Breeding goals & design

Redefinition of the selection index in response to the expectations of Polish Holstein-Friesian breeders.

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Abstract

A selection index should reflect the desired direction of genetic improvement within a given population. Its development must take into account the current population status, breeder expectations, market trends, and the breed standard, which defines the desired conformation parameters. The selection index formula must be periodically updated because the population changes as a result of breeding efforts, market conditions change and affect breeders' expectations, and opportunities arise to evaluate breeding values for new traits. In Poland, work was undertaken to update the formula for the Production and Functionality (PF) index for the Polish Holstein-Friesian breed. A key motivation was adapting the index to the new breeding value estimation system (the single-step method) and incorporating new traits: resistance to dermatitis digitalis, milking speed, calving ease, and calf survival. In the first stage, the expectations of key stakeholders were determined: breeders, breeding advisors, and insemination entities. Surveys were conducted to identify priorities, which were then translated into the relative weightings of individual traits in the index. In the next stage, a method for combining traits into sub-indices was proposed, and correlation analyses were conducted between the current and new PF index formulas as well as with the EBVs for individual component traits. The new formula includes five sub-indices: production, health (resistance and longevity), fertility, udder together with feet & legs, and functionality (milkability, calving ease, conformation traits). The modified PF index formula results in stronger correlations with health and fertility traits, at the cost of slower genetic gain for conformation traits. The correlation between the current and the new version of the PF index is 0.95. Acceptance of the index by breeders and breeding advisors is key to achieving the predicted response to selection. Only by basing breeding decisions on these selection indices can the estimated genetic gains be translated into population improvement in the desired direction. Breeders have further expectations for the Polish Federation of Cattle Breeders and Dairy Farmers, including a dedicated index for herds using robotic milking systems and the development of evaluations for new traits-especially feed efficiency, mastitis resistance, and resistance to metabolic diseases. This indicates the direction for future work.

Keywords: 2026

How to Cite:

Rzewuska, K., Quinton, C. & Stachowicz, K., (2026) “Redefinition of the selection index in response to the expectations of Polish Holstein-Friesian breeders.”, World Congress on Genetics Applied to Livestock Production Digital Archive 2026(1): 2286371. doi: https://doi.org/10.31274/wcgalp.23965

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