Discover the latest updates in genetic evaluations from CDCB and USDA AGIL. How will the new 305-AA yield measurement and Constructed IDs impact your herd?
CDCB and USDA Animal Genomics and Improvement Laboratory (AGIL) implemented essential changes to improve genetic assessment accuracy on August 13, 2024. This paper underlines these critical developments and their advantages for the dairy sector. Supported by USDA AGIL’s innovative genomics research, CDCB is well-known for its exact genetic assessments. Among other improvements, the adoption of Constructed IDs and 305-AA standardized yield measurement highlights their dedication to precision and innovation, increasing the dairy industry’s output and sustainability.
CDCB and USDA AGIL Introduce the New Standardized Yield Measurement Known as 305-AA
In a step meant to transform dairy genetics, the USDA AGIL and CDCB have unveiled the new standardized yield measurement known as 305-AA. This much-awaited change departs significantly from the mature equivalent (ME) standard, effective since 1935. Standardized yield records now benchmark the average age of 36 months or 305-AA. Inspired by current studies, this adjustment marks a methodological turn to reflect a more contemporary dairy environment.
The new 305-AA yield assessment replaces changes relied upon over the last 30 years and incorporates updated age, parity, and season parameters. The recalibrated changes seek to permit fair phenotypic comparisons among cows of various ages, sexes, and calving seasons. The main objective is to evaluate dairy performance under many settings and management strategies.
One significant modification is adjusting herd averages to approach real yields. Under the former ME method, breed-specific yield projections varied by around 10 percent higher than actual yields. Effective June 12, 2024, the estimates of the 305-AA yield become available via CDCB’s WebConnect for animal and data searches. Moreover, the officially adopted, on August 13, 2024, new 305-AA changes are entirely included in the CDCB genetic examinations.
Table 1. The ratio of mature equivalent to 36-month equivalent milk, fat, and protein yields from 1994 or recent data
| Breed | 1994 Factor | ME / 36-month SD ratio in recent data | ||
| Milk | Fat | Protein | ||
| Ayrshire | 1.10 | 1.092 | 1.076 | 1.067 |
| Brown Swiss | 1.15 | 1.156 | 1.150 | 1.142 |
| Guernsey | 1.05 | 1.043 | 1.009 | 1.013 |
| Holstein | 1.10 | 1.082 | 1.081 | 1.059 |
| Jersey | 1.10 | 1.079 | 1.063 | 1.064 |
| Milking Shorthorn | 1.15 | 1.110 | 1.100 | 1.090 |
This move from 305-ME to 305-AA offers a perceptive analogy. Recent data shows that standardized yields calculated from the 1994 ME factors are routinely more significant than those adjusted to the 36-month equivalent. This change marks a reassessment of yield projections to more closely reflect the contemporary dairy environment and current dairy animal performance.
A vital component of this shift is the modification in standard deviation (SD) “ME / 36-month” ratios, usually seen to be somewhat greater in earlier data than in recent changes. These little variations indicate calibrating output estimations to fit modern dairy production methods and genetic developments.
For predicted transmitting abilities (PTAs), these changes have significant ramifications. Updated ratios closer to 1.08 for Holsteins (HO) and Jerseys (JE) and generally more tiny numbers for fat and protein point to a minor scaling or base adjustment in PTA values. These changes assist representative assessments of dairy cow genetics, improving the validity and applicability of these measures according to contemporary industry requirements. Thus, a sophisticated, data-driven approach to genetic studies helps the dairy industry by promoting informed breeding and management choices.
Enhancing Precision: Modern Dairy Environments and Refined Seasonal Adjustments
Recent data analysis has improved seasonal adjustments to reflect the effect on lactation yields of the changing dairy environment. Modern architecture and construction methods have lessened the seasonal impact on yields, hence stressing improvements in dairy settings. The revised approach reveals minor variations by estimating seasonal impacts within five separate climatic zones defined by average state climate scores. This change emphasizes the advantages of better dairy conditions, lessening the need for significant seasonal changes and more accurate genetic tests. This method guarantees lactation yields are assessed in a framework that fairly represents current environmental and management circumstances using region-specific modifications, enabling more precise and fair comparisons of dairy output.
Robust Validation: Testing New Factors Across Decades of Lactation Records
The new parameters were tested rigorously using 101.5 million milk, 100.5 million fat, and 81.2 million protein lactation data from 1960 to 2022. The validation focused on the relationships of Predicted Transmitting Ability (PTAs) for proven bulls born after 2000. Results were rather good, with correlations of 0.999 for Holsteins, above 0.99 for Jerseys and Guernseys, and somewhat lower, ranging from 0.981 to 0.984, for Brown Swiss and Milking Shorthorns. These strong connections underscore the dependability of the new elements. The study also observed minor changes in genetic trends: a decline for Brown Swiss and Jerseys and a rise for Guernseys. These revelations help us better evaluate our genes, guaranteeing justice and ongoing development.
Revolutionizing Genetics: The Full Integration of Constructed IDs into the CDCB Database
When fully adopted by August 2024, Constructed IDs represent a significant turning point for CDCB. Targeting partial pedigrees, particularly for animals without maternal ancestry information, this invention launched in mid-2023 and ends in July 2024. Constructed IDs link approximately 3.2 million animals in the National Cooperator Database to newly discovered relatives, developed by significant research by USDA AGIL using over a decade of genetic technology experience.
This improvement increases the dependability and accuracy of genetic tests. The worldwide influence is significant given these complex interactions across the closely linked U.S. dairy community. More precise breeding choices help directly impacted and related animals to improve their genetic quality and raise U.S. assessments. Designed IDs strengthen the genetic bases for further development by filling critical pedigree gaps.
Refined Criteria and Data Integration: Elevating Heifer Livability Evaluations for Improved Genetic Precision
Recent improvements in heifer liability (HLV) show how committed the USDA AGIL and CDCB are to accuracy and dependability in genetic assessments. Fundamental changes exclude recent heifer fatalities from 2022–24 and rectify previously missed data resulting from changes in cow termination codes. These wholly integrated reports improve HLV assessments immediately. Improving the speed and depth of evaluations is a crucial modification that calls for a minimum of 1 percent mortality loss annually for the data of a herd to be legitimate. Faster adaptability to evolving reporting methods made possible by this change from cumulative to yearly criteria guarantees current herd health dynamics are faithfully captured. These improvements have generally resulted in a significant increase in the dependability of HLV assessments, particularly for bulls with daughters in the most recent data sets, generating more robust genetic predictions for offspring and informed breeding choices.
Pioneering Genetic Insights: Brown Swiss Rear Teat Placement (RTP) Evaluation
A significant turning point in dairy cow breeding is the introduction of the conventional and genomic assessment for Brown Swiss Rear Teat Placement (RTP). Using about 15,000 assessments from January 2024, CDCB and USDA AGIL accurately calculated the RTP parameters. On the 50-point linear scale, about 80 percent of the evaluations lie between 25 and 35 points. Heritability for RTP is 0.21, somewhat similar to front teat placement at 0.22; repeatability is 0.33.
Ranges for Rear Teat Placement in Brown Swiss
| Predicted Transmitting Abilities (PTA) | Reliabilities | |
| Males | -2.4 to 3.1 | 0 to 98% |
| Females | -3.7 to 2.9 | 0 to 79% |
For bulls with reliabilities between 0 and 98% and for women between 0 and 79%, the PTA values for RTP in Brown Swiss are -2.4 to 3.1 and -3.7 to 2.9, respectively. This assessment uses exact measures and rigorous statistical techniques and emphasizes genetic heterogeneity within the breed.
Breeding choices depend on this thorough assessment, which helps farmers choose ideal RTP characteristics, enhancing herd quality and production. Driven by reliable, data-based conclusions, the August 2024 release of these assessments marks a new chapter in Brown Swiss genetics.
Refined Precision: Streamlining Genetic Markers for Enhanced Genomic Predictions
Effective August 2024, the genetic marker update improved the SNPs used in genomic predictions, lowering the list from 78,964 to 69,200. This exact choosing approach removed low call rates, poor genotyping quality, minor allele frequencies, and markers with minimal effects. The X chromosome’s length allowed all SNPs to be maintained there. This update improved efficiency by helping to reduce processing time and storage usage by 12%. About 74% of the deleted SNPs originated from high-density chips.
Five other gene tests—HH7 and Slick, among others—were also included in the update. Confirming the low effect on trait averages and standard deviations, preliminary studies revealed a roughly 99.6% correlation between genomic predictions from the old and new SNP lists. For animals with less dense genotypes or partial pedigrees, this recalibration improves the accuracy of genetic assessments.
Incorporating Genomic Advancements: Annual Breed Base Representation (BBR) Updates
Accurate genetic evaluations depend on annual Breed Base Representation (BBR) revisions. This update, set for August, guarantees that the most relevant genetic markers are included in BBR calculations. Consistent with past upgrades, a test run based on February 2024 data confirmed the stability and strength of the new SNP set. The CDCB maintains BBR calculations at the forefront of genetic assessment by including this improved SNP set, giving dairy farmers the most reliable data for informed breeding choices.
Integrating Cutting-Edge Gene Test Data: Enhancing Haplotype Calculations for Holstein HH6 and Jersey JNS
A significant step forward in genetic assessments is combining Holstein Haplotypes 6 (HH6) and Jersey Neuropathy with Splayed Forelimbs (JNS) direct gene test data into haplotype calculations. By providing thorough gene test results to CDCB, Neogen and the American Jersey Cattle Association (AJCA) have been instrumental in this process. More exact haplotype estimations have come from including these direct gene tests in imputation procedures. Test runs greatly increase performance, Particularly for animals with gene test results and their offspring. This integration improves genetic prediction accuracy and emphasizes the need for cooperation in enhancing dairy cow genes.
The Bottom Line
Incorporating innovative modifications to maximize yield metrics, genetic evaluations, and pedigree correctness, the August 2024 genetic assessments signal a turning point in dairy herd management. These advances improve the dependability and accuracy of tests. While improved seasonal and parity corrections reflect current conditions, the new 305-AA standardizes yield measures for fair comparisons. We designed IDs to decrease pedigree gaps, improving assessments and criteria for Heifer Livability (HLV) and rear teat placement for Brown Swiss. Simplified genetic markers and combined genomic advances such as HH6 and JNS gene testing further improve assessment accuracy. These developments provide consistent data for farmers, enhancing the general health and output of dairy cows. Supported by a thorough study, the August 2024 assessments mark a significant breakthrough and inspire manufacturers to use these innovative approaches for more sustainability and efficiency.
Key Takeaways:
- The 305-AA standardized yield records, adjusted to 36 months, replace the previous mature equivalent (ME) adjustments.
- Implemented new factors enable fairer phenotypic comparisons across cows of different ages, parities, and seasons.
- Seasonal adjustments are now estimated within regional climate zones, reflecting improved management and housing reducing environmental impact on yields.
- Implementation of Constructed IDs enhances pedigree completeness and genetic evaluation accuracy.
- Heifer Livability (HLV) evaluations refined through revised modeling and data integrations, particularly focusing on recent years’ reports.
- Brown Swiss Rear Teat Placement (RTP) evaluations introduced, offering significant genetic insights with traditional and genomic evaluations.
- Reduction of SNPs from 78,964 to 69,200 for streamlined genomic predictions, enhancing processing time and accuracy.
- Annual BBR updates incorporate the new set of SNP markers, ensuring consistency and precision in breed representation.
- Direct gene tests for Holstein HH6 and Jersey JNS now included in haplotype calculations, improving prediction accuracy.
Summary:
The CDCB and USDA Animal Genomics and Improvement Laboratory (AGIL) have introduced a new standardized yield measurement, 305-AA, on August 13, 2024. This change allows fair comparisons among cows of various ages, sexes, and calving seasons. The revised approach estimates seasonal impacts within five separate climatic zones. Robust validation of the new parameters was conducted using 101.5 million milk, 100.5 million fat, and 81.2 million protein lactation data from 1960 to 2022. Results showed good correlations for Holsteins, Jerseys, Guernseys, Brown Swiss, and Milking Shorthorns. The August 2024 genetic assessments represent a significant turning point in dairy herd management, enhancing the dependability and accuracy of genetic tests. Constructed IDs link approximately 3.2 million animals in the National Cooperator Database to newly discovered relatives, improving genetic quality and raising U.S. assessments.
Learn more:
- CDCB’s Katie Schmitt to Address Future of Genomic Selection at 2024 US National Jersey Meetings
- What Dairy Breeders Need to Know About the Transition to 305-AA Yield Estimates
- Introducing 305-AA: CDCB’s New Standardized Milk Yield Measurement for Enhanced Accuracy
