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Articles from 2004 In February

Study Focuses on Auto-Sort, Paylean Payback

The introduction of automatic weighing and sorting technology and the rollout of Paylean, aimed at improving finishing growth rate and carcass leanness, have captured pork producers' attention in recent years.

In an effort to evaluate the impact these new technologies could have on profitability, researchers from Purdue University's Departments of Animal Science and Agricultural Economics recently conducted a five-part research project in which they created a model to evaluate the economic returns from feeding Paylean in conjunction with optimal nutrition and applying different strategies for marketing pigs.

Paylean, Elanco Animal Health's trade name for ractopamine hydrochloride, improves growth performance and carcass leanness by increasing lean tissue growth and decreasing fat deposition. The ractopamine response in growth rate and protein deposition increases rapidly within the first couple days of feeding, then plateaus and gradually declines over the 3- to 5-week feeding period. Therefore, optimum feeding levels and duration were studied. Through the model, researchers were hoping to target strategies for maximizing the daily returns above feed and variable costs.

They learned that the optimal marketing age is reduced with Paylean. One research phase showed starting Paylean three to seven days too early or too late did not substantially reduce the economic returns from feeding the product.

Automatic weighing/sorting technologies allowed researchers to evaluate whether knowing exact pig weights could improve management and returns, with or without Paylean.

The returns from feeding Paylean are dependent on proper nutrition, especially lysine, and the other essential amino acid levels, they noted. Feeding the right ration at the right time, and marketing at the best possible weight, are crucial parameters.

Economic returns from using Paylean in finishing rations are tied to making sure animals are at the correct weight to initiate feeding and for hitting market weight targets. Minimizing sort loss is not the objective, they emphasize. Rather, the objective is to maximize the daily returns above daily feed and other variable costs.

Fixed schedules that are too tight (too short), or too loose, reduce the annual returns to the grow-finish facility. The emptying and quick refilling of grow-finish units, in conjunction with optimal Paylean use and marketing strategies, all work together to help producers maximize grow-finish returns, they said.

Five separate research reports summarize the Purdue University findings. Results of the first two reports are summarized herein. The next three reports will appear in the next issue of National Hog Farmer.

Report 1:

Model Development and Optimal Management Strategies

The Purdue University research is based on a stochastic model developed to simulate pigs moving through the grow-finish production stage. The model can be used to optimize the level of nutrition, the concentration and duration of Paylean feeding, and annual pig flow under different marketing strategies.

Past research studying the economic benefits of Paylean used a growth model for a single pig with average growth properties, researchers explained. However, pigs are raised in groups and all-in, all-out management usually means group size equals barn capacity. Finishing barn turnover depends on the marketing day of the last batch, not the pig with the average growth rate.

The Purdue research investigates feeding Paylean to a group of pigs using a growth model that reflects a unique body weight growth curve and carcass composition growth curve for each pig, similar to the normal variation seen in a group. An economic model was then developed to simulate realistic industry practices.

Researchers wanted the model to objectively predict how to maximize daily return for a typical 1,000-head, grow-finish barn. Model parameters were estimated for a modern high-lean genetic line of gilts raised under a segregated early weaning (SEW) program. The return was optimized under 10-year average prices and costs. The price of Paylean was assumed to be $2.25/g., the 2002 market price.

The model looked at the optimal management strategies for four payment schemes, designed to simulate producers with various marketing channels and market structures.

  • Scheme 1 simulated carcass payment with discounts on underweight and overweight carcasses.

  • Scheme 2 represented a carcass merit payment system adopted from Hormel's Carcass Lean Value Program based on last-rib backfat thickness.

  • Scheme 3 represented a lean-to-fat price ratio of 2:1, with discounts on underweight and overweight carcasses.

  • Scheme 4 simulated a lean-to-fat price ratio of 4:1, with discounts on underweight and overweight carcasses.

The carcass weight discount grid for Schemes 1, 3 and 4 were also adopted from Hormel's Carcass Lean Value Program and was the standardized grid for the column of 0.51-0.90 in. last-rib backfat. Schemes 1 and 2 reflected the marketing approaches by independent producers. Scheme 3 simulated the producers under limited coordination with packers. And, Scheme 4 reflected vertically integrated producers, because the lean-to-fat ratio of 4:1 allowed producers to capture the full benefit of the increase in carcass lean and value.

The model optimized the return for 50-day-old feeder pigs to market. The optimization for dietary lysine and Paylean concentration management focused on the late finishing pigs starting at 101 days of age, with an average weight of 146 lb. for SEW gilts. In the model, pigs were fed three diets from 101 days of age to market, with switching days for diets 2 and 3 optimized by the model.

For Paylean-treated pigs, the second and third diets contained the same concentration of Paylean. Pigs were not started on Paylean until they weighed more than 150 lb. Accumulative weight gain on Paylean was restricted to less than 90 lb. These restrictions reflect FDA regulations on product usage. The program focused on the optimization relative to today's average slaughter weights of 260-270 lb., fitting the payment schemes outlined above; therefore, most starting weights were above 200 lb.

Pigs were marketed in 170-head truckload lots. One or more truckloads could be marketed on the same day, so marketing batches could be six or less for the 1,000-head finisher. The model specified that pigs must be marketed as long as the number of pigs heavier than the sort weight exceeded one truckload. The exception being the last batch that was marketed when the optimal profit for these pigs relative to the opportunity cost of refilling the barn was reached, regardless of the pig weights. Labor cost was included in the daily variable cost; no extra labor cost was included in the marketing management segment of the model.


The results demonstrate it was optimal to market “control” pigs in three batches under Schemes 2, 3 and 4. However, under Scheme 1, pigs were marketed as four batches (Table 1 ). The optimal marketing age for the last batches ranged from 162 to 166 days of age, with the earliest age associated with Scheme 4.

The marketing day for the first batch was in a close range of Days 153 to 155 across marketing schemes. Without Paylean, the dietary lysine concentration in each diet and the optimal time to start each diet were similar under each payment scheme. Two marketing batches were optimal for Paylean-fed pigs under Schemes 2, 3 and 4. Three batches were optimal under payment Scheme 1 (Table 2 ). The marketing ages for the last batch ranged from Days 155 to 160, six to seven days earlier than control pigs.

The sort weights for control and Paylean-treated pigs were very close, indicating the payment grid was important in determining the optimal market weight for both treated and non-treated (control) programs.

Optimal Returns

The optimal return per day, per barn (barn-day) ranged from $230 to $302 for control pigs. The returns were higher with higher lean-to-fat price ratios.

Numbers of underweight carcasses ranged from 41 to 75 head, with the highest number associated with Scheme 4. The numbers of overweight carcasses ranged from 42 to 92 head, with the highest number belonging to payment Scheme 1. The combined sort loss with Schemes 1 to 4, respectively, was $938, $1,327, $774 and $929.

Sort loss for Scheme 2 was higher than the others for two possible reasons. First, unlike the other three schemes, the carcass weight discount rate in Scheme 2 was not standardized. And, carcass fatness was discounted more severely under Scheme 2.

The net return for pigs fed Paylean was estimated to be from $245 to $347 per barn-day, going from Scheme 1 to 4, respectively. This equates to an additional profit over the control pigs of $5,624 to $16,368 per year, per barn in a 1,000-head, grow-finish facility based on marketing Schemes 1 through 4.

When converted to return per pig, these annual net returns from using Paylean corresponded to approximately $1.77 to $4.93 higher return per pig than control pigs. The net returns from using Paylean increased from Scheme 1 to 4, with a greater value of lean relative to fat ratio resulting in a higher net return.

Sort loss from pigs fed Paylean was higher than control pigs under each payment scheme. The numbers of pigs receiving discounts due to underweight or overweight carcasses were also higher for Paylean treatment. This indicated that with higher returns in Paylean-fed pigs, it was economically optimal to sacrifice some sort loss in order to market the pigs at a younger age and have faster barn turnover.

The optimal Paylean concentration ranged from 4.5 to 8.6 g./ton, which increased from payment Scheme 1 to 4. Because higher Paylean concentrations further increase the lean growth rate and the payment for lean is higher in Schemes 3 and 4, maximizing lean accretion requires a higher crude protein and lysine level to be fed. Consequently, the optimal dietary lysine concentrations in the second and third diets varied considerably under each payment scheme.

Average duration for feeding Paylean ranged from 24 to 29 days from Schemes 1 to 4, respectively. Under all schemes, it was optimal to have the first semi-load of pigs being fed Paylean between 18 to 24 days before marketing.

The stochastic model indicates that pigs fed Paylean were marketed at a younger age, and in fewer batches, than pigs without Paylean. Returns were higher for the Paylean-treated groups than for controls. The estimated increase with Paylean use was $3.11/pig, averaged over the four payment schemes.

The researchers concluded it is economically optimal to sacrifice some sort loss in order to market the pigs at a younger age, realize a faster barn turnover, and obtain a higher average daily return for pigs fed Paylean.

Report 2:

Investigating Optimal Paylean Onset Time Based on Accurate Pig Weights

This segment of the research investigates whether starting Paylean supplementation at precisely the correct day before slaughter would impact the returns over variable costs or returns to facilities and labor. Use of an automatic weighing system could improve the accuracy of the start time, researchers said.

They found that when the deviation from optimal timing is less than one week, the impact on returns is small, perhaps a few hundred dollars/barn/year. However, as Table 3 shows, the potential lost income increases if supplementation is started 21 days late ($5,527) or 21 days too early ($8,681).

Producers may inadvertently reduce economic returns by basing the supplement start date on inaccurate pig weights. The stochastic growth model discussed in the first report implicitly assumed producers know the exact weight of each animal and thus could make precise decisions based on this complete knowledge. This assumption can't be realized unless producers are using technology such as new automatic weighing and sorting systems, the researchers said.

The difference between the estimated weight and the true weight is referred to as the visual inspection error. Research has shown the standard deviation of visual inspection error ranged from 9 to 11 lb., depending on producer experience. Therefore, if the decision to begin feeding Paylean is based on the average weight of the group, starting time may not be optimized.

Simulation research was conducted for SEW gilts to demonstrate the implications of starting Paylean at a less optimum time. The researchers used their new model to look at optimizing the return and management for alternative Paylean onset ages under a payment scheme utilizing a lean-to-fat price ratio of 2:1. This payment scheme discounts underweight and overweight carcasses, and simulates a carcass merit payment system. The model restricted Paylean to be fed either earlier or later than the optimal onset age, as well as fixed the Paylean concentration at 5.9 g./ton, while leaving the dietary lysine concentrations in each diet, time to switch to diet 3 and marketing management to be optimized.

The optimal Paylean onset age was Day 128, which corresponds to the zero value in Table 3 . The column under Day 28 in the table simulates a 28-day delay in Paylean feeding relative to the optimal. This results in not feeding Paylean to the first batch of heaviest pigs and means the whole barn averages only 7.6 days on Paylean.

As expected, results indicate that the further away from the optimal Paylean onset age, the less return was obtained. It was found when the Paylean starting day was shifted further from the optimal, the potential loss would increase at an accelerating rate (Figure 1 ). The loss was calculated as the difference of the annual return between the obtained level under restriction and the non-restricted optimal. The loss resulting from delaying Paylean onset by one week, relative to the optimal usage of Paylean, was $623/barn/year. This total grew to $2,672 if the delay covered two weeks. The curve of annual losses vs. the numbers of days off the optimal Paylean starting age shown in Figure 1 was non-symmetric.

The loss of delaying Paylean administration by three days was approximately $68/barn/year, while starting Paylean three days earlier would result in a loss of $161/barn/year. The simulation results indicated that feeding Paylean at an earlier age relative to the optimal incurred a lower loss than delaying Paylean feeding as we move from seven to 14 days away from the optimal. The magnitude of the loss suggested that the acceptable window for Paylean onset was around 14 days, seven days ahead of, and seven days behind, optimal.

For some conservative producers, the strategies of Paylean onset time might depend on the ratio of return from Paylean, such as the amount of net return/dollar spent on the product. This ratio was also calculated in Table 3.

The highest ratio of net return/dollar spent on Paylean was 3.57, where Paylean was started at Day 143 of age, and pigs were fed Paylean for an average of 16.1 days, with the first group being fed Paylean for 10 days prior to market. While this may maximize the return/dollar spent, the producer would be missing out on approximately $2,700 of profit potential per year for each 1,000-head barn by not feeding the optimal Paylean duration. Bottom line, the highest return ratio does not provide the maximal return per day for the barn.

The optimal number of batches of pigs marketed was between one and four. When Paylean was started too early, such as 21 days ahead, it was optimal to market pigs in one day. On the contrary, when Paylean feeding was started too late, such as a delay of 28 days, it was optimal to market the pigs in four batches, resulting in a slightly longer (10-12 days) barn turnover period.

Paylean use was profitable under every duration of feeding and always returned more profit than the control pigs. The returns per barn, per day were optimized when Paylean was fed close to the optimal durations of 24 to 28 days, depending on the marketing program used. Feeding Paylean for longer periods of time produced higher returns than feeding Paylean for shorter periods. Paylean-fed pigs did have greater sort loss than the control pigs, indicating that the lowest sort loss is not the best indicator of the highest profit for the facility.

Researchers: Ning Li, Paul V. Preckel, Allan P. Schinckel and Brian T. Richert, Departments of Agricultural Economics and Animal Science, Purdue University. Contact Schinckel at (765) 494-4836.

Next month, results of the Purdue University Paylean model research will focus on the impact of fixed-schedule finishing barn closeouts, returns for more accurate sorting, and split-weight feeding management programs.

Keep Vaccinating for PRV

Despite closing in on pseudorabies (PRV) eradication in the U.S., the infected feral pig population still threatens the commercial swine industry.

Case in point is the recent PRV case in Arkansas that was traced to casual contact with feral or wild pigs.

Even though Iowa has been in Stage IV (surveillance) since April 2003, state veterinarian John Schiltz recommends continuing PRV vaccination.

“Iowa imported approximately 15 million feeder pigs in 2003, with some of them coming from states with feral swine,” he says. “The ongoing threat of PRV remains a legitimate concern for our state's swine producers.”

In an outbreak, states require expensive quarantine and rapid depopulation of infected herds. North Carolina, for example, would require testing in a 2.5-mile radius and vaccination of all pigs to take place, says Fred Kirkland, state department of agriculture. North Carolina, in Stage V (free), exports 21,000 hogs/day.

About 520,000 breeder or feeder pigs move interstate weekly, says the U.S. Department of Agriculture.

“It is important to ensure that these trailers are thoroughly cleaned and disinfected between loads to prevent PRV spread between farms,” notes Harry Snelson, swine technical services veterinarian for Schering-Plough Animal Health. “This is particularly important during the winter when the virus may survive for prolonged periods in organic material or on cold, moist surfaces.”

Winter vaccination is a small price for PRV insurance, says Schiltz.

Later Weaning: The Quiet Revolution

Pork producers have been lowering weaning age for over two decades. But an extensive field study in a 7,300-sow commercial herd raises serious questions about the economic burden of early weaning.

The first article in this series presents the results of a Kansas State University (KSU) study that took a hard look at the effects of weaning age on pig performance, costs and revenue relationships and the implications on finishing pig throughput.

Researchers found that as age at weaning increased, growth rates improved (particularly in the nursery), and postweaning variability and mortality declined. Bottom line — weaning older pigs was more profitable.

The KSU study served as the impetus for several Kansas and Nebraska producers to pull back on weaning ages. Thus began a “quiet revolution.” Their experiences with slightly later weaning ages and the move to later weaning in Denmark are featured in articles that follow.

In the U.S., it is common to wean pigs at between 12 and 19 days of age. Generally speaking, pigs within this age range are considered to have equal value, providing they meet minimum criteria.

No doubt, segregated early weaning programs have fostered the development of better diets for early weaned pigs; farrowing intervals have been shortened and pigs/crate/year have edged upward.

But, a quintet of KSU researchers felt there was more to this early weaning story than simply pushing more and more pigs through a set of farrowing crates. The team of researchers included Rodger Main, DVM; Steve Dritz, DVM; Michael Tokach; Robert Goodband; and Jim Nelssen. The group took a hard look at the impact of weaning ages on biological traits and profit margins of early weaning (15 days of age) vs. later weaning (21 days of age) programs.

Two trials involving 5,728 pigs were conducted to determine the effects of weaning age on performance in a three-site production system. Pigs from the 7,300-sow farm flowed to single-source, all-in, all-out nursery and finishing sites. Each 8 × 12 ft. nursery pen had an equal number of barrows and gilts, allotted to replicate normal weight distribution within each age group. Feeders and waterers were standardized.

In the first trial, involving 2,272 pigs, the researchers' objective was to quantify the impact of weaning age on pig performance within the three-site system. Litters were weaned at 12, 15, 18 or 21 days of age. All pigs were fed a common, three-phase nursery diet regimen (Table 1 ).

The second trial, with 3,456 pigs, aimed to evaluate whether changes in nursery diets would significantly affect growth in pigs weaned at different ages. Pigs were weaned at 15, 16, 18, 19, 21 or 22 days of age (expressed in the adjoining tables as 15.5, 18.5 and 21.5 days of age).

Each age group was fed a nursery feed budget classified as either “more complex” or “less complex” (Table 2 ). The classifications were based on the complexity of the formulation and the quantity of the complex diets fed.

Pigs were weighed individually at 42 days postweaning, with pen totals calculated. Weight and gender information were used to re-allot pigs within treatment groups: 1,920 pigs in Trial 1, 3,000 pigs in Trial 2.

In Trial 1, 10 barrows and 10 gilts were placed per 7.5 × 22 ft. finishing pen, while 12 barrows and 13 gilts were placed per 9.5 × 22 finishing pen in Trial 2. Pens were one-third slotted, two-thirds solid concrete. Feeders and waterers were standardized. Barns were curtain-sided, naturally ventilated. All pigs received the same finishing diet, designed to ensure that all nutrient requirements were exceeded for all groups.

Pigs were weighed off test individually at 156 days postweaning in Trial 1 and 153 days in Trial 2, with pen totals calculated.

In Trial 1, each block was sent to slaughter over a 28-day period, after being weighed off test. These pigs represented the “non-limited” finishing capacity group where all age groups were grown to a common market weight regardless of their growth rate.

In Trial 2, all pens in each block were marketed the day after being weighed off test. These were designated the “limited” finishing capacity group, which assumes finishing space is limited and all pigs are sold after a fixed number of days after weaning, regardless of age or weight.

Older Pigs Perform Better

In both studies, as weaning age increased, postweaning average daily gain (ADG) and wean-to-finish ADG improved. Likewise, as weaning age increased, pounds sold/pig weaned climbed and mortality rates dropped (Tables 3, 4, 5 ).

“The improvements in growth rate and mortality largely occurred in the initial 42 days postweaning, with some ongoing growth improvement to slaughter,” KSU researchers reported. The studies show increasing weaning age up to 21.5 days predictably improves grow-finish throughput within the three-site production system.

More specifically, in Trial 1, researchers noted that not only did weaning weight increase with age at weaning, but the variation in weaning weights was less as pigs got older.

“Nursery ADG, average daily feed intake (ADFI), mortality rate and 42-day postweaning weight improved as weaning age increased from 12 to 21 days,” they added. Likewise, feed conversion improved and 42-day post-weaning weight variation decreased as weaning age increased (Table 3 ).

In the finishing barns, ADG, off-test weight, off-test weight variation and average weight per day of age improved as weaning ages increased (Table 4 ). No differences in finishing mortality or carcass yield were noted. “However, when adjusting carcass lean measures to a common carcass weight, improvements in 10th-rib fat depth and percentage lean were observed as weaning age increased. The largest improvements in fat depth and lean percentage were observed as weaning age increased from 18 to 21 days (of age),” the researchers said.

As one might expect, when the full wean-to-finish period was analyzed, ADG, average gain/day postweaning, pounds sold/pig weaned and mortality rate improved as weaning age increased (Table 5 ).

“Average daily gain was calculated to be a more holistic measure of throughput, as weight and days lost due to mortality were not accounted for in the ADG calculations,” they said. “Contrarily, average pig gain is simply a measure of growth rate that is not influenced by mortality. Similar to ADG, pounds sold/pigs weaned more holistically evaluated the effects of weaning age on production system throughput.”

Generally, results in Trial 2 mirrored those recorded in Trial 1, with the exception that feed conversion in the nursery was poorer as weaning age increased. The complexity of nursery feeds (Table 6 ) did not affect growth rate, feed efficiency or mortality. However, pigs fed the more complex nursery feed budgets tended to have less variation in weight at 42 days postweaning.

Performance in the finishing stage of the second trial reflected that seen in Trial 1. Weaning age did not affect off-test weights, mortality rate or carcass yield. However, when measures of leanness were adjusted to a common carcass weight, wean age by nursery feed budget interactions were seen for 10th-rib fat depth, loin depth and lean percentage (Table 7 ). The more complex feeds improved carcass yield and, as a result, increased average carcass weights.

“These results indicate that weaning age has a significant and repeatable effect on growing pig performance within a given set of health and management conditions. These linear improvements in growth and livability largely occur in the 42-day postweaning period, with some ongoing growth improvements in the finishing phase. Altering nursery feed budgets according to weaning age did not affect wean-to-finish growth performance,” they concluded (Table 8 ).

Impact on Costs, Revenue

KSU researchers also studied the effects of weaning age on growing pig costs and revenues within the three-site production system, assuming “limited” or “non-limited” finishing capacities as described above.

“In both trials and finishing capacity scenarios, income over costs and cost/cwt. improved linearly as weaning age increased,” they reported. “Increasing weaning age up to 21.5 days resulted in linear increases in weaned pig value within a three-site production system.”

The tendency to assign a common value to pigs regardless of weaning age or weight, so long as they meet a minimum standard, may be a mistake because it could lead to false conclusions about the financial performance of the breeding herd.

Sow farms can be viewed as either a cost center or a profit center. Regard-less, pig value or cost of production is calculated on a per-pig-weaned basis. “Weaned pig production is the only segment of the production chain that does not have weight as the common denominator for cost information or in the matrix for revenue generation,” the researchers noted.

“These accepted standards for measuring cost and generating revenue operate under the premise that all weaned pigs meeting a minimum standard are of equal value,” they added. Consequently, weaning age is reduced in an effort to wean more pigs from the farrowing crates available.

To test the philosophy, researchers applied cost and revenue information to growth performance data to model the economic implications of the various weaning ages on a per finishing pen basis from results of Trials 1 and 2. Trial 1 had 96 pens with 20 pigs/pen; Trial 2 featured 120 pens with 25 pigs/pen.

A standardized cost/year of $30/pig space in the nursery and $38/pig space in finishing, using the assumptions in Table 9 , were used. Actual nursery feed costs were used. However, since feed consumption was not measured in finishing, researchers applied a common finishing feed cost/lb. of gain. Results are presented on a per-pig-weaned and a per-head-sold basis.

“Expressing performance and financial information on a per-pig-weaned basis enables all wean-to-finish throughput, cost and revenue information to be brought back to a common denominator,” they explained. “This enables treatment differences in throughput and financial performance to be quantified in a manner that directly relates to value of the weaned pig and removes mortality-induced bias in traditional wean-to-finish closeout data analysis.”

Because the complexity of the feed budget had no effect on wean-to-finish growth performance in Trial 2, cost and revenue data were analyzed on a per-finishing-pen basis.

In Trial 1, feeder pig cost increased as weaning age increased because older pigs ate more. Quantitatively speaking, however, feeder pig costs were moderately flat as weaning age increased from 12 to 21 days, partially because mortalities declined as weaning age increased.

“In both the limited and non-limited finishing capacity scenarios, revenue and income over costs/pig weaned increased and cost/cwt. decreased as weaning age increased from 12-21 days,” the researchers stated (Table 10, 11 ). “Cost/head sold decreased with weaning age, when all age groups can be marketed at an equal pig weight,” they added. Trial 2 results reinforced those found in Trial 1.

“Increasing pounds sold/pig weaned improved margins and production cost/cwt. These studies indicate that weaning age substantially affects the value of weaned pigs within a given three-site production system,” the researchers observed.

Rates of Improvement

Carrying their analysis one step further, data from the trials were modeled to determine the linear rates of improvement observed as weaning age increased from 15 to 21.5 days.

“Each day increase in weaning age increased initial weight (taken prior to weaning) by 0.57 lb. and weight sold to slaughter by 3.71 lb./pig weaned,” the researchers explained. “In the financial analysis, income over cost increased 94¢/wean age day in the limited finishing space scenario and 53¢/wean age day in the non-limited finishing scenario.

“Therefore, if finishing space is limited, increasing weaning age from 16 to 19 days is predicted to improve income over cost by $2.82/pig,” they said.

In this final analysis, KSU researchers drew data from 192 finishing pens (4,518 pigs) and presented the results as the “rate of change/day increase in weaning age.” These rates of change were also translated to a “per pound of weaning weight” basis (Table 12 ). These data need to be interpreted with the understanding that the incremental pound increase in weaning weight is due to increased lactation length, they reminded.

“The primary difference in the limited vs. non-limited finishing capacity is that the value of growth rate is more fully recognized when finishing spaces are limited,” they said.

“The linear improvements observed with the increasing weaning age illustrate the magnitude of the measured response to increasing weaning age from 15 to 21.5 days in these studies. Understanding the effect of weaning age on weaned pig value demonstrates the need to identify lactation crate utilization inefficiencies or facility restrictions that may be constraining whole-system throughput.

“There was a $3.18 (non-limited grow-finish space) to $5.64 (limited grow-finish space) per weaned pig difference in realized margin observed as weaning age increased from 15 to 21.5 days.

“These data indicate that simply assessing a common value to weaned pigs, regardless of age or weight, may lead to incorrect conclusions concerning sow herd productivity. Improving lactation crate utilization, altering weekly farrowing targets, decreasing week-to-week variability in the number of sows farrowed or increasing lactation capacity are the primary means of increasing and maintaining consistency in weaning age,” researchers concluded.

Evaluating Weaning Age Scenarios

Early weaning technology made a significant impact on the swine industry in the early '80s. It was a procedure to improve pig health and provide dramatic advances in performance.

Coupled with improved diets and multi-site production, early weaning and segregated early weaning changed the way pigs were reared worldwide.

In addition to the disease application of early weaning, the more rapid turnover of farrowing crates improves pigs/crate/year. Progress in litters/sow/year and pigs/sow/year was also anticipated.

Drawbacks to Early Weaning

Producers and veterinarians soon recognized, however, that early weaning could adversely affect wean-to-service intervals, farrowing rate and litter size.

Also, early weaned nursery pigs require more costly diets, a higher level of management and some changes in the environment.

With increased contract production and wean-to-finish barns, there could be some disadvantages to smaller, early weaned pigs. Recent studies suggest smaller weaned pigs may be at a disadvantage for mortality and performance through finishing.

Early Weaning Questioned

The value of early weaning is being questioned, especially if reproductive performance is declining. Would litter size improve if lactation length were longer? Could we boost farrowing rate at the same time?

The two case reports that follow will attempt to answer those questions by reviewing retrospective data and changes in weaning age.

It is important when doing this analysis to try and predict all the possible biases in the data. These could include sows that recycle, sows with long wean-to-service intervals, parity differences among the lactation length categories, genetic differences and changes in nutrition.

As long as there is good distribution of the lactation lengths for the entire time period under review, most of these potential biases should have a minimal impact on the evaluation. Total born was analyzed due to the potential for other influences on born alive. Sows that recycled after breeding were excluded from the dataset. The lactation length data was reviewed individually and then grouped as it best fit for this review.

Case Study No. 1

In 2001, this 1,600-sow herd had an average weaning age of 15 days, which has gradually increased to 18.2 days.

A PigCHAMP cohort analysis (grouped by previous service date) for the first eight months of 2001 showed an average lactation length of 14.5 days and total born of 11.1 pigs/litter. The same time period in 2003 showed 17 days lactation length and 11.3 total born.

This difference doesn't look too dramatic. However, the report includes total born data from Parity 1 gilts. Repeat breeders are also included. When the analysis was made in more detail, including servicing of non-repeat sows from 9/01/00 to 08/01/03, there appears to be some differences between the two lactation lengths.

There were 1,435 sows with a 7-13 day lactation length that had 10.91 pigs born/litter. In comparison, 6,178 sows with a 14-20 day lactation length had 11.49 pigs born/litter. There were also 225 sows with 21-24 lactation days that had 12.0 pigs born/litter.

Farrowing rate for 5,045 sows with a 10-16 day lactation length was 81%, while 3,748 sows with a lactation length of 17-22 days had an 85% farrowing rate.

Case Study No. 2

This 880-sow herd is a different genetic line than the first case. The herd had a 14-day average weaning age in 2000 and 17.2 average weaning age in 2003. The same service dates were reviewed as in the first case study. The previous lactation length of 10-17 days resulted in 2,749 litters with a total born of 11.88 pigs. When the lactation lengths of 18-25 days were summarized, the total born increased to 12.61 pigs. Interestingly, the farrowing rates were the same as those in the first herd. For a lactation length of 10-16 days (2,622 sows), the farrowing rate was 81%, and for 17-21 days (1,384 sows), the farrowing rate was 85%.

Thus, both of these herds showed some improvement in total born and farrowing rate when lactation length increased.

There are many more factors that must be considered when making the decision to increase wean age or lactation length.

Although it is difficult to collect on-farm data for all aspects of production impacted by weaning age, these cases demonstrate some of the analyses that may be helpful in making weaning age decisions.

Remember that it is important to review the records of all phases of production before making the decision. Just because a change is right for one operation doesn't necessarily validate it for yours.

Later Weaning Is a No Brainer

For a Kansas pork producer, switching back to a later weaning schedule just made sense for his production flow and to generate more dollars for his farm.

Sixty-five-year-old pork producer Dale Keesecker of Washington, KS, has tried all the production technologies designed to pinpoint the best time to wean pigs.

He says that most older weaning ages worked to varying degrees, until genetics, housing and nutrition advances were made; then changes to earlier weaning followed.

However, his latest shift back to later weaning, to an average of 21 days, may be the best move of all. That's because animal health and swine genetics have advanced to the point where early weaning is no longer necessary in some herds. And the move to a three-week weaning schedule may give some producers a rare opportunity — the chance to improve performance and cut production costs, he says.

He says this management shift has brought the swine industry almost full circle and has reinforced the value of “relearning old technology.”

Weaning History

In 1958, when Keesecker began producing hogs, and much of his production was raised outdoors, weaning pigs at 8 weeks of age made sense to reach adequate litter weights.

During the 1960s, as genetics started to improve, he was one of the early adopters of weaning pigs at 6 weeks of age. Weaning pigs at 4 weeks of age followed in the 1970s. With the '80s came a push to maximize production and elevate animal health through a variety of early weaning programs, he says. He tried all the early weaning schemes from 10 to 16 days of age.

But those early weaning programs dealt producers like Keesecker almost as many problems as solutions in trying to limit feeding of expensive diets to young pigs and in getting sows to breed back.

So when Kansas State University issued its 2002 report on the advantages of 21-day weaning, and on the advice of his consulting veterinarian Steve Henry, the shift looked like a “no brainer.” Keesecker made the switch to later weaning about a year ago.

Research Benefits Prove True

“The Kansas State data said if you delayed the weaning age from 15 to 21 days, nursery weights would improve by about 2-3 lb./pig coming out of the nursery and then also improve finishing weights,” says Keesecker. And he has found that to be pretty much true. It also improves exit weight from the finisher by about 12-14 lb./market hog.

“That means we are selling the same age hogs at market as when we were weaning at 15 days of age, but they are 12-14 lb. heavier,” he relates. Hogs are being sold at about 6 months of age at 280-290 lb.

The veteran Kansas producer stresses one of the keys to his survival in the swine industry has been that changes must reflect positively on the economics of his several-thousand-sow, farrow-to-finish operation.

Keesecker says producers have more control over their input costs than they do over the price they receive for their pigs.

“If we can apply technology like this, it makes the bottom line better, and it is about the only method we have right now to decrease the cost of production,” emphasizes Keesecker. He figures later weaning knocks 10 days off his normal 180 days to market and reduces cost of production by 6% (180 days × 6% = 10.8 days).

Better Nursery Pigs

“The thing I notice most of all from this is how much hardier the pigs are coming into the nursery,” he states. “They are just so much more aggressive, so much easier to start on feed and there are fewer stragglers to deal with.” Pigs are 14-16 lb. instead of 8-10 lb. and are much more durable, he adds.

Older weaned pigs express fewer vices such as navel suckling, says farm manager Rick Richard.

Environment plays a role, too. Keesecker admits that switching to an older weaning age fits better with his conventional nursery and finishing pig flows. He never made the leap to wean-to-finish production.

Pig flow has stayed healthy, a combination of being negative for porcine reproductive and respiratory syndrome (PRRS) and tighter pig groupings. Mortality in the nursery is running at less than 1%, he says.

Pig uniformity from weaning at 21 days old carries on through to finishing, reducing the need to seek out specialty markets for lightweight finishing pigs, adds Richard. “It simplifies the flow and basically allows us to turn more finishing spaces,” he notes.

More than anything, producers need to make sure they keep pumping feed into sows, and always feed to their individual needs, says Richard.

Making the Switch

Producers normally have two options for extending weaning age in their operation: either adding farrowing space or reducing sow herd size. For Keesecker, with his eye on the bottom line, neither approach was financially attractive.

So he plotted a different course. He explains, “The way we were able to farrow the same number of sows per week as before (when weaning early), while increasing the weaning age by six days, is that we tightened up the downtime. Instead of having maybe three to four days downtime to wean and clean up, we have cut that down to about 12 hours.”

Granted, that makes labor and scheduling much more challenging.

“The difference is now we don't have the luxury of putting our sows in the crates three days or more before they are due to farrow. Also, where we used to wean today and clean the farrowing barn tomorrow, now we wean, clean the barn tonight and load it the next morning,” explains Keesecker.


Of all the reasons to stay with early weaning, the biggest may be animal health. For Keesecker, that was not an issue. He has fought the E. colis and rotavirus.

But the biggest culprit he faced for several years, PRRS, has become a thing of the past. His operation has been PRRS-negative going on two years, and most of the secondary diarrhea, influenza and strep problems that flare up with PRRS have disappeared along with the pesky virus.

Who You Gonna Call?

This rhetorical question, borrowed from the popular '84 Ghostbusters movie, serves as a timely lead-in to my thoughts this month.

The phrase fits perfectly with the situation our cattlemen neighbors found themselves in when news of the first case of bovine spongiform encephalopathy (BSE) in the U.S. broke on Dec. 23.

This was the worst possible news for the beef and dairy industries. In the pork industry, an outbreak of hog cholera, foot-and-mouth disease or African swine fever would be on par with the BSE scare.

At first blush, the BSE news could fairly be described as devastating. It was a situation in dire need of damage control. As more information trickled in, cooler heads prevailed and a strategic plan was initiated to provide the news media and the general public with a more balanced view of the real risks and a badly needed dose of facts and common sense.

Luckily, the beef industry had the National Cattleman's Beef Association (NCBA) and the checkoff-funded Cattleman's Beef Board to field hundreds of calls, set up teleconferences and generally provide some credible science to a situation hell-bent for sensationalized headlines on every news program from your local radio station's farm report to CNN.

The coordinated efforts of NCBA and USDA officials served as the baseline for steady, sensible information to a general public that has been sensitized to disasters ranging from the misguided apple Alar scare to the devastating sight of the crumbling Twin Towers on Sept. 11.

Calm was needed.

Common sense was essential.

Scientific facts were the criteria for credibility.

Industry Response Is Critical

Think for a moment — what would have been our industry's response if this had been an outbreak of hog cholera or African swine fever instead of a Holstein cow diagnosed with BSE? Who would you call?

The U.S. pork industry is currently blessed with the counterparts of the beef organizations. As you know, the National Pork Producers Council (NPPC) is your public policy and advocacy organization serving you in legislative and regulatory arenas. The National Pork Board allocates checkoff dollars to research, producer and consumer education and pork promotions.

Although the BSE situation did not hit the pork industry as hard as it did the beef industry, there were questions about the susceptibility of pigs to the disease, the impact on domestic pork supplies and our export markets. Both the NPPC and the Pork Board stepped up to the plate. Staff and elected officers (pork producers) of both organizations were armed with scientific facts and the perspective needed to satisfy the scoop-hungry news corps.

Without this coordinated effort — who would have been standing at the podium fielding the edgy questions, addressing innuendos about the safety of the meat supply, reassuring the public that every precaution was being taken, and reaffirming that the safety of their food was comparable to no other in the world?

What If Checkoff Goes Away?

In the past three to four years, there has been a lot of discussion about the self-help checkoff programs. There's been a good deal of fussing about the role of the National Pork Board and the mandatory checkoff, NPPC and its voluntary “producer consent” contributions and the priorities of each.

This sort of challenge and push for accountability are usually good. They foster discussion and often bring focus and, when needed, change.

I can't think of a better time for beef and pork producers to step up and answer these questions:

When disaster strikes — who you gonna call?

Will you have credible spokespeople available to provide sensible answers, facts and perspective, to represent your industry fairly and accurately?

Who you gonna call when the TV news bureau resurrects film footage of an infected animal in another country taken 15 years ago and uses it to portray the current situation?

Who are you going to call when information is distorted, exaggerated and presented as fact?

You are free to debate the strengths and weaknesses of the two organizations that represent the U.S. pork industry — and you should. At the end of the day, both should represent U.S. pork producers and the products they provide to this country and the world. But never, ever underestimate their value to your industry in a time of crisis. On those difficult days, someone must step to the microphone to represent your industry with well-documented facts.

An appeal to the U.S. Supreme Court concerning mandatory commodity checkoff programs is drawing nearer. The outcome is unpredictable. But one thing is for sure, failure to plan for and establish an industry “voice” critically needed in a time of crisis would surely haunt us all.

Danes Outshine U.S.

Danish pork producers out-distance U.S. producers in weaned pigs/sow/year performance, fueled in large part by age at weaning.

While U.S. pork producers contemplate boosting weaning age, Danish producers have excelled at the management practice for years.

By stretching the length of the lactation period, the Danes have vastly increased numbers of weaned pigs produced/sow/year (Table 1). The chart reflects the top five breeding herds in Denmark using Danbred genetics.

How They Wean More Pigs

Danish producers are a pig and a half/litter ahead of their American counterparts and wean pigs at 25-30 days of age. Live born pigs/litter can exceed 13.5, while Danbred North America's best customers are achieving 12.0, states Larry Himmelberg, swine nutritionist and director of Customer Support at Danbred North America.

John Waddell, a Sutton, NE, swine veterinarian who consults with Danbred, says the ban on antibiotic growth promoters (AGPs) prompted the Danes to extend weaning age.

“When the ban on AGPs in the nursery phase in Denmark occurred at the start of 2000, there were a lot of farms with enteric problems when weaning pigs,” he notes. “So one of the things they did to get around that was to start weaning older, taking a more robust pig into the nursery.” The next year Europe imposed a ban on weaning under 21 days old.

Table 1. Top Five Danish Breeding Herds Using Danbred Genetics, 2002
Herd Number 1 2 3 4 5
Herd Size 429 661 518 483 216
Pigs weaned/sow/year * 30.5 29.9 29.9 29.4 29.4
Litters/sow 2.38 2.36 2.42 2.40 2.43
Born alive/litter 13.9 14.1 13.3 13.4 12.9
Pigs weaned/litter 12.8 12.8 12.4 12.2 12.1
Age at weaning (days) 30 27 28 28 25
Weight at weaning (lb.) 15.2 15.2 15.4 15.8 16.1
Prewean mortality (%) 7.8 9.0 6.9 8.5 11.0
Farrowing rate (%) 95.1 87.0 93.5 - 90.3

A side benefit the Danes saw from later weaning was that subsequent litters of pigs were bigger (one-tenth of a pig/day of increased weaning age), says Waddell.

Himmelberg says Danbred North America producers have reported like results.

Tom Rathje, Danbred's geneticist, doubts the gains seen in weaned pigs by later weaning are unique to Danbred genetics.

“You are dealing with a lot of factors here, but a couple that stand out is letting the uterus return to normal (after farrowing); you are not forcing the pregnancy before the complete involution of the uterus (return to normalcy) occurs in the sow,” he explains. “More time is also advantageous to reestablishing a normal hormonal pattern and estrous cycle.”

Another factor in the Danes' favor, which has a huge impact on live born, is age at first mating, says Waddell. Danish farmers don't rush to get gilts mated right away.

“If you hold that gilt for another month before she is bred, in her lifetime she may produce way more pigs to make up for 30 non-productive days that we have been afraid we are going to lose by breeding her late,” he states.

They advise gilts should be 230 to 250 days old and at least 320 lb. at first mating.

Himmelberg says some of Danbred's U.S. customers have been able to improve live born averages of Parity 1 females from 10.5 pigs to 11.25. Key to that is breeding gilts older and heavier, he says.

Waddell says Danish producers also delay all boar exposure until gilts reach maturity and move to the breeding barn. This practice enhances gilts' ability to cycle, breed and settle.

Danbred North America is also studying the benefits of foregoing boar exposure until 25-30 days prior to mating.

And the genetics company is urging producers to look at later weaning. The economics of increasing weaning age look especially attractive if postweaning pig performance is improved, in addition to sow productivity, says Himmelberg.

But producers have one other option, says Waddell. “If you wean once a week, you've got a seven-day age spread from the oldest to the youngest pig. If you go to twice-a-week weaning, you narrow that age spread down to 3.5 days, taking off that lower weaning age.”

Modified Model Predicts Value Of Changing Genetic Lines

Collaborative research conducted at the Agriculture Department's (USDA) U.S. Meat Animal Research Center (MARC) has led to the inclusion of a high-lean growth genetics option in a current swine growth model. The update to the model was completed by the University of Kentucky.

This addition to the model permits producers and researchers to compare the economic impact of changing genetics.

Swine production variables used in the comparison of two genotypes are contained in Table 1. The comparison of production parameters and economic return of a moderate and high-lean genotype are detailed in Table 2.

The MARC research bore out that a high-lean growth genetic line reached slaughter weight 10 days earlier than its moderate-lean growth competitor. This produced a net gain of $1.11/pig prior to inclusion of carcass premiums for percent lean.

The MARC project updates the swine growth model (NCPIG) developed by the North Central Regional Swine Modeling Committee. NCPIG simulates the interactions of feed intake, nutrient digestion, body maintenance, tissue accretion and individual animal response to an environment over time.

Table 2. Economic Comparison for the Simulated Barrows
Item Moderate-Lean Growth High-Lean Growth
Initial weight, lb. 68.47 69.53
Market weight, lb. 244.46 245.04
Carcass weight, lb. 191.72 191.96
Days on feed 94 84
Average daily gain, lb./day 1.87 2.09
Feed to gain, lb.:lb. 2.45 2.41
Total feed intake, lb. 432.32 423.09
Total feed cost, $ 30.26 29.62
Total pig investment, $ 67.10 66.10
Total pig return, $ $92.03 92.14
Net gain/pig, $ $24.93 26.04

Table 1. Swine Production Cost Variables Used as Inputs for Both Genotypes
Fixed Production Costs Variable Production Costs
Initial pig value in facility $20/pig Interest rate 10.0%
Facility without misting- cooling $7/pig Labor 3¢/pig/day
Operating costs $1.50/pig Veterinary cost $3/pig
Marketing cost $2/pig
Feed Costs Carcass Sale Price
Ration $140/ton Base value $48/cwt.

Researcher: Tami M. Brown- Brandl, U.S. Meat Animal Research Center. Contact Brown-Brandl by phone (402) 762-4279; fax (402) 762-4273 or e-mail brandl@

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Water Medicator

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(Circle Reply Card No. 101)

Swine Flu Vaccine

Novartis Animal Health introduces PneumoSTAR SIV, a killed vaccine for use in healthy, seronegative pigs, providing seven-week protection against disease caused by swine influenza virus (SIV) subtypes H1N1 and H3N2. The product offers single-shot convenience with broad-spectrum efficiency, says Brad Bosworth, technical services veterinarian for Novartis. PneumoSTAR SIV provides broad cross-reactivity among various SIV strains for more effective immunity. The product is sold in 100- and 250-dose bottles, and is labeled for intramuscular administration with a 1-ml. dose at three weeks of age or older.
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Truck Trailer Corrosion Barrier

For decades, the truck trailer industry has battled the corrosion that naturally occurs between dissimilar metals, such as aluminum and steel. Corrosion caused by oxidation can also occur between like metals. Electrolytes such as water, dirt and oil can accelerate the corrosion process. Electrolysis Corrosion Kontrol (ECK) is the only patented solution to this problem. ECK is a single-application coating that creates a barrier between metals. The coating contains zinc, which prevents both electrolic and galvanic corrosion. The product is easy to apply by spray or brush. One application of ECK may last 10 years or more and won't crack, dry or peel. ECK is distributed by Powerbrace Corp.
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Next-Generation Tractor

McCormick International USA launches its next-generation McCormick MTX B-Series tractor range (100 to 160 PTO hp), featuring the exclusive BetaPower six-cylinder, 6.7-liter, turbo-diesel engine, based on Cummins technology. The transmission in the MTX line has been improved with the introduction of the AutoSpeed option. While AutoSpeed is still a semi-power shift transmission, range change modulation will be ground-speed sensitive for faster range changes under rolling loads. The MTX B-Series also features the company's first cab suspension, automatic climate control, new cab instruments and a one-piece lift-up bonnet for easier service access to the engine and cooling system.
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Tire Monitoring System

More than 87% of the tire blowouts that occur are the result of damage due to low tire pressure. PressurePro, made by Rosefield Technology, is a tire pressure monitoring system that is simple to install and use. Small sensors screw onto the valve stems. The monitor plugs into the power accessory (lighter) in the vehicle. The monitor displays current tire pressures for all types of vehicles with pneumatic tires, and alerts when tire pressures fall by 10% and again at 20%. The system reads from one to 34 tire positions and accommodates tires up to 150 psi.
(Circle Reply Card No. 105)

Swing Gate Operator

An efficient, solar-powered farm and ranch swing gate operator is introduced by Court Security Systems Inc. The AGS 104 farm and ranch swing gate operator allows up to 190 opening and closing cycles/day with full sunlight. Without any sunlight, the unit provides 18 opening and closing cycles/day for nearly two weeks. A high-power solar option extends operation from two to three weeks in the absence of sunlight. This option is provided by a permanent magnet DC motor. The gate system uses a permanently lubricated, continuous-duty gear motor that allows for continuous operation. The final gear drive features hardened and ground worm gear to handle gates up to 13 ft. wide and up to 300 lb. The AGS 104 is constructed with a solid, 3/16-in. steel frame with a baked-on, powder-coated finish. The gate system can be locked in either the open or closed position to provide livestock control or driveway security.
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Send product news submissions to Dale Miller, Editor (952) 851-4661;

Illinois Processing Plant Finally Opens

After three years of work and an investment of $700,000 by its 200 farmer members, the Meadowbrook Farms Cooperative pork processing facility is open for business.

The state-of-the-art plant sits on 42 acres in Rantoul, IL. It will eventually slaughter and process over 16,000 hogs/week, serving retailers, further processors, foodservice professionals and exporters.

“Our entire focus has been to put together a system that will enable us as producers to take control of our business from feedlot to consumer,” says Meadowbrook Farms chairman and pork producer Roger Walk. “By harnessing the best designs and processes available, we developed a facility that gives us a real marketplace advantage — that we can feel really proud of, and that allows us to make real choices in how we run our farm operations.”

The plant offers highly customized processing and products to serve domestic and international markets.

The plant includes the highest environmental standards and sanitary and humane operating conditions. The plant will use 1/3 less water in sanitizing the meat to be cut and packaged, contributing to meat quality.

The plant has constructed a $1.7 million facility to treat plant discharge.

All rendering products will be transported to offsite facilities specifically designed for that process.

Hogs are delivered to an indoor bay and held in a climate-controlled area before slaughter.

A unique inventory control and monitoring software system drives Meadowbrook's approach to a smaller-scale pork processing plant to yield very consistent, high-quality, portion-controlled cuts.

“We can monitor each individual hog and each cut from that hog from farm of origin to customer delivery,” says James Burke, Meadowbrook Farms ( president and CEO.