Friday, March 12, 2021

How much sense does the latest Genomic selection fad make?

 From the Oct/Nov 2018 Dairy Route letter

By the time you have read the same article six times (in six different “free circulation” dairy magazines) it is easy to believe you must be reading a trend.   In fact you may just be reading the same article, circulated to these magazines by one advertiser, edited six different ways, to influence semen buying behavior.    Public Relations companies have perfected the art of generating “press releases” to promote product concepts making them look like magazine articles.


A return to the economics of the 1950s


In the early days of the AI industry, dairy farmers always had enough replacements.    Typically they would breed yearling heifers to beef bulls in order to have a supply of deacon calves to sell at premium “beef type” prices in the auction barns.    They waited to see if the heifer was any good, and then bred the “keepers” for their dairy replacements.    This practice persisted into the 1960s until DHIA began to collect “calving ease” data in order to convince dairymen to use dairy bulls on dairy heifers.


The failure of genetic ranking to preserve fertility (1970 thru 2000)


As we entered into the Earl Butz era of farming “fencerow to fencerow” and bottled milk received new government subsidy, the genetics industry shifted into high gear ranking on “PD Milk”.     Geneticists geared up to produce faster maturing dairy cows and select on high peak milk days, naively assuming any other desired gene traits would just maintain themselves.    This proved to be a false assumption as maintaining such cows required more corn energy and breeding efficiency suffered (in spite of the high energy ration designs).    Suddenly, it became apparent that mainstream milk volume dairies were not producing enough replacements to make up for high culling rates and shorter cow life.


The “magic bullets” of Ov-Synch reproduction and sexed (gender sorted) semen


Professor Ash at Arizona State University was concerned with the low reproduction rates in the dairy herds (Arizona and elsewhere) that had to endure subtropical temperature and humidity.    As the cow environments were not conducive to effective heat detection, Ov-Synch techniques evolved to replace heat detection with timed insemination.    Results were not great, but were good enough that his work resulted in other university trials and a general trend evolved spreading Ov-Synch north where skilled dairy labor was beginning to be in short supply for expansion dairies.


Colorado State University had been experimenting with methods to sort sperm cells between the X and Y chromosome so as to predetermine the sex of resulting calves.     At a certain point they believed they had a commercially viable patent, so they put it up for auction.    A group of OSU graduate students in animal science from Colombia had the winning bid—most US AI studs being asleep at the switch in a belief that changes in sire indexing to include fertility and health traits would solve the problem of herd replacement numbers proportional to herd turnover rates.


Ov-Synch improved reproduction rates in larger herds, enough to absorb the higher costs.    Higher repro rates in turn made higher-cost, lower-conception sexed semen more reasonable in the eyes of those dairy managers who were spending premium dollars chasing scarce replacement heifers (produced mostly in the smaller to mid size herds with engaged dairy breeding skills).      As long as milk prices rose, these technology-enhanced management options seemed affordable and many dairymen utilized them.

Let’s do the math on today’s economics


The sales pitch is:   (a) test your herd for Genomic value, (b) breed your lowest G value cows to sexed Beef semen to sell premium feeder calves, (c) cull your lowest G value heifers as deacons, (d) breed all retained heifers to the highest G value sires using sexed Dairy semen to provide adequate replacements.

Any conventional dairy semen still used goes into the higher G value cows, where sexed conception was not expected to be adequate to maintain reproduction rates.     


Problems with this “idea”l scenario:   (a) conception is lower with sexed semen, therefore semen costs per pregnancy will go up, beyond the higher cost [2x to 3x conventional] of the initial sexed product.

(b) “Up front” Genomic testing costs are equal to semen costs, given you may test twice as many heifers as you end up raising.   (c) Genomic values are still 40% parent average, meaning there will be constant culling of calves born from older “survivor” cows who will have the oldest, therefore lowest G value, pedigrees.   Might those have been your best calves?   Realized productive longevity will be negated by a Genomic theory that has assigned the highest values to two generations of animals yet to be evaluated on their actual productive ability rather than on objective evaluation of actual results.


The only difference between 1950 and 2020 breeding approaches is who gets the beef semen


In the practical 1950s, the least proven animal on the farm (the heifer) got bred Beef.   In the theoretical approaching 2020s, the most productive animal on the farm (matured cows) gets bred Beef.    While the official genetic theory of “Lifetime Net Merit” appears to find matured cows the most profitable, semen marketers selling on Genomics want you to believe the immature cow is better and the unfreshened calf the most valuable.     (Even Zoetis, whose future is based on Genomic measurements, shows data that a matured cow milks 30% more on average than the best of new heifers— greater than any increment of genetic “value” ever accomplished.)


Try this scenario instead


(a)     Skip the genomic testing of heifers and save $50 per head up front.

(b)    Breed those heifers with conventional beef sire semen, just like granddad did, and sell every calf at a premium price as deacons (a beef breed heifer will still bring a premium too) while saving $50 on semen costs per conception.     This minimizes your dairy bull calves without sexed semen use.

(c)     Analyze your cows on their first calving with aAa to determine their optimum mating, and breed accordingly (with conventional semen) to produce a higher percentage of adaptable replacements.   This only costs $6 per cow lifetime—a fraction of Genomic testing, which does not assist mating.

(d)    Select mating sires on a matrix of traits that most directly influence your future milk price (bf% and pr%, fertility, physical health, ease of calving) using conventional semen, which is more fertile.

(e)     Gain maturity from aAa matching so that 30% additional milk volume is gained on a majority of the herd.    Reduce involuntary culling rate from more balanced physiques that result from aAa.

(f)   Also use Beef semen on any cow after three dairy services.    There is no need to raise a heifer calf

       from any cow whose slower fertility may be heritable and associated with metabolic diseases.   As

       long as you propogate more fertile cows, you will always have enough heifers.


Time to do the math


There were lots of great ideas we bought into when the base price of milk was in the $20 range.    Are these still great ideas when the base price of milk is around $14?      How many “ideal” management practices are actually affordable on the margin of their productivity, at any given price of milk or beef or feed costs?


The Genetics industry is fully capable of getting carried away by the theoretical possibilities of its technologies.    There is already talk of gene editing—a process that would in fact mean that all future sires would be “clones” (totally alien to the natural biology of cow herd propogation as done on our dairy farms).      


As a dairyman, you must first be a businessman (concerned with profit over costs and positive returns over all invested capital).    Every time our industry has lost focus on profits and become enthralled with all the theoretical productivity of new technologies, dairymen have lost out.    The basics still apply.    

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