Two groups of pigs (n = 1,258, initially 233.2 lb; group 1 PIC 337 × 1050; group 2
PIC 327 × 1050) were used in a 20-d experiment to determine the effects of 30% dried
distillers grains with solubles (DDGS) and 5% added fat prior to slaughter on growth
performance, carcass characteristics, and economics of finishing pigs. There were a total
of 20 replications per treatment. All pigs were fed a common diet with 30% DDGS
until 20 d prior to slaughter, at which point they were weighed and allotted to dietary
treatments. The dietary treatments were arranged in a 2 × 2 factorial with 2 diet types,
a corn-soybean meal–based diet with or without 30% DDGS and added fat of 0 or 5%
(group 1 = tallow; group 2 = choice white grease). Diets were formulated on a standardized
ileal digestible (SID) lysine basis and balanced on an SID lysine to NE ratio.
There were no treatment × group interactions for any of the measured responses, so data
for the two groups were combined for analysis. For the overall experiment, there was a
tendency (P < 0.10) for a diet type × added fat interaction for ADG; this interaction was
significant (P < 0.05) for F/G and caloric efficiency on an ME and NE basis. These were
the result of pigs fed the diet with 30% DDGS having greater ADG and F/G improvements
when fat was included compared with those fed the corn-soybean meal–based
diet without DDGS. For the caloric efficiency interaction, pigs fed 30% DDGS had an
improvement with added fat, whereas those fed the corn-soybean meal–based diet with
added fat had worse caloric efficiency than pigs fed the corn-soy diet without added fat.
Although diet type did not affect final live weight, pigs fed the diet containing DDGS
had reduced HCW (P < 0.05), which was the result of reduced carcass yield (P < 0.05).
Adding 5% fat to the diet containing DDGS did not improve carcass yield. Jowl fat
iodine value was increased by added fat (P < 0.05) and feeding DDGS (P < 0.05). For
economics, there was a diet type × added fat interaction (P < 0.05) for cost per pound
of gain, which was the result of a larger increase in cost for pigs fed added fat in the
corn-soybean meal–based diet compared with the diet containing DDGS. Income
over feed cost did not differ among dietary treatments. In conclusion, adding 5% fat
to finishing pig diets containing 30% DDGS approximately 20 d prior to slaughter
improved ADG and F/G but did not overcome the reduction in carcass yield from
feeding DDGS.
