In research conducted at the University of Illinois, choice white grease had a higher energy value than soybean oil, according to a team of scientists.
These results help to assign accurate values to different fats, ensuring best growth rate and feed efficiency at lowest feed cost, says University of Illinois professor James E. Pettigrew. Having the correct relative energy values for various fats could save producers $2/ton or more.
“Pork producers need to correctly evaluate dietary fats, such as soybean oil and choice white grease, for grow-finish pigs because a recent report showed higher net energy for choice white grease than for soybean oil,” he says.
Two recent studies were conducted at the University of Illinois to determine whether responses of finishing pigs (from about 150 lb. to market weight) would confirm that difference and to apply the observations to other sources.
In the first study, a total of 135 barrows housed in 45 pens were placed on one of the following five dietary treatments:
• A corn-soybean meal diet without added fat;
• Added fat plus 3% soybean oil;
• Added fat plus 6% soybean oil;
• Added fat plus 3% choice white grease; or
• Added fat plus 6% choice white grease.
There were two diet phases in the trial: Day 1-21 for Phase 1 and Day 21-49 for Phase 2. Dietary treatments within each phase were formulated to contain equal standardized ileal digestible lysine/Mcal of metabolizable energy.
The results of the first study are shown in Table 1. Pigs fed all-fat diets were more efficient in Phase 1 (7.9%), Phase 2 (10%) and overall (8.6%) than pigs fed the control diet. Pigs fed 6% fats were more efficient in Phase 2 (9.4%) and overall (8.6%) than pigs fed 3% fat. Pigs fed choice white grease had higher average daily gain (7.6%) and were more efficient (5%) in Phase 1 than pigs fed soybean oil.
In the second study, a total of 144 barrows were housed in 48 pens and placed on one of six dietary treatments:
• A corn-soybean meal diet without added fat;
• Added fat plus 6% soybean oil;
• Added fat plus 6% choice white grease;
• Added fat plus 6% palm oil;
• Added fat plus 6% animal-vegetable blend; or
• Added fat plus 6% tallow.
Again, there were two dietary phases: Day 1-19 for Phase 1 and Day 19-47 for Phase 2. Dietary treatments within each phase were formulated to contain equivalent standardized ileal digestible lysine/Mcal of metabolizable energy.
The results of the second study indicated that pigs fed soybean oil, palm oil, animal-vegetable-blend and tallow were all more efficient in each phase and overall, and grew faster in Phase 1 than pigs fed the control diet. Pigs fed choice white grease had greater average daily gain (9.9%) than those pigs fed soybean oil in Phase 1.
Researchers concluded that the first study indicated that choice white grease had a higher energy value than soybean oil. The second study confirmed that different fats may produce different practical results, consistent with different energy values.
Results of both trials confirmed the performance benefits of added fats.
Researchers: Y. Liu, D.Y. Kil, V.G. Perez-Mendoza and J.E. Pettigrew, all of the University of Illinois at Urbana. Contact Pettigrew by phone (217) 244-6927, fax (217) 333-7861 or e-mail jepettig@illinois.edu.