Genetic parameters for dry matter intake in beef cattle as a function of water restriction: Insights into environmental sensitivity and genetic-by-environment interactions

Authors: SHAFFER, WILL - Kansas State University; HIDALGO, JORGE - University Of Georgia; BELLO, NORA - The Ohio State University; NOLAND, RYLIE - University Of Missouri; BORMANN, JENNIFER - Kansas State University; WEABER, ROBERT - Kansas State University; KREHBIEL, CLINT - Texas Tech University; CALVO-LORENZO, MICHELLE - Elanco Animal Health, Inc; RICHARDS, CHRIS - Oklahoma State University; PLACE, SARA - Colorado State University; DESILVA, UDAYA - Oklahoma State University; Kuehn, Larry; ROLF, MEGAN - Kansas State University

Submitted to: Journal of Animal Science Supplement
Publication Type: Abstract Only
Publication Acceptance Date: 4/30/2023
Publication Date: 11/6/2023
Citation: Shaffer, W., Hidalgo, J.A., Bello, N., Noland, R., Bormann, J.M., Weaber, R.L., Krehbiel, C., Calvo-Lorenzo, M.S., Richards, C., Place, S.E., DeSilva, U., Kuehn, L.A., Rolf, M.M. 2023. Genetic parameters for dry matter intake in beef cattle as a function of water restriction: Insights into environmental sensitivity and genetic-by-environment interactions [abstract]. Journal of Animal Science Supplement. 101(3):349-350. https://doi.org/10.1093/jas/skad281.414.
DOI: https://doi.org/10.1093/jas/skad281.414

Interpretive Summary:

Technical Abstract: Genetic selection for animals more tolerant or less sensitive to inadequate water availability may become critical to beef production, particularly as water resources become scarce or represent a meaningful cost to producers. The objectives of this study were 1) to explore the genetic component and environmental sensitivity (ES) of dry matter intake (DMI) to water restriction (WR) and 2) to evaluate genetic-by-environment interactions (G×E) with respect to WR using a reaction norm. A group of 788 crossbred steers arranged across seven cohorts were provided feed and water whereby daily water intake (WI) and DMI values were recorded automatically on an individual basis. After an initial acclimation period, data was collected for 70 days in which ad libitum water was provided and baseline WI was determined on each steer. Next, steers were restricted by approximately 10% of their baseline WI every seven days until 50% WR was achieved and subsequently maintained for 42 days. The reaction norm was modeled with a linear random regression allowing for additive genetic animal-specific intercepts and slope parameters as a function of the WR environmental covariate. The relationship covariance matrix for the additive genetic animal parameters was estimated using genotypes. The model was fit using the THR3GIBBSf90 program in the BLUPf90 software. The additive genetic variances for different values of WR and the additive genetic covariances between different values of WR were estimated as covariance functions comprising the WR values, the additive genetic intercept and slope variances, and the additive genetic covariance between the additive genetic intercept and slope parameters. The posterior median (95% highest posterior density) ES to WR, which is represented by the WR covariate in the linear random regression model, was -0.410 (-0.422, -0.399) (kg DMI daily)/(10% WR), indicating a population-level DMI sensitivity to WR. The posterior estimated additive genetic correlation between the additive genetic animal intercept (ad libitum WI) and the additive genetic animal slope (sensitivity to WR) was -0.75 (-0.88, -0.59), indicating selection for increased DMI at ad libitum WI will increase the ES. The posterior median additive genetic correlation between 0% and 25% WR was estimated at 0.96 (0.94, 0.99) and between 0% and 50% WR was 0.78 (0.65, 0.91), thereby indicating G×E had little influence on the estimated breeding values (EBV) ranking of animals as WR increased. The results of this study do not indicate major G×E concerns in DMI with respect to WR and therefore little loss in accuracy of selection due to G×E in a standard animal model; however, ES to WR may be important to producers as selection on DMI at ad libitum WI could increase ES.