The pork industry faces unprecedented challenges from disease, which increases cost of production and use of antibiotics, and reduces production efficiency, carcass quality, and animal wellbeing. One solution is to improve the overall resilience of pigs to a broad array of common diseases through genetic selection. Behavioral changes in eating and drinking are usually the very first clinical signs when animals are exposed to stressors such as disease. Changes in feed and water intake behaviors in diseased pigs may reflect the way they cope with the challenge and, thus, could be used as indicator traits to selection of disease resilience. The objectives of this study were to estimate genetic parameters of feed and water intake and behavior traits for wean-to-finish pigs in a natural polymicrobial disease challenge model, estimate genetic correlations of feed and water intake and behavior traits with growth rate and clinical disease traits, and to develop indicator traits for selection of disease resilience.
In general, water intake traits had moderate to high estimates of heritability, especially for average daily water dispensed, duration, and number of visits (0.44 to 0.58). Similar estimates were observed for corresponding feed intake traits (0.35 to 0.51). Most genetic correlation estimates among drinking traits were moderate to high (0.30 to 0.92) and higher than among feeding traits (0 to 0.11). Compared to other water intake traits, water intake duration and number of visits had relatively stronger negative genetic correlation estimates with treatment rate and mortality, especially across the challenge nursery and finisher (-0.39 and -0.45 for treatment rate; -0.20 and -0.19 for mortality).
Most water and feed intake traits under severe disease challenge had moderate to high estimates of heritability, especially for feed or water intake duration and number of visits. Phenotypic and genetic correlations among feed intake traits under disease were generally low but water intake traits showed high correlations with each other. Water intake duration and number of visits are potential indicator traits to select for disease resilience because of their high heritability and had moderate genetic correlations with treatment and mortality rates under severe disease.