A University of Nebraska study suggests that feed alternatives, such as dried distillers grains with solubles (DDGS) and phytase, can replace expensive calcium-phosphates in grow-finish diets while maintaining growth performance.
To evaluate this practice, a 12-week study was performed using 24 crossbred barrows, individually penned, placed on test at 86.7 lb. with ad libitum access to feed and water.
Four diets were studied: a traditional corn-soy diet; a corn-soy diet with 1,000 FTU of phytase; a corn-soy diet with 20% DDGS; and a corn-soy diet with 20% DDGS, 1,000 FTU of phytase and no supplemental inorganic phosphorus (Table 1).
Pigs were fed in three phases. Phase 1 was 90-125 lb., Phase 2 was 125-185 lb. and Phase 3 was 185-260 lb.
Diets met nutritional standards except for phosphorus, which was formulated to be adequate in available phosphorus for the corn-soy and 20% DDGS diet without phytase treatments.
Adding 20% DDGS to the diet allowed reduction in dicalcium-phosphate levels needed to meet phosphorus requirements.
Based on phytase manufacturer claims, 0.05% added phytase liberates up to 0.20% available phosphorus, meaning the available phosphorus shown in Table 1 represents only the available phosphorus estimates before phytase liberation of additional available phosphorus. Phytase levels remained the same for all three phases of the trial to supply available phosphorus at or above nutritional requirements.
Growth performance data is shown in Table 2. Treatment did not impact any growth parameters during the first grower phase (90-125 lb.). Pigs fed the diet with phytase and no DDGS produced the lowest average daily gain and average daily feed intake (1.73lb./day and 4.75 lb./day, respectively).
In the grower period, the combination of DDGS and phytase (90-125 lb.) resulted in the greatest reduction of price per ton of feed ($15) compared to the traditional diet, without affecting animal performance.
For the second and third (finisher) phases (125-185 lb. and 185-260 lb., respectively), no differences were observed in average daily gain, average daily feed intake or feed efficiency.
Small differences between treatments indicate that phytase and DDGS inclusion in diets separately or together can reduce or eliminate the need for calcium-phosphates in latter growth stages.
There were no differences observed among the treatments during the three feeding phases for the growth performance parameters measured.
Based on the cost per ton of each dietary treatment (using Aug. 27, 2008 prices), the addition of DDGS and phytase separately or together can reduce feed costs.
Importantly, DDGS inclusion in diets can also reduce the amount of other ingredients, which also reduces feed cost.
Overall, these results concur with other research that DDGS and phytase can totally replace calcium-phosphates in nursery diets. Properly formulating diets with phytase and DDGS can reduce or eliminate dependence on traditional phosphorus sources in grow-finish diets.
Researchers: Justin Bundy, Phillip Miller, Roman Moreno, Thomas Burkey, Erin Hinkle and Huyen Tran, all of the University of Nebraska. For more information, contact Phillip Miller by phone (402) 472-6421, fax (402) 472-6362 or e-mail pmiller1@unl.edu.