PSXIV-10 Estimation of Genetic Parameters of Traits Associated with Water Efficiency, Feed Efficiency and Growth in Beef Cattle

Abstract

Abstract Concerns about water availability, quality and accessibility have intensified. The livestock industry, particularly the beef sector, is under pressure to adopt more sustainable practices that optimize water usage while improving growth and feed efficiency. The objective of this study was to estimate the genetic parameters of traits associated with water efficiency, feed efficiency and growth in beef cattle. The data were collected from 916 seedstock bulls and heifers representing six breeds (Angus, Charolais, Hereford, Limousin, Simmental and Sim-Angus) in a facility equipped with Vytelle SENSE feed intake, water intake and in-pen body weight recording systems, located at the West Virginia University central testing facility in Wardensville, WV. The animals were part of six performance tests between November 2019 and September 2022, with an average age at the start of the test of 284 days, and an average test duration of 73 days. The rations were formulated to achieve 1.5 to 1.6 kg/d ADG (depending on the test) and had a high forage inclusion (>75% corn silage and >15% dry hay, as fed). The facility consists of 5 pens and animals were rotated every two weeks through the pens, so all animals are exposed to all pens. The phenotypes analyzed were average daily water intake (DWI), residual water intake (RWI), average daily dry matter intake (DMI), residual feed intake (RFI), and average daily gain (ADG). RWI and RFI were used to measure the water and feed efficiency of the animals. The genetic parameters were estimated with multi-trait animal models using Echidna mixed model software. In all models, breed, sex and the contemporary group (trial number and pen group) were included as fixed effects, the age at the start of the test was added as a covariate, and the animal was treated as a random effect. RWI and RFI were analyzed by adding ADG and metabolic mid-weight as additional covariates. The estimates of heritability for DWI, RWI, DMI, RFI and ADG were 0.49 (± 0.11), 0.40 (± 0.10), 0.35 (± 0.11), 0.16 (± 0.07) and 0.47 (± 0.11) respectively. Average daily water intake exhibited a positive genetic correlation with RWI (0.90), DMI (0.71), and ADG (0.76). On the other hand, the genetic correlation between RWI and RFI was not significantly different from zero, and genetic correlation between RWI and ADG was slightly positive. These results suggest that selecting for enhanced water efficiency in beef cattle can effectively decrease the daily water consumption without any adverse effect on feed efficiency, although it may have a small impact on growth. The complete genetic and phenotypic correlations are in Table 1. In conclusion, the traits associated with water intake and efficiency in beef cattle have a sizable genetic component and show potential for genetic improvement.