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This Article Abstract Full Text (PDF) All Versions of this Article: jas.2008-0909v1 86/12/3600    most recent 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 Reiners, K. Articles by Van den Weghe, H. F. A. Search for Related Content PubMed PubMed Citation Articles by Reiners, K. Articles by Van den Weghe, H. F. A.

The effect of heated mash on performance and feeding behavior of newly weaned piglets¹

Research Centre for Animal Production and Technology, Georg-August University of Goettingen, D-49377 Vechta, Germany

	Abstract

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The influence of heated mash on growth and feeding behavior of newly weaned piglets was investigated. An automatically ventilated nursery with 4 identical pens was used. Twenty piglets weaned at 21 d were housed in each pen. The experiment was repeated 3 times. In total, data were obtained from 240 piglets of 12 pens. The pens were provided with a sensor-controlled, automatic feeding device, which dosed a ready-mixed mash in a trough. In each of 2 of the pens, the feed was mixed with warm water at 36°C, during the first week of weaning. This heated mash had a temperature of 34°C at the outlet of the automatic feeding device (experimental group). In the 2 control groups, the water was not heated and the temperature of the mash was 14°C at the outlet of the automatic feeding device. From the second week of weaning, the mash had a temperature of 14°C at the outlet of the automatic feeding device in all 4 pens. Piglets were weighed at weaning, at weekly intervals through 49 d after weaning, and on d 139 after weaning. Behavior of the whole group, as well as behavior of selected focal animals, was evaluated for the first 48 h after weaning. In addition, skin condition of piglets was assessed on day of weaning and on d 7, 14, and 21 after weaning. The amount of feed consumed by the piglets was recorded on a daily basis throughout the whole period of nursery. Over the total period of the study, piglets in the experimental group gained 3.98 ± 1.66 kg (P = 0.047) more than the control group. The difference was particularly clear during the nursery period (49 d) when the experimental group gained 0.89 ± 0.23 kg more than the control group (P = 0.03). Although piglets in the control group consumed 37.15 ± 0.15 kg of feed over the complete nursery period, the experimental group consumed 42.56 ± 0.15 kg per piglet (P = 0.023). By heating the mash feed in the first week after weaning, both growth performance as well as feed consumption of piglets could be increased. No difference in feed conversion and feeding behavior was found between groups.

Key Words: feeding behavior • performance • piglet • weaning

	INTRODUCTION

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Frequently, several hours can pass before piglets consume feed for the first time after weaning. In addition to separation from the mother and confrontation with piglets from another litter, the abrupt change in feed associated with weaning places great demands on the ability of the animals to adapt (Morméde and Hay, 2003). After weaning, the digestive system of piglets has to completely readjust to solid food. As a result of the reduction in feed intake, there is often a regression of the intestinal villi with simultaneous deepening of the crypts. Hence, the absorption area available for nutrients is decreased (Kelly and Coutts, 2000). In the first week after weaning, there is frequently a depression in growth which has wide-ranging consequences for the subsequent course of the nursery and finishing period (King and Pluske, 2003). For these reasons, design of the feeding system for weaned piglets is of particular importance. Weaned piglets that were fed with liquid or mash feed had better BW gain than piglets that received dry feed (Kim et al., 2001; Hessel and Van den Weghe, 2005). It was assumed that the reason for this was that liquid or mash feed was more similar to the milk of sows and so more attractive to the piglets. To additionally increase the similarity of the feed to sow milk, the mash was heated for 1 wk after weaning in the present study. The objective of the study was to investigate the additional influence of heated mash on feeding behavior, feed consumption, and BW gain of newly weaned piglets compared with nonheated mash.

	MATERIALS AND METHODS

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The local animal care and use committee approved the design of the study.

Experimental Design

The study was conducted at the Research Centre for Animal Production and Technology of the Georg-August University of Goettingen in Vechta, Germany. An automatically ventilated and heated nursery with 4 pens of 4.60 x 1.80 m was used. Two pens served as experimental pens, and the other 2 pens were control pens. Twenty piglets, weaned at 21 d, were housed in each pen. The experiment was repeated 3 times. In total, data were obtained from 240 piglets of 12 pens, resulting in n = 6 replicates per treatment. Pens were separated by solid partitions. Each pen was divided into a fully slatted activity area of 1.80 x 1.80 m and a concrete-lined resting area of 2.80 x 1.80 m. The resting area had an incline of 6% and was equipped with a sectional electrical floor heating. The nursery had a temperature of 27.0°C in the first week after weaning. From wk 2 until the end of the nursery, the temperature was decreased weekly by 0.5°C. All pens were provided with a sensor-controlled mash feeder (PreMixer, Euro Feed System GbR, Essen i. Oldb., Germany) in the first 3 wk of the study (Figure 1). The PreMixer dispensed a ready mixed mash controlled by a sensor that monitored the feed depth in the feeding trough. The distance between sensor and trough was 1 cm. As long as the sensor did not come into contact with the mash, 23 g of dry feed per min was transported over an auger toward the trough and mixed with water in a ratio of 1:1.5 (water:feed) shortly before discharge. Mixing time and mixing cycle were set at 2 min. The control unit of the feeder registered the daily operation time. The trough of the PreMixer had an inner diameter of 250 mm. During the first 7 d of the nursery period, water for the PreMixers of 2 pens (experimental group) was heated to 36°C in a storage tank at the feeder, before it was mixed with the feed. The temperature of the ready mixed mash was 34°C at the outlet of the feeders in the experimental group. In the other 2 pens, the water was not heated before mixing with the feed (control group). The temperature of the mash in the control group was 14°C at the outlet of the PreMixers. Beginning from d 8 of the nursery period, the temperature of the mash at the outlet of the feeders was 14°C in all pens.

View larger version (28K): [in this window] [in a new window]   Figure 1. Schematic of the feed level-controlled mash feeder.

The study in the nursery lasted 49 d. After the nursery period, pigs were moved to a finishing unit and housed with the same pigs as during nursery. The finishing unit included 4 identically constructed pens of 7.2 x 2.6 m, which were fully slatted and automatically ventilated. Each pen was equipped with a conventional tube mash feeder (3 i 1- Feeder, ACO funki, Rendsburg, Germany). Feeders were replenished daily at 0830 and 1800 h. To balance for any effects of position of the pens in the nursery and in the finishing unit on behavior and performance, location of the groups within the pens was rotated between periods.

Animals. Animals had the same origin in all 3 periods of the experiment. Newly weaned piglets [(Large White x German Landrace) x Pietrain] were used. Piglets were weaned on a conventional pig farm at 21 d of age and were transported to the nursery on a commercial pig trailer immediately after weaning. The transport distance was 12 km. Piglets were randomly mixed from 15 litters from suckling period into the nursery. To balance the effect of sex, the sex ratio was adjusted (10 male and 10 female pigs were moved into each pen). Table 1 presents the mean BW of the piglets as a function of period and group at the day of weaning. Piglets were introduced to the experiment at an initial BW of 5.83 ± 0.83 kg in the experimental group and 5.89 ± 0.90 kg in the control group.

Feeding. For the first 10 d after weaning, piglets received a prestarter feed with 16.3 MJ of ME/kg of DM and 21% CP. From d 11 until the end of the nursery period, a feed with 13.52 MJ of ME/kg of DM and 18% CP was offered. In the finishing unit, pigs received a feed with 13.5 MJ of ME/kg of DM and 17% CP up to a BW of 60 kg. Beginning from a BW of 60 kg until the end of the experiment, pigs were offered a feed containing 13 MJ of ME/kg and 16% CP (Table 2). Feed was available ad libitum throughout the experiment.

Pigs that died during the experiment were excluded from analyses. In total, data were available for 231 piglets: 115 in the experimental group and 116 piglets in the control group.

Performance. Each piglet was weighed individually on the day of weaning and at weekly intervals during the nursery period. To exclude compensatory effects, animals were also weighed on d 90 of the finishing period.

Feed Consumption and Feed Conversion. Average feed consumption for each pen was determined daily during the entire nursery period. To determine feed consumption, feed at the beginning of the time period and feed left in the feeder (orts) at the end of that period were weighed. Additionally, the control unit of the feeder recorded the time it was operating (delivering 23 g of dry feed/min) each day. The feed consumption (disappearance of feed) was calculated as (beginning feed + feed delivered) minus the orts. Average G:F was calculated for each pen daily and averaged for each week during the nursery period.

Feeding Behavior. Feeding behavior of the piglets was continuously recorded on videotape during the nursery period. For this purpose, 4 cameras (WV-BP, 330, Panasonic, Tokyo, Japan) were installed in the barn. Cameras were connected to a multiplexer (WJ-FS216, Panasonic), which monitored the pictures and simultaneously recorded them to a time lapse recorder (AG-6730, Panasonic). Both feeding behavior of selected focal animals and feeding behavior of the whole group were analyzed. Piglets were considered to be eating when they were standing at the feeder with their heads extended into the trough for more than 5 s. To minimize errors caused by using different observers, all behavioral observations were conducted by a single observer. The intraobserver reliability was tested for 60 min on each observation day and amounted to 96%.

To characterize the feeding behavior of the whole group, 5-min scan samples of the videotapes were used, during which the number of piglets that were eating was noted. Observations for the whole group were made during the initial 48 h after weaning, beginning at 1700 h on the day of weaning, immediately after the piglets were assigned to their pens in the nursery.

For observation of the behavior of focal animals, 3 piglets in each pen were marked daily at feeding time. In this way, the heaviest, the lightest, and 1 piglet with an average BW of each pen were marked after piglets have been balanced by sex. Feeding behavior of the selected focal animals was continuously analyzed using the focal sampling method of the program package "The Observer" (Version 3.0, Noldus, Wageningen, the Netherlands). With this method, the beginning and the end of each feeding bout was recorded. The observations were performed on d 1 and 2 after weaning, beginning at 0800 and ending at 1600 h.

Skin Condition. It was assumed that piglets that received heated mash would visit the trough more frequently. This may influence skin condition of the pigs because of increased fights at the trough. To assess skin health and injuries, a classification of the skin of the piglets was made according to the method of Ekesbo (1984) on the day of weaning and on d 7, 14, and 21 after weaning. The classification of the skin on day of weaning was carried out immediately after transport before piglets were assigned to their pens in the nursery. The reasons for injuries collected on weaning were found to be exclusively in the preceding suckling period or were associated with the subsequent transport into the nursery.

To minimize the influence of observer, the classification of skin condition was carried out by a single observer in all replicates. Figure 2 shows the body regions of the piglets where skin condition was evaluated. Different features were assessed and classified according to severity (Table 3).

View larger version (20K): [in this window] [in a new window]   Figure 2. Schematic of body regions of the piglets that were considered for scoring.

The statistical analysis of the data was performed using the software program SAS 9.1 (SAS Inst. Inc., Cary, NC). Pen was considered the experimental unit. Data showing a Gaussian distribution or data that could be transformed into a Gaussian distribution were analyzed using the MIXED procedure. Results are presented as least squares means with SE (t-test). Least squares means were separated using the PDIFF procedure.

Variables that did not follow a Gaussian distribution or that could not be transformed into a Gaussian distribution were analyzed using a Wilcoxon 2-sample test (NPAR1WAY procedure). Data resulting from the Wilcoxon 2-sample test were presented as means (SEM).

Performance. Residuals predicting the BW gain at each weighing date as a function of sex and BW at weaning were calculated using the GLM procedure. The residuals calculated in this manner were pooled by pen and replicate and analyzed with the MIXED procedure. The model for analysis included the fixed effect of group and a random effect of replicate. No effect of replicate was found.

Feed Consumption and Feed Conversion. The statistical analysis of feed consumption and feed conversion was carried out using the MIXED procedure, including fixed effects of group, week of nursery, and the interaction of group x week of nursery. Replicate was included as a random effect. No interaction between group and week of nursery was found. Moreover, no effect of replicate was established.

Feeding Behavior of the Group. To analyze the behavioral data of the groups, hourly means were calculated for each group. In addition, data were split into time blocks (period of 8 consecutive hours). The time blocks were chosen on the basis of the light program in the nursery. The duration of light was 8 h, resulting in 2 time blocks in which the nursery was not lit (1600 until 2400 h and 0000 until 0800 h) and a block during which the light was switched on (0800 until 1600 h). Data for the number of piglets eating could be logarithmically transformed into a normal distribution. These data were analyzed using the MIXED procedure. The model included the fixed effects of group and time block, as well as the interaction group x time block. Replicate was taken into account as a random effect. No effect of the interaction group x time block was established. Furthermore, no effect of replicate was found.

Feeding Behavior of Focal Animals. For evaluation of behavioral data of the 72 selected focal animals (36 per group), there was a data set of 10,899 observations. Daily averages were determined for all of the focal animals and observation day to give a pen mean. These data could be logarithmically tranformed into a normal distribution. The subsequent statistical analysis was carried out with the MIXED procedure, including fixed effects of observation day, group, and group x observation day. Replicate was included as a random effect. No effect of replicate was found. Moreover, no interaction between group and observation day was established.

Skin Condition. For the statistical analysis of skin condition data of piglets, a total of 960 data points were available. A classification of the belly was not made, because no irritations were observed. Callus and thick joints of forelegs, front claws, hind legs, and hind claws were pooled by pen and replicate for each observation day. Moreover, injuries of forelegs, front claws, hind legs, hind claws, nasal septum and bridge, ears, head, neck and shoulders, back, back part, and tail were pooled by pen and replicate for each observation day. Data of the skin condition were not normally distributed and could not be logarithmically transformed into a normal distribution. Data were analyzed using the NPAR1WAY procedure.

	RESULTS

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Performance of the Pigs

Heating of the mash in the first week after weaning had a positive effect on the BW gain of piglets both during the nursery and finishing periods (Table 4). Over the complete experimental period (139 d), pigs in the experimental group gained 90.9 ± 1.16 kg compared with 86.92 ± 1.16 kg for the control group (P = 0.047).

	DISCUSSION

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During weaning, piglets are abruptly separated from the sow and transferred to a novel environment. They are confronted with piglets from another litter, and feeding changes from the milk of a sow to solid feed (Held and Mendl, 2001; Jensen, 2002; King and Pluske, 2003). The animals are subjected to a whole range of stressful situations, which may have wide-ranging consequences for health, may impede growth, and thus result in economic consequences (Morméde and Hay, 2003). To achieve high efficiency in modern pig production, housing and feeding systems should be adapted to animal requirements as much as possible (Madec et al., 2003).

In the research presented here, newly weaned piglets were offered mash feed, to facilitate the change in feed from the milk of a sow to solid feed and to increase feed consumption and growth performance of the piglets. Investigations carried out by Kim et al. (2001) showed that piglets that received fluid feed after weaning had greater feed intake than piglets that received dry feed. Partridge et al. (1992) also showed that piglets that received mash feed consumed 13% more feed and grew 11% faster than piglets that were fed dry feed in the form of pellets. These results were confirmed in preliminary tests of Hessel and Van den Weghe (2005) at the Research Centre for Animal Production and Technology, Vechta, Germany. Piglets that were fed with mash feed had greater BW gain. Feed consumption was likewise greater in piglets that received a mash feed.

In the present study, mash was heated during the first week after weaning for piglets in the experimental group to additionally increase the acceptance of the feed mash. The additional heating of the mash in wk 1 after weaning had a positive effect on BW gain of the pigs, both during nursery as well as in the later finishing period. The fact that piglets having greater BW gains in the nursery maintain the lead in the finishing period was also shown by Williams (2003) and King and Pluske (2003). Piglets that show a growth depression in the first days after weaning will be inferior to pigs that have an increased BW gain in the course of the entire nursery and finishing period (Brooks and Tsourgiannis, 2003). Heating the mash in the first week after weaning also had a positive effect on feed consumption of piglets. It can be assumed that feed consumption of piglets was greater because of the greater resemblance of mash and the milk of a sow. The feed offered was more attractive to the piglets, because the lag from the milk of a sow to solid feed consumption was less apparent. It is conceivable that, because of its heating, the mash had a more intensive smell, which attracted piglets to consume more feed. Furthermore, it can be assumed that piglets that received heated mash ate faster. Comparable studies concerning the effect of heated mash on feed consumption of newly weaned piglets are currently not available. Concerning rearing of lambs and calves, however, a positive effect of heated milk during the nursery period could be established (Large, 1965). Bauer et al. (1971) showed that calves that were offered heated milk instead of cold milk had a greater feed consumption.

Previous studies showed a reduction in feed intake in the initial period after weaning (Brooks et al., 2000; Dunshea, 2003; Huguet et al., 2007). The authors consider the main reason to be the changeover from the milk of a sow to dry feed associated with weaning. The importance of early feed intake after weaning has been described (Pluske et al., 1996; Van Beers-Schreurs et al., 1998; McCracken et al., 1999; Kelly and Coutts, 2000). These authors view the decreased feed intake immediately after weaning to be the reason for a depression in growth. In the present study, it was assumed that heating of mash would affect the feeding behavior of piglets immediately after weaning. It seemed obvious that the number of trough visits would increase in the initial hour after weaning. Therefore, the feeding behavior of the pigs was exclusively observed in the initial 48 h after weaning. No effect of heated mash either on behavior of focal animals or on behavior of the group was established. As a result of greater BW gain of piglets and a greater feed consumption over the entire nursery period, it could be assumed that feeding behavior was affected by the heated mash in the course of the nursery period. Furthermore, 5-min scan samples were used to characterize feeding behavior of the group. It is conceivable that piglets were consuming feed between scan samples. Therefore, the sampling interval should be shortened in further investigations. The missing effect of heated mash on feeding behavior of the piglets could also be justified by the assumption that the consistency of the feed had a greater effect on the feeding behavior than the heating of the mash. All pens in the nursery were equipped with a sensor-controlled mash feeder. Feed was always freshly prepared and served in the trough; the piglets did not have to dose the feed into the trough and mix it with water by themselves. In previous investigations, the average number of piglets in the trough area was greater at the sensor-controlled mash feeder compared with a conventional tube mash feeder (Hessel and Van den Weghe, 2005). Results of this study indicate that heating mash feed for nursery pigs during wk 1 after weaning is an additional effect to feed consistency to increase the feed consumption of piglets and to prevent the depression of growth in the first week after weaning.

	Footnotes

 
¹ We gratefully acknowledge the support of the H. Wilhelm Schaumann Foundation (Hamburg, Germany) for providing financial support for this research.

² Corresponding author: kerstin.reiners{at}agr.uni-goettingen.de

Received for publication January 27, 2008. Accepted for publication July 13, 2008.

	LITERATURE CITED

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Bauer, J., M. Kirchgessner, and M. Burgkart. 1971. Zur mutterlosen Lämmeraufzucht. Züchtungskunde 43:55–62.

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Brooks, P. H., and C. A. Tsourgiannis. 2003. Factors affecting the voluntary feed intake of the weaned pig. Pages 81–115 in Weaning the Pig–Concepts and Consequences. J. R. Pluske, J. Le Dividich, and M. W. A. Verstegen, ed. Wageningen Academic Publishers, Wageningen, the Netherlands.

Dunshea, F. R. 2003. Metabolic and endocrine changes around weaning. Pages 61–75 in Weaning the Pig–Concepts and Consequences. J. R. Pluske, J. Le Dividich, and M. W. A. Verstegen, ed. Wageningen Academic Publishers, Wageningen, the Netherlands.

Ekesbo, I. 1984. Methoden zur Beurteilung von Umwelteinflüssen auf Nutztiere unter besonderer Berücksichtigung der Tierge-sundheit und des Tierschutzes. Wien. Tierarztl. Monatsschr. 71:186–190.

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Kim, J. H., K. N. Heo, J. Odle, I. K. Han, and R. J. Harrell. 2001. Liquid diets accelerate the growth of early-weaned pigs and the effects are maintained to marked weight. J. Anim. Sci. 79:427–434.[Abstract/Free Full Text]

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Large, R. V. 1965. The artificial rearing of lambs. J. Agric. Sci. 65:101–108.

Madec, F., J. Le Dividich, J. R. Pluske, and M. W. A. Verstegen. 2003. Environmental requirements and housing of the weaned pig. Pages 337–360 in Weaning the Pig–Concepts and Consequences. J. R. Pluske, J. Le Dividich, and M. W. A. Verstegen, ed. Wageningen Academic Publishers, Wageningen, the Netherlands.

McCracken, B. A., M. E. Spurlock, M. A. Roos, F. A. Zuckermann, and H. R. Gaskins. 1999. Weaning anorexia may contribute to local inflammation in the piglet small intestine. J. Nutr. 129:613–619.[Abstract/Free Full Text]

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Van Beers-Schreurs, H. M. G., M. J. A. Nabuurs, L. Vallenga, H. J. Kalsbeek-van der Valk, T. Wensing, and H. J. Breuking. 1998. Weaning and the weanling diet influence the villous height and crypt depth in the small intestine of pigs and alter the concentrations of short-chain fatty acids in the large intestine and blood. J. Nutr. 128:947–953.[Abstract/Free Full Text]

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This Article Abstract Full Text (PDF) All Versions of this Article: jas.2008-0909v1 86/12/3600    most recent 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 Reiners, K. Articles by Van den Weghe, H. F. A. Search for Related Content PubMed PubMed Citation Articles by Reiners, K. Articles by Van den Weghe, H. F. A.