Tuesday, March 30, 2021

Why are “Lineback” bulls getting more usage?


CONCEPTIONS   Dairy Route Newsletter                 February March 2020



Healthier cows, good fertility, but a key difference is they have black pigment hooves.   Lots of hoof trimming professionals believe the black hoof has less heel warts and hoof rot, requires a lot less hoof trimming.    This coloring comes from the original dutch Friesian-type “Holsteins”.

The relative heritability of traits and qualities in genetic selection

An ex-dairyman friend of mine who now has a cow-calf beef herd in Alabama posted recently in an online discussion “the heritability of disposition characteristics is 45%.”    He caught my eye because this is higher than nearly all linear traits (production, type, fitness) measured in “dairy” and we pay no attention to this at all in genetic selection for dairy cows.

To give you perspective, here is a chart of the heritabilities as calculated by AIPL (USDA) for the 14 traits that go into the “Lifetime Net Merit” (G-LMN$) ranking index:
Milk (pounds),  Butterfat (pounds),  Protein (pounds)  estimated 20% heritable.     *For Jerseys, Milk and Butterfat are 23% heritable.    Somatic Cell Score  estimated 12% heritable.
Body Weight Composite  from stature and linear frame traits,  estimated 40% heritable.    *For other breeds than Holstein, more like 35% heritable.
Udder Composite  27% in Holsteins,  (*20% in all other breeds).
Feet and Legs Composite  15% heritable.
Calving Assistance Composite  only 7% heritable.   
Daughter Pregnancy Rate  only 4% heritable, while Productive Life  more like 8% heritable.    
Cow Conception Rate 2% heritable, twice as much as Heifer Conception Rate 1% heritable.
Health Trait Composite and Livability are both only 1% heritable.

The only linear measurement traits higher in heritability than “disposition” are Protein % content (55%) and Butterfat % content (50%)—roughly twice their estimates in “pounds” because that much less affected by feeding management and other environmental variants.

So how can we anticipate disposition problems in case we want easier-tempered cows?

There is data from some areas of the world in milking speed and disposition, and here are some examples of how sires we handle fare in these observations: (100 being breed average)
566H1231  Rev Me Up Red      MS 108   DP 109          054H 552   Barbwire Red       MS  97  DP  94
566H1261  Jo Dandy                 MS 106   DP 109          566H1180  Rollag                    MS  92  DP  96
566H1235  All Game                 MS 108   DP 108          566H1199  Cambridge           MS101  DP  97
566H1246  Can Do                     MS 101   DP 108          566H1254  By Golly                MS104  DP  97
099H0509  Perpetual                MS 100   DP 107          566H1211  Blender                 MS  98   DP 98
Basically, comparing these “top five” disposition ratings vs the “bottom five” from International Protein Sires offerings, there seems to be a high correlation between temper and milking speed (and does that seem as logical to you as it does to me?)     We observe from the “aAa” breeding guide that the more “balanced” cow is generally more even-tempered, as well as healthier and more reproductive, thus having longer “Productive Life”.    Comparing studs, Intl. Protein Sires have above average temperament ratings, how much of that can relate to their preference for sires from longer-lasting cow families?    Certainly that bad-tempered cow often ends up with a shorter herdlife, so again, logical selection can lead to a more easily-managed herd requiring less labor and veterinary intervention.

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