Comparison of Fat-free Lean versus Lipid-free Soft Tissue Growth

Allan Schinckel, Professor Swine Genetics
Purdue University

Three Equations

1991 for light weight pigs - Purdue, fat-free lean, lbs.
1991 for heavy weight pigs - Purdue, fat-free lean, lbs.
1989 NPPC-Lipid-free Soft Tissue, lipid-free soft tissue, lbs.

Eq. 1 = 10.96 + (.431 CW) - (18.82 FD10R) + (2.358 LEA)

Eq. 2 = 25.19 + (.3668 CW) - (21.18 FD10R) + (2.753 LEA)

Eq. 3 = 11.45 + (.5102 CW) - (19.93 FD10R) + (2.593 LEA)

Compare two pigs, one average pig and one lean pig.

Live Weight, lbs.

CW, lb.

FD10R, in

LEA, in2

EQ. 1

EQ. 2

EQ. 3

Pig 1

250

185

.9

5.6

87.96

89.4

102.4

300

222

1.2

6.4

99.15

98.8

117.4

Difference, lbs.

12.19

9.4

15.0

"Lean" Gain/CW gain

.3294

.254

.4054

 

Pig 2

260

193

.7

7.1

97.7

100.7

114.4

310

233

.85

8.0

114.3

114.7

134.1

Difference, lbs.

16.5

14.0

19.7

"Lean" Gain/CW gain

.4125

.350

.4925

Note: Equation 1 is not really for pigs in this weight range. Equation 2 is for pigs in this weight range. CW=carcass weight, FD10R=10th rib backfat depth

 

For pig 1, equation 2 predicts that only 25.4% of the additional carcass weight is fat-free lean. Equation 3 predicts that 41.25% of the 37 lb. increase in carcass weight is lipid-free soft tissue.

For pig 2, equation 2 predicts that 35.0% of the 40 lb. increase in carcass weight is fat-free lean gain. Equation 3 predicts that 49.25% of the additional carcass weight gain is lipid-free soft tissue gain.

Can these results be true that the rate of gain for lipid-free soft tissue is 40-60% greater than the growth of fat-free lean after 250 lbs. live weight?

Assume the average pig, 25.4% of carcass weight gain is fat-free lean and 10.6% of the marginal carcass weight growth is skin and bone. That means 64% of the additional growth is carcass fat growth. If carcass fat growth contains 23.3% non-lipid components, then the marginal growth of lipid-free soft tissue is 40.54% of carcass weight gain.

With the lean pig, 35.0% of the additional carcass weight gain is fat-free lean. Bone and skin growth is expected to be 15% of the carcass weight gain for lean pigs. With 50% of the marginal carcass gain being fat tissue gain and with the fat tissue containing 28.5% non-lipid components, the marginal growth of lipid-free soft tissue mass is 49.25%.

Lipid-Free soft tissue gain includes the growth of fat-free lean gain and the non-lipid components of the fat tissue both contained within the muscle and dissected fat depots. As the ratio of fat gain to lean gain increases, the ratio of lipid-free soft tissue gain to fat-free lean gain increases.

Lipid-free gain is 20-25% greater than fat-free lean gain from 50 to 250 lbs. live weight. After 250 lbs. live weight, lipid-free soft tissue mass can be 40 to 60% greater than fat-free lean gain due to the high ratio of fat tissue growth to muscle growth. As the ratio of fat tissue growth to muscle growth increases, the extent to which lipid-free tissue growth is greater than fat-free lean growth increases. Because genetic, nutritional, and environmental differences affect the rate and composition of muscle and fat tissue growth, the ratio of non-lipid soft tissue to fat-free lean growth will be quite variable.

 

Growth of Fat-free Lean versus Lipid-free Lean from 220-335 lbs. Live Weight Range

 

Fat-free Lean

Lipid-free Soft Tissue

Live Weight

Barrows

Gilts

Barrows

Gilts

220

67.5

72.1

83.3

88.2

251

78.0

86.2

95.9

102.5

282

84.9

95.9

104.9

114.4

335

96.6

104.9

123.7

130.3

 

Incremental growth per lb. live weight gain.

Weight Range

220-335

.253

.285

.351

.366

251-335

.221

.223

.331

.331

Ratio of lipid-free soft tissue gain to fat-free lean gain.

Weight Range

Barrows

Gilts

220-335

1.39

1.28

251-335

1.50

1.48

a1991 Purdue lean growth trial - can be obtained from data in the Wagner et al., 1999 paper and proceedings to the cooperators of the 1991 lean growth trial (1992).


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