Adding Glycerol Improves Pelleting, Provides Nursery Growth Alternative

Dec 15, 2007 5:20 PM

The diets were fed to 182 pigs in a 26-day growth period. Pigs weighed around 23 lb. at the beginning of the trial, and were randomly allotted to treatment, with between five and six pigs/pen, and five pens/treatment.

The results indicated glycerol can be included in a diet up to 6%, either alone or in combination with soy oil without affecting final body weight in pelleted phase 2 nursery diets. Pigs fed increasing levels of glycerol had increased average daily feed intake (ADFI). Feed:gain increased with increasing soy oil or the soy oil/glycerol blend, resulting in similar average daily gain between pigs fed soy oil, glycerol or the 50:50 soy oil/glycerol blend.

Adding glycerol to the diet did not influence feed:gain compared to the control. Results of the feeding trials are shown in Table 4.

Glycerol could be added in place of corn in some swine diets to decrease diet cost, according to the researchers. Glycerol's benefits during the pelleting process can also help lead to energy savings for the production mill.

Researchers: Crystal N. Groesbeck; Leland. J. McKinney; Joel M. DeRouchey; Mike D. Tokach; Robert D. Goodband; Jim L. Nelssen; Steve S. Dritz, DVM; Allen W. Duttlinger; and Keith C. Behnke, Kansas State University. Contact Groesbeck at 785-532-1270 or email cgroesbe@ksu.edu.

**Table 1. Effects of Added Glycerol on Pellet Production Efficiency, Exp. 1ab**
	Added Glycerol, %
Item	0	3	6	9	12	15
Conditioning temperature, °F	149.7	150.0	150.2	150.2	149.8	149.8
Hot pellet temperature, °F	169.1	167.8	166.1	169.9	161.9	163.0
Delta temperature, °F	18.9	17.3	15.5	19.2	11.7	12.6
Voltage, volts	250.4	250.0	248.9	252.3	250.1	250.3
Amperage, amps	29.3	25.2	23.6	22.9	19.5	18.1
Motor load, %	54.7	45.7	41.7	41.0	33.3	30.3
Pellet durability index
Standard, %	90.1	92.1	93.5	95.7	94.9	94.7
Modified, %	87.5	89.4	91.2	93.9	92.3	91.6
Production rate, tons/hour	1.32	1.27	1.24	1.11	1.09	1.10
Total energy, kilowatt hour/ton	7.62	6.81	6.51	7.09	6.10	5.60
aAll diets were corn-soybean meal-based swine grower diets. bEach experimental diet was replicated by manufacturing a new batch of feed three times.

**Table 2. Effects of Added Glycerol on Pellet Production Efficiency, Exp. 2ab**
		Soy Oil		Glycerol		Blendc
Item	Control	3%	6%	3%	6%	6%	12%
Conditioning temp., °F	150.4	151.3	150.6	151.3	150.5	151.1	150.4
Hot pellet temp., °F	171.1	165.5	161.0	165.4	164.1	159.9	156.7
Delta temp., °F	20.2	13.9	10.0	13.7	13.2	8.4	5.9
Voltage, volts	247.7	249.9	245.8	248.4	250.1	249.4	249.3
Amperage, amps	28.3	23.0	19.6	23.7	22.8	20.9	16.0
Motor load, %	53.6	45.9	34.6	42.9	41.6	36.3	26.9
Pellet durability index
Standard, %	92.6	81.6	58.3	94.7	95.5	85.4	80.3
Modified, %	89.9	74.7	40.0	91.9	92.2	78.3	65.8
Production rate, tons/hour	1.38	1.42	1.40	1.35	1.38	1.40	1.36
Total energy, kilowatt hour/ton	7.58	6.09	5.16	6.50	6.18	5.45	4.44
aAll diets were formulated to the same lysine to metabolizable energy ratio. bEach experimental diet was replicated by manufacturing a new batch of feed three times; each run consisted of 750-lb. batches. cAddition of 50% soy oil and 50% glycerol.

**Table 3. Effects of Added Glycerol on Pellet Production Efficiency, Exp. 3a**
		Lactose		Glycerol
Item	Control	3.6%	7.2%	3.6%	7.2%
Conditioning temperature, °F	150.3	150.2	150.3	149.7	150.3
Hot pellet temperature, °F	166.9	168.3	171.3	164.5	158.3
Delta temperature, °F	16.5	18.2	20.9	14.7	8.0
Voltage, volts	252.2	251.9	248.0	251.7	252.3
Amperage, amps	21.6	22.2	23.0	19.3	17.2
Motor Load, %	33.8	37.1	38.4	30.1	27.1
Pellet durability index
Standard, %	86.1	88.5	90.1	89.9	91.8
Modified, %	87.0	89.2	90.8	89.8	92.0
Production rate, tons/hour	0.98	1.03	1.02	0.99	0.97
Total energy, kilowatt hour/ton	8.10	8.00	8.20	7.20	6.60
aEach experimental diet was replicated by manufacturing a new batch of feed three times; each run consisted of 750-lb. batches.

**Table 4. Effects of Glycerol on Pellet Mill Production and Nursery Pig Performance**
		Soy oil, %		Glycerol, %		Blend, %
Item	Control	3	6	3	6	6	12
Pellet mill data
Amperage, amps	28.2	23.0	19.6	23.7	22.8	20.9	16.0
Motor load, %	53.6	45.9	34.6	42.9	41.6	36.2	26.9
Production efficiency, kilowatt hour/ton	7.8	6.1	5.2	6.5	6.2	5.5	4.3
Pellet durability index, %	93.0	81.6	58.3	94.7	95.5	85.4	80.3
Day 0 to 26
Average daily gain, lb.	1.17	1.26	1.22	1.25	1.26	1.22	1.25
Average daily feed intake, lb.	1.73	1.73	1.68	1.79	1.80	1.67	1.68
Feed/gain	0.68	0.73	0.73	0.70	0.70	0.73	0.74
Final weight, lb.	54.34	56.76	55.88	56.76	56.76	55.88	56.54