Breeding goals & design

Developing the Rwandan Dairy Profit Index

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Abstract

This study presents the development of an economic breeding objective and selection index (the Rwanda Dairy Profit Index - RDPI) to rank bulls for the Rwandan dairy industry. Supported by the Rwanda Agriculture and Animal Resources Development Board and the Royal Jersey Agricultural and Horticultural Society, the RDPI has been developed as a genetic selection tool that can be used to support import decisions for exotic bulls, for use via artificial insemination. Economic values were calculated for milk yield (per 1 litre), fertility (NR56) (per 1%), calving interval (per 1 day), cow mature weight (per 1 kg), and longevity (per 1 day), along with discounted genetic expression coefficients. Scaling factors were applied to adjust UK-derived Predicted Transmitting Abilities (PTAs) for differences in mean phenotypic levels between Rwanda and the UK, to reflect the Rwandan production environment. Applied economic weights, in RWF per trait unit, were +97.68 for milk yield, +213.20 for fertility, -2,405.46 for calving interval, -2,773.66 for cow mature weight, and +455.17 for longevity. The RDPI was tested using across-breed PTAs from 1,982 UK and international bulls, taken from the UK national genetic evaluation. Comparing the average PTAs of the top 100 bulls on the UK indexes and the RDPI, the RDPI favour bulls with daughters that have lower milk yield compared to the PLI, SCI, and the ACI. The top 100 bulls on the RDPI have lower milk fat and protein, higher fat and protein percentage, higher somatic cell count, longer calving interval, smaller mature weight, and lower NR56 compared to the PLI, SCI, and the ACI. The top 100 bulls on the RDPI have higher longevity compared to the PLI and SCI and equivalent longevity to those ranked on the ACI. The breeding objective and associated RDPI generates a very different ranking of exotic bulls, when compared to indexes designed for industrialised dairy industries (using UK indexes as an example). The average economic merit of the top 100 bulls, based on the underlying RDPI breeding objective, drops by an average of 37% when bulls are ranked in the PLI, SCI, and ACI. This suggests that bulls selected on the UK indexes will not deliver the most profitable outcomes in the Rwandan production environment. The RDPI is the first dairy breeding objective and selection index created for the Rwandan dairy industry and thus represents an advancement in data-driven genetic selection for the industry. Aligning selection decisions with local profitability drivers, via use of the RDPI, offers an opportunity to enhance productivity and profitability in the Rwandan industry and will require ongoing refinement as local data and breeding programs mature, and breeding goals evolve.

Keywords: 2026

How to Cite:

Byrne, T., Balogun, I., Kirk, T., Chizk, M., Savoia, S., Shumbusho, F. & Hambrook, D., (2026) “Developing the Rwandan Dairy Profit Index”, World Congress on Genetics Applied to Livestock Production Digital Archive 2026(1): 2272208. doi: https://doi.org/10.31274/wcgalp.23412

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