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Articles from 1999 In December

Lightweight Pigs Benefit From Milk Replacer

Feeding lightweight (under 10 lb.) weaned pigs supplemental liquid milk replacer can ease their transition into the nursery, according to researchers at the University of Missouri.

Small weaned pigs have the ability to gain 1.6 lb. in the first three days after weaning when they are offered liquid milk replacer along with dry feed. In contrast, pigs offered only a dry diet lost 1/3 lb. during that period, reports Missouri swine nutritionist Gary Allee.

A total of 264 pigs, weaned at 17 days (plus or minus two days) were used in four different experiments. They represented the bottom 15% of four weaning groups. A dry diet was provided to all pigs, ad libitum, in two phases.

The phase I diet, fed for two weeks, contained 3.5% spray-dried plasma and at least 15% lactose. The phase II diet, fed to the completion of the study, contained 2.5% blood cells and at least 7.5% lactose. Spray-dried plasma and blood cells are different feed additives both derived from whole blood.

The milk replacer (Merrick's Litter Life) was supplied ad libitum to the pigs through an in-line system. A hydro pump was attached to a central, 30-gal. tank and the milk was pumped to bowls equipped with nipples.

In experiment 1 (48 pigs averaging 9.5 lb.) and experiment 2 (72 pigs averaging 9.3 lb.), the pigs were randomly assigned to one of four treatments. Pigs were assigned two/pen in experiment 1 and three/pen in experiment 2. Four treatments were offered, including dry diet only and the dry diet supplemented with milk replacer for 3, 5 or 7 days, respectively. The pigs were weighed and dry feed consumption recorded on days 0, 3, 5, 7, 10 and 29.

In the third experiment, 72 pigs weighing 9.9 lb. were penned three/pen. Weight and dry feed consumption were recorded on days 0, 3, 5, 7, 10 and 29.

In the fourth experiment, 72 pigs (9.6 lb.) were given only the first three treatments (no milk replacer, three days of milk replacer and five days of milk replacer) and were penned four/ pen. Weight and dry feed consumption were recorded on days 0, 3, 5, 7 and 21.

The results show no significant difference in dry feed intake for the four experiments. In experiment 1, the pigs given milk replacer for either five or seven days were heavier at day 10 than pigs not fed any milk replacer. Pigs fed the milk replacer for three days had an intermediate weight. The researchers note that the weight difference was lost, since there was no significant effect of the milk replacer on pig weights on day 29.

In experiment 2, pigs given milk replacer for five or seven days were heavier throughout the study. They weighed more than the three-day milk replacer group and the pigs fed no milk replacer. The researchers note that after day 5, there was no significant difference in weights between the pigs fed no milk replacer and the pigs receiving the three-day treatment.

In experiment 3, the pigs fed no milk replacer were lighter than all the other groups for the entire study. Pigs given milk replacer for either three or seven days consumed more dry feed than the pigs given no milk replacer and the five-day treatment group.

In experiment 4, pigs fed no milk replacer were lighter and total dry feed intake for the 21-day study was not affected by the milk replacer treatment.

Milk replacer intake was measured only in the first two experiments. For the first three days postweaning, pigs consumed 0.39 and 0.35 gal./day. Intake increased to 0.52 and 0.54 gal./day in the subsequent two days. On days five to seven, pigs drank 0.71 and 0.72 gal./day, respectively.

Allee notes that pigs still face a postweaning-like lag when milk replacer is removed, but it is shorter and less detrimental, as shown by heavier pigs at the end of the experiments.

In all of the studies except the first, the advantage of feeding milk replacer was maintained through day 21 to 29. The advantage is that pigs weighed 5-6 lb. more at four weeks postweaning or 3 lb. more at three weeks postweaning, when compared to pigs fed only a dry diet.

The researchers summarize that the most beneficial response comes from feeding milk replacer for three to five days postweaning. Feeding milk replacer to small pigs may be a management tool to help reduce variation among nursery pigs.

Researchers: Gary Allee, Kevin Touchette and Jeff Berkemeyer, University of Missouri. Phone Allee at (573) 882-7726 or e-mail alleeg@

Odor, Hydrogen Sulfide Emissions Vary Widely

Hog odor and hydrogen sulfide (H2S) emissions from outside manure storage facilities and from hog buildings vary widely, according to a report from a University of Minnesota research team.

The team concluded the different ranges for odor and H2S support earlier work by research leader Extension ag engineer Larry Jacobson in which he found little correlation between odor and H2S levels.

In the latest study of 29 farms in three, 30-mile-diameter clusters around Minnesota, the sources of odor and H2S were identified for outdoor manure storage units and confinement buildings on hog, dairy, beef, turkey and broiler operations.

H2S levels were measured for most of the samples collected because of the state's regulatory standard for the gas. Data collected is expected to be used for predicting odor and gas concentration levels downwind from livestock operations.

Because of seasonal effects seen in earlier research, it was decided to sample from each site in spring, summer and fall. Samples were collected in 10-liter tedlar (type of plastic) bags at the source of the odor or gas. Air samples were analyzed for H2S using a Jerome meter. Odor samples were analyzed within 30 hours of collection by olfactory testing using a panel of eight people.

Overall, odor concentrations in the air emitted from buildings ranged from 20 to 1,500 odor units and H2S levels ranged from 10 to 1,200 parts per billion (ppb).

Emission rates of odors and gases exhausted from buildings were also highly variable.

Values ranged from 0.1 to 30 odor units (calculated by multiplying odor units times air flow rate divided by area). H2S values ranged from 0.1 to 26 (a measure of microgram/second/square meter).

Odor and H2S concentrations and emissions from pig buildings were about one order of magnitude (a factor of 10) higher than those detected from dairy and poultry buildings. Odor and H2S levels for manure storage units were also higher for pigs than for dairy.

Researchers: Larry Jacobson, Richard Nicolai, David Schmidt and Jun Zhu, University of Minnesota. Phone Jacobson at (612) 625-8288.

Ultrasound Assists In Reproductive Evaluation

Research at the University of Illinois shows the value of using real-time ultrasound (RTU) to monitor and assess the reproductive status of sows and gilts.

Researchers Rob Knox and Gary Althouse, DVM, report that the ability to look inside the animal, nonsurgically, gives breeding herd managers and veterinarians a powerful management and diagnostic tool for improving and troubleshooting breeding herd performance.

As research continues on RTU, one of the early benefits has been early pregnancy diagnosis. According to the Illinois researchers, differences between pregnant and non-pregnant females can be visualized as early as day 17 and day 18 after mating and becomes very prominent by days 19 to 20.

The early detection with RTU may allow greater precision in determining pregnancy status than external monitoring procedures. Identifying open sows at that early stage allows for rapid rebreeding and fewer non-productive sow days.

The researchers used RTU to investigate the variation in ovulation after detection of estrus in sow groups weaned at different times of the year, in response to length of lactation, parity and interval from weaning to estrus.

Data collected shows that the greatest number of sows (55%) ovulate from 36 to 48 hours after onset estrus. Approximately 20% of sows ovulate before and another 20% of sows ovulate after the 36- to 48-hour period.

Knox and Althouse also note that the RTU is useful for diagnosing pathologic conditions in sows. For example, cystic ovaries and uterine infections can readily be diagnosed, therefore aiding the veterinarian and producer in treatment, mating or culling decisions.

The University of Illinois Departments of Animal Science and Veterinary Medicine and the Illinois State University Department of Agriculture collaborated on the RTU project. Researchers developed techniques to perform transrectal imaging in standard gestation crates quickly and without stress or strain on the sow.

The technique involves the attachment of the ultrasound probe to a transrectal stabilizing rod. Once inserted into the rectum, the probe allows visualizati on of the reproductive tract.

The technology is based on B-mode ultrasound, which emits and collects ultrasonic waves via a transducer. The waves echo off tissues, with differences between tissues displayed on a monitor in a continuous scale from black to white. The resulting image of the reproductive structures are then interpreted for reproductive status.

The researchers evaluated both portable units and medical grade imaging devices. They found differences between the units in their ability to provide adequate resolution for imaging the ovaries clearly. Knox and Althouse suggest that if monitoring of ovarian activity is desired, the equipment must provide the necessary resolution for differentiating ovarian structures (i.e., follicles, corpora lutea and inactive ovaries).

Researchers: Rob Knox and Gary Althouse, University of Illinois. Phone Knox at (217) 244-5177 or e-mail Phone Althouse at (217) 333-8116.

Odor Levels Reduced With Feed Changes

Hog odors can be reduced by feeding highly digestible, low-fiber ingredients, reducing the protein content and adjusting the macro minerals of the diet, according to researchers at North Carolina State University (NCSU).

NCSU researcher Theo van Kempen is studying the acidification of pig urine through the addition of phosphoric acid to the diet instead of dicalcium phosphate . Van Kempen says the acidification works well for reducing ammonia emissions and methane production.

The phosphoric acid and gypsum replaced dicalcium phosphate and limestone as sources of phosphorus and calcium in the study. Ammonia emissions were reduced from 20% to 50% and methane was also reduced.

Preliminary data from the study suggests odor emissions actually increased with the phosphoric acid treatment.

The North Carolina research conflicts with earlier Dutch research findings that the phosphoric acid reduces hog odors.

Researchers are also studying ways to remove ammonia from the environment and ways to convert it into non-odorous compounds.

High ammonia levels in barns are irritating for pigs and humans. In people, the irritation can result in lung damage, greater susceptibility to opportunistic infections, loss of productivity through increased sick leave and even disability. In hogs, the effects are similar, but appear as "failure to thrive" and result in low market weights and reduced profitability.

The NCSU research focused on engineering microorganisms to be more efficient in removing ammonia from their environment and converting it into stable, non-odorous compounds. The microorganisms can be engineered to efficiently utilize ammonia. Used as a probiotic or in bio-filters, they may help to reduce ammonia levels.

The researchers also tested feed ingredients as a contributor to hog smell. Most odor compounds are derived from remnants of the digestive process and end up fermenting in the large intestines or in the manure.

The fermentation of protein results in odorous compounds such as para-cresol and phenol, which have the highest correlation to odor sensation. The key to reducing odor production is reduce the remnants of the digestive process, particularly protein, and the undigested secretions made by the animal.

Both can be reduced, according to the researchers, by choosing highly and easily digestible feed ingredients. Fibrous ingredients are not only poorly digestible, but they also increase the protein secretions by the intestines.

In highly fibrous diets, fiber-degrading enzymes may reduce the impact of the fiber on odor production. The NCSU researchers admit that research in this area is scant, but point to a 2-3% improvement in protein digestibility. That change can reduce the indigestible protein by 13% to 20% and has a positive impact on odor emission.

Researchers: Theo van Kempen and Jeanne Koger, North Carolina State University. Phone van Kempen at (919) 515-4016 or e-mail t_vankempen@ncsu. edu.

Storage, Not Pelleting, Limits Lysine

Researchers at the University of Illinois tested the effects of pelleting and in-feeder storage on lysine bioavailability in nursery pig diets.

Ioannis Mavromichalis and David Baker found pelleting of a complex phase 1 diet (28% lactose, 1.4% lysine) did not reduce the lysine bioavailability.

The pellets tested were 5 mm, larger than most commercial pellets which commonly are 2-4 mm. The researchers are currently testing smaller pellet sizes for lysine damage.

While pelleting did not have an impact on lysine bioavailability, storage did. The researchers found that placing the diet in metallic feeders in an occupied nursery facility for one week reduced bioavailability of lysine by an average of 12%. The lysine loss was observed in both meal feed and pelleted feed (Table 1).

The Maillard or non-enzymatic browning reaction that renders lysine unavailable is favored by high temperatures, humidity, time and presence of trace minerals. The nursery diets are susceptible to lysine destruction during pelleting and during prolonged storage in warm and humid conditions. In addition, producers fill feeders with enough feed for four to 10 days to reduce labor and storage space, thus exposing costly diets to the warm and humid nursery environment for prolonged periods of time.

In order to avoid losses of lysine and ensure maximum performance, the researchers suggest more frequent feeding intervals, especially in the critical two weeks postweaning. Prolonged storage of starter diets during summer months is also discouraged. Fresh nursery diets should be prepared and fed immediately.

Researchers: Ioannis Mavromichalis and David Baker, University of Illinois. Phone Mavromichalis at (217) 333-4366 or e-mail

PigCHAMP Divestiture Announced

On Dec. 1, the University of Minnesota (U of M) took the first steps to divest itself of the development and marketing of the popular swine recordkeeping software program, PigCHAMP. The new stakeholders are a small group of employees and consultants currently active in the day-to-day management of the program.

The agreement gives shareholders exclusive, worldwide rights to the software developed at the U of M in the mid-'80s. Simply put, the U of M has turned over the entire PigCHAMP package, giving them extensive rights to manage and develop it. In turn, the University will receive annual cash payments, royalties and full access to the database.

William Russell, president of Russell Associates, LeSueur, MN, led the negotiations and will serve as the new CEO. Glen Leighty, U.S. sales manager, will assume responsibilities for business planning, sales and marketing. Both are investors in the venture.

"Any employee as of the takeover that wishes to buy stock will be allowed to," Russell notes. A dozen or less investors are anticipated.

University negotiators made it clear they were looking for a Minnesota-based, agriculturally oriented company that would provide full access to the confidential database. They were looking for "honest brokers." "In other words, we were not looking at PigCHAMP for the customer list or as a way of eliminating competition," Leighty explains.

The company will be capitalized by the initial sale of 200,000 shares. The First Farmers & Merchants Bank of LeSueur (MN) will provide a line of operating credit.

The transaction, in a real sense, is a lease arrangement. The U of M will continue to market and service the software program through a licensing agreement with PigCHAMP Inc., the newly formed Minnesota Corporation.

"We have the authority to do most anything with it that you could do if you (actually) owned it, including mergers or whatever," says Russell. Any modifications or additions or new products that are developed belong to PigCHAMP Inc.

"Over the period of seven years, the estimated cost (cash payments and royalties) may total up to $1 million, depending on the volume of sales," Russell explains.

"Even though the Windows product and improvements may phase out any of the products originally acquired," he continues. "We'll actually be paying royalties for a while on newly developed products that don't belong to the university. Within seven years, anything we originally leased may be gone." University technical support for upgrades will continue, in trade, for allowing researchers access to the data.

Other anticipated changes:

* Conversion from DOS software to Windows within a year. The original DOS format will not be completely eliminated, to ensure ongoing support for those without Windows capabilities.

* Key U of M veterinary college staff, scientists and "strong users" from around the world will be asked to serve as advisers for new product development.

* A new, multi-level maintenance and support fee structure will match services to customer wants and needs.

* Some new concepts, technical support and training will be expanded, on the Internet.

* Compatibility with NPPC's Production & Financial Standards. Russell can be reached at (507) 665-6266; or contact Leighty at (612) 624-7425.

Reduced Crude Protein Doesn't Hurt Growth

In studies on reducing crude protein in swine diets, researchers at Michigan State University have found that nitrogen excretion and ammonia can be reduced without affecting the growth rates.

The research tested six diets on six, 90-lb. pigs. The diets included 15% crude protein (CP) corn-soybean diet; 12% CP plus crystalline amino acids (CAA) diet; 9% CP plus CAA diet; 6% CP plus CAA diet; a protein-free diet and a casein-based diet containing 15% CP.

The 15% CP corn-soybean diet is typical and meets the requirements for growing pigs. The reduced CP levels contained the same corn-soybean meal ratio and were supplemented with CAA to maintain the ideal protein pattern. The protein-free and casein diets served as negative and positive controls.

Casein, a milk protein, has protein digestibility of 98%. Both the casein and protein-free diets were used to estimate the amount of endogenous nitrogen loss and its contribution to ammonia production.

The pigs were housed in metabolism crates, where total urine and feces were collected from each pig over five-day periods, pooled by pig and treatment after each experimental period and frozen.

The samples were mixed into slurries and incubated for 31 days. Ammonia (NH3) production was measured and odor panel tests conducted.

The preliminary data showed a reduction in the NH3 levels, tested for three consecutive days after the 31 days of anaerobic storage.

Results show a 63% reduction in NH3 in the 12% CP diet as compared to the 15% CP diet. The 9% CP plus CAA and the 6% CP plus CAA diets had similar reductions. NH3 reduction was the greatest in the protein-free diet. The NH3 production in the casein-based diet was similar to the 15% CP diet. Researchers note that despite the high digestibility of a feed ingredient, the endogenous nitrogen can contribute to NH3 production.

The results show nitrogen retention was similar for each diet except the 6% CP plus CAA diet, where retention was decreased. The pigs had a similar growth rate while on the 15% CP, 12% CP plus CAA and 9% CP plus CAA diets. Growth was depressed on the 6% diet.

Researchers: Emily Otto, Mel Yokoyama and Nathalie Trottier, Michigan State University. Phone Trottier at (517) 432-5140, or e-mail

Major Salmonella Project Yields Some Surprises

Salmonella infections on hog farms are much more dynamic than ever was thought, according to University of Minnesota's Thomas Blaha, DVM.

To gain control of these infections, producers will have to do two things: 1. Do a salmonella-targeted (very thorough) job of cleaning and disinfecting between groups of pigs, and

2. Adopt daily working conditions to prevent the "exchange" of environmental and herd salmonella strains.

Blaha is the Allen D. Leman Chair and coordinator of a long-term grant project, "Salmonella Abatement in the Pork Chain" for the National Pork Producers Council.

Salmonella dynamics are characterized by changing prevalence and serotype patterns. Researchers have identified up to 18 different serotypes of salmonella on a single hog farm, explains Blaha.

Fecal-oral spread of salmonella is well known as the most common means of on-farm spreading. But what is not so well known is the complex interaction between salmonella-infected animals and their contaminated environment and the role it plays in the pattern of infection in a herd. This dynamic interaction must be identified and understood before control measures can be put in place to reduce the amount of salmonella carried into the food chain by market hogs, stresses Blaha.

In Europe, Blaha's research has shown how salmonella-free starter poultry flocks developed the same level of salmonella prevalence after placement as conventional health flocks without salmonella elimination. Environmental contamination was identified as the source of infection. Salmonella control was only achieved by permanently reducing the organism from the environment.

"Salmonella is not like pseudorabies, for example, where we can eradicate it and be done with it. Something has to be added to a quality assurance system which has salmonella reduction as one of its primary tenets," points out Blaha.

Researchers at the University of Minnesota have confirmed the role of the salmonella-contaminated environment in infecting hog herds. About 10% of environmental samples taken on four Minnesota hog farms were salmonella-positive.

Work at USDA's Agricultural Research Service (ARS) and Iowa State University showed that salmonella elimination can be achieved by segregated early weaning with pigs reared in isolation. Later on, two groups were created, one stayed in isolation, the other was fed out in a traditional facility. The animals in isolation remained salmonella-free, while those raised conventionally became positive for salmonella.

In the Minnesota project, which begun in 1996, scientists followed one complete production cycle of two herds. One herd had high prevalence (HP) for salmonella and one had low prevalence (LP) for the disease in their slaughter hogs.

Objectives were: 1. To identify farm "salmonella-specific" critical areas and practices;

2. Judge the use of the Danish ELISA test for detection of infected herds; and

3. Use salmonella subtyping methods to identify factors linked to salmonella infections in swine.

In the first objective, 400 pigs were repeatedly sampled for fecal salmonella shedding. The rectal swabs of some 15 sows and their offspring from HP and LP farms and 809 environmental samples were tested for salmonella strains.

For results of the first objective, some 69 of 205 pigs from the HP farm tested positive for salmonella at least once during the entire production cycle in the rectal swab study (Table 1). Thirteen pigs were positive at two sampling periods and two pigs on three. Just one sample from the LP farm was positive.

In Tables 2 and 3, the impact of environment is detailed. Samples were categorized as:

EI - direct contact with study group animals (pen surface, feeders, waterers, etc.);

EII - indirect contact with the study animals but nearby (water, feed, ventilation and heating equipment, walkways); and

EIII - indirect contact with the study animals, outside hog raising areas (organic matter outside buildings, walkways, feed trucks).

Specifically, the results of cleaning procedures on each farm were checked by taking post-cleaning environmental samples, shown in Table 3.

The latter study revealed two critical areas for improvement.

First, clean and disinfect barns before bringing in pigs. On the HP farm, 28% of the post-wash samples were salmonella positive; at the LP farm, only 4% of these samples were positive.

And, Blaha suggests, daily working procedures are more important to influencing the "exchange" of environmental and herd salmonella strains than the working system of the farm.

Key examples include maintaining barn-specific boots and immediately cleaning up outside feed spills.

In the second objective, 1,000 blood samples collected during the study and meat pieces collected at slaughter were checked for salmonella antibodies using the mixed ELISA test from BI/NOBL Laboratories.

The majority of those blood and meat juice samples proved negative for salmonella. Only five samples from the HP farm and three samples from the LP farm were positive.

These results confirm that serological testing can only be used as a diagnostic tool on a herd basis. It is not an individual indicator of salmonella herd status, explains Blaha.

The third objective went beyond testing the two Minnesota herds. It involved testing 25 herds in the state. Detected were 384 salmonella strains (28 serotypes) that were tested for resistance patterns by the ARS Laboratory in Athens, GA. Several different clones of the same strain were found in both the animals and the environment of the study farms, says Blaha.

Also, 92% of the Salmonella typhimurium strains found in pigs and environment of four study farms are common for pigs and humans.

That brings out the importance of understanding on-farm epidemiology and zoonotics (communicable diseases from animals to people) of the salmonella strains. DNA fingerprinting will be useful in this regard, says Blaha.

The majority of test isolates showed resistance to one or more antibiotics. But resistance to four antibiotics was rare, Blaha reports, noting the need for more research in this area.

"The fact that there is no significant difference in the frequency of resistance between strains from lymph nodes and strains from the environment, shows that the phenomenon of antimicrobial resistance in salmonella species is much more complex than often discussed as direct consequence of the use of antimicrobials in animals, which urgently needs further research."

Blaha stresses it is very important to understand the pork industry will never be rid of salmonella. Permanent reduction controls must be an integral part of an on-farm, pork quality assurance program.

Researcher: Thomas Blaha, DVM, University of Minnesota. Phone Blaha at (612) 625-8290 or e-mail blaha002@

The Wean-To-Finish Revolution

When wean-to-finish barns were first introduced, many felt that it was a new gimmick that would soon pass and would never work long term.

Wean-to-finish (W-F) appeared to go against many of the pig-raising principles we felt were necessary to starting and raising weaned pigs. Large pens, cement floors and curtain-sided hog barns were a long way from the hot nursery days that many of us still remember.

But as more producers began to try it and experience success, we quickly realized that W-F barns were a reality and had a place in the future of pork production.

W-F barns are not for everyone. But they have found their place in a number of different systems.

We have some producer clients who feel W-F is the only way to raise pigs. And we have others who have gone back to the traditional nursery and finisher system. If the producer is committed to making it work, W-F can be successful as long as everyone understands the limitations. There are advantages and disadvantages to the W-F barns. These need to be considered when making the decision whether to use them or not.

Key Advantages Some of the key advantages to W-F production systems are less powerwashing, less moving of pigs and, in some cases, improved feed efficiency and average daily gain. Some studies have shown a 0.1 improvement in average daily gain and a 0.15 improvement in feed efficiency.

Other studies have shown no improvement in feed efficiency and only a small improvement in average daily gain.

We must also keep in mind that most of the early data that has been evaluated is data from new barns. Some of the later data indicates that performance may decrease slightly as the barns get older.

Case Study One of our producers had been selling early weaned pigs on the open market. Because of the depressed prices, he felt that he would be better off maintaining ownership of those pigs.

So he decided to build two, 1,000-head, W-F barns. He liked the idea of starting with the W-F barn because he had no existing nursery and could always add a nursery if he was disappointed with the performance in the W-F barns.

After two turns through the barns, he is quite satisfied because he doesn't have to move the pigs from the nursery to the finisher and it saves a nursery clean-up and powerwashing.

The performance in this producer's W-F barns has been excellent. He has experienced less respiratory problems than his customers, who were housing pigs in traditional nursery and finisher barns.

At this point, he will continue using his W-F barns. He also feels his performance is better from a feed efficiency and average daily gain standpoint than his customers. This is a difficult comparison but it is consistent with what others have seen in the W-F barn systems.

Most of the advantages seen in the W-F barns is likely due to one less move and mixing of the pigs. This reduces the stress associated with mixing groups of pigs. It also cuts down a pathogen transfer from pig to pig. It isn't hard to imagine that this mixing and sorting can set the pigs back by seven days.

Disadvantages A disadvantage of W-F barns is the challenge of starting the pigs. This problem is over-rated. Most pigs seem to start well provided they are given access to good feed, a comfort board and a dry, warm area to lay. Because of these requirements, the barns are usually 10-20% more expensive to build.

Another disadvantage is utilization of barn space. The extra room available to the weaned pig is expensive when compared to a traditional nursery. If production from the finishing barn is measured by pounds per square foot, the traditional nursery/finisher can have up to a 30% advantage over the W-F barns. To alleviate this, some producers will "double load" these barns until they are 40-50 lb. and then move half the pigs to another finishing barn.

A Toss Up? When all factors are sorted out for W-F vs. traditional nursery/finisher systems, there is no clear-cut answer. Both systems will work well and individual producers need to evaluate how each production system will fit into their specific situation.

With today's challenging market situation, producers need to look carefully to find every advantage they can to improve their bottom line in terms of cost of production.