Alternative ingredients such as distiller’s dried grains with solubles (DDGS) and wheat middlings can serve as viable alternatives in finishing pig diets. But those dietary choices may be compromised due to resulting poor growth performance and yield.
Producers should consider their effect on performance and their value when considering income over feed costs before deciding whether to use the alternative ingredients.
DDGS and wheat middlings are two common alternative ingredients used to lower the cost of corn and soybean meal for swine diets. DDGS are corn by-products from ethanol production that have about three times the crude fat, protein and fiber of corn, with a similar energy value. DDGS also has a higher bioavailability of phosphorus than corn. Wheat middlings is one of the most common cereal by-products used in swine diets, by-products of the flour milling industry. Wheat middlings have higher crude protein and fiber but are lower in energy than corn.
Limited data exists on feeding DDGS and wheat middlings together in swine diets. In this trial, their value is rate for grow-finish performance, carcass characteristics and carcass fat quality in terms of whether the reduced diets costs make them viable options for grow-finish diets.
A total of 288 pigs were placed on test averaging 103 lb. Pens of eight pigs (four barrows and four gilts) were allotted to one of four dietary treatments that included a corn-soybean-meal-based diet, a diet with 30% DDGS, a diet with 30% DDGS and 10% wheat middlings and a diet with 30% DDGS and 20% wheat middlings (Tables 1 and 2).
Pigs were weighed on Day 0, 20, 36, 52 and 84 to determine average daily gain, average daily feed intake and feed/gain. Treatment diets were formulated to constant standardized ileal digestible (SID) lysine:metabolizable energy ratios within each phase.
Samples of DDGS and wheat middlings were collected and analyzed for nutrient content and amino acid concentration (Table 3) at the University of Missouri Agricultural Experiment Station Chemical Laboratories.
At the end of the 84-day trial, pigs were weighed and shipped to Triumph Foods at St. Joseph, MO, for carcass data collection. Hot carcass weights were measured and each carcass evaluated for percentage yield, backfat, loin depth and percentage lean. Jowl samples were measured for iodine value. Percentage yield was assessed by dividing hot carcass weight by live weight obtained prior to transport to the packing plant.
Overall, pigs fed increased levels of wheat middlings produced lower average daily gain and feed/gain. There was no difference among the four groups for average daily feed intake. Final weights trended lower as dietary wheat middlings increased. Pigs fed up to 20% wheat middlings were unable to offset the lower dietary energy from wheat middlings, thus gaining less and having worse feed efficiency than pigs fed diets without wheat middlings (Table 4).
Increasing wheat middlings in the diet decreased feed cost per pig and feed cost per pound of gain, but also decreased total revenue. Similarly, feeding DDGS decreased feed cost per pig and feed cost per gain. But feeding 30% DDGS increased the income over feed costs (IOFC).
In terms of carcass characteristics, increasing wheat middlings decreased percentage yield and hot carcass weight and tended to decrease loin depth. Pigs fed wheat middlings also had decreased backfat and increased percentage lean. Increasing DDGS from 0 to 30% decreased carcass yield and backfat depth and increased percentage lean and jowl iodine value. The decreased yield may be a result of increased gut fill from being fed higher dietary fiber as the level of DDGS and wheat middlings increased.
Researchers: J.A. Barnes, J.M. DeRouchey, M.D. Tokach, R.D. Goodband, S.S. Dritz and J.L. Nelssen. For more information, contact Barnes by phone (785) 532-1270 or e-mail [email protected]