Influence on Growth Performance

Energy System

Ingredient energy values and the dietary energy system utilized must be constantly evaluated to ensure energy costs are minimized. This is because different energy systems provide varying accounting of the differences in energy utilization derived from ingredients based on their composition. The NE system is the most accurate in estimating the energy value of ingredients in a diet and the influence of dietary energy on growth performance. Because of this, diet formulation should be conducted with the net energy system due to the differences in measuring energy losses from digestion and absorption. This will aid in evaluating the different effects dietary energy can have on pig growth and carcass performance.

Growth Performance

Understanding how energy influences maintenance and tissue accretion is important as this will change throughout the grow-finish period and dictate growth performance.

Historically, increasing the energy concentration of the diet has shown to improve pig growth performance (De la Llata et al., 2001). Although, this response is dependent on the pigs’ phase of growth. Producers must understand how pigs respond to dietary energy in the grow-finish phase of production as the growth performance response to increasing energy in the diet can change based on genetics, health status, environmental temperature, and stocking density.

Early in a pig’s life, lean growth and, thus, daily gain, is limited by feed intake. As pigs grow and feed intake increases, lean deposition eventually reaches a plateau, where further increases in energy intake don’t increase growth (Figure 1). In earlier periods where feed intake is lower, a linear response in lean growth can be observed as energy intake increases. Thus, pigs will respond to the increasing dietary energy with increased growth. In situations where feed intake is high and pigs are on the plateau for lean growth, a diminishing response to increasing energy is observed. Whether pigs are on the linear or plateau portion of the response to energy depends on the genetics, health status, and feed intake of the pigs. Producers must understand where the plateau occurs in order to determine optimal energy level in the diet.

Furthermore, increasing the dietary energy concentration in a diet increases feed costs and potentially has negative consequences on carcass composition. An economic evaluation should be conducted to determine if the improvements in pig growth performance are greater than the increased dietary costs associated with the added dietary energy.

Fact Sheet: Energy