich Livestock Service, Inc “For the Best in Bulls” Since 1952 your independent AI source
Physical character of “frail” (short herdlife) cows
Every herdsman has a personal definition of the
‘frail” cow—half of it is behavioral and half of it visual. Frail cows are culled every day, but keep
reappearing in the heifers we raise to replace them. To avoid producing new “frail” cows, we
need to understand how they get “mated” in the first place.
The limitations of the physique define the potential behavior of frailty
What does the “frail” cow look
like? Usually she is the cow who looks
like she is working hard. In other words, she has a lighter boned frame
and very spare muscling, with lower body condition scores.
She may have a shallow body; she may
have a narrow frame from head to rump.
Her respiration will be more rapid as breaths will be shallow. As she matures, the pace of aging appears
rapid, with udder deepening and movement stiffening. The cow may be slower about cycling and
rebreeding after each calving. She
literally “milks herself to death”, if not lost to injury from clumsiness or
repro failure from lack of body conditioning. Note: her “genotype” has
given her this “phenotype”.
The above describes the “all sharp weight” ( aAa qualities 1+2+3 ) dairy cow physique
The qualities of the skeleton
(bone) and the soft tissue (muscle, cartilage, tendons, nerves)
are heritable on a very basic “qualitative” gene level, alongside
the glandular functions that influence both skeletal and soft tissue
development. These underlie the more
surface expressions of individual linear traits on the “quantitative” gene
level, on which geneticists (and sire analysts) focus for their relationship to
the productivity of the animal.
In “aAa” observation, the “sharp”
qualities of (1) dairy, (2) tall, and (3) open
produce more refined bone and feminine spread of the pelvis; a
faster growth rate for long bones, resulting in lean muscle mass;
and a minimal, elastic connective tissue between the bones. The dairy metabolism is oriented to
more will to milk, the tall metabolism is oriented to faster maturity,
and the open skeletal structure is oriented to more persistent
production during pregnancy. Thus,
in comparative genetic evaluation, the “sharp” qualities provide advantages in
responding to feed energy density, a faster physical maturity, and sustained
milk yield after rebreeding, that translate into bigger “plus” PTA yield
volumes, especially at immature lactation ages.
Performance physiques require supporting “substance” qualities to stay healthy and live
These same qualities, when intensified
by multiple generations of selection in their favor, reduce the adequacy of “round” qualities that provide substance,
stamina and fluid mobility.
Thus, the size and
ability of the heart, the rumen, the liver, the uterus, ie, all internal
organs, to meet their functions, as is being dictated by the genotype’s
production gene possession, is dependent on maintaining a level of “round
weight” ( aAa qualities 4+5+6 ) to support and sustain the drain of
nutrients from the physique of these “sharp weight” quantitative gene actions.
Lacking one or more of the “round”
qualities of (4) strong, (5) smooth, and (6) style, sets
a cow up to have more troubles with circulation, flushing toxins from udders,
swelling of joints, poor respiration, hyperventilating on hot or humid days,
sturdiness of stance, uneven wearing or growth of hooves and related lameness,
maintaining body condition, the fluidity of leg motion, getting up and down in
stalls.
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