That advantage does a wean-to-finish system offer compared to a conventional nursery/grow/ finish production system? The answer: It gets hogs to market 12 days sooner. At least that's the conclusion of a University of Missouri study.

For the study, researchers weaned 2,000 barrows from a 2,400-sow, farrow-to-wean, breeding stock operation over a four-week period. Barrows were the only market animals available for the wean-to-finish study.

Twice a week, researchers weaned 250 pigs at 11 to 14 days of age, placing them in groups that matched the system's normal production flow. In all, 998 pigs were placed in a nursery facility on an isolated site. Two weeks later, another group of 999 pigs entered a total-slat, double-curtain, wean-to-finish facility 50 miles from the other nursery facility.

After spending five weeks (496 pigs) and seven weeks (495 pigs) in the nursery, researchers moved those pigs into a grow/finish unit, all located within the same site.

Barrows in both the conventional wean/grow/finish system and the wean-to-finish system were marketed when 175 to 190 pigs had reached an average weight of 260 pounds. Researchers speculate that marketing both barrows and gilts together would alter the days to market. Traditionally, the fat barrows would be marketed first, then the leaner growing gilts, with the poorer growing barrows and gilts going last. Overall though, you should still see a 12-day difference between wean-to-finish and conventional systems, says Tom Fangman, University of Missouri commercial agriculture Extension veterinarian.

Growth and health performance were similar for botproduction systems. "There were no significant differences in feed efficiencies, but there was a small margin of improvement in the wean-to-finish group," he notes.

Overall, here's how the results came out:

  • There was no observed difference in average daily gain, average daily feed intake or feed efficiency between pigs raised in a wean-to-finish barn vs. those placed in a nursery then moved to a grow/finish barn.
  • When pigs more than 12 weeks old were exposed to Lawsonia intracellularis, a bacterial pathogen that causes ileitis, death losses were higher in a wean-to-finish barn than in the conventional system.

    Due to the reduced pathogen exposure of pigs in the wean-to-finish facility, the pigs responded well to medical treatments, allowing researchers to curb the ileitis. One objective of a wean-to-finish system is to minimize pathogen exposure, notes Fangman. By doing so, it minimizes active stimulation of the immune system, which results in better growth rates. However, when immunologically naive pigs are exposed to a patho-gen lie Lawsonia intracellularis, death loss in wean-to-finish pigs is higher.

  • Clinical signs associated with Colibacillosis, a neonatal E.coli diarrhea, were observed five days after weaning pigs in the conventional nursery. For pigs raised in the wean-to-finish facility, clinical signs occurred 21 days after weaning. With a larger dunging space in the wean-to-finish facility, it took longer for the fecal material to build-up, resulting in more E.coli exposure.
  • Concrete slats in the wean-to-finish barn appeared to be too wide to allow fecal material from small pigs to fall into the pit. This resulted in increased fecal contamination of the environment and exposed young pigs to pathogens.

    "The large slat surface area probably led to pooling urine and feces in the first 2 to 3 weeks," says Fangman. We need to find better ways to manage the bigger slats – clean some material off or find other preventative measures to alleviate exposure." Researchers also found porcine respiratory and reproductive syndrome to be consistent in both systems.

  • If pigs remain in the same group from the nursery to the grow/finish facility, resocialization is minimized. This eliminates some of the wean-to-finish system's benefit, but there was still an advantage. Fangman associates this with the increased pen space during the animal's first eight-week growth phase.

Although wean-to-finish does offer fewer days to market, it comes at a cost. (See sidebar on page 26.) "In a 2,400-sow system with an increased cost of $20 per pig space, labor savings have to exceed $3 per pig in a wean-to-finish system to breakeven," notes Fangman.

However, you may make up the difference in labor savings, because wean-to-finish systems require less power washing and one less move. These reduced hassles may improve employee morale, which may reduce turnover.

"We create an environment to grow a healthier, more efficient pig," says Fangman. "However, these pigs can be more immunologically naive and must be managed in a way to prevent any pathogen transfer from any other pigs in the production system." There are some advantages in terms of system flexibility, which can accommodate future expansion needs. Also, by maintaining low-pathogen exposed pigs, you can potentially reduce antibiotic use, says Fangman.

Calculating the Costs
The main emphasis of the University of Missouri study was to see if the 12-day decline observed in the wean-to-finish group would offset its added $20-per-pig-space cost compared to that of a traditional nursery/grow/finish system. Missouri researchers used the production data gathered from this study along with the known building costs associated with this system in central Missouri. The conclusion was that the breakeven for wean-to-finish was $89.47 per pig; the breakeven for conventionally raised pigs was $86.44. This suggests that the labor advantage would have to be greater than $3 a pig for the wean-to-finish system.

Wean-to-Finish Conventional Grow/Finish
Pig Space
Nursery spaces 0 4,000
Cost per pig space $0.00 $146.38
Finishing spaces 12,000 8,000
Cost per pig space $163.88 $163.88
Facility cost of system $1.966 million $1.896 million
Barrows/week 500 500
Weeks to fill room 2 2

Production Data
Average weight in 10.1 lbs. 9.9 lbs.
Average age in 13 days 13 days
Market weight 260 lbs. 260 lbs.
Days to market 193 205
Average daily gain 1.39 lbs. 1.3 lbs.
Feed efficiency 3.02 2.92
Mortality rate 6.95% 4.5%
Cull hogs sold 2.3% 5.3%

Cost Data
Feed price/ton $114 $114
Medications ($/pig) $1.36 $1.16
Breakeven (assume weaned pig cost of $31 per head)
cost per hundredweight $34.60 $33.82
cost per head $89.47 $86.44

University of Missouri

Weighing Advantages vs. Disadvantages

If you're considering building or converting to a wean-to-finish facility, Tom Fangman, University of Missouri commercial agriculture and Extension veterinarian, recommends weighing these advantages and disadvantages:

Advantages:

  • Decreased power washing and improved employee morale.
  • Decreased pig movement and resocialization.
  • Avoid overcrowding associated with the late-nursery growing phase.
  • Easier to maintain a strict all-in/all-out production schedule because of fewer moves.
  • Pigs reach market weight faster.
  • Decreased transportation costs.
  • Decreased labor costs for cleaning and disinfecting facilities.

Disadvantages:

  • Starting weaned pigs in large pens (minimal disadvantages).
  • Under utilization of barn space at weaning.
  • A 30 percent disadvantage in pounds of pork produced per square foot of floor space annually.
  • Increased surface area of slats collects and holds additional fecal material for potential enteric bacteria exposure. Suggest management attention to prevent this.

Applications:

  • Single phase expansion – build wean-to-finish buildings first and then you may utilize existing nursery facilities for a shorter period of time, about four weeks vs. six weeks.
  • System flexibility based on pig flow – same facility can be used as grow/finish or wean-to-finish unit as needed.
  • Over stocking to allow for separation of faster growing pigs from poorer growing pigs.