The repeatability of individual nutrient digestibility in pigs

Digestibility of nutrients in pig diets is an important component of overall feed efficiency. Targeted improvement of digestibility is currently mainly achieved by optimization of pig diets, based on information generated from digestibility trials that aim to establish fecal digestibility coefficients of different nutrients across a variety of ingredients. Genetic selection for nutrient digestibility is hampered by shortage of data on individual digestibility, but might help to further improve efficiency of pork production. The present study aimed to estimate the repeatability of fecal digestibility in pigs, as a first step to judge the perspectives for a breeding approach of nutrient digestibility. To achieve this, data was accumulated across nine digestibility trials, containing 1150 digestibility records of 416 growing pigs, measured across the trials. The data was analyzed with a model estimating variances for trial, diet, common litter, and individual animal effect for digestibility of Dry Matter, Ash, Organic Matter, Crude Protein, Crude fat and Non-Starch Polysaccharides. The factors diet and trial together explained the majority of the phenotypic variance, due to the design of the trials. Within diet and trial, common litter and individual animal effect contributed 0-10% of the phenotypic variance. The repeatability estimates ranged from 7% for Ash to 16% for Crude Protein, which suggests there may be genetic variation between pigs in digestibility. In conclusion, the repeatability estimates indicate it is worthwhile to collect phenotypic data that enable the estimation of genetic parameters for digestibility, if these data can be obtained at reasonable cost.