Assessing the interaction of stocking density and dietary energy concentration on finishing pig performance

Abstract Text:

The objective of this study was to determine if the dietary energy that maximizes performance is dependent upon stocking density. A total of 932 pigs (PIC Camborough Plus x 327) were used within three replications of 18 trt. Treatments arranged as a 2 x 3 x 3 factorial included: gender (barrows and gilts), dietary energy (2.15, 2.3 and 2.45 Mcal NE/kg) and stocking density (14, 17 or 20 pigs/pen providing 0.92, 0.76 and 0.65 m²per pig, respectively). Pigs were randomized to pens within gender and pens were balanced for initial BW (75 kg/pig). Wheat and barley based diets were formulated to meet or exceed the pigs’ nutrient requirements (NRC 2012) and were fed in three phases within gender for each energy concentration. Dietary energy was varied using tallow and oat hulls. The SID lysine/NE ratios were constant within each phase and energy concentration. Pigs were weighed weekly, feed was weighed daily, and pigs were marketed at 120 kg BW. Overall, as the dietary energy increased from 2.15 to 2.45 Mcal NE/kg, feed intake decreased from 3.98 to 3.69 kg/d, ADG increased from 1.20 to 1.26 kg/d, G:F improved from 0.31 to 0.34 and caloric intake increased from 8.50 to 9.11 Mcal NE/day (P<0.05). Increasing stocking density from 14 to 20 pigs/pen decreased ADG ( 1.25 to 1.20 kg/d), ADFI (3.98 to 3.69 kg/d) and caloric intake (9.11 to 8.50 Mcal NE/day) (P<0.05). There was no effect of dietary energy concentration or stocking density on caloric efficiency (Mcal NE/kg gained, P>0.05). The improvement in ADG with increasing dietary energy was greater for barrows (dietary energy by gender, P<0.05). The dietary energy concentration which maximized growth was not affected by stocking density (stocking density by dietary energy, P>0.05). In conclusion, the performance of growing finishing pigs was improved by increasing the dietary energy and decreasing stocking density, but an interaction was not observed.

Keywords: dietary energy, stocking density, swine