Genotyping Early, Focus, and Invest Wisely

Smarter Selection for Poll Dorset Breeders in Tough Seasons

In challenging seasons, every kilogram of feed and every hour of labour counts. Making informed decisions early about which animals are worth investing in can help stud and commercial operations stay efficient and profitable. That’s where genomic testing steps in, providing accurate information on an animal’s genetic potential before you’ve invested valuable resources.

Rather than spreading feed and management effort across the entire drop, genotyping allows breeders to identify the top animals early and make selection and management decisions with confidence. It’s not about cutting corners, it’s about focusing on the sheep that will truly drive progress in your breeding program and deliver value to your clients.

Why Early Genotyping Matters

When feed, labour, or measurement capacity are limited, many studs reduce the number of animals they physically record. However, preselecting animals for measurement based on their appearance or early growth can introduce selection bias, reducing the accuracy of Australian Sheep Breeding Values (ASBVs) and potentially slowing long-term genetic gain.

Genomic information helps overcome this issue. By genotyping animals early, breeders can maintain selection accuracy and minimise bias, even if only a portion of the flock is later phenotyped.

Key Research Findings

A recent study by Clarke, Brown, Bradley, and Swan (2025) explored how different preselection strategies affect the accuracy of ASBVs in the MERINOSELECT population. The team analysed more than 270,000 animals from 13 Merino flocks, including 77,780 genotyped sheep, comparing several levels of recording:

Each scenario was tested with and without genotyping.

The results clearly showed that:

• Genotyping all animals increased correlations between ASBVs and true breeding values (TBVs) from as low as 0.70 → 0.98 for individuals across traits.

• For sires, correlations remained very high (0.93–0.99) even when data were reduced, but accuracy declined most sharply when no phenotypes were collected.

• Genotyping all animals and phenotyping the top 50 per cent based on selection index provided the highest ASBV accuracy and the least bias of all reduced-recording strategies.

• This “genotype all, phenotype top half” approach maintained over 90 per cent of the selection advantage achieved by fully measured flocks

• Bias in mean ASBVs was substantially reduced when genotypes were included, particularly for key yearling traits such as weight (YWT), eye-muscle depth (YEMD), greasy fleece weight (YGFW), and fibre diameter (YFD).

What It Means for Poll Dorset Breeders

For Poll Dorset studs, where selection focuses on growth, muscle, and fat traits linked to prime lamb production, this research offers a clear message. Preselecting animals for recording based on visual assessment or early weights can distort ASBVs, even in terminal breeds. Genomic testing provides an objective baseline that removes much of that bias.

By genotyping all lambs early, studs can:

• Identify top sires and replacement ewes before significant feed and labour are invested.

• Maintain ASBV accuracy across core terminal traits like Post-Weaning Weight (PWT), Eye-Muscle Depth (EMD), and Fat Depth (FAT) even when only part of the drop is measured.

• Continue genetic progress in years when seasonal or economic pressure limits measurement capacity.

This also benefits commercial clients, who depend on accurate ASBVs when purchasing rams. Reliable data ensures that stud breeding decisions remain transparent and performance driven.

Putting It Into Practice

1. Genotype early – Test all lambs at marking or weaning to identify high-genetic-merit animals before major feed costs begin.

2. Use genomic rankings to target phenotyping – If measuring all isn’t possible, focus on the top 50 per cent by genomic index.

3. Maintain genetic reference quality – Keep some phenotyping across a range of animals to ensure you remain well related to the genomic reference population.

4. Tailor strategies – Prioritise traits most relevant to Poll Dorset breeding (growth rate, muscle depth, fat cover).

5. Think long-term – Efficiency now shouldn’t compromise future genetic gain.

The Takeaway

When feed and labour are limited, genotyping all animals and phenotyping the top 50 per cent offers the best balance of cost, accuracy, and genetic progress. This approach minimises bias, preserves ASBV reliability, and keeps Poll Dorset studs focused on producing high-performance rams that deliver consistency and value, even in tough years. However, selectively phenotyping for ASBVs should not become an annual practice, reserve it for exceptional circumstances to avoid long-term impacts on data quality and genetic progress.

Learn More

Neogen’s Smart Flock Elite genomic test helps breeders make early, confident selection decisions across economically important traits.

For more information, visit www.sheepdna.com.au or contact Neogen Australasia on (07) 3736 2134 or naa-sheep@neogen.com.

Reference: B.E. Clarke , D.J. Brown , P. Bradley and A.A. Swan. GENOTYPING REDUCES PRESELECTION BIAS ON MERINOSELECT ASBVS IN MERINO FLOCKS (2025) Proc. Assoc. Advmt. Anim. Breed. Genet. 26: 463-466