Form and Function

Phenotypes in livestock, usually defined as the physical manifestation of genetic traits or the "set of observable characteristics of an individual resulting from the interaction of its genotype with the environment", are a key element for genetic selection and herd composition decisions. From an animal science perspective, this usually equates to the actual performance of the animal under given conditions or in a particular environment, such as milk production or weight gain in feedlots. With recent advances in agtech and ML/AI, new phenotypes are being actively researched and compiled related to climate impact, including but not limited to, lifetime carbon footprint, methane emissions, and pasture forage intake.

For context, some of the most common phenotypes are weaning weights, carcass traits, milk production, teat, and udder scores, etc for both dairy and beef cattle. In the case of beef bulls or sires – other phenotypes are related to foot angle, claw set, sheath, gait, or other traits that affect physical ability to cover cows across various terrain.

Furthermore, these traits can be correlated with economic value. These "economic index values" give higher weights to traits that drive profitability or other production goals with monetary value. Many if not all major breed associations usually indicate such EPDs with a "$" sign.

A key example emerges out of the dairy industry in Ireland. According to the ICBF the goal with the creation of the $Carbon sub-index was to 'accelerate the rate of genetic gain in the national herd by breeding more efficient and environmentally friendly dairy cows'. Currently, the Irish Economic Breeding Index now contains a 'carbon sub-index' in the overall calculation and increases weight of physical traits that reduce emissions which is then pegged to the price per ton of carbon (https://www.farmersjournal.ie/dairy/breeding-and-health/carbon-sub-index-added-to-the-ebi-733833) .

Lactanet , a dairy industry and governmental R&D group out of Canada, has also developed a methane efficiency index which is defined as "methane production genetically independent of milk, fat, and protein yields". The index was developed by "collecting methane (CH4) emission and milk MIR spectral data on individual cows in various research herds." The key goal was to control for methane emissions without adversely impacting yield or production levels.

As for the beef side of the equation, work out of CSIRO done in collaboration with the Australia Brahman Breeders Association, is seeking to establish Grazing Feed Efficiency Enhanced Breeding Values (EBVs). This effort is being accomplished by using CERES TAG ear tags that use algorithms to track data and convert it "into animal behavior characteristics, time grazing, resting, ruminating, walking, drinking and other actions.” Paired or overlayed with soil carbon accrual studies, the actual impact of herd grazing patterns can be further correlated with SOC outcomes.

Overall, both industries are seeing the value in these newly measurable phenotypes. Such traits and their phenotypes will pay dividends going forward for both the sustainability of the dairy and beef industries.

Sources:

https://www.beefcentral.com/genetics/smart-tags-aid-in-bin-project-steers-used-for-grazing-feed-efficiency-research/

https://www.agproud.com/articles/58489-the-ongoing-debate-over-epd-vs-phenotype#:~:text=A%20phenotype%20is%20what%20we,weather%2C%20feeding%20ration%2C%20etc.

https://beef.unl.edu/using-epds-and-economic-index-values

https://lactanet.ca/en/introducing-methane-efficiency/#:~:text=Methane%20Efficiency%20is%20a%20functional,and%20105%20(Figure%201).