Practice Tip Peer reviewed
Fact sheets – considerations regarding marketing heavy-weight pigs, and high-fiber ingredient withdrawal strategy before slaughter in finishing pigs  
Márcio A. D. Gonçalves, DVM, PhD; Steve S. Dritz, DVM, PhD; Mike D. Tokach, MS, PhD; Joel M. DeRouchey, MS, PhD; Jason C. Woodworth, MS, PhD; Robert D. Goodband, MS, PhD

MADG, SSD: Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, College of Agriculture, Kansas State University, Manhattan, Kansas. MDT, JMDR, JCW, RDG: Department of Animal Sciences and Industry, College of Veterinary Medicine, College of Agriculture, Kansas State University, Manhattan, Kansas. Corresponding author: Dr Márcio A. D. Gonçalves, Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, Kansas.

Dr Gonçalves is currently with Genus PIC PLC, 100 Bluegrass Commons Blvd, Suite 2200, Hendersonville, TN 37075; Tel: 615-265-2729; Fax: 615-265-2848; E-mail: This article was published as part of Dr Gonçalves’ PhD thesis, Kansas State University, Manhattan, Kansas; 2015.

RIS citationCite as: Gonçalves MAD, Dritz SS, Tokach MD, et al. Fact sheets – considerations regarding marketing heavy-weight pigs, and high-fiber ingredient withdrawal strategy before slaughter in finishing pigs. J Swine Health Prod. 2017;25(1):29–33.
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Keywords: swine, market weight, market pig, fibrous ingredients
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Received: July 24, 2015
Accepted: April 28, 2016

This practice tip includes fact sheets on marketing heavy-weight pigs and withdrawal of high-fiber ingredients before slaughter

Conflict of interest

None reported.


Scientific manuscripts published in the Journal of Swine Health and Production are peer reviewed. However, information on medications, feed, and management techniques may be specific to the research or commercial situation presented in the manuscript. It is the responsibility of the reader to use information responsibly and in accordance with the rules and regulations governing research or the practice of veterinary medicine in their country or region.

Fact Sheet: Considerations regarding marketing heavy-weight pigs

Fast facts

Adequate pen space and marketing strategies are crucial to maximize the value of heavier market-weight pigs.

New facilities and equipment (feeder space, drinker height, gate height, alley width, loading ramp) must account for heavier market weight.

There is a need for more empirical data on nutrient requirements of heavier-weight pigs.

Market weight has linearly increased by 5.8 kg every 10 years during the last four decades.1 This trend is driven by the dilution of fixed costs over more weight per pig and improvement in genetics and nutrition that result in more efficient and leaner pigs at heavier body weights than in previous years.1 Because market weight has been increasing linearly, the definition of “heavy” market weight is dynamic. Currently, heavy market weight could be defined as a group average of above 130 kg.

Average daily gain (ADG) is expected to be 0.5% to 1.5% lower in pigs fed to 145 kg body weight (BW), compared to those fed to 125 kg BW.2,3 Space allowance is one of the main factors that will limit gain when pigs get heavier. Similarly, feed efficiency is expected to worsen by 4% to 9% when average final weight increases from approximately 125 to 145 kg.2-5 Also, as body weight increases, a slight increase in carcass yield has been reported.6,7

Genetic considerations

Different genetic lines will perform differently when raised to heavier market weights, probably due to differences in lean and fat deposition.2,4,8 For instance, a Spanish study8 has shown that market pigs sired by three different terminal boar lines showed up to a 3.6% difference in performance for ADG and a 4.0% difference in feed-to-gain (F:G) at the time of marketing (130 kg).

Nutritional considerations

More nutrient requirement information is needed. Factorial approaches have been used to estimate amino-acid requirements for heavy-weight pigs.3 As an example, the estimates for the standardized ileal digestible (SID) lysine (Lys) requirements for pigs fed from 125 to 140 kg3 and from 140 to 160 kg9 were 0.56% and 0.51%, respectively. However, there is no body of empirical studies in these weight ranges to increase confidence in these modeled estimates. Other examples include the nutrient requirements when feeding ractopamine. Hot carcass weight was higher in pigs fed ractopamine up to 130 kg BW,10 suggesting that ractopamine is still effective at higher market weights. The National Research Council (NRC) model3 estimates the SID Lys requirement from 125 to 140 kg BW is 0.77% when using 10 g of ractopamine per ton; however, again, there is a need for empirical studies to confirm this estimate.

Health considerations

Assuming the same rate per day in mortality, a longer feeding period will incur a slight increase in mortality. In addition, increased risk for lateral infections and loss of additional heavy-weight pigs will increase the overall F:G of a barn due to the amount of feed consumed.11 Additionally, depending on the time during the finishing period when diseases are occurring, and the duration of vaccine immunity, adding 2 to 4 weeks until harvest, may require altered vaccination strategies.12

Management considerations

Pen space and marketing strategy are key factors when marketing heavy-weight pigs. If pen space is limited, feed intake, and thus growth, will decrease. Compared to a market weight of 120 kg, space allowance requirements increase 5% per pig for 130 kg BW or 11% for 140 kg BW.13 A 136-kg market weight requires 0.90 m2 per pig for maximum ADG, while 0.77 m2 per pig causes a 5% reduction in ADG.13 Strategies that market pigs at regular intervals before closing out a barn provide more space for remaining pigs and allows them to increase their growth. For example, removing pigs to increase space allowance from 0.65 to 0.84 m2 per pig over the last 3 weeks before reaching market weight (140 kg) increased growth rate by 4.8%.14

Heat production and ventilation will be affected when marketing heavy-weight pigs.15 Pigs produce approximately 8% more heat for each 10-kg increase in BW.15 It is estimated that from 110 to 132 kg BW, there is approximately a 15% increase in heat production per pig.1 The recommended air flow in the barn is 19.9 m3 per hour per 115-kg pig, 22.1 m3 per hour per 127-kg pig, and 24.3 m3 per hour per 138-kg pig. Thus, ventilation rate increases with increased market weight on a per-pig basis; however, at the barn level, ventilation may not change dramatically if the production system is marketing pigs at regular intervals before closing out the barn.

Adding 4 extra weeks of growth (ie, 125 to 145 kg) could potentially increase the proportion of gilts that would present with pubertal estrus.16 This could have a modest impact on feed intake and ease of handling market gilts.

Transportation is another factor to be taken into consideration when marketing heavy-weight pigs. Heavier pigs require more space during transport to maintain welfare and reduce transport losses.17 Thus, the recommended space allowance on trucks for pigs marketed in the summer is 0.46 m2 per pig at 114 kg BW, 0.55 m2 per pig at 136 kg BW, or 0.65 m2 per pig at 182 kg BW.17 Therefore, fewer pigs will be marketed in each load as pig body weight increases.

Facility and equipment design considerations

Due to continued trends for increased body weight of pigs at marketing, building designs should account for this change. Heavier pigs are wider and taller; thus, feeder space, drinker height, gate height, and alley width must be carefully considered.

The amount of feeder space needed is normally 1.1 times shoulder width.1 Because shoulder width increases from 31.5 to 32.7 cm when pigs grow from 125 to 140 kg BW,18 the requirement for width of a feeder space increases from 34.7 to 36.0 cm.

For a 140-kg BW pig, drinker height should be approximately 77 cm for a 90-degree nipple drinker and 92 cm for a downward-mounted nipple drinker.19 However, the drinker height should be adjusted to the shoulder height of the smallest pig in the pen.19 Shoulder height increases by 2.8 cm when pigs grow from 125 to 140 kg BW;19 therefore, gate height might be a factor to be taken into consideration when building new facilities. Finally, for pigs heavier than 125 kg, 15 degrees or less is the recommended loading-ramp angle, compared to 20 degrees for lighter pigs.17

Packing plant considerations

Factors associated with marketing heavy-weight pigs that can have an impact in the packing plant are rail capacity, rail height, primal cut size, and cooling capacity. Pigs could be heavier than the facility is designed for; thus, the amount of weight that rails support may be a limiting factor. Increased length of the carcass could pose a challenge for food safety if the rail is not high enough. Increased primal cut size will require adjustment of cut sizes from the retail market perspective. Similarly, increased weight will require an extra amount of cooling time for the carcass; thus, a different cooling-time strategy may be required.


Contribution no. 16-008-J from the Kansas Agricultural Experiment Station, Manhattan, KS 66506-0210.


*1. Brumm M. Impact of heavy market weights on facility and equipment needs. Proc Allen D. Leman Swine Conf. St Paul, Minnesota. 2012;165–168.

*2. Jungst S, Matthews N, Booher C, Fields B, Dreadin T, Tabor S, Anderson J, Martin J, Williams A, Jobin M, Sosnicki A, Wilson E. Growth curves for commercial PIC337RG pigs fed high and low energy diets. PIC Tech Memo. Hendersonville, Tennessee. 2012;ES51-344. Available at Accessed 18 October 2016.

3. NRC. Model for estimating nutrient requirements of swine. In: Nutrient Requirements of Swine. 11th rev ed. Washington, DC: National Academy Press; 2012:127–156.

*4. Jungst S, Matthews N, Booher C, Fields B, Dreadin T, Tabor S, Anderson J, Martin J, Williams A, Jobin M, Sosnicki A, Wilson E. Growth curves for PIC327L sired pigs fed diets with differing energy levels. PIC Tech Memo. Hendersonville, Tennessee. 2012;ES50-344.(5) 6. Available at Accessed 18 October 2016.

5. Latorre MA, Lázaro R, Valencia DG, Medel P, Mateos GG. The effects of gender and slaughter weight on the growth performance, carcass traits, and meat quality characteristics of heavy pigs. J Anim Sci. 2004;82:526–533.

6. Virgili R, Degni M, Schivazappa C, Faeti V, Poletti E, Marchetto G, Pacchioli MT, Mordenti A. Effect of age at slaughter on carcass traits and meat quality of Italian heavy pigs. J Anim Sci. 2003;81:2448–2456.

7. Apple JK, Maxwell CV, Galloway DL, Hutchison S, Hamilton CR. Interactive effects of dietary fat source and slaughter weight in growing-finishing swine: I. Growth performance and longissimus muscle fatty acid composition. J Anim Sci. 2009;87:1407–1422.

8. Latorre MA, Medel P, Fuentetaja A, Lázaro R, Mateos GG. Effect of gender, terminal sire line and age at slaughter on performance, carcass characteristics and meat quality of heavy pigs. Anim Sci. 2003;77:33–46.

9. Manini R, Piva A, Prandini A, Mordenti A, Piva G, Dourmad JY. Protein retention in Italian heavy pigs: Development of a factorial approach for the determination of lysine requirement. Livest Prod Sci. 1997;47:253–259.

10. Fernández-Dueñas DM, Myers AJ, Scramlin SM, Parks CW, Carr SN, Killefer J, McKeith FK. Carcass, meat quality, and sensory characteristics of heavy body weight pigs fed ractopamine hydrochloride (Paylean). J Anim Sci. 2008;86:3544–3550.

11. Dritz SS. Influence of health on feed efficiency. In: Patience J, ed. Feed Efficiency in Swine. Wageningen, The Netherlands: Wageningen Academic Publishers; 2012:225–237.

12. Roth JA, Thacker EL. Immune system. In: Straw B, Zimmerman J, D’Allaire S, Taylor DJ, eds. Disease of Swine: 9th ed. Ames, Iowa: Blackwell Publishing; 2006:15–35.

13. Gonyou HW, Brumm MC, Bush E, Deen J, Edwards SA, Fangman T, McGlone JJ, Meunier-Salaun M, Morrison RB, Spoolder H, Sundberg PL, Johnson AK. Application of broken-line analysis to assess floor space requirements of nursery and grower-finisher pigs expressed on an allometric basis. J Anim Sci. 2006;84:229–235.

*14. Flohr JR, Tokach MD, Dritz SS, Woodworth JC, DeRouchey JM, Goodband RD. Using meta-analyses to generate alternative prediction equations for the space requirements of finishing pigs. Kansas State University Agricultural Experiment Station and Cooperative Extension Service. 2015;1:39.

15. Brown-Brandt TM, Nienaber JA, Xin H, Gates RS. A literature review of swine heat production. Trans ASAE. 2004;47:259–270.

16. Tummaruk P, Tantasuparuk W, Techakumphu M, Kunavongkrit A. The association between growth rate, body weight, backfat thickness and age at first observed oestrus in crossbred Landrace × Yorkshire gilts. Anim Reprod Sci. 2009;110:108–122.

*17. Grandin T. Welfare of pigs during transport. Pork Information Gateway. 2002. Available at Accessed 10 October 2016.

18. Petherick JC. A biological basis for the design of space in livestock housing. In: Baxter SH, Baxter MR, MacCormack JASC, eds. Farm Animal Housing and Welfare. Boston, Massachusetts: Martinus Nijhoff Publisher; 1983:103.

*19. Gonyou HW. Water use and drinker management. Prairie Swine Centre, Saskatoon. 1996. Available at Accessed 22 September 2016.

* Non-refereed references.

Fact Sheet: High-fiber ingredient withdrawal strategy before slaughter in finishing pigs

Fast facts

High-fiber diets fed until market reduce carcass yield.

Many high-fiber ingredients also contain high concentrations of unsaturated fatty acids which can increase carcass fat iodine value.

High-fiber ingredient withdrawal of approximately 15 to 20 days is able to restore carcass yield and reduce impact on iodine value.

If high-fiber ingredient diets are economical, a high-fiber ingredient withdrawal of 15 to 20 days prior to market maximizes income over feed cost across different market scenarios.

It is often economically viable to use high-fiber ingredients such as distillers dried grains with solubles (DDGS) and wheat middlings in finishing pig diets. Because most swine producers are paid on a carcass basis, it is important to understand the impact of high-fiber ingredient diets on carcass characteristics and economics. Feeding high-fiber ingredient diets up to market has been shown to reduce carcass yield due to increased gut fill and visceral weight.1 Many high-fiber ingredients contain unsaturated fatty acids, which also increases iodine value (IV).1

What is high-fiber ingredient withdrawal?

High-fiber ingredient withdrawal is the replacement of the high-fiber ingredients in finishing diets by low-fiber ingredient(s) (eg, a diet based on corn and soybean meal) for a specific time before market.

Impact of high-fiber ingredient withdrawal on carcass yield and carcass weight

Carcass yield is lower in pigs fed high-fiber ingredient diets until market than in pigs fed a diet based on corn and soybean meal.2,3 Carcass yield is restored after 15 to 51 days withdrawal of the high-fiber ingredients, becoming comparable to carcass yield when a corn-soybean meal diet is fed.2-6 The lower carcass yield is a result of increased large intestine weight and fecal volume when pigs are fed a diet high in insoluble fiber.7,8 Because yield is the ratio between carcass and live weight, an increase in live weight without a change in carcass weight leads to a lower yield. A descriptive summary of eight experiments8 in which high-fiber ingredient diets were fed for periods of varying durations suggests an increase of 0.16% in carcass yield for each 1% reduction in neutral detergent fiber. The negative impact on carcass yield of feeding high-fiber ingredient diets until market is reported to be greater in immunocastrated than in physically castrated pigs.5

Impact of high-fiber ingredient withdrawal on carcass fat quality

Iodine value is a practical means of measuring unsaturated (“soft”) fat, by measuring the relative number of double bonds in the fatty acids. More unsaturated dietary fat is associated with a higher carcass fat IV. From a dietary fat perspective, linoleic acid (C18:2n-6) and α-linoleic acid (C18:3n-3) are the main drivers of higher IV.9 Therefore, withdrawing feeding ingredients such as DDGS and wheat middlings, which have higher levels of unsaturated fatty acids (ie, linoleic acid) will reduce the amount of unsaturated fat in the carcass and consequently reduce IV. Iodine value was linearly improved with up to 20 days withdrawal of the high-fiber ingredients, but this was not long enough to fully restore IV.8 However, IV value was fully restored by using a 9-week withdrawal of high-fiber ingredients.10 Conversely, withdrawal of high-fiber ingredients that contain no unsaturated fatty acids is not expected to influence IV value.

High-fiber-ingredient withdrawal time to mitigate negative yield effects

Two recent studies evaluated withdrawal of high-fiber ingredients in diets with 30% DDGS and 19% wheat middlings for 5, 10, 15, and 20 days (Experiment 1) and 9, 14, 19, and 24 days (Experiment 2) before market.8 In Experiment 1, carcass yield of pigs marketed on the same day was restored in a quadratic manner with increase in high-fiber ingredient withdrawal time, being fully restored at 15 days. In Experiment 2, hot carcass weight of pigs marketed on the same day was linearly increased when high-fiber ingredient withdrawal time was increased. The data suggested a high-fiber ingredient withdrawal time of approximately 15 to 20 days is needed to fully restore carcass yield.8

Impact of high-fiber ingredient withdrawal on economic performance

Economic calculations have demonstrated8 that when feeding high-fiber diets, a high-fiber ingredient withdrawal period of approximately 15 to 20 days maximized income over feed cost across widely variable ingredient and pork market prices. In those scenarios, the benefits ranged from $2.20 to $2.90 per pig (all currency in $US).8 High-fiber ingredient withdrawal was modeled to be more economical independent of the production flow (ie, fixed weight or fixed time basis).8 The economics are driven by pigs fed a low-fiber ingredient diet maintaining feed intake while consuming a more calorie-dense diet, which leads to improved carcass weight relative to live weight.


Contribution no. 16-006-J from the Kansas Agricultural Experimental Station, Manhattan, KS 66506-0210.


1. Salyer JA, DeRouchey JM, Tokach MD, Dritz SS, Goodband RD, Nelssen JL, Petry DB. Effects of dietary wheat middlings, distillers dried grains with solubles, and choice white grease on growth performance, carcass characteristics, and carcass fat quality of finishing pigs. J Anim Sci. 2012;90:2620–2630.

*2. Gaines AM, Spencer JD, Petersen GI, Augspurger NR. Effect of corn distiller’s dried grains with solubles (DDGS) withdrawal program on growth performance and carcass yield in grow-finish pigs [abstract]. J Anim Sci. 2007;85:438.

*3. Jacela JY, Benz JM, Dritz SS, Tokach MD, DeRouchey JM, Goodband RD, Nelssen JL, Prusa KJ. Effect of dried distillers grains with solubles (DDGS) withdrawal regimens on finishing pig performance and carcass traits [abstract]. J Anim Sci. 2010;88:53.

4. Asmus MD, DeRouchey JM, Tokach MD, Dritz SS, Houser TA, Nelssen JL, Goodband RD. Effects of lowering dietary fiber before marketing on finishing pig growth performance, carcass characteristics, carcass fat quality, and intestinal weights. J Anim Sci. 2014;92:119–128.

5. Asmus MD, Tavarez MA, Tokach MD, Dritz SS, Schroeder AL, Nelssen JL, Goodband RD, DeRouchey JM. The effects of immunological castration and corn dried distillers grains with solubles withdrawal on growth performance, carcass characteristics, fatty acid analysis, and iodine value of pork fat depots. J Anim Sci. 2014;92:2116–2132.

6. Nemechek JE. Effects of pelleting and dietary fat and fiber levels on pig growth and fat quality [PhD dissertation]. Manhattan, Kansas: Kansas State University. 2014:121.

7. Graham AB, Goodband RD, Tokach MD, Dritz SS, DeRouchey JM, Nitikanchana S. The interactive effects of high-fat, high-fiber diets and ractopamine HCl on finishing pig growth performance, carcass characteristics, and carcass fat quality. J Anim Sci. 2014;92:4585–4597.

*8. Coble K, DeRouchey JM, Tokach MD, Dritz SS, Goodband RD, Woodworth JC. The importance of implementing a by-product withdrawal strategy prior to slaughter in finishing pigs: A review of strategies that mitigate the negative impact on carcass yield [abstract]. J Anim Sci. 2015;93:48.

9. Paulk CB. Predicting market pig weights and fat iodine value and effect of zinc on growth performance and immune function of finishing pigs [PhD dissertation]. Manhattan, Kansas: Kansas State University. 2014:171.

10. Xu G, Baidoo SK, Johnston LJ, Bibus D, Cannon JE, Shurson GC. The effects of feeding diets containing corn distillers dried grains with solubles, and withdrawal period of distillers dried grains with solubles, on growth performance and pork quality in grower-finisher pigs. J Anim Sci. 2010;88:1388–1397.

* Non-refereed references.