From the November December 2015 Dairy Route Letter
Since the introduction of Genomic testing, most AI
systems have geared up their selling of linear mating to capture all your
business, utilizing Genomic sires whenever possible so that their averages can
appear better against competing sales efforts.
Only one new (of many old)
problems with this—not only has University research continually proven that
linear-based mating adds no value, the data on how Genomic ranked sires perform
once daughters are milking in your herd indicates that while the “index” rank
averages out, the performance on many desirable traits does not. Thus, if you are buying into an “index
ranking” mating service, you could easily go backwards from the resulting
heifers it produces. Here is
why this can happen:
Example: Lifetime Net Merit
The formula for this index has
changed dramatically through its time, given its first format was simply 70%
Milk (lbs) + 30% Fat (lbs)—a “single trait selection” approach that set
commercial dairymen up for decades of “inbreeding depression” (loss of
fertility and longevity). The latest
version of $NM is still heavy of “health and fertility” and is calculated this
way:
Butterfat (lbs) 22% + Protein
(lbs) 20% + Productive Life (mo’s) 19% + Udder Composite 8% + SCS* 7% + DPR 7% + Body Size* 5% + Calving Ease 5% +
Foot & Leg Composite 3% + Milk (lbs)* 1% + HCR 2% + CCR 1%. [Traits marked * are preferred negatively]
In other words, it is
possible to go multiple generations in Net Merit rankings and never
use a sire who improves milk volume (this relates to how multiple component
pricing determines our pay prices). It
is also possible, and perhaps more long-term detrimental, to never use
a sire with normal cow size.
Dr David Kendall,
Geneticist for ST Genetics, is suggesting (and we agree) that
dairymen should use their own personal “index” based upon their current weak
points in genetic traits, rather than pay extra for any sire just because he
ranks highly (today) on any “one size fits all” index. Simple is better.
Examples of the “Kendall approach” that fit real-world herd situations
Your herd averages 90 pounds per
day (on 3x milking which is supposed to improve udder health). In spite of that, your SCC is costing you
quality premiums. It takes 4 straws per
cow to get pregnancies so calving intervals are stretched out past 400
days. Milk price is low due to low bf%
and lower pr%.
The selection traits to focus on
are:
SCS – 3.00 is average, so seek
out bulls well below 3.00 and you will see lower SCS in new heifers.
DPR-- +0.0 is average, but
DPR runs counter to PTA Milk yield, so seek out bulls better than average
(-1.00 above +1500m) (-0.25 above
1000m) (0.50 above 500m) (1.25 below 500m) to gain fertility.
bf% and pr% -- cows in a
negative energy state will convert protein to energy in the rumen trying to
meet body demands. PTA pr% should
be emphasized whenever you see cows below 3.0% (HO) to 3.3% (JE) in early
months of lactation. PTA bf% should
be emphasized on any cows below 3.6% (HO) to 4.4% (JE) as these levels are
below the averages of the Federal Milk Order for components.
You will find that cows with
higher test% (pr and bf) have less trouble with negative energy and thus will
also have shorter calving intervals than higher yield, lower test% cows.
Looking beyond index rank to the “numbers” undertneath
To keep this fair, I am only
going to use Genomic sires we offer (from International Protein Sires and
ST Genetics) to do these comparisons.
EXAMPLE: 2371
GTPI vs
2370 GTPI (both $
18.00)
566HO1217 Synergy PULASKI 54HO 754 Mr Sunview
Coin SUNFISH *RC
2371 G-TPI (aAa 351426) 2370 G-TPI (aAa 231456)
PTA Milk: + 523
PTA Milk: +1834 (1311 pounds more)
PTA Fat + Protein: +105 PTA Fat + Protein: +109 (essentially equal)
SCS 2.81
SCS 2.75 (both look
good)
Udder Composite + 1.43 Udder
Composite + 1.72 (statistically better)
Foot & leg Comp - 0.07 Foot
& Leg Comp + 0.84 (clearly
better)
While both of these are from deep
pedigreed cow lines, there have been more successful AI sires from cows behind
“Sunfish *RC” than so far behind “Pulaski”. Our choice to stock for your use remains “Sunfish
*RC” given more people want high milk gains with equal high dollar value
protein gains and understand that heifers who milk like that take one more
cycle to breed back (- 1.1 DPR) but cow family longevity (at lower SCS)
suggests these will be fertile cows over the long haul.
EXAMPLE: $798 G-Net Merit vs
$723 PE-Net Merit
151HO 696 Mr Shot DOZER 1491 552HO2451 De-Su RANSOM
$798 G-NM (aAa 423156) $723
PE-NM (aAa 342165)
PTA Milk: +1452
PTA Milk: + 365 (1087 pounds less)
PTA Fat: -.02%
+ 49 PTA Fat: +.14%
+ 50 (higher bf test %)
PTA Protein:+.01% + 48 PTA
Protein: +.08% + 34 (higher pr test %)
DPR: + 2.9
DPR: + 2.9 (possibly equal?)
PL: + 9.3 (breed elite) PL: + 8.6 (insignificant diff)
SCS 2.59 SCS 2.80 (both promising)
+1.52 Type +1.65 UDC
+1.01 FLC
+1.32 Type +1.05 UDC +2.20 FLC
calving ease 6.7%
calving ease 5.5% (better or real calves)
What is the key difference between
these two? Progeny data on
“Ransom”. Two areas in which
Genomics has not been too successful: (1) predicting calving ease, (2) assuming
high milk bulls can still be really good on DPR (daughter pregnancy rate). Exceptional FLC on “Ransom”. Genomic type is based on a more limited set
of markers; the trend is for type data to be lower in reality than in the
theoretical G-based world. The
promising Genomic sire is higher for $NM, but the progeny data coming in on
“Ransom” indicates he is a well-rounded improver, his $NM not as biased by
assumptions in the index model for specific traits.
COMPARE PROGENY TESTED SIRES vs OTHER PROGENY TESTED SIRES
COMPARE GENOMIC TESTED SIRES vs OTHER GENOMIC TESTED
SIRES
The calculation systems favor the
newest “Genomic” bulls over the older “High Reliability %” bulls with extensive
progeny data. Have reasons beyond
just “index” for any Genomic sires you use.