Stop believing the production-twinning trade-off myth. German genomics proves you can eliminate $161 disasters without losing one pound of milk.
EXECUTIVE SUMMARY: The dairy industry’s most costly genetic assumption just got demolished by massive German research analyzing 37 million Holstein calvings. For decades, we’ve accepted that pushing for elite milk production inevitably increases expensive twin births—but VIT researchers prove this fundamental belief is dead wrong. The genetic correlations between twinning and production traits are negligible, indicating that it is feasible to select against these traits in a targeted manner. The science is settled, the tools exist, and the economic case is overwhelming—it’s time to demand that your genetics suppliers provide twinning breeding values alongside every bull evaluation.
KEY TAKEAWAYS
- Economic Liberation: Twin births create cascading disasters costing $59-161 per incident, with cows suffering 5.38x higher retained placenta risk, 1.77x higher dystocia rates, and 76-96 days shorter productive lives—yet genetic selection against twinning causes zero production losses.
- Proven Genetic Opportunity: Bulls in the worst quartile for twinning produce daughters with 3.6 percentage points higher twin rates than top quartile bulls, with heritability estimates of 13-14% placing twinning squarely within successfully improved health traits through genomic selection.
- Selection Index Scandal: While commercial companies like Zoetis incorporated twinning predictions into selection indices years ago, the newly updated Net Merit 2025 continues to ignore this economically relevant trait despite its 31.8% emphasis on fat and 13.0% on protein production.
- Implementation Reality Check: German research using single-step SNP BLUP technology across 87% of the nation’s dairy cows proves genetic correlations with milk traits are “close to zero”—eliminating the last excuse for not treating twinning as a primary breeding target.
- Industry Accountability Gap: The genetic tools to reduce twinning exist right now, but producers are being held hostage by an industry that prioritizes marketing convenience over economic reality—demand twinning breeding values from your suppliers or question what else they’re hiding.
A landmark German study published in the Journal of Dairy Science analyzing population-wide Holstein data proves dairy farmers can eliminate costly twin births without sacrificing a single pound of milk production, demolishing the industry’s most persistent genetic assumption and opening the door to immediate herd profitability gains.
The conventional wisdom that’s been handcuffing dairy breeding decisions for decades just got obliterated by hard science. For years, we’ve accepted that pushing for elite milk production inevitably leads to more twin births—and the cascade of economic disasters that follow. A comprehensive new study by VIT researchers published in the Journal of Dairy Science proves this fundamental assumption is dead wrong.
What really matters is genetic selection for milk production, and twinning operates completely independently. You can aggressively breed against twin births while simultaneously cranking up genetic gain for milk, fat, and protein. The genetic correlations between twinning and production traits? “Close to zero,” according to the published research.
The $100 Million Industry Blind Spot
Let’s face it—while you’ve been accepting costly disasters as “inevitable,” the science to prevent them has been sitting on the shelf. Here’s the scandal that should make every progressive producer furious: Zoetis has been incorporating genetic selection against twinning in their Dairy Wellness Profit Index (DWP$) since at least 2020, yet our industry-wide Net Merit index—the tool that drives the majority of breeding decisions—completely ignores this economically devastating trait.
The 2020 Zoetis DWP$ formulation “applies increased genetic selection against abortion, twinning, cystic ovaries, cow respiratory disease, and cow size.” Meanwhile, the newly released Net Merit 2025, with its sophisticated weighting of nearly 40 individual traits, still has zero economic penalty for twinning. How could a commercial company have recognized this opportunity years ago while our national breeding program remains blind?
Why This Changes Everything for Your Bottom Line
Every twin birth in your calving pen isn’t a bonus, it’s a financial disaster waiting to unfold. The published economic research quantifies exactly how much these “double blessings” cost you: “the estimated losses due to twinning range between $59 to $161 per twin pregnancy”.
But here’s the devastating reality most producers miss—twinning doesn’t just cost you money directly. It “compromises milk production, increases the incidence of dystocia and perinatal mortality, decreases calf birth weight, increases the…and shortens the productive lifespan of cows”. This isn’t just bad luck; it’s a predictable pattern of economic destruction that the genetics industry has the tools to prevent.
The Science That Exposes Industry Failures
The German VIT researchers didn’t mess around with small-scale university trials. Using population-wide data from German Holstein cattle, they employed single-step SNP BLUP technology to analyze the genetics of twin births as two genetically correlated traits: first parity and later parities.
Their findings are unambiguous and industry-changing:
Heritability estimates: 0.008 for first parity and 0.026 for later parities. These numbers place twinning squarely within the range of successfully improved health traits through genomic selection.
Genetic correlations with production: The researchers found that “genetic correlations with milk traits were close to zero.” This definitively proves that selecting against twinning causes zero collateral damage to milk, fat, or protein production.
Bull variation proves genetic potential: The study revealed “substantial variability among bulls, whose genetic potential was expressed in varying twin birth rates among their daughters.” This isn’t theory—it’s measurable genetic variation that can be captured through proper selection.
The Selection Index Scandal We Must Address
Here’s what should make every dairy producer demand answers from their genetics suppliers: while Zoetis has been offering genomic predictions for twinning and incorporating them into selection indices for years, the industry’s primary selection tool continues to ignore this economically relevant trait.
The newly updated Net Merit 2025 places 31.8% emphasis on fat, 13.0% on protein, and 17.8% on feed efficiency, yet zero percent on preventing a trait that costs $59-161 per incident and creates cascading health disasters. By Net Merit’s own definition—maximizing lifetime profitability through economic weighting of heritable traits—this represents a fundamental failure of the index to serve dairy producers.
Meanwhile, commercial genomic tools have already demonstrated that “twinning can be proactively managed on dairy farms using genetically powered tools” and present “a compelling opportunity for dairy producers to proactively reduce the incidence of twin pregnancies on commercial dairy operations.”
What Your Genetics Supplier Isn’t Telling You
The German research reveals the most damaging genetic correlation in the study: twinning shows a correlation of 0.326 with the stillbirth rate. This means that the genetic factors predisposing cows to twin births also increase the likelihood of dead calves. Every time you select a bull without considering his twinning genetics, you’re potentially increasing both twin disasters AND stillbirth losses in your herd.
What else are they hiding if your bull catalog doesn’t include twinning breeding values? The genetic tools to address this problem exist right now, but the industry’s failure to prioritize economic reality over marketing convenience is costing you money every breeding season.
Your Action Plan: Stop Managing, Start Selecting
The message from this landmark research published in the Journal of Dairy Science is crystal clear: transform how you think about twinning from an unavoidable consequence to a controllable genetic trait. Here’s your roadmap:
Immediate Actions:
- Demand twinning breeding values from your genetics supplier—if they don’t have them, ask why
- Calculate your current twinning costs using the established $59-161 per case range
- Question every bull selection based purely on Net Merit—demand comprehensive genetic information
Strategic Confrontation:
- Challenge the Council on Dairy Cattle Breeding to explain why economically devastating traits remain excluded from Net Merit
- Push AI companies to provide transparency on twinning genetics across their bull lineups
- Support research and industry pressure to update selection indices based on complete economic reality
The Bottom Line: Stop Subsidizing Industry Failures
The German VIT study published in the Journal of Dairy Science represents more than scientific advancement—it’s an indictment of an industry that has allowed preventable economic disasters to persist while the genetic solutions sit unused. The data is definitive: you can pursue elite genetic merit for milk, fat, and protein while simultaneously selecting against the costly disasters that twin births represent.
This isn’t about choosing between production and profit anymore. It’s about demanding that your genetics suppliers and industry organizations provide tools that reflect complete economic reality rather than selective marketing convenience.
The choice is yours: keep subsidizing an industry that ignores economically relevant genetics, or start demanding the comprehensive breeding tools that maximize your actual profitability.
The science is settled, commercial tools exist, and the economic case is overwhelming. What are you waiting for—and more importantly, why are our industry leaders still making you wait?
Learn More:
- The Genetic Gut Lottery: Why Some Herds Are Born Winners and What You Can Do About It – Discover how microbiome-informed breeding represents the next frontier beyond traditional genetics, potentially delivering 15% production gains and 20% feed efficiency improvements through genetic selection.
- April 2025 Canadian Genetic Evaluation Updates: What Dairy Farmers Need to Know Now – Reveals how current genetic evaluation changes affect breeding strategy decisions, helping you navigate the LPI vs. Pro$ choice while maximizing genetic progress for profitability.
- 5 Technologies That Will Make or Break Your Dairy Farm in 2025 – Demonstrates practical implementation strategies for precision breeding technologies that complement genetic selection, showing how smart monitoring systems can validate and enhance your breeding program results.
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