The effects of copper source and concentration on growth performance, carcass characteristics, and pen cleanliness in finishing pigs.

A total of 1,143 pigs (PIC 337 × 1050, initially 25.1 ± 0.03 kg BW) were used in a 111-d study to determine the effects of copper sulfate (CuSO; Prince Agri-Products, Quincy, IL) or tribasic copper chloride (TBCC; IntelliBond C; Micronutrients, Indianapolis, IN) on growth performance, carcass characteristics, and pen cleanliness. Pens of pigs were allotted to 1 of 6 dietary treatments, balanced on average pen weight in a randomized complete block design with 25 to 28 pigs per pen and 7 replications per treatment. Treatments included a corn-soybean meal-based diet (corn-soy), a high-by-product diet with 30% distillers dried grains with solubles and 15% bakery meal (by-product diet), and the by-product diet with 75 or 150 mg/kg added Cu from CuSO or TBCC. All diets contained 20 mg/kg Cu from CuSO in the trace mineral premix. At the conclusion of the trial, a digital photo of each pen was taken to allow 3 independent observers to score manure texture and buildup and to assess pen cleanliness prior to power washing. Furthermore, the time required to power wash each pen was also measured. Overall, pigs fed the by-product diet tended to have increased ADFI ( = 0.083) and had decreased G:F ( = 0.005) compared to those fed the corn-soy diet. No Cu source × level interactions or Cu source differences were observed ( > 0.05). From d 0 to 71, pigs fed increasing Cu had increased (quadratic, < 0.05) ADG, d 71 BW, and ADFI. From d 71 to 111, pigs fed increasing Cu tended to have increased ADFI (linear, = 0.068) and decreased G:F (quadratic, = 0.056). Overall (d 0 to 111), increasing Cu increased (linear, < 0.01) ADG, final BW, and ADFI (quadratic, = 0.026). Hot carcass weight increased (linear, = 0.023) by 2.4 kg with increasing Cu. Increasing Cu also increased loin depth (linear, = 0.019) and percentage lean (quadratic, = 0.024). Manure buildup and wash time (s/pen) increased ( < 0.05) for by-product diet pens compared to corn-soy pens; however, neither wash time nor pen cleanliness were influenced by added Cu. In summary, increasing dietary Cu in high-by-product diets improved growth and feed intake, resulting in increased final BW and HCW for pigs fed both Cu sources, without influencing pen wash time.

Effects of distillers dried grains with solubles and added fat fed immediately before slaughter on growth performance and carcass characteristics of finishing pigs.

The addition of dietary fat has been shown to increase HCW and carcass yield in pigs fed low-fiber corn-soy diets; however, data on added fat in high-fiber, low-energy diets is less available. Therefore, the potential for dietary fat to ameliorate the negative effect high-fiber diets have on carcass yield during the last 3 wk before slaughter is of high importance. This experiment was conducted to determine the interactive effects of 30% distillers dried grains with solubles (DDGS) and 5% added fat fed before slaughter on growth performance and carcass characteristics. A total of 1,258 pigs in 2 groups (initially 105.8 ± 0.1 kg BW; group 1 PIC 337 × 1,050; group 2 PIC 327 × 1,050) were used in a 20-d experiment. All pigs were fed a common diet with 30% DDGS until 20 d before slaughter. Then, all pens were weighed and allotted to treatments with 20 replicate pens per treatment. Dietary treatments were arranged in a 2 × 2 factorial with 2 diet types (corn-soybean meal-based with or without 30% DDGS) and added fat (0 or 5%; group 1 = tallow; group 2 = choice white grease). Diets were formulated to a constant standardized ileal digestible Lys:NE ratio. There were no treatment × group interactions for any response criteria. Thus, data for the 2 groups were combined for analysis. Overall, there was a tendency for a diet type × added fat interaction for ADG ( = 0.054), whereas this was significant for G:F ( = 0.008). This was a result of 5% added fat increasing ADG and G:F to a greater magnitude for pigs fed the diet containing 30% DDGS (8.6 and 10.4%, respectively) than for pigs fed the corn-soy diet (2.0 and 2.9%, respectively). Although diet type did not affect final live BW, pigs fed the diet containing DDGS had decreased HCW and carcass yield ( < 0.05). Adding 5% fat did not affect carcass yield. In conclusion, adding 5% fat to finishing pig diets containing 30% DDGS approximately 20 d before slaughter improved ADG and G:F but did not overcome the reduction in carcass yield from feeding DDGS.