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Effect of withholding feed from swine before slaughter on carcass and viscera weights and meat quality¹

Department of Dairy and Animal Science, Pennsylvania State University, University Park 16802

	Abstract

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Two experiments were conducted to determine the effect of feed withholding on carcass and viscera weights and meat quality in grow-finish swine. Experiment 1 included 528 pigs that were marketed from 24 pens and subjected to either 6 (control) or 24 h of feed withholding before marketing. Experiment 2 included 324 pigs that were marketed from 36 pens that were subjected to 6 (control), 16, or 24 h of feed withholding before marketing. In both experiments, pigs from each pen were marketed over a 14-d period in three groups, each 7 d apart. In Exp. 1, withholding feed for 24 h decreased viscera weight, carcass weight and yield, and feed intake during the 14-d marketing period compared with the control group (P < 0.05). Subjective measures of color, firmness, and marbling in fresh pork did not differ for the two treatment groups. In Exp. 2, withholding feed for 16 or 24 h decreased (P < 0.05) viscera weight compared with that of the control group. Withholding feed for 24 h decreased feed intake during the 14-d marketing period compared with intake of the control group. Withholding feed for 16 h did not decrease carcass weight, but carcass weights in the 24-h group were lower than those of the 16-h group in this Exp. 2 (P < 0.05). Color, firmness, marbling, and shear force did not differ among treatment groups in Exp. 2; however, cooking loss in pork from the control group exceeded that of the 24-h treatment. Gain:feed and ADG were not affected by treatment during the marketing period in either experiment. We conclude that withholding feed for either 16 or 24 h decreases viscera weight and feed intake during the marketing phase in finishing swine. These changes could potentially benefit both the producer and the processor with only minimal effects on carcass weight and pork quality.

Key Words: Carcass Weight • Feed • Meat Quality • Swine • Viscera • Withdrawal

	Introduction

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Pork processors typically slaughter a large percentage of hogs they receive on the day of arrival. Because most pigs have free access to feed until marketing, the typical time off feed may be less than 24 h before slaughter. Reports of several studies have documented decreases in warm carcass yield when feed withdrawal times exceeded 24 h (Saffle and Cole, 1960; Bowland and Standish, 1966; Warriss and Down, 1985), but deleterious effects seem to be diminished when feed withholding is less than 24 h (Warriss, 1982; Eikelenboom et al., 1991; Morrow et al., 2002). Other benefits of withholding feed for 12 to 24 h before slaughter include decreased weight of the gastrointestinal tract, decreased risk of accidental laceration of the tract during evisceration, decreased feed wastage, increased carcass yield, and a decrease in cost of manure treatment at the abattoir (Morrow et al., 2002).

Under commercial conditions, producers typically remove the heaviest pigs from a pen several times over a period of 3 to 5 wk to meet the desirable weight range at the abattoir. Morrow et al. (2002) mimicked this approach by marketing pigs in three groups over a 4-wk period and found that pork quality decreased linearly with successive marketing groups. However, neither feed intake during the marketing period nor carcass economic values were presented in that report. Therefore, the objectives of these experiments were to determine the effect of withholding feed from market hogs for 6 to 24 h preceding slaughter on carcass weight and value, pork quality, and on feed intake and growth performance during a 2-wk marketing period in commercial swine-finishing facilities.

	Materials and Methods

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Experiment 1
Facilities.
This study was conducted during the summer in a mechanically ventilated, two-room, 3,000-pig capacity, commercial swine grower-finisher barn located in central Pennsylvania. Each room contained 60 pens, each of which measured 2.44 m x 7.40 m and had totally slotted concrete floors and two nipple waterers. For this experiment, 24 pens were used in one room. The feeders were double-sided, had five feeding spaces per side (20.3 cm each), and served two adjacent pens, one of which was kept empty throughout the experiment to monitor feed intake on a single-pen basis.

Animals and Feed.
All pigs were of similar genetic composition from the Pro-Genetic breeding system of White Oak Mills (Elizabethtown, PA). Pigs were ear-tagged and tattooed with unique identification numbers approximately 3 wk before the beginning of the experiment. The feed was a commercial, pelleted soy-corn diet containing approximately 0.70% lysine (as-fed basis) formulated to meet or exceed nutrient requirements for pigs weighing 80 to 120 kg (NRC, 1998). Feed intake during the 2-wk marketing period was estimated by recording the depth of the feed in the feeder before and after filling. To convert feed-depth measurements to weights, the depths of known amounts of feed were measured as the feeder was filled and emptied by hand, and a regression equation was calculated (feed weight, kg = –6.64 + 2.31 x feed depth, cm; r² = 0.97).

Allotment.
All pigs were weighed 14 d before the beginning of the experiment (d –14). Each pen contained 22 to 28 pigs. On d –6, the lightest pigs were removed from the pens, as necessary, to equalize the number of pigs (n = 22) in all pens. At the same time, pen groups were allotted to one of two experimental treatments in a manner that equalized BW and gender ratio for the two treatments, and moved to one of 24 new pens in one room. The allotment to new pens enabled the formation of blocks to control for the effects of pen location within the room. The treatments included 6-h feed withholding (control) and 24-h feed withholding. The 6-h group had free access to feed until removed from the pens and loaded for transport. Feed was withdrawn from the 24-h group 18 h before load out.

Pigs within each pen were allotted to one of three marketing groups: the heaviest four pigs, the next heaviest eight pigs, and the 10 lightest pigs in each pen were assigned to the first, second, and third marketing groups, respectively. After pens were assigned to treatment, they were distributed among three blocks of eight pens each. Blocks were located at various distances from the exhaust fans and contained four pens on each side of the service aisle. Each side contained two randomly allotted barrow pens (one of each treatment) and two randomly allotted gilt pens (one of each treatment). Thus, blocks contained eight pens distributed according to treatment and gender equally on each side of the aisle.

The projected duration from the beginning of load out, which commenced at 0600, until the first pig was stunned, was 6 h for each marketing group. This included approximately 4 h for load out and transit, and approximately 2 h for rest time at the abattoir (exact times not recorded). After arrival, pigs had access to water but not feed. Actual time when the first pig was stunned was 1157, 1155, and 1133 for the first, second, and third marketing groups, respectively. Outdoor temperatures were recorded at the farm when the truck departed from the swine facility and on arrival at the abattoir and averaged to estimate the mean temperature during transit.

Data Recorded.
On d 0, all pigs were weighed between 0600 and 1100, after which all feeders were filled. At approximately 1200, all feeders were inventoried and shut off to the pigs in the 24-h pens by turning down the feeder adjustment as far as possible. On d 1 at approximately 0600, feed was inventoried in all feeders, and the four pigs from each pen allotted to the first marketing group were loaded and transported to the abattoir. Throughout the study, feeders were filled four to seven times per week, and inventories were recorded before and after each filling to estimate feed intake.

Optical probe data (Fat-O-Meat’er, SFK Technology, Inc., Cedar Rapids, IA), carcass weight, payment by the abattoir, and viscera weight (all internal organs except kidneys) were recorded for each pig. Payment by the abattoir reflected actual carcass value based on carcass weight and price. Final carcass price varied according to weight sort penalties and adjustments for lean percent predicted by the Fat-O-Meat’er. On d 2 after slaughter, color, firmness, and marbling scores were subjectively evaluated (NPPC, 1991) by a single observer, who examined the gluteus medius muscle from the right side of the carcass.

On d 7, all remaining pigs were weighed, feed measurements were taken, and feeders were shut off in the 24-h pens as described for d 0. On d 8, the eight pigs allotted to the second marketing group were removed from each pen and transported to the abattoir. Growth rates and G:F ratios were calculated for the period from d 0 to 7. Data were collected at marketing as described for d 1 and 2, respectively.

On d 14, all remaining pigs were weighed, feed measurements were taken, and feeders were shut off in the 24-h pens as described for d 0. Growth rates and G:F ratios were calculated for the period from d 7 to 14. On d 15, the 10 remaining pigs from each pen were transported to the abattoir. Data were collected at marketing as previously described for d 1. Due to an unexpected shut down of the abattoir on d 16, subjective pork quality evaluation was postponed until d 19.

Experiment 2
Facilities.
Experiment 2 was conducted during the fall in a six-room, 3,600-pig-capacity, mechanically ventilated grower-finisher barn located approximately 2 km northwest of the facility used in Exp. 1, which was not available for additional studies. Each room contained 24 pens, each of which measured 3.04 m x 5.64 m and had totally slotted concrete floors and two nipple waterers. Twelve pens in each of three rooms were used in this study. The feeders were double-sided, had five feeding spaces per side (25.4 cm each), and served two adjacent pens, one of which was kept empty throughout the experiment to monitor feed intake on a single-pen basis.

Animals and Feed.
The genetic background, timing, and type of identification system, diet formulation, and feed intake estimation were as described for Exp 1. To convert feed-depth measurements to weights, a regression equation was calculated as described for Exp. 1 (feed weight, kg = –4.5 + 2.32 x feed depth, cm; r² = 0.97).

Allotment.
Twelve days before the beginning of the experiment (d –12), all pigs were weighed. Each pen contained from 25 to 28 pigs. On d –4, the heaviest pigs were removed from the pens, as necessary, to provide similar numbers (n = 24 to 26) of pigs in all pens. At the same time, pen groups were allotted to one of three experimental treatments in a manner that equalized BW and gender ratio for the three treatments and moved into one of 12 new pen locations in each of three finishing rooms. The allotment to new pens enabled the formation of blocks to control for the effects of room and pen location within the room. The treatments included 6- (control), 16-, and 24-h feed withholding. The 16-h treatment was added in an attempt to minimize the negative effect of feed withdrawal on carcass weight observed in Exp. 1. Nine pigs within each pen were selected to be marketed, three at a time, in each of three marketing groups 7 d apart. Average initial BW (first marketing group = 108 kg, second marketing group = 101 kg, third marketing group = 95 kg) served as the basis for selection of these pigs for the respective marketing groups. In accordance with typical marketing practices for this enterprise, on the first marketing date, only the three sample pigs were marketed; on the second date, the three sample pigs and three others were marketed; and on the third date, the three sample pigs and all others remaining in the pen weighing at least 105 kg were marketed, after which the experiment was terminated.

The 12 new pen locations were distributed between two blocks of six pens each within each room. One block comprised the room half nearest to the exhaust fans; the other comprised the room half more distant from the fans. Each block contained three randomly allotted barrow pens (one of each treatment) and three randomly allotted gilt pens (one of each treatment). Blocks therefore contained six pens with all treatments and both genders distributed randomly within the block.

Recording of outdoor temperatures, handling of pigs after arrival at the abattoir, and projected times from the beginning of load out until the first pigs were stunned were as described for Exp. 1. The actual times when the first pig was stunned were 1211, 1200, and 1200 for the first, second, and third marketing groups, respectively.

Data Recorded.
On d 0, all sample pigs were weighed. At approximately 1200, all feeders were inventoried and shut off in the 24-h pens by turning down the feeder adjustment as far as possible. At approximately 2000, feeders in the 16-h pens were shut off. On d 1 at approximately 0600, feed was inventoried in all feeders, and the three sample pigs from each pen allotted to the first marketing group were loaded and transported to the abattoir. During the next 6 d, feeders were filled each day and inventories were recorded before and after each filling to estimate feed intake.

Data were collected as described in Exp 1. In addition, a cross-sectional sample (approximately 19 mm thick) of the gluteus medius muscle was placed in a plastic bag and stored at approximately 5°C. The following day, the muscle samples were trimmed, weighed on a digital scale (model PJ1220; Mettler Instrument Co., Highstown, NJ), and wrapped in aluminum foil. The samples were heated in a convection oven (model RP 26 electric range, General Electric Corp., Louisville, KY) at 177°C until they reached an internal temperature of 70°C (cooking time approximately 50 m). Temperature was measured during cooking using an Electrotherm HT680A, thermocouple thermometer equipped with a K-type thermocouple (chromelalumel, Cooper Instrument Corp., Middlefield, CT). The samples were then removed from the oven, allowed to cool for 15 min, unwrapped, blotted dry, and reweighed. After reaching room temperature, three cores (13-mm diameter) were taken by using a sharpened metal coring tool from the each of the muscle samples. Maximum shear force measurements using a single-blade shear head (texture corder TR-5, Food Tech Corp., Rockville, MD) were recorded on each core, and averaged for each muscle sample.

On d 7, all remaining sample pigs were weighed and feed measurements were taken and feeders were shut off in the 16- and 24-h pens as described for d 0. On d 8, the three sample and three nonexperimental pigs from each pen allotted to the second marketing group were transported to the abattoir. Data were collected at marketing as described for d 1 and 2, respectively.

On d 14, all remaining sample pigs were weighed, feed measurements were taken, and feeders were shut off in the 16- and 24-h pens as described for d 0. On d 15, the three sample pigs from each pen were transported to the abattoir. Data were collected at marketing as described for d 1 and 2, respectively.

General
Pigs in both experiments were handled in accordance with good husbandry practices. The Penn State Animal Care and Use Committee approved the study protocols (IACUC Approval No. 94R009).

Of the 528 animals that began Exp. 1, and the 324 pigs that began Exp. 2, five and seven pigs were removed from the respective studies due to injury, sickness, or inadvertent mixing with other pigs at the abattoir. For removed pigs that gained weight, feed intake was judged to be equal to the respective pen average, and that amount was deducted from the recorded totals for that pen. For removed pigs that lost weight during the study, feed intake was assumed to be zero.

In addition to these missing data described for Exp. 1, no optical probe data were recovered from one pig from the 6-h group. Color, firmness, and marbling scores could not be recorded on hams that were lost from two pigs in the 6-h group and one in the 24-h group. Finally, viscera weights were not recorded for two pigs in the 24-h group because of a delay in slaughtering these pigs.

Statistical Analyses
Data were analyzed via Proc GLM (Ver. 6.12, SAS Inst., Inc., Cary, NC) as a randomized complete block, with pen as the experimental unit. Fixed effects for Exp. 1 included treatment, gender, marketing date, block, side (of service aisle), treatment x gender, treatment x marketing date, and block x side. Fixed effects for Exp. 2 included treatment, gender, room, marketing date, block, treatment x gender, treatment x marketing date, and room x block. Live weight at d 0 was used as a covariate for all data except color, firmness, marbling, shear force, and feed intake data. A P-value of 0.05 was used to declare statistical differences.

	Results

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Experiment 1
Subjecting pigs to 24 h of feed withholding reduced (P < 0.05) carcass weight, carcass yield, and viscera weight, but had no effect on any other carcass measurement (Table 1). Growth rates of pigs between the first and second, and between the second and third marketing dates were similar for both treatments. From the beginning of the experiment (24 h before the first marketing date) until 24 h before the third marketing date, pigs in the 24-h group consumed less (P < 0.05) feed than those in the 6-h group. Gain:feed during the 2 wk following the first marketing date were similar for both treatments. Significant (P < 0.05) block x side interactions were detected for d-7 BW, and ADG (d 7 to 14). In addition, gilts had heavier carcasses, less fat depth, and higher carcass yield and actual economic value than barrows (P < 0.05; data not shown).

	Discussion

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Growth rates of pigs remaining in the pens after others had been marketed were not affected by feed withdrawal. Bates and Newcomb (1997) reported that pigs remaining in the pen after heavier pen mates were marketed earlier had greater weight gain and feed intake; however, feed was not withheld in that study. Scroggs et al. (2002) observed that pigs remaining in the pen after an equal number of pigs were marketed previously ate more feed, but converted feed to live weight gain less efficiently than their counterparts in nonsplit marketed pens. In the latter study, there were six pigs per pen and researchers provided 1.83 m²/pig before marketing, and 3.66 m²/pig after half the pigs were marketed. In our study, the 22 pigs initially allotted to the pens were provided 0.82 m²/pig before the first marketing, 1.01 m²/pig after the first marketing, and 1.81 m²/pig after the second marketing.

For reasons that are not clear, the negative effects associated with 24-h feed withholding that we observed in Exp. 1 were not as apparent in Exp. 2. The commercial facility used in Exp.1 was not available for Exp. 2. Although the feed and the genetic background of the pigs were identical in both experiments, the building design was different. Furthermore, we were constrained by the normal operating practices of each facility in determining the allotment of animals to each pen. Space allotment per pig for Exp. 2 was less than that of Exp 1. The 24 to 26 pigs initially allotted to the pens in Exp. 2 were provided 0.66 to 0.71 m²/pig before the first marketing, 0.75 to 0.82 m²/pig after the first marketing, and 1.01 to 1.14 m²/pig after the second marketing. Thus, although pigs in the second experiment were provided with less space than those in the first experiment, the negative effects associated with carcass yield, weight, and value were not manifested. These experiments were conducted at different times of the year, which may have influenced carcass weights. In Exp. 1, the average temperature during transit was 19, 26, and 26°C for the first, second, and third marketing groups, respectively. In Exp. 2, the corresponding values were 2, 6, and 9°C, respectively (data not shown). Based on the temperature differences between the two experiments, pigs in Exp. 1 may have had higher respiratory rates and moisture losses during transit and lairage compared with those of Exp. 2. Brown-Jandl et al. (1998) observed significant increases in respiratory rate and moisture loss in pigs subjected to temperature differences of a lower magnitude than those observed between our two experiments. Perhaps the water loss associated with the increased respirations was more pronounced in pigs subjected to feed withdrawal during warm weather. However, more research is needed to determine whether high ambient temperature during the marketing period limits the economic advantage of withholding feed. Finally, repeated feed withholding may be associated in an increased incidence of ulcers (Straw et al., 1994), which could decrease feed intake and carcass weight. We did not evaluate gastric health in this study; however, neither dark stools nor pale skin, which are characteristic signs of stomach ulcers (Friendship, 1999) were observed at any time in either experiment.

Bowland and Stanish (1966) reported that hot carcass yields were decreased in pigs that had not received feed for either 44 or 68 h compared with those of pigs from which feed was withheld for 20 h. Jones et al. (1985) observed that both viscera weights and carcass weights were decreased in pigs subjected to either 41- or 65-h feed withholding compared with pigs that were without feed for 17 h. Murray and Jones (1994) reported that withholding feed for 24 h decreased warm carcass yield by 12 g/kg of live weight compared with pigs slaughtered immediately off the feeder. This finding is consistent with the carcass weight decreases observed in our study for the comparison of the 6- and 24-h groups (average decrease in carcass weight yield = 6.8 g/kg). Whereas we observed approximately 1.0-kg decrease in warm carcass weights in the 24-h group (both experiments combined), Warriss and Down (1985) observed that warm carcass weights were 1.4 kg lighter from market hogs that had been subjected to feed withdrawal for 24 h compared with a 4-h feed withdrawal for the control group.

The reduction in viscera weights was consistent in both experiments and for both the 16- and 24-h treatment groups. These results are in general agreement with observations from other studies (Saffle and Cole, 1960; Jones et al., 1985; Murray and Jones, 1994). Although not evaluated in our experiment, decreased viscera weights may decrease the incidence of accidental lacerations (Miller et al., 1997). The effects of feed withholding had no effect on color, firmness, or marbling in either experiment. Cooking loss and shear force were measured only in Exp. 2, and pork from the 6-h treatment had greater cooking loss than did pork from the 24-h group. Morrow et al. (2002) reported that the redness score of pork from hogs subjected to either 12- or 24-h feed withholding was lower than that of 0-h feed withholding, but water-holding capacity, lightness score, yellowness score, and Japanese color score were not affected. Eikelenboom et al. (1991) recommended a 16- to 24-h feed withdrawal to provide improvement in color, firmness, and water-holding capacity in pork. De Smet et al. (1996) observed an increase in redness score and a decrease in the shear force of the cooked sample after an overnight withdrawal of feed.

Morrow et al. (2002) marketed pigs in three groups over a 4-wk period, which was similar to the approach taken in the present experiment, and reported that pork quality (as indicated by ultimate pH, water-holding capacity, and lean color) decreased from the first to last marketing group. In Exp. 1, we found that marketing date significantly affected (P < 0.05) color (scores increased with successive marketing dates) but not firm-ness or marbling (data not shown). In Exp. 2, marketing date affected (P < 0.05) firmness (scores decreased with successive marketing dates) and marbling (scores were greatest on the second marketing date and least on the third marketing date), but not color (data not shown). The lack of consistency between our two experiments makes it difficult to interpret the relationship between marketing date and these subjective measures of pork quality. Cooking loss and shear force observations were made only in Exp. 2. Cooking loss did not exhibit a logical pattern, averaging 36.3, 41.3, and 35.3% (SE = 0.41) for first, second, and third market dates, respectively. Shear force averaged 8.1, 8.8, and 9.8 kg (SE = 0.22) for the first, second, and third market dates, respectively. Because average shear force appears to increase with market date, it is possible that repeated feed withholding may have detrimental effect on pork tenderness; however, additional study is warranted to confirm this observation.

In both Exp. 1 and 2, feed withholding resulted in significant feed savings. When averaged for both experiments, 24-h feed withholding decreased feed consumed by 2 kg/pig (as-fed bais) during each marketing period. We are not aware of previous reports comparing feed intake by pigs with free access to feed with that of pigs subjected to repeated feed withholding during the marketing period.

	Footnotes

 
¹ Appreciation is expressed to Hatfield Quality Meats and the Pennsylvania Pork Producers Council for partial financial support; White Oak Mills for the use of pigs and facilities; and to D. Bailey, J. Bollinger, D. Dunbar, M. Fournier, T. Fritz, C. Harvey, D. Hartman, C. Myers, A. Nesslerodt, P. Pitcher, M. Snook, N. Snook, F. Strause, and L. Troup for their assistance in data collection.

² Correspondence: 306 ASI Building (phone: 814-863-3671; fax: 814-865-7442; e-mail: kbk2{at}psu.edu).

Received for publication June 7, 2004. Accepted for publication December 8, 2004.

	Literature Cited

Top Abstract Introduction Materials and Methods Results Discussion Literature Cited

 


Bates, R. O., and M. D. Newcomb. 1997. Removal of market ready pen mates improved growth rate of remaining pigs. J. Anim. Sci. 75(Suppl. 1):247. (Abstr.)

Bowland, J. P., and J. F. Standish. 1966. Influence of fasting, water deprivation and stress on carcass shrink of pigs and rats. J. Anim. Sci. 25:377–380.[Abstract/Free Full Text]

Brown-Brandl, T. M., J. A. Nienaber, and L. W. Turner. 1998. Acute heat stress effects on heat production and respiration rate in swine. Trans. ASAE. 41:789–793.

De Smet, S. M., H. Pauwels, S. De Bie, D. I. Demeyer, J. Callewier, and W. Eeckhout. 1996. Effect of halothane genotype, breed, feed withdrawal, and lairage on pork quality of Belgian slaughter pigs. J. Anim. Sci. 74:1854–1863.[Abstract]

Eikelenboom, G., A. H. Bolink, and W. Sybesma. 1991. Effects of feed withdrawal before delivery on pork quality and carcass yield. Meat Sci. 29:25–30.

Friendship, R. 1999. Gastric ulcers. Page 688 in Diseases of Swine. Iowa State Univ. Press, Ames.

Jones, S. D. M., R. E. Rompala, and C. R. Haworth. 1985. Effects of fasting and water restriction on carcass shrink and pork quality. Can. J. Anim. Sci. 65:613–618.

Miller, M. F., M. A. Carr, D. B. Bawcom, C. B. Ramsey, and L. D. Thompson. 1997. Microbiology of pork carcasses from pigs with differing origins and feed withdrawal times. J. Food Protec. 60:242–245.

Morrow, W. E., M. T. See, J. H. Eisemann, P. R. Davies, and K. Zering. 2002. Effect of withdrawing feed from swine on meat quality and prevalence of Salmonella colonization at slaughter. J. Am. Vet. Med. Assoc. 220:497–502.[Medline]

Murray, A. C., and S. D. Jones. 1994. The effect of mixing, feed restriction and genotype with respect to stress susceptibility on pork carcass and meat quality. Can. J. Anim. Sci. 74:587–594.

NPPC. 1991. Procedures to Evaluate Market Hogs. Natl. Pork Prod. Counc., Des Moines, IA.

NRC. 1998. Pages 111–116 in Nutrient Requirements of Swine. 10th ed. Natl. Acad. Press, Washington, DC.

Saffle, R. L., and J. W. Cole. 1960. Fasting effects on dressed yields, shrinkage, and pH of contractile tissue in swine. J. Anim. Sci. 19:242–248.[Abstract/Free Full Text]

Scroggs, L. V., H. G. Kattesh, J. L. Morrow, K. J. Stalder, J. W. Dailey, M. P. Roberts, J. F. Schneider, and A. M. Saxton. 2002. The effects of split marketing on the physiology, behavior, and performance of finishing swine. J. Anim. Sci. 80:338–345.[Abstract/Free Full Text]

Straw, B., S. Henry, J. Nelssen, A. Doster, R. Moxley, D. Rogers, and D. Webb. 1994. Prevalence of gastric ulcers in normal, sick, and feed-deprived pigs. J. Anim. Sci. 72(Suppl. 2):55. (Abstr.)[Free Full Text]

Warriss, P. D. 1982. Loss in carcass weight, liver weight, and liver glycogen, and the effects on muscle glycogen and ultimate pH in pigs fasted pre-slaughter. J. Sci. Food Agric. 33:840–846.

Warriss, P. D., and N. F. Down. 1985. Bacon yield from fasted pigs. Anim. Prod. 40:143–151.

This Article Abstract Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Kephart, K. B. Articles by Mills, E. W. Search for Related Content PubMed PubMed Citation Articles by Kephart, K. B. Articles by Mills, E. W.