Effect of cereal type, disintegration method and pelleting on stomach content, weight and ulcers and performance in growing pigs

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1 Livestock Production Science 66 (000) locte/ livprodsci Effect of cerel type, disintegrtion method nd pelleting on stomch content, weight nd ulcers nd performnce in growing pigs E.K. Nielsen, K.L. Ingvrtsen* Deprtment of Animl Helth nd Welfre, Dnish Institute of Agriculturl Sciences, Reserch Centre Foulum, P.O. Box 50, DK-8830 Tjele, Denmrk Received 4 April 1999; received in revised form 7 October 1999; ccepted 10 Jnury 000 Abstrct The purpose of this study ws to investigte the effects of cerel type nd feed processing on the prevlence of gstric lesions in prs oesophge, stomch size, stomch content nd firmness nd performnce in growing pigs. Dt from 30 pigs were included in 3 3 fctoril experiment. The fctors investigted were cerel type (brley or whet), disintegrtion method (grinding or rolling) nd feed form (pelleted or non-pelleted). Gstric lesions were investigted t slughter nd scored on scle from 0 (norml) to 10 (very severe chnges). The ground feed ws produced on hmmer-mill, mounted with 3-mm screen for brley nd 4.5-mm screen for whet. Only 0% of the ground feed consisted of prticles bigger thn 1 mm in dimeter, wheres it ws pproximtely 50% of the rolled feed. Disintegrtion method nd pelleting did not influence performnce significntly nd the differences between whet nd brley were due to the higher energy content in whet rther thn whet per se. Whet, ground feed nd pellets reduced the empty stomch weight. Non-pelleted rolled feed incresed both the firmness nd dry mtter percentge of the stomch content compred to ground feed. Rolled brley could be pelleted without decrese in firmness of the stomch content s opposed to whet. Pigs receiving rolled brley or whet in non-pelleted form hd nerly no gstric lesions (verge score 5 0.7) s opposed to pigs receiving ground brley or whet (verge score 5.8). Rolled brley could be used s pellets without cusing high level of gstric lesions (verge score 5 1.3), while rolled pelleted whet cused high level of gstric lesions (verge score 5 4.3). The combintion of ground whet s pellets resulted in the highest score of gstric lesions (verge score 5 4.9). A high firmness of the stomch content coincided with low score of gstric lesions. 000 Elsevier Science B.V. All rights reserved. Keywords: Pig-feeding; Whet; Brley; Rolled; Ground; Stomch weight nd content; Gstric lesions 1. Introduction finishing pigs tht hs been published vries from to 100% (O Brien, 199; Plomo et l., 1996). The The prevlence of gstric lesions in growing lrge vritions in prevlence re, t lest in prt, due to the subjective ssessment of the ulcer condition. *Corresponding uthor. Tel.: ; fx: Still, gstric lesions in pigs pper to hve incresed during the lst two decdes. In Germny, Frerking et E-mil ddress: klusl.ingvrtsen@grsci.dk (K.L. Ingvrtsen). l. (1996) hve reported n increse in gstric ulcers / 00/ $ see front mtter 000 Elsevier Science B.V. All rights reserved. PII: S (00)00165-

2 7 E.K. Nielsen, K.L. Ingvrtsen / Livestock Production Science 66 (000) 71 8 from 1.1% in to 7.7% in In weight nd the firmness of the stomch content nd recent Spnish study, the prevlence of gstric ulcers performnce in growing pigs. hs been found to be 9.8% (Plomo et l., 1996). In Dnish study including 4038 growing pigs t three Dnish slughterhouses, 36% of the pigs hd chnges in the prs oesophge. Approximtely 6%. Mterils nd methods of the pigs hd ulcers (Nielsen, 1998). The effect of cerel type, disintegrtion method The development of gstric lesions my be innd feed form on the prevlence nd severity of fluenced by number of fctors relted to feeding gstric lesions, stomch weight, stomch content nd nd housing (Friendship, 1999). In prticulr, fine performnce results ws investigted in 3 3 feed structure, tht is smll feed prticles, hs been fctoril design. shown to increse the prevlence of gstric lesions (Mhn et l., 1966; Reimnn et l., 1968; Mxwell et l., 1970; Pedersen et l., 1970; Fltlndsmo nd.1. Animls, feeding, feed composition nd Slgsvold, 1971; Simonsson nd Bjorklund, 1978; housing Blckshw et l., 1980; Kirschgessner et l., 1985; Nielsen, 1986; Potkins et l., 1989). The pelleting of The experiment included 30 crossbred pigs from the feed my lso increse the prevlence of gstric 40 litters ech consisting of 8 pigs. The distribution ulcers (Chmberlin et l., 1967; Nielsen, 1990), but by sex ws 16% cstrted mles, 4% intct mles the bigger the prticles were prior to pelleting, the nd 4% femle pigs. The verge initil live weight less severe the gstric lesions ppered to be (Flt- of the pigs ws kg (X6SEM). Bsed on lndsmo nd Slgsvold, 1971; Nielsen, 1986). the sex nd live weight, the eight pigs from ech Cerel type influences the risk of gstric ulcers. litter were divided s evenly s possible into the Mize hs been shown to predispose to gstric eight tretment groups. Block effect ws included in ulcers, while ots prevents these lesions (Reese et l., the model to ccount for time when the pigs entered 1966). Whet ppers to predispose to gstric ulcers the experiment nd litter effects. Since ech pen more thn brley (Smith nd Edwrds, 1996). The housed two pigs, ech block consisted of two litters likely predisposing fctor of mize nd whet is the (16 pigs). reltively low fibre content which influences the The pens in which the pigs were housed hd firmness of the stomch content (Johnsen et l., concrete floor, which ws 1 m wide nd 1.65 m deep 1996; Knudsen, 1997). Generlly, feed utilistion is while the dung pssge with sltted floor mesured improved with incresed disintegrtion of the feed m. The feed dispenser hd trough length of (Simonsson nd Bjorklund, 1978; Nielsen, 1986; 5 cm. Wondr et l., 1995; Sloth et l., 1998). However, All pigs were weighed every second week nd fed high degree of disintegrtion my increse the risk of ccording to this weight. Feed composition is shown gstric ulcers. Consequently, there hs been n in Tble 1. The pigs were fed twice dily nd interest in rolling rther thn grinding cerel finely received 1 l of wter per kg feed during the first for pigs (Pedersen et l., 1970). Rolled cerels my week of the growth period incresing to l in the be fed to growing pigs without compromising per- course of 1 month. The dily mount of feed ws formnce significntly (Mdsen et l., 1970; Simon- kept constnt per kg pig irrespective of cerel type in sson nd Bjorklund, 1978; Nielsen, 1993; Svne, the feed mixture to void possible confounding 1995) but little is known bout the effects on gstric between feed intke (kg) nd gstric exmintion. As helth. the whet mixture contined 6% more net energy per The objective of the current experiment ws to kg feed compred to the brley mixture, the feeding exmine the effect of cerel type (brley vs. whet), level ws proportionlly higher for the pigs receiving disintegrtion method (ground vs. rolled) nd feed whet. Furthermore, to get homogeneous bsis for form (pelleted vs. non-pelleted) on the prevlence evluting the stomch content, including mount, nd severity of gstric lesions, empty stomch consistency, nd dry mtter of the individul pigs,

3 E.K. Nielsen, K.L. Ingvrtsen / Livestock Production Science 66 (000) Tble 1 by spring-loded rollers nd by djusting the grin Feed composition nd energy content flow. To ensure sufficient compression of the Feed component % on weight bsis cerel (high degree of rolling) nd to minimise the Brley mix Whet mix content of whole nd hlf grins, it ws necessry to reduce the grin flow to pproximtely hlf of Brley Whet norml cpcity even though the rollers were tight- Soy ben mel ened to the mximum. The ground feed ws pro- Ft.0.0 duced on President hmmer mill, type 50S (Kris- Molsses tensen, 1991). Fig. 1 shows ground nd rolled brley. Diclcium phosphte In pilot study of sieve nlyses, it ws found tht Clcium crbonte Sodium chloride mm screen should be used for brley nd Lysine mixture (40%) mm screen for whet in the hmmer mill to Vitmin nd micro minerl mixture obtin pproximtely the sme prticle size in the ME (MJ/ kg feed, clculted) ground feed. For ech new btch of feed produced, FUp / kg feed (clculted) smples were tken of the feed mixtures for sieve FUp kg DM 5MJ NE kg DM?7.7 5MJ ME kg nlyses to determine prticle size. These nlyses 1 DM? (Just, 198). were performed with Retsch sieves t Reserch Centre Foulum. The sieves hd the following hole sizes: 4,, 1, 0.50, 0.5, 0.15 nd mm. the two pigs in the pen were seprted nd fed individully during the week prior to slughtering. Feed nd wter were mesured out precisely in the.4. Pelleting nd prticle size in pellets rtio of 1 to, nd the pigs were denied free ccess Hlf of ech feed lot ws pelleted. In the pellet to wter in the week prior to slughtering. press, the holes of the mtrix hd dimeter of 5 mm nd length of 35 mm. The feed ws stemconditioned.. Cerel type nd reched temperture of 808C during pelleting (Tellefsen, 1996). In order to investigte the influence of pelleting on The diet consisted of pproximtely 70% brley or prticle size, 50 g of pellets were completely mcerwhet (Tble 1). The diets were not corrected for the ted in wter nd sieved using 1-mm sieve. The differences in energy nd fibre content due to content ws poured onto filter pper to llow most of differences between the cerel types. Pigs receiving the wter to drin off before drying t 808C. The brley consequently hd more fibre thn those redried smple ws gently crushed on the pper nd ceiving whet on DM bsis. The content of soluble subsequently sieve nlysis ws performed. It ws nd insoluble fibres re 5.6 nd 16.6% for brley nd thus possible to mesure the proportion of prticles.5 nd 11.3% for whet, respectively (Knudsen, bigger nd smller thn 1 mm in the pelleted feed. 1997). Mcertion time ws investigted by dding wter to the pellets. The degree of mcertion ws controlled.3. Feed disintegrtion nd prticle size every 5th minute nd the time spent to completely mcerte the pellets in wter ws registered. The feed ws produced t Reserch Centre Foulum. The cerel ws disintegrted either by.5. Slughtering rolling to obtin corse feed structure or by grinding resulting in fine feed structure. Rolling The pigs were slughtered t n verge live ws done on smll Mortensen industril roller, weight of kg (X6SEM) t the Dnish which hd two smooth rollers tht were rotting with Crown Slughterhouse in Bjerringbro. All pigs hd the sme speed. The degree of rolling ws djusted their lst mel t hours on the dy of

4 74 E.K. Nielsen, K.L. Ingvrtsen / Livestock Production Science 66 (000) 71 8 Fig. 1. Ground (left) nd rolled brley (right). slughter. Around 9.00 hours, the pigs were tken the difference between the weight of the stomchs from the pens, trnsported to the slughterhouse nd with nd without content. Hving mixed the stomch slughtering ws commenced immeditely fter rri- content mnully, smples were tken to determine vl t the slughterhouse t round hours. dry mtter content nd crude fibre. After removl of the gstrointestinl trct, the Pigs from six blocks (96 pigs) were chosen for stomchs were mrked with metl number nd the determintion of the consistency of the stomch mtching pig number ws registered. Subsequently, content. Consistency ws scored on scle from 1 the stomchs followed the trnsport system to the (thin/ wtery) to 5 (firm). ph ws mesured in mixed intestinl deprtment. smples of the stomch content pproximtely 3 h fter slughtering..6. Gstric investigtions The scle used in the present study to score the observed lesions in the prs oesophge (po) re The gstric exmintion comprised vrious me- ws bsed on the scle used by Bustd nd Nfstd surements of the stomch weight, stomch content (1969) but modified to 0 10 points scle. Types of nd firmness, nd n exmintion of pthologicl chnges nd the mtching score re illustrted in Fig. chnges in the mucosl membrne in prs nd were s follows: oesophge. The judging of the pthologicl chnges ws done without knowledge of the previous tret- 0 Norml (prs oesophge, cm) ment of the pigs. 1 Minor prkertosis The mount of stomch content ws determined s Medium-severe prkertosis

5 E.K. Nielsen, K.L. Ingvrtsen / Livestock Production Science 66 (000) Fig.. Exmples of different degrees of gstric lesions in prs oesophge. 3 Severe prkertosis (erosion of the epi- 5 Medium severe gstric lesion or scr thelium: depending on the degree of erosion, 6 Severe gstric lesion or scr, nd/ or crter points were dded for prkertosis) formtion surrounding the entire oesophgel 4 Minor gstric lesion or scr entrnce into the stomch

6 76 E.K. Nielsen, K.L. Ingvrtsen / Livestock Production Science 66 (000) Reduction of prs oesophge to pproximte- gm 5systemtic effect of sex; cstrtes, mles nd ly cm cused by scr nd/or contrction femles or mixed, hm51,...,6j of the oesophgel opening to dimeter of B 5rndom effect of block, hn51,...,0j n pproximtely 10 mm eijlmno 5rndom residul vrition 8 Reduction of prs oesophge to pproximtely 3 4 cm cused by scr nd/ or contrction of the oesophgel opening to dimeter of pproximtely 7 mm. The oesophgus is often slightly cllused 9 Reduction of prs oesophge to pproximte- The results presented in Tbles 8 re lest squre mens from the bove model. 3. Results nd discussion ly 1 3 cm cused by scr nd/or contrction of the oesophgel opening to dimeter of pproximtely 4 mm. The oesophgus is cl- lused 10 () The pig died from bleeding ulcer. (b) Lethl contrction of the oesophgel opening to dimeter of pproximtely No sttisticl effects of sex were observed in the present study nd consequently not reported or discussed in the following Prticle size mm, nd the oesophgus is very cllused. The pig could drink but feed could not Prticle distribution of the feed is shown in Tble pss through to the stomch.. The ground feed contined more of the fine nd less of the corse feed prticles compred to the In cse of more thn one chnge in the stomch, rolled feed. The ground feed contined lmost twice the severest chnge decided the score obtined. s mny prticles smller thn 0.5 mm thn the rolled feed, while the rolled feed contined three.7. Sttisticl methods times s mny feed prticles bigger thn 1 mm compred to the ground feed. The clculted verge Averge results from pigs in one pen were reprticle size ws considerbly bigger for the rolled grded s the experimentl unit. The experimentl compred to the ground feed, 0.88 vs mm. The dt were nlysed using the procedure PROC MIXED in rtio between the mount of prticles bigger nd SAS (SAS Institute, 1994; Little et l., 1996) using smller thn 1 mm ws 0. for the ground nd 1.1 the following model: for the rolled feed. The brley ws ground little Yijlmno 5 m 1 i 1 bj 1 dl 1 bij 1 dil 1 bdjl more finely when using 3-mm screen thn whet, 1 bdijl 1 lm 1 Bn 1 eijlmno which ws processed using 4.5-mm screen. m 5lest squre men Given good rolling technique, whole grins cn i 5systemtic effect of disintegrtion method, be voided. Fig. 3 shows prticle frctions from hi5ground, rolledj sieve nlysis of rolled nd ground whet fter it hs bj 5systemtic effect of cerel type, hj5whet, been processed in feed-mixer normlly used for brleyj mixing the feed components of the diet. The processdl 5systemtic effect of pelleting, hl5pelleted, ing in the feed-mixer chnges the corse structure of non-pelletedj the cerels fter the rolling. This chnge occurs bij 5systemtic effect of interction between rpidly since the prticle distribution ws lmost disintegrtion method nd cerel type identicl, irrespective of the mixing period being 1, 5 dil 5systemtic effect of interction between or 15 min. disintegrtion method nd pelleting bdjl 5systemtic effect of interction between cerel type nd pelleting 3.. Effect of pelleting on prticle size bdijl 5systemtic effect of interction between disintegrtion method, cerel type nd pel- To obtin mesure of the degree of disinte- grtion of rolled brley nd whet in the pelleting leting

7 E.K. Nielsen, K.L. Ingvrtsen / Livestock Production Science 66 (000) Tble Distribution of prticles in feed mixture of brley nd whet depending on disintegrtion method Disintegrtion method Ground Rolled Feed mixture with Brley Whet Brley Whet Screen (mm) Prticle frction (mm) Percent.0.5 mm Percent.1 mm Prticle rtio,.1 mm:,1 mm Averge prticle size (mm) Clculted verge dimeter of feed prticles (d ). gw process, sieve nlyses of pelleted feed were per Performnce formed fter preceding mcertion nd drying (Tble 3). The proportion of prticles bigger thn 1 mm in The llocted brley nd whet feed mixtures per pelleted feed ws 10% units lower in rolled whet kg pig were the sme on weight bsis. The pigs (33%) compred to rolled brley (43%). In non- receiving the whet mixture thus consumed pproxipelleted feed mixtures with rolled brley nd whet, mtely 6% more net energy (P,0.001) thn pigs pproximtely hlf of the feed (5%) consisted of receiving the brley mixture due to the higher energy prticles.1 mm (Tble 3). This shows tht the content in whet. The higher energy intke incresed corse prticles in rolled whet re crushed more the dily gin by 4% (P,0.001) (Tble 4). Whether when pelleted compred to rolled brley. Mcertion the feed ws ground or rolled, or whether it ws time for pellets of rolled brley ws 0 min com- pelleted or not hd no significnt effect on the dily pred to 1.5 h for pellets of rolled whet. This gin. In contrst, Wondr et l. (1995) found tht difference is probbly due to wter penetrting the pelleted feed hs positive effect on verge dily corse components of the brley pellets more rpidly gin nd feed efficiency. The feed conversion ws thn the more crushed prticles in pellets of rolled % lower (P,0.01) when feeding whet compred whet tht lso contin more ft. to brley. In generl, feed conversion is getting worse when feed prticles increse in size (Simonsson nd Bjorklund, 1978; Nielsen, 1986; Wondr et l., 1995; Tble 3 Influence of pelleting on prticle size in feed bsed on rolled Sloth et l., 1998). In the present experiment, rolling cerel (percentge of prticles.1 mm) nd mcertion time of of the feed did not decrese dily gin nd feed pellets in wter conversion rtio compred to the ground feed. The Cerel type in feed mixture Brley Whet reson for this is most likely tht the endosperm ws Before pelleting,.1 mm (%) sufficiently crushed during rolling to enble n effective feed conversion rtio. Despite n effective Feed mcerted nd dried: rolling, the corse structure ws preserved, especilly Non-pelleted feed mixture,.1 mm (%) 5 47 Pelleted feed mixture,.1 mm (%) in the husks. The whet mixture resulted in len met content which ws 0.7 percentge units lower Mcertion time of pellets (min) (P,0.001) thn in pigs receiving the brley mixture.

8 78 E.K. Nielsen, K.L. Ingvrtsen / Livestock Production Science 66 (000) 71 8 Tble 4 Effect of cerel type, disintegrtion method nd pelleting on feed intke, dily weight gin, feed conversion rtio nd len met percentge Tretment Cerel type Disintegrtion method Pellets S.E. Brley Whet Ground Rolled 1 No. of pens Culled pigs Initil live weight (kg) b Finl weight (kg) ** FUp per pig dily.15.8*** * 0.10 Dily gin (g) *** FUp per kg gin.63.69** Len met percentge *** *, ** or *** s superscript within row nd tretment re significntly different t P,0.05, P,0.01 or P,0.001, respectively. b Finl weight5wrm crcss weight This difference could be relted to the higher energy pred to the whet mixture. This indictes tht the content of whet, inducing higher energy density of retention time of whet in the stomch is shorter thn the diet nd lower protein/ energy rtio. Such tht of brley. This cn lso explin tht the vritions re known to ffect the len met content stomchs weighed less when feeding whet com- (Jørgensen et l., 1985). pred to brley Stomch weight nd content Disintegrtion method Rolled feed incresed (P,0.001) stomch weight Cerel type by 9% compred to ground feed (Tble 5). Similrly, The stomch of pigs receiving brley weighed 6% rolled feed incresed (P,0.001) the dry mtter more (P,0.01) thn stomchs of pigs receiving percentge nd firmness of the stomch content whet (Tble 5). The dry mtter percentge ws compred to ground feed, but only if the feed ws higher (P,0.01) when using the brley mixture non-pelleted (Tble 6, Fig. 4). A similr interction compred to the whet mixture (7.1 vs. 5.0%). between disintegrtion method nd pelleting mni- The brley mixture resulted in 6% lrger (P, fested itself with regrd to consistency of stomch 0.001) mount of dry mtter in the stomch com- content (P,0.05) (Tble 6). Tble 5 Influence of cerel type, disintegrtion method nd pelleting on stomch weight nd content Tretment Cerel type Disintegrtion method Pellets S.E. Brley Whet Ground Rolled 1 No. of pens Stomch weight (g) ** *** ** 64.0 DM in stomch (g) *** b ph (4.36) (4.30) ** (4.37) (4.8) 0.7 c Consistency score *** (1.5) (3.3***) (.1) (.7*) 0.48 *,** or *** s superscript within row nd tretment re significntly different t P,0.05, P,0.01 or P,0.001, respectively. b Interction between cerel type nd pelleting results in brckets. c Scle from 1 to 5 (15thin/wtery; 55firm). Bsed on 96 pigs (48 pens). Interction between disintegrtion method nd pelleting (Tble 6) nd between cerel type nd pelleting results in brckets (Tble 7).

9 E.K. Nielsen, K.L. Ingvrtsen / Livestock Production Science 66 (000) Fig. 3. Different prticle frctions of whet. Rolled to the left nd ground to the right. Fig. 4. Top: Exmple of firm stomch content, rolled feed, consistency score55. Bottom: Exmple of liquid stomch content, ground feed, consistency score51. The ph ws lower (P,0.01) in the stomch is in ccordnce with previous investigtion where content of pigs receiving rolled feed thn in pigs ph ws found to be bove 4.7 when pigs were fed receiving ground feed (4.6 vs. 4.40). This shows crcked corn diet while ph ws observed s low s tht corse feed structure increses the concen- 3.4 when the diet ws finely ground (Mxwell et l., trtion of cids in the stomch content. This finding 1970). Stomch content ph ws found to be lower (P,0.05) in non-pelleted whet compred to pelleted whet (4.1 vs. 4.40) while no difference ws Tble 6 Interction between disintegrtion method nd pelleting for dry observed between pelleted nd non-pelleted brley mtter nd consistency score in stomch content 1 (4.36 vs. 4.35). Disintegrtion method Ground Rolled S.E Pelleting Pelleted 1 1 Pelleted feed reduced (P,0.01) stomch weight No. of pens by 5% from 610 to 579 g (Tble 5). Regrding the b DM (%) consistency of the stomch content, n interction No. of pens b c Consistency score between cerel type nd pelleting ws found for rolled feed (P,0.05). Pelleted rolled brley resulted 1 Figures in the sme row with different superscript letters re in considerbly firmer stomch content thn pelsignificntly different t lest t the 5% level. Scle from 1 to 5 (15thin/wtery; 55firm). Bsed on 96 pigs leted rolled whet (consistency score of 3.9 nd 1.4 (48 pens) points; Tble 7). The hrd husk nd endosperm of

10 80 E.K. Nielsen, K.L. Ingvrtsen / Livestock Production Science 66 (000) 71 8 Tble 7 the tretments. The ppernce of the stomch Interction between cerel type nd pelleting for consistency score 1 mucos in pigs receiving rolled non-pelleted whet when feeding rolled feed ws very good (stomch score50.6). Pelleting of Cerel type (rolled) Brley Whet S.E. rolled whet cused pthologicl chnges s the Pelleted 1 1 stomch score incresed from 0.6 to 4.3. Pelleting of No. of pens rolled brley, however, only incresed the stomch b ph score from 0.8 to 1.3 (Tble 8). This interction Consistency score b (P,0.01) shows tht rolled brley s opposed to 1 Figures in the sme row with different superscript letters re rolled whet could stnd pelleting without incresing significntly different t lest t the 5% level. the prevlence of lesions noticebly. As mentioned Scle from 1 to 5 (15thin/wtery; 55firm). bove, this ws probbly due to the fct tht feed prticles of rolled brley were better preserved during pelleting thn whet prticles which ffected brley ws probbly the reson why its structure ws the consistency of the stomch content (Tble 7). better preserved during pelleting thn in the cse of When compring the consistency score in Tble 7 whet. with the stomch score for rolled feed in Tble 8, it All three experimentl fctors, cerel type, dis- ppers tht firm stomch content coincides with integrtion method nd pelleting thus influenced low stomch score in ccordnce with Muggenburg stomch size nd the properties of the empty et l. (1964). Despite higher occurrence of gstric stomch weight nd content. lesions in pigs fed whet they hd better performnce due to the higher energy content of tht 3.5. Gstric lesions diet. This shows tht high performnce is not indictive of low levels of pthologicl chnges of The distribution of stomch scores nd verge the stomch. stomch score is shown in Tble 8. The percentge Rolling s disintegrtion method therefore ppers of pigs with prkertosis or gstric lesions vried to be cpble of crushing the endosperm sufficiently between 9.6 to 97.1% dependent on the diet in to void reduced feed conversion rtio. Furtherccordnce with previous investigtions (O Brien, more, the grin (especilly the husks) re crushed in 199; Plomo et l., 1996). In generl, brley nd such wy tht rolled feed protects prs oesophge rolling prevented pthologicl chnges of the ginst pthologicl chnges. stomch, while whet, grinding nd pelleting in- The degree of rolling is, of course, importnt for cresed the prevlence nd severity of the chnges. the degree of crushing, nd in the present experi- There were, however, interctions between some of ment, the grins were crushed or divided into Tble 8 Influence of cerel type, disintegrtion method nd pelleting on gstric lesions Cerel type Brley Whet S.E. Disintegrtion method Ground Rolled Ground Rolled Pelleted No. of pens Norml (score 0) (%) Prkertosis (score 1 3) (%) Gstric lesions (score 4 6) (%) Severe lesions (score 7 10) (%) Averge stomch score 3.7 b.1 bc 1.3 c 0.8 d ,d 4.3 c Figures in the sme row with different letters re significntly different t lest t the 5% level. Scle from 0 to 10 (05norml; 105very severe tissue chnges; see detils in mterils nd methods). 1

11 E.K. Nielsen, K.L. Ingvrtsen / Livestock Production Science 66 (000) reltively fine prticles. If the roller hd been dpigs. Just, A., 198. The net energy vlue of blnced diets for growing Livest. Prod. Sci. 8, justed to corser structure, the pelleted feed Jørgensen, J.N., Fernndez, J.A., Jørgensen, H.H., Just, A., mixture would probbly hve resulted in fewer Antomicl nd chemicl composition of femle pigs nd gstric lesions. Likewise corser grinding would brrows of Dnish Lndrce relted to nutrition. Z. Tierphysiol. probbly hve reduced the prevlence of gstric Tierernhrg. u. Futtermittelkde 54, lesions. If the rtio of prticles bigger nd smller Kirschgessner, M., Roth, F.X., Bollwhn, W., Heinritzi, K., Mstleistung, Nhrstoffverdulichkeit und Mgenschleimhutthn 1 mm in dimeter is bout 1, then the prs vernderungen von Schweinen bei unterschiedlicher Futteroesophge ws without chnges. struktur. I. Einfluss eines unterschiedlichen Vermhlungsgrdes The fibre content of whet is only pproximtely des Futters. Zbl. Vet. Med. A. 3, % of tht of brley (Knudsen, 1997), nd the feed Knudsen, K.E.B., Crbohydrte nd lignin contents of plnt mterils used in niml feeding. Anim. Feed Sci. Tech. 67, composition ws not corrected to obtin the sme fibre content in the two feed mixtures. The low fibre Kristensen, E.F Formling og vlsning f korn [Grinding content of whet is not the primry fctor cusing nd rolling of grin]. SjF Beretning nr pp. (In Dnish). pthologicl chnges in the gstric mucos, s pigs Little, R.L., Milliken, G.A., Stroup, W.W., Wolfinger, R.D., receiving rolled whet in non-pelleted form hd SAS System For Mixed Models. SAS Institute, Cry, NC. Mhn, D.C., Pickett, R.A., Perry, T.W., Curtin, T.M., Fetherston, helthy stomchs. This suggests tht the feed struc- W.R., Beeson, W.M., Influence of vrious nutritionl ture or prticle size is of mjor importnce to the fctors nd physicl form of feed on esophgogstric ulcers in prevlence nd severity of gstric lesions. swine. J. Anim. Sci. 5, In the present experiment, cerel type, disintehøjt Mdsen, A., Mortensen, H.P., Lrsen, A.E Byg høstet ved vndindhold og tilst propionsyre [Brley hrvested t grtion method, nd pelleting influenced the consishigh wter content nd dded propionic cid]. Forsøgslb. tency of the stomch content notbly nd the fre- Årbog, (in Dnish). quency nd severity of gstric lesions. Generlly, Mxwell, C.V., Reimnn, E.M., Hoekstr, W.G., Kowlczyk, T., fctors incresing stomch content firmness re Beneveng, N.J., Grummer, R.H., Effect of ditry therefore expected to be ble to prevent gstric prticle size on lesion development nd on the contents of lesions. vrious regions of the swine stomch. J. Anim. Sci. 30, Muggenburg, B.A., McNutt, S.H., Kowlczyk, T., Pthology of gstric ulcers in swine. Am. J. Vet. Res. 5, Nielsen, E.K., Foderets formlingsgrd, form og fodring- References smetode (Feed structure, pelleting nd feeding method). Hyologisk Tidskrift 7, 41 45, (in Dnish). Bustd, B., Nfstd, I., Gstric ulcers in swine. 4. Effects Nielsen, E.K The influence of feeding on development nd of dietry prticle size nd crude fiber contents on ulcertion. helth of slughter pig stomchs nd on ppetite. 41th Ann. Pth. Vet. 6, Meet. EAAP, Toulouse, Frnce, Vol., p. 76. Blckshw, J.K., Cmeron, R.D.A., Kelly, W.R., Effect of Nielsen, E.K Indflydelse f kulhydrters struktur og feeding regimen on gstric ulcertion of the prs oesophge of foderets forrbejdning p forekomst f mvesr hos svin intensively rised pigs. Austr. Vet. J. 56, [Influence of crbohydrtes nd feed processing on gstric Chmberlin, C.C., Merrimn, G.M., Lidvll, E.R., Gmble, C.T., lesions in pigs]. Internl Report 1, Dnish Institute of Animl Effect of feed processing method nd diet form on the Science, pp (in Dnish). incidence of esophgogstric ulcers in swine. J. Anim. Sci. 6, Nielsen, E.K Foderets effekt p mvens volumen, mvein dholdets konsistens, mvesr og produktionsresultter hos Fltlndsmo, K., Slgsvold, P., Effect of grin prticle size slgtesvin. Effekt f kornrt, foderstruktur, pelletering, fodringnd pellets on development of gstric ulcers in swine. J. Anim. smetode og strøelse [Effect of feed on stomch volume, Sci. 33, consistency of stomch content, ulcers nd performnce in Frerking, H., Mtschullt, G., Muller, E., Ikes, D., Todliche pigs. Effect of cerel type, feed structure, pelleting, feeding Mgenschwurestndige Zunhme bei Schwein und Klb. method nd strw bedding]. Dnish Institute of Agriculturl Tierrztliche Umschu 51, Sciences, Report no. 4., 5 pp. (in Dnish). Friendship, R., Gstric ulcers. In: Disese of Swine. Iow O Brien, B.B., 199. Gstric ulcers. In: Disese of Swine. Iow Stte Univ. Press, Ames, IO, pp Stte Univ. Press, Ames, IO, pp Johnsen, H.N., Bch Knudsen, K.E., Sndstrom, B., Skjøt, F., Plomo, A., Crmon, L., Grcı, A., Brvo, J., Snchez, M., Effect of vrying content of soluble dietry fibre from Pujds, P., Delllleu, J., Study bout incidence of whet flour nd ot milling frctions on gstric emptying in gstroesophgic ulcers in Spnish pig production. In: Proc. of pigs. Br. J. Nutr. 75, the 14th IPVS Congress, Bologne, Itly, p. 711.

12 8 E.K. Nielsen, K.L. Ingvrtsen / Livestock Production Science 66 (000) 71 8 Pedersen, K.B., Nielsen, E.K., Mdsen, A., Mvesr hos dhed, slmonell-forebyggelse og produktionsresultter hos svin (Gstric lesions in growing pigs). Ugeskrift for gronomer slgtesvin [The effect of prticle size nd heting tretment/ 47, , (in Dnish). pelleting of feed on gstric lesions, prevention of slmonellosis Potkins, Z.V., Lwrence, T.L.J., Thomlinson, J.R., nd performnce in growing pigs]. Ntionl Committee for Pig Oesophgogstric prkertosis in the growing pig: effects of Breeding, Helth nd Production-Dnish Bcon nd Met the physicl form of brley-bsed diets nd dded fibre. Res. Council, Report no. 385 (in Dnish) Vet. Sci. 47, Smith, W.J., Edwrds, S.A., Ulcertion of the prs Reese, N.A., Muggenberg, B.A., Kowlczyk, T., Hoekstr, W.G., oesophge the role of fctor in whet. In: Proc. of the Grummer, R.H., Effect of corn, whet, ots nd lflf 14th IPVS Congress, Bologne, Itly, p lef mel on the development of gstric ulcers in swine. J. Svne, M Foderstrukturens betydning for produktionsresul- Anim. Sci. 5, 1 4. tterne og mve-trmsundheden hos slgtesvin fodret med Reimnn, E.M., Mxwell, C.V., Kowlczyk, T., Beneveng, N.J., vdfoder [The effect of feed structure on performnce nd Grummer, R.H., Hoekstr, W.G., Effect of fineness of gstric lesions in slughter pigs receiving wet feed]. Ntionl grind of corn on gstric lesions nd contents of swine. J. Anim. Committee for Pig Breeding, Helth nd Production-Dnish Sci. 7, Bcon nd Met Council, Report no. 303 (in Dnish). SAS Institute, SAS/ STAT* Softwre: Chnges nd En- Tellefsen, L., Hndbog i Pilleteringsteknik (Hndbook in hncements, Relese SAS, Cry, NC. Feed Pelleting Techniques). Sprout-Mtdor, Esbjerg, (in Dn- Simonsson, A., Bjorklund, N.-E., Some effects of the ish). fineness of ground brley on gstric lesions nd gstric contents Wondr, K.J., Hncock, J.D., Behnke, K.C., Strk, C.R., in growing pigs. Swed. J. Agric. Res. 8, Effects of mill type nd prticle size uniformity on growth Sloth, N.M., Tybirk, P., Dhl, J., Christensen, G Effekt f performnce, nutrient digestibility, nd stomch morphology in formlingsgrd og vrmebehndling/ pelletering p mvesun- finishing pigs. J. Anim. Sci. 73,