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Nebraska Index Line Genetics Return $23.76/pig University of Nebraska researchers project returns of $23.76/hog marketed, based on a simulated 1,250-sow, farrow-to-finish farm stocked with Nebraska Index Line females. The index line was developed with 19 generations of selection for increased litter size. (see The Pigs/Litter Bar Has Been Raised, National Hog Farmer, Jan. 15, 2001). Using biological

Nebraska Index Line Genetics Return $23.76/pig

University of Nebraska researchers project returns of $23.76/hog marketed, based on a simulated 1,250-sow, farrow-to-finish farm stocked with Nebraska Index Line females.

The index line was developed with 19 generations of selection for increased litter size. (see “The Pigs/Litter Bar Has Been Raised,” National Hog Farmer, Jan. 15, 2001).

Using biological data, the researchers simulated 1,250-sow farms stocked with either the index line or the control line, which represented the original genetic line with random selection only. Each was a closed herd that used natural service to propagate the pureline females. Danbred Landrace semen was used to produce F1 gilts, which were then bred with Danbred terminal line semen to produce market pigs.

Table 1. Reproductive Statistics and Estimated Number of Index and Control Sows Necessary to Maintain a 1,250-Breeding Sow Operation
% FRb NBAc DLd Litterse % of
Replacements Market
C 98.2 8.49 0.20 116 4.0 41 733
L × C 81.5 8.27 0.20 160 5.5 339 524
T(L × C) 86.5 10.37 0.20 2,635 90.5 - 18,909
Total 2,912 100.0 380 20,166
I 93.5 10.90 0.20 116 4.0 37 909
L × I 84.3 10.28 0.20 131 4.5 345 564
T(L × I) 88.9 12.11 0.20 2,664 91.5 - 22,944
Total 2,912 100.0 382 24,417
aC = Control, I = Index, L × C = Landrace × Control, L × I = Landrace × Index, T (L × C) = Terminal DH × (Landrace × Control) 3-way cross, T (L × I) = Terminal DH × (Landrace x Index) 3-way cross.
bFR = Farrowing rate of gilts and sows designated for breeding.
cNBA = Number born alive per litter.
dDL = Death loss.
eLitters = Number of litters per year.

Based on the data, the index herd produced 24,417 pigs/year. The control herd produced 20,166 pigs/year. (See Table 1.)

The model assumed pigs were weaned at 12 days and raised in a nursery until Days 55 to 60, when they moved to a finishing building. Market weight was set at 250 lb.

Housing costs were set at $130/pig for nursery space, $175/pig for finishing and $1,100/breeding female for breeding, gestation and farrowing.

Depreciation was figured at 15 years for buildings, 10 years for major equipment and five years for minor equipment.

Other costs were obtained from the 1999 Iowa State University Swine Report, the Maternal Line Genetic Evaluation Program Economic Analysis and a local Nebraska producer.

The gross income per pig was calculated on the Sioux Preme Packing Co. matrix. Pureline pigs were predicted to have carcass value of 93% of the base price. The F1 pigs were predicted to have 102% of the base price. The terminal cross pigs earned 103% of the base price. The base carcass price was $64.67/cwt.

Feed efficiency differed between the pureline, F1 and terminal cross pigs, because pureline pigs took 31 more days to market and their feed: gain ratio was 0.59 poorer than the terminal cross pigs.

Table 2. Income Statement for Integrated Breeding Systema
Line I L × I T (L × I)
Gross revenue/pig sold $105.47 122.62 127.49
Less death loss cost/pig sold $1.62 1.62 1.62
Net revenue/pig sold $103.85 121.00 125.87
Variable costs/pig sold
Feed costs $61.00 45.10 41.31
Labor costs $13.10 13.10 13.10
Veterinary, drugs and supplies $1.60 1.60 1.60
Utilities $2.22 2.22 2.22
Fuel and oil $0.40 0.40 0.40
Water costs $1.98 1.98 1.98
Building and equipment repairs $2.52 2.52 2.52
Transportation costs $1.35 1.35 1.35
Semen cost - $13.10 1.32
Waste management $1.50 1.50 1.50
Marketing $4.00 4.00 4.00
Interest on variable costs $2.85 2.85 2.85
Total variable costs/pig $92.52 89.72 74.15
Contribution margin/pig 11.33 31.28 51.72
Fixed cost/pig sold
Building depreciation (15 year) $8.43 8.43 8.43
Major equipment depreciation (10 year) $0.65 0.65 0.65
Depreciation on minor equipment (5 year) $0.16 0.16 0.16
Interest on buildings and major equipment $4.76 4.76 4.76
Insurance and taxes on buildings and major equipment $2.80 2.80 2.80
Professional fees $1.00 1.00 1.00
Maintenance cost (breeding stock) $8.18 8.18 8.18
Total fixed costs/pig sold $25.98 $25.98 $25.98
Net return per/sold $-14.65 $5.30 $25.74
Number of pigs sold 909 564 22,944
Net return on total Number of pigs sold $-13,313.47 $2,991.30 $590,663.91
Total net return $580,341.74
Rate of return on investment 18%
Cash return/pig soldb $-5.41 $14.54 $34.98
aI=Index line; L × I = Danbred USA Landrace × Index, and T (L × I) = Duroc-Hampshire (L × I).
bCash return/pig sold = net return/pig sold plus all depreciation costs.

Semen costs were different. The pureline pigs were produced by natural service, and the maintenance of sows, boars and gilts was assigned as $8.18/pig. Semen cost was $13.10 for the F1 pigs and $1.32 for the three-way cross pigs. (See Table 2 for all costs.)

The net return for the pureline pigs was -$14.65/pig, because they grew slow, had poor feed conversion and had substandard carcasses. The return improved for the F1 pigs and was $5.30/pig. Finally, the net return was $25.74/pig for the terminal cross hogs.

Based on those net returns, the 1,250-sow model had a total net return of $580,341.74 and a return on investment of 18%.

Researchers: Rodger Johnson, Derek Petry and Brian McAllister, University of Nebraska. Phone Johnson at (402) 472-6404 or e-mail

Keep Distance Between Boars And Sows

University of Illinois researchers found length of estrus was shorter for sows housed adjacent to boars and lasted 43 hours. That compared to 57 hours for sows housed in crates or pens which were at least 50 ft. from the boar pens.

Researchers found that housing sows in crates had no detrimental effect on their ability to detect estrus.

In the experiment, pigs were weaned at 21 days and 122 mixed parity sows randomly assigned by parity to one of three treatments — crate housing at least 50 ft. from boars, pen housing at least 50 ft. from boars and pen housing adjacent to the boars.

Estrous detection began at 6 a.m. four days after weaning and was performed again in 15 minutes, 30 minutes, one hour, two hours, four hours and eight hours through Day 8 after weaning.

Estrous detection involved observation of the standing response after application of 10 minutes of boar exposure, back pressure and side rubbing.

For sows in crates, the boar was moved to the front of the crate. Sows in pens were moved to a pen adjacent to the boar. Sows penned adjacent to the boar were observed for a 10-minute period.

The percentage of sows expressing estrus within eight days was lower for the sows penned adjacent to boars (81%) versus sows housed in crates (95%) and sows in pens (100%).

Synchrony of estrus was also reduced in the sows penned next to the boars. The percentage of sows detected in estrus on Days 4 to 6 was more than 50%.

On Day 5 after weaning, 48% of sows housed next to boars were detected in estrus, compared to 82% in crates and 89% in pens away from boars.

The housing of sows adjacent to a boar did not shorten the wean-to-estrus interval, which averaged 5.8 days.

Most striking, however, was that regardless of housing system, once a sow was detected standing, the chances of eliciting another standing response was 17% lower, within the eight-hour period from the first boar exposure.

The researchers draw several conclusions from the study. First, maintaining adequate distance between boars and sows is critical for detection of estrus. Second, the time interval between estrous detection stimuli may affect the ability to detect subsequent estrus. Third, there is no negative effect of housing system on detection of estrus for crates when compared to pens, when both systems maintain effective separation. Finally, sows housed adjacent to boars have shorter estrous periods, therefore artificial insemination timing may need adjustment.

Researchers: Rob Knox, Shawn Breen, Stacy Roth, Kilby Willenburg, Gina Miller, Kelli Ruggerio and Sandra Rodriguez-Zas, University of Illinois. Phone Knox at (217) 244-5177 or e-mail