Sows with high milk production had both a high feed intake and high body mobilization

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1 Animl (2017), 11:11, pp The Animl Consortium 2017 doi: /s niml Sows with high milk production hd oth high feed intke nd high ody moiliztion A. V. Strthe 1, T. S. Bruun 2 nd C. F. Hnsen 1 1 Deprtment of Lrge Animl Sciences, Fculty of Helth nd Medicl Sciences, University of Copenhgen, Grønnegrdsvej 2, 1870 Frederikserg C, Denmrk; 2 SEGES Dnish Pig Reserch Centre, Axeltorv 3, 1609 Copenhgen, Denmrk (Received 19 Octoer 2016; Accepted 16 Decemer 2016; First pulished online 15 Ferury 2017) Selection for incresed litter size hve generted hyper-prolific sows tht nurses lrge litters, however limited knowledge is ville regrding the connection etween milk production, feed intke nd ody moiliztion of these modern sows. The im of the current study ws to determine wht chrcterized sows with high milk production nd nursing lrge litters, differences etween sows of different prities nd effects of lcttionl performnce on next reproductive cycle. In totl 565 sows (prity 1 to 4) were studied from 7 dys efore frrowing until wening. On dy 2 postprtum litters were stndrdized to 14 piglets. Weight nd ck ft thickness of sows were mesured t dy 7 preprtum, dy 2 postprtum nd t wening. Litters were weighed t dy 2 nd t wening. Person correltion coefficients etween vriles were clculted nd regression models were developed. The verge dily feed intke (ADFI) of the sows ws 6.1 ± 1.1 kg/dy, verge dily gin (ADG) of the litter ws 2.92 ± 0.53 kg/dy nd sows wened 13.0 ± 1.1 piglets. First prity sows generlly hd lower ADFI nd milk production nd decrese in totl orn piglets in next litter compred with prity 2 to 4 sows, which could e explined y reltively higher proportion of their ody reserves eing moilized compred with multiprous sows. The ADG of the litter ws positively relted y ADFI of the sows, litter size nd BW loss nd incresing the ADFI with 1 kg/dy throughout lcttion likely incresed the ADG of the litter with 220 to 440 g/dy in prity 1 to 4, respectively. Incresing the ADFI y 1 kg/dy reduced the BW loss with 6.6 to 13.9 kg of prity 1 to 4 sows, respectively, during lcttion, wheres incresing the verge milk yield with 1 kg/dy rised the BW loss with 4.3 to 21.0 kg of the four prities during lcttion. The numer of totl orn piglets in the next litter ws positively relted to the numer of piglets orn in the previous litter. In conclusion, oth high feed intke nd high moiliztion of ody reserves ws prerequisite for high milk production. The sows might e very close to the physicl limit of wht they cn ingest nd future reserch should therefore, focus on optimizing the dietry energy nd nutrient concentrtions of diets for lctting hyper-prolific sows nd herein distinguish etween primiprous nd multiprous sows. Keywords: ody moiliztion, feed intke, milk production, reproduction, sow Implictions To otin high litter weight t wening the sow must consume high mounts of feed, ut high milk yield often cuses high BW loss. Counterproductive, ody moiliztion is positive for the offspring, ut might e hrmful to the sow. This study showed tht sows with the highest milk production nd litter gin hd oth high feed intke nd lrge moiliztion. The sows might hve reched their upper physicl limit for how much feed they could ingest nd therefore future reserch should focus on correct nutrient concentrtions of lcttion diets of hyper-prolific sows. E-mil: cfh@sund.ku.dk Introduction Milk production in sows is ffected positively y feed intke during lcttion (Koketsu et l., 1997; Vdmnd et l., 2015). Mny sows turn ctolic during the lcttion period to mintin their milk production, ecuse they re unle to increse the feed intke t the sme rte s milk production is incresing (vn den Brnd et l., 2000; Hnsen et l., 2012). However, possily due to differences in the numer of nursing piglets, studies on sows show contrdicting results when it comes to linking ody moiliztion nd milk production, nd whether high feed intke (5.0 to 7.6 kg/ dy) cn prevent excessive BW loss (Eissen et l., 2003; Mosnier et l., 2010). A low sow feed intke (2.8 to 3.0 kg/ dy) nd gret ody moiliztion (38 to 40 kg) during 1913

2 Strthe, Bruun nd Hnsen lcttion cn hve negtive effect on the following reproductive cycle y incresing wening-to-estrus intervl (WEI) nd decresing the numer of totl orn piglets (Bidoo et l., 1992; Koketsu et l., 1996; Zk et l., 1998). In ddition, prity of the sow lso influences milk production nd reproductive performnce. First prity sows give irth to fewer piglets nd hve lower feed intke compred with multiprous sows (Eissen et l., 2000). First prity sows might therefore hve different interply etween feed intke, ody moiliztion, milk yield nd reproduction thn older sows ccording to Dourmd et l. (1996). Hyper-prolific sows re pushed to the limit nd eyond during lcttion to increse milk yield, however, more knowledge is needed to clrify the connection etween milk production, feed intke, ody moiliztion nd susequent reproduction in hyperprolific sows nursing lrge litters of 12 to 14 piglets. The im of this study ws, therefore, to chrcterize hyper-prolific sows with high milk production. We hypothesized tht milk yield would e influenced y numer of nursing piglets, prity, feed intke nd ody moiliztion. Mteril nd methods This study ws conducted with the pprovl of the Dnish Animl Experimenttion Inspectorte (Authoriztion No ). Animls nd diets The study ws conducted in commercil Dnish herd using 565 prity 1 to 4 sows (Lndrce Yorkshire) mted with Duroc semen (Htting KS, Horsens, Denmrk). Originlly the study ws conducted to test the effect of six dietry vlineto-lysine rtios for lctting sows (see Strthe et l., 2016), ut no tretment effects were seen on ny of the mesured prmeters nd therefore dt ws pooled for this ssessment. Ech week, lock of 18 sows were selected for the tril sed on prity nd in totl 32 locks of sows were included. The nimls were studied from 1 week preprtum until wening (dy 26 postprtum). Twenty four hours postprtum (dy 2), the litters were stndrdized to 14 medium or lrge piglets (1.78 ± 0.24 kg). Sows were fed using SpotMix feeding system (Schuer Agrotronic, Prmchkirchen, Austri) tht enled individul feeding curves for ech sow. From 7 dys preprtum to 2 dys postprtum ll sows were fed the sme diet (Tle 1). From dy 2 postprtum, sows were llotted to six dietry tretments only vrying in vline concentrtion (Tle 1). Gilts were fed 2.3 kg from dy 2 postprtum nd feed llownce ws incresed to mximum of 7.6 kg t dy 17. Multiprous sows were fed 2.3 kg from dy 2 postprtum nd feed llownce ws grdully incresed to mximum of 8.6 kg t dy 17. These feeding curves were used s guideline for the mximum dily llownce of the sows; nd were the curves normlly used in the herd, s it ws the experience tht they were close to the mximum intke cpcity of the sows. The feed llownce ws djusted for the individul Tle 1 Ingredients nd dietry composition (s-fed) of the lcttion diets 1 Ingredients (%) Diet 1 Diet 2 Brley Whet 39.9 Soyen mel Sugr eet pellet 6.0 Plm oil 1.62 Soy oil Monoclcium phosphte Limestone Slt L-lysine L-threonine DL-methionine Vitmin nd minerl premix Vitmin nd minerl premix Phytse Composition (clculted) DM (%) CP (%) SID Lysine (g/kg) Energy (MJ ME/kg) SID = stndrdized ilel digestile; DM = dry mtter; ME = metolizle energy. Diet 1 ws fed from dy 80 of gesttion until the dy fter frrowing nd diet 2 ws fed from dy 2 postprtum nd until wening of the litter. 1 In the originl six dietry tretments (Strthe et l., 2016) L-vline ws included in diet 2 from 0.00% to 0.43%, respectively. 2 Provided per kg of the diet: 8130 IU vitmin A; 810 IU vitmin D 3 ; mg DL-lf tocoferol, 4.06 mg vitmin K 3 ;2.03mgvitminB 1 ; 5.08 mg vitmin B 2 ; 3.05 mg vitmin B 6 ; 0.02 mg vitmin B 12 ; mg D-pntothenic cid; mg nicin; 1.52 mg folic cid; mg iron (FeSo 4 ); mg copper (CuSO 4 ); mg mngnese (MnO); 0.20 mg iodine (C(IO 3 ) 2 ); 0.36 mg selenium (N 2 SeO 3 ). 3 Provided per kg of the diet: 9070 IU vitmin A; 910 IU vitmin D 3 ; mg DL-lf tocoferol, 4.32 mg vitmin K 3 ;2.27mgvitminB 1 ; 5.67 mg vitmin B 2 ; 3.40 mg vitmin B 6 ; 0.02 mg vitmin B 12 ; mg D-pntothenic cid; mg nicin; 1.70 mg folic cid; mg iron (FeSo 4 ); mg copper (CuSO 4 ); mg mngnese (MnO); 0.23 mg iodine (C(IO 3 ) 2 ); 0.38 mg selenium (N 2 SeO 3 ). 4 Phyzyme XP provided 500 phytse ctivity (FTU) per kg of diet (Dnisco Animl Nutrition, Mrlorough, UK) sows dily nd when feed residuls were present in the trough the llownce ws downgrded with 0.25 kg. Feed residuls were not recorded. Records nd smpling Sows were weighed nd ck ft (BF) thickness of sows ws mesured y ultrsound t the P2 site (Sono-Grder II; Renco Corportion, Minnepolis, MN, USA) t dy 7 preprtum, dy 2 postprtum nd t wening. Litter weight ws recorded t litter stndrdiztion nd t wening. On susmple of 72 second prity sows, dditionl mesurements of BW nd BF were mde on dy 17 nd litter weight t dys 10 nd 17 postprtum. Blood smples were collected from the jugulr vein of these sows t dys 2, 10, 17 nd 26 postprtum. Spot smples of urine were collected on the sme dys s lood smples, nd milk smples were otined t dy 17 postprtum. Detiled description of smpling nd chemicl nlysis of feed, lood, urine nd milk re given in Strthe et l. (2016). 1914

3 Chrcteristics of hyper-prolific lctting sows Clcultions nd sttisticl nlysis All clcultions nd sttisticl nlyses were crried out in R (R Core Tem, Vienn, Austri) with the individul sow s the experimentl unit. Milk yield ws estimted from equtions y Hnsen et l. (2012). Chnges in ody pools of ft nd protein were estimted using equtions y Dourmd et l. (2008).The descriptive sttistics of dt ws reported s men nd SD nd results of nlysis were reported s lest squres men nd SE. The effect of prity ws nlyzed using the following model: Y ij = μ + α i + γ j + ε ij Feed intke, kg/dy Prity 1 Prity 2 Prity 3 Prity 4 where Y ij is the response vrile, µ the overll men, α i the effect of prity (i = 1, 2, 3, 4), γ j the rndom effect of lock (j = 1, 2,, 32) nd ε ij the rndom error component which ws ssumed to e N (0,σ 2 ). When nlyzing the effect on sow BW nd BF thickness, the interction etween prity nd stge of lcttion ws lso included in the model. Multiple comprisons were mde when the ANOVA indicted tht there were significnt differences. Tukey s test ws used in multiple comprisons of mens to djust the P-vlues. The multiple comprisons were done using the multcomp pckge in R. Sttisticl significnce ws declred t P < Reltionships etween response vriles (verge dily gin (ADG) of litter, BW nd BF loss of sow during lcttion, totl orn piglets in next litter nd WEI) nd explntory vriles were evluted y Person correltion coefficients to determine which vriles should e used in the multiple regression nlysis. All explntory vriles tht were significnt t the 5% level were offered in multiple regression models. Multiple regression models were developed for the ADG of the litter, BW loss of the sow during lcttion nd totl orn piglets in next litter for prity 1 to 4, respectively, using ckwrd elimintion pproch for reduction of the model. Multiple coefficient of determintion (djusted R 2 ) nd prmeters of the explntory vriles nd their SE were estimted. Results Descriptive nlysis of dt nd time effects The sows hd n verge dily feed intke (ADFI) t 6.1 kg/dy during lcttion (Figure 1). In verge sows wened 13.0 ± 1.1 piglets nd the ADG of the litter ws 2.92 ± 0.53 kg/dy. Sows in verge lost 22.1 ± 12.7 kg of BW nd 2.9 ± 1.7 mm of BF from dy 2 postprtum until wening, respectively. Milk contents of lctose, ft nd protein were 5.58 ± 0.89%, 7.17 ± 2.07% nd 4.71 ± 0.71%, nd the dily outputs of these nutrients were 648 ± 115, 832 ± 184 nd 544 ± 74.3 g/dy, respectively. Sow plsm concentrtions of glucose (5.27 ± 0.64 mmol/l; P = 0.19) nd lctte (1.76 ± 0.75 mmol/l; P = 0.11) were similr on ll smpling dys, wheres concentrtions of non-esterified ftty cid (NEFA) decresed, plsm ure nitrogen incresed nd plsm nd urine cretinine decresed during lcttion (P < 0.001, Figure 2) Dy in milk Figure 1 Feed llownce ws registered dily for individul sows nd feed llownces (kg/dy) for prity 1 to 4 sows re given from litter stndrdiztion to wening. The ADG of the litter ws highest in mid-lcttion (3.15 ± 0.55 kg/dy; dys 10 to 17) compred with erly (2.87 ± 0.52 kg/dy; dys 2 to 10) nd lte (2.89 ± 0.89 kg/dy; dys 17 to 26) lcttion (Figure 3; P < 0.05). The loss of BW nd BF in sows ws highest from dys 2 to 17 (17.9 ± 11.7 kg nd2.6±1.6mm)compredwithdys17to26(8.0±7.9kg nd 0.7 ± 1.5 mm; Figure 3; P < 0.001). Sow prities The highest ADFI ws recorded for the prity 3 nd 4 sows, wheres prity 1 sows hd the lowest ADFI (P < 0.001; Figure 1). All prities wened the sme numer of piglets (P = 0.15), ut prity 1 sows hd lower ADG of the litter compred with multiprous sows (2.55 v.2.97to3.04kg/dy, P < 0.001). The totl BW loss (kg) during lcttion ws lowest inprity1nd3compredwith2nd4(p < 0.01), ut the totl BF loss (mm) ws similr mong ll prities (P = 0.45). On verge, first prity sows lost 10% of their BW nd 7.7% of ody protein during lcttion, which ws the sme s second prity sows, ut first prity sows lost 26% of the ody ft compred with 20% in second prity nd 16% in prity 3 or 4 (P < 0.001). In the susequent reproductive cycle, prity 1 sows hd longer WEI (P < 0.001) nd drop from 16.2 to 15.2 piglets in the next litter compred with the multiprous sows which hd the sme or incresed litter size (P < 0.001; Tle 2). Correltions The ADG of the litter ws positively correlted with BW nd BF loss during lcttion, respectively (P < 0.001, Tle 3). The ADFI during the entire lcttion period nd the weekly ADFI (ADFI 1 to 4) most likely hd positive effect on ADG of the litter (P < 0.001; Tle 3). Incresed outputs of the individul nutrients in milk (lctose (r = 0.72), ft (r = 0.58) nd protein (r = 0.64)) ws positively relted to ADG (P < 0.001) of the litter. A high plsm cretinine (r = 0.28 to 0.49) throughout lcttion seemed to hve positive 1915

4 Strthe, Bruun nd Hnsen () Plsm Lctte, mmol/l Time: P= () Plsm glucose, mmol/l 6.0 Time: P= Dys in milk Dys in milk (c) Plsm ure N, mmol/l c Time: P<0.001 c (d) Plsm NEFA, mmol/l 0.4 Time: P< Dys in milk Dys in milk (e) Plsm cretinine µmol/l Time: P< Dys in milk c c Urine cretinine, µmol/l Dys in milk Time: P<0.01 Figure 2 Plsm nd urine smples were collected 4 h fter the morning feeding on dys 3, 10, 17 nd 26 postprtum. Plsm ws nlyzed for () lctte, () glucose, (c) plsm ure N, (d) non-esterified ftty cids (NEFA) nd (e) cretinine, nd urine ws nlyzed for (f) cretinine. Results for plsm ure N, glucose nd cretinine ws given s mens nd SD nd results for plsm NEFA nd lctte nd urine cretinine ws given s mens nd 95% confidence intervls.,,c Mens without common superscript differ (P < 0.005). (f) effect on ADG (P < 0.05), wheres plsm NEFA hd positive effect in the lst week (r = 0.35; P < 0.01), nd plsm ure N hd negtive effect in the 1st week (r = 0.38; P < 0.01). A higher litter size nd ADG of the litter ws relted to incresed ody moiliztion during lcttion (P < 0.001, Tle 3). The ADFI ws negtively correlted to BW loss or BF loss during lcttion (P < 0.001, Tle 3). Totl dily output of ft in milk ws positively correlted to the BF loss (r = 0.40; P < 0.01). High concentrtions of NEFA (r = 0.30 nd 0.28; P < 0.05) or cretinine (r = 0.36 nd 0.37; P < 0.01) t dys 10 nd 17 ws correlted with incresed BW loss, wheres high plsm ure N t dy 2 ws linked to decresed BW (r = 0.36) nd BF (r = 0.32) loss (P < 0.01). A shorter WEI ws ssocited with high ADFI during the entire lcttion period, nd WEI ws lso positively correlted to high numer of orn piglets in the next litter (P < 0.001, Tle 3). In contrst, WEI ws correlted with higher proportionl loss of BW nd BF during lcttion (P < 0.05; Tle 3), high numer of wened piglets (P < 0.01, Tle 3) or higher dily outputs of protein (r = 0.31; P < 0.05) or lctose (r = 0.29; P < 0.05) in milk. Wening-to-estrus intervl ws likely negtively ffected y plsm NEFA t dy 17 (r = 0.27; P < 0.05), plsm cretinine t dy 10 (r = 0.36; P < 0.01) nd urine cretinine t dy 10 (r = 0.50; P < 0.01) nd dy 17 (r = 0.29; P < 0.05). The ADFI of weeks 2 to 4 ws positively correlted to numer of totl orn piglets in next litter (P < 0.001; Tle 3). Regression nlysis The results of the multivrite regression nlysis re shown in Tle 4. The vriles included in the regression models of prity 1 to 4 sows explined 55%, 63%, 68% nd 73% of the vrition in ADG of the litter, respectively. Averge dily feed intke nd BW loss of the sow during lcttion ws incorported in the regression models for ll four prities. The prmeters for ADFI were highest mong the vriles in the regression models nd vried from 0.22 to 0.44 kg/dy mening tht incresing the ADFI with 1 kg/dy would increse the ADG of the litter with 220 to 440 g/dy provided tht other vriles were held fixed. An increse in BW loss of 1 kg only incresed ADG with 20 to 30 g/dy, nd n extr piglet in the litter incresed ADG y 70 to 150 g/dy. In totl 70%, 69%, 65% nd 73% of the vrition in BW loss of the sows during lcttion ws explined y the models for prity 1 to 4, respectively. Averge dily feed intke, BW t stndrdiztion, BF loss during lcttion nd milk yield were included in models for ll four prities. Incresing the ADFI y 1 kg/dy decresed the BW loss y 6.6 to 13.9 kg during lcttion, wheres incresing the verge milk yield with 1 kg/dy rised the BW loss y 4.3 to 21.0 kg during lcttion. In models for the numer of totl orn piglets in next 1916

5 Chrcteristics of hyper-prolific lctting sows () Averge dily gin, kg/dy () Body weight loss, kg (c) Bck ft loss, mm Dy 2-10 Dy Dy Period of lcttion Dy 2-17 Dy Period of lcttion Dy 2-17 Dy Period of lcttion P<0.001 litter no vriles were included in ll four models which only explined 8%, 6%, 4% nd 14% of the vrition in the numer of totl orn piglets in next litter for prity 1 to 4, respectively. For prity 2 to 4 one extr pig orn would increse litter size in the susequent reproductive cycle with 0.18 to 0.26 piglets. Discussion Averge dily gin of the litter This study clerly showed tht the ADG of the litter ws positively ffected y the ADFI of the sow, litter size nd the BW loss of the sow during lcttion. Averge dily feed intke seemed to hve the highest impct on ADG compred with litter size nd BW loss. It might e difficult to increse the ADFI y 1 kg/dy, ut n increse in ADFI y 100 g/dy could potentilly increse the litter wening weight y 0.5 to 1.0 kg. Milk production hs the highest priority for the sow during lcttion, which mens tht lmost ll dietry nutrients re directed towrd the mmmry glnds. When the P<0.05 P<0.001 Figure 3 Chnges in () verge dily gin of the litter, () BW loss of the sow nd (c) ck ft loss of sow during different periods of lcttion. Results re gives s men nd SD., Mens without common superscript differ (P < 0.005). sow increses feed intke, more energy nd nutrients ecome ville for the synthesis of milk, which is converted into piglet growth (Koketsu et l., 1997; Eissen et l., 2003). The ADFI in individul weeks of lcttion lso hd positive correltion to the ADG of the litter, especilly in weeks 3 nd 4 even though the effect of the totl ADFI for the entire lcttion period ws more pronounced. This mkes sense ecuse round dys 16 to 18 postprtum the sows rech their mximum milk production nd therefore hs the highest energy nd nutrient requirement (Strthe et l., 2015); Koketsu et l., (1997) lso investigted the effect of ADFI in individul weeks of lcttion on litter weight t wening; nd similrly found tht ADFI of weeks 2 nd 3 hd higher impct thn ADFI in week 1. It is nevertheless importnt to mention tht the sows in the current study did not hve d liitum ccess to feed, ut n upper limit ws set on the feed llownce. Consequently, it is not possile to determine for how long the positive effect of feed intke on ADG will continue to increse linerly efore n upper limit will e reched. However, ecuse oth the ADFI nd the ody moiliztion of the sows ws high in litters with the highest ADG, it could e speculted tht the feed llownce might hve een very close to the physicl limit for how much the sows could ingest. If this is the cse, then it emphsizes the importnce of investigting optiml dily requirements of energy nd nutrients insted of feed llownces to ensure high productivity of hyper-prolific sows. Sow ody moiliztion during lcttion The BW loss of ll sows during lcttion decresed with incresing feed intke, wheres n incresed milk yield enlrged the BW loss. Agin, it might e unrelistic to increse the ADFI with 1 kg/dy, ut lower increse t for instnce 200 g/dy could potentilly decrese the BW loss with 1.3 to 2.8 kg. A high milk yield is needed to ensure high litter gin nd it does, therefore, not from production point of view mke sense to decrese milk yield. Severl studies hve shown tht incresed litter size nd ADG of the litter incresed the BW nd BF loss of the sows during lcttion (Auldist et l., 1994; Kim nd Ester, 2001; Eissen et l., 2003), ecuse the sow compenstes for the indequte feed intke to mintin high milk production. It is expensive for the sow to moilize excessively from ody reserves, ecuse the ody reserves must e reconstituted during the following gesttion resulting in n incresed feed cost. According to Dourmd et l. (1996), sows were cple of regining BW nd BF lost during lcttion through the following gesttion when sows lost etween 12 or 35 kg BW nd 2.5 nd 4 mm BF, ut only if fed high-energy level (10.0 Mcl ME/dy v. 7.1 nd 8.5 Mcl ME/dy). Severl older studies showed tht incresing the feed llownce of the sow cn minimize the ody moiliztion (Clowes et l., 1998; Pluske et l., 1998; Eissen et l., 2003), ut if the physicl upper limit for feed intke of the sow is lredy reched focus should e shifted towrd optimizing nutrient concentrtions of the feed insted nd in this wy try to limit the moiliztion of ody reserves. 1917

6 Strthe, Bruun nd Hnsen Tle 2 Effects of prity on sow nd piglet performnce Prity P-vlue SE Prity n Feed intke ADFI (kg/dy) 5.4 c *** ADFI dy 2 to 6 (kg/dy) 2.8 c *** ADFI dy 7 to 13 (kg/dy) *** ADFI dy 14 to 20 (kg/dy) 6.4 c *** ADFI dy 21 to wening (kg/dy) 7.0 c *** Piglets Totl orn *** Litter size t wening NS ADG piglet (g/dy) *** ADG litter (kg/dy) *** Body condition sows BW chnge dy 7 to 2 (kg) 27.2 c *** BW dy 2 (kg) 191 d 240 c *** BW loss dy 2 to 26 (kg) ** BW loss dy 2 to 26 (% of BW dy 2) *** BF dy 2 (mm) *** BF loss dy 7 to 2 (mm) NS BF loss dy 2 to 26 (mm) NS BF loss dy 2 to 26 (% of BF dy 2) * Ft loss (kg) * Ft loss (% of ft dy 2) 25.8 c *** Protein loss (kg) ** Protein loss (% of protein dy 2) 7.7 c c 0.67 *** Milk production 1 Averge milk yield (kg/dy) *** Pek milk yield (kg) *** Dy of pek milk yield (dy) *** Reproduction Wening-to-estrus intervl (dys) *** Length of gesttion (dys) *** Totl orn next litter 15.2 c *** NS = not significnt; ADFI = verge dily feed intke; ADG = verge dily gin; BF = ck ft.,,c Mens within row with different superscript letters re different. 1 Milk yield ws estimted from litter gin (g/dy) nd litter size using equtions y Hnsen et l. (2012). *P 0.05, **P 0.01, ***P Sow productivity nd metolism Differences were seen etween sows of different prities regrding milk production nd ody moiliztion. First prity sows might e more sensitive to nursing lrge litters nd moilizing high proportions of ody ft reserves could hve cused the second litter drop seen in the current study. First prity sows moilized 26% of their ody ft nd Schenkel et l. (2010) showed tht first litter sows dropped in second litter, when moilizing >20% of their ody ft, wheres moiliztion of ody protein did not ffect litter size. In ddition, first prity sows hd prolonged WEI compred with multiprous sows. This indictes tht the metolism of primiprous sows might differ from multiprous sows during lcttion ecuse they re not fully grown. Therefore, other feeding strtegies or dietry compositions thn used for older sows could help prevent negtive effects of excessive moiliztion on the susequent reproductive cycle of these first prity sows. Ure N in plsm incresed during the first 3 weeks of lcttion s reflection of incresed ctolism of mino cids cused y the higher protein intke (Le Cozler et l., 1998; Mosnier et l., 2010), which ws in ccordnce with Mosnier et l. (2010) nd Quesnel et l. (2009). The decrese in plsm cretinine throughout lcttion mtches the higher BW loss during the 1st weeks of lcttion compred with the lst week efore wening. In contrst, Mosnier et l. (2010) reported constnt concentrtion of cretinine in plsm, ut in tht study the sows did not lose weight during lcttion. A higher moiliztion of ody protein increses plsm cretinine nd the moilized protein is to gret prt redirected towrd milk protein. In the current study, higher dily protein output in milk resulted in higher litter gin. A lrge protein moiliztion during lcttion is not desirle, ecuse it is expensive for the sow to restore muscle protein in the following gesttion (Dourmd et l., 1996), nd this 1918

7 Chrcteristics of hyper-prolific lctting sows Tle 3 Person correltion coefficients etween vriles (n = 565) ADG (kg/dy) BW loss (kg) BF loss (mm) WEI Totl orn in next litter Items r P-vlue r P-vlue r P-vlue r P-vlue r P-vlue Feed intke ADFI (kg/dy) 0.45 *** 0.27 *** 0.19 *** 0.17 *** 0.24 *** ADFI dy 2 to 6 (kg/dy) 0.17 *** 0.20 *** 0.09 * ADFI dy 7 to 13 (kg/dy) 0.33 *** 0.17 *** 0.16 *** 0.15 *** 0.21 *** ADFI dy 14 to 20 (kg/dy) 0.43 *** 0.19 *** 0.20 *** 0.15 *** 0.21 *** ADFI dy 21 to wening (kg/dy) 0.40 *** 0.20 *** 0.11 ** 0.14 ** 0.23 *** Piglets Totl orn piglets 0.01 NS 0.10 * 0.10 * 0.16 *** 0.26 *** Litter weight dy 2 (kg) 0.19 *** 0.18 *** 0.18 *** 0.05 NS 0.07 NS Litter size t wening 0.50 *** 0.33 *** 0.30 *** 0.13 ** 0.01 NS ADG litter (kg/dy) 0.48 *** 0.42 *** 0.05 NS 0.14 ** Body condition sows BW loss dy 7 to 2 (kg) 0.04 NS 0.13 ** 0.03 NS 0.03 NS 0.48 *** BW dy 2 (kg) 0.36 *** 0.26 *** 0.05 NS 0.30 *** 0.35 *** BW loss dy 2 to 26 (kg) 0.48 *** 0.55 *** 0.01 NS 0.01 NS BW loss dy 2 to 26 (% of BW dy 2) 0.39 *** 0.96 *** 0.56 *** 0.09 * 0.11 ** BF loss dy 7 to 2 (mm) 0.05 NS *** 0.03 NS 0.15 *** BF dy 2 (mm) 0.21 *** 0.29 *** 0.37 *** 0.16 *** 0.04 NS BF loss dy 2 to 26 (mm) 0.42 *** 0.55 *** 0.02 NS 0.03 NS BF loss dy 2 to 26 (% of BF dy 2) 0.38 *** 0.49 *** 0.93 *** 0.09 * 0.05 NS Ft loss dy 2 to 26 (kg) *** 0.89 *** 0.84 *** 0.01 NS 0.03 NS Protein loss dy 2 to 26 (kg) *** 0.97 *** 0.33 *** 0.01 NS 0.01 NS Milk production 2 Dys in milk (dys) 0.01 NS 0.05 NS NS 0.08 Milk yield (kg/dy) 0.89 *** 0.49 *** 0.43 *** 0.03 NS 0.09 * Pek milk yield (kg) 0.93 *** 0.49 *** 0.43 *** 0.01 NS 0.10 * Dy of pek milk yield (dy) 0.82 *** 0.34 *** 0.29 *** 0.14 ** 0.16 *** Reproduction WEI (dys) 0.11 * Length of gesttion (dys) 0.01 NS NS = not significnt; WEI = wening-to-estrus intervl; ADFI = verge dily feed intke; ADG = verge dily gin; BF = ck ft. ADG of the litter, BW nd BF loss of the sow, WEI nd totl orn in next litter were used s response vriles. 1 Estimted with equtions y Dourmd et l. (2008). 2 Estimted with equtions y Hnsen et l. (2012). P 0.10, *P 0.05, **P 0.01, ***P study indictes tht milk production hs gret impct on protein metolism of the sow, nd therefore n importnt focus of future reserch should e optimiztion of protein nd mino cid requirements during lcttion. The plsm concentrtion of NEFA, which is likely n indirect mesurement of ody ft moiliztion (Le Cozler et l., 1998; Mosnier et l., 2010) ws highest during the first 2 weeks nd then decresed to lmost zero in the lst 2 weeks of lcttion, which is in ccordnce with oservtions mde y Trottier nd Ester (1995). This conforms with the higher BF loss during the 1st week compred with the lst week of lcttion s reported in the current study. Sow reproduction in the following cycle A higher feed intke during lcttion ws ssocited with shorter WEI, which is in ccordnce with findings in previous studies (Koketsu et l., 1997; Zk et l., 1997) tht reported higher frequency of LH pulses fter wening in sows with high feed intke during lcttion. Luteinizing hormone pulses re prerequisite for the sow to return to estrus fter wening. The regression models with totl orn piglets in next litter s response vrile only explined very little of the vrition (4% to 14%) in our dt. The reson could e tht mny fctors esides the ones mesured in the current study in-etween mting nd frrowing hve gret influence on litter size. Sows giving irth to mny piglets in the firstlitterre prone to give irth to high numer of piglets in the susequentlitter(luciet l., 2000; Hughes et l., 2010), nd in the regression models for prity 2 to 4 positive effect of numer of orn piglets in the preceding litter ws seen. A positive Person correltion coefficient ws found etween ADG of the litter, nd the litter size in the susequent litter nd sows nursing lrge litters similrly hd the highest ADFI during lcttion. Studies hve shown tht feed intke especilly during the lst week efore wening, cn hve positive effect on emryo survivl (Bidoo et l., 1992; Zk et l., 1997). 1919

8 Strthe, Bruun nd Hnsen Tle 4 Regression models for verge dily gin (ADG) of the litter, BW loss of sows during lcttion nd totl orn piglets in next litter for prity 1 to 4 (n = 565) 1 Responses Regression model R 2 ADG prity (SE = 0.44) (SE = 0.08) ADFI (SE = 0.004) BWL (SE = 0.03) LS (SE = 0.02) BFL (SE = 0.05) ADFI ADG prity (SE = 0.30) (SE = 0.04) ADFI (SE = 0.002) BWL (SE = 0.02) LS (SE = 0.01) BFL 0.63 ADGprity (SE = 0.38) (SE = 0.07) ADFI (SE = 0.003) BWL (SE = 0.02) LS (SE = 0.02) BFL (SE = 0.04) ADFI ADG prity (SE = 0.41) (SE = 0.07) ADFI (SE = 0.002) BWL (SE = 0.03) LS 0.73 BWL prity (SE = 11.2) 6.65 (SE = 1.78) ADFI (SE = 0.05) BWS (SE = 0.73) MY (SE = 0.51) BFL (SE = 0.22) LWS 2.60 (SE = 1.15) ADFI (SE = 0.07) BWF 0.99 (SE = 0.34) BFS 0.70 BWL prity (SE = 12.5) (SE = 0.93) ADFI (SE = 0.03) BWS (SE = 2.89) MY (SE = 0.38) BFL (SE = 0.16) LWS (SE = 0.49) TPM 0.19 (SE = 0.05) BWF 5.85 (SE = 2.12) PMY 0.69 BWL prity (SE = 18.6) 13.9 (SE = 1.64) ADFI (SE = 0.04) BWS (SE = 4.60) MY (SE = 1.85) ADFI (SE = 0.20) LWS (SE = 0.59) TPM 0.23 (SE = 0.06) BWF 11.9 (SE = 3.38) PMY 0.65 BWL prity (SE = 14.1) 11.2 (SE = 2.24) ADFI (SE = 0.04) BWS (SE = 0.69) MY (SE = 0.54) BFL 2.94 (SE = 1.17) ADFI (SE = 0.50) TPM (SE = 1.53) ADFI (SE = 0.28) BFS 0.73 TBNL prity (4.23) (SE = 0.38) BFF 0.50 (SE = 0.26) TPM 0.08 TBNL prity (SE = 2.24) (SE = 0.06) TBP (SE = 0.58) ADFI 0.74 (SE = 0.44) ADFI TBNL prity (SE = 9.17) (SE = 0.08) TBP (SE = 4.87) ADG 1.23 (SE = 0.58) TPM 1.98 (SE = 0.94) PMY 0.04 TBNL prity (SE = 4.92) (SE = 0.10) TBP (SE = 1.14) ADG 0.82 (SE = 0.39) TPM 0.14 The djusted R 2 is given for ech model. 1 ADG = verge dily gin of the litter (kg/dy); ADFI = verge dily feed intke (kg/dy); ADFI1 = ADFI from stndrdiztion to dy 6 (kg/dy); ADFI2 = ADFI from dy 7 to 13 (kg/dy); ADFI3 = ADFI from dy 14 to 20 (kg/dy); ADFI4 = ADFI from dy 21 to wening (kg/dy); BWL = BW loss during lcttion (kg); BFL = ck ft loss during lcttion (mm); BFL% = ck ft loss (% of BF t dy 2); LS = litter size t wening (n piglets); TBP = totl orn piglets (n piglets); BWS = BW sow t stndrdiztion (kg); BFS = ck ft t stndrdiztion (mm); BFF = ck ft loss dy 7 to 2 (mm); WEI = wening-to-estrus intervl (dys); TBNL = totl orn piglets in next litter (n piglets); TPM = time of pek milk yield (dy postprtum); MY = milk yield (kg); PMY = pek milk yield (kg); LWS = litter weight t stndrdiztion (kg). In conclusion, primiprous sows hd lower feed intke, ADG of the litter nd lower litter size in the next reproductive cycle, which ws likely cused y higher degree of ody moiliztion compred with multiprous sows. Both high feed intke nd high moiliztion of ody reserves were prerequisite for high milk production. A low feed intke incresed ody moiliztion nd hd negtive effects on the susequent reproduction, lthough lrge increse in dily feed intke is perhps not relistic. Insted, future reserch should focus on optimizing the dietry energy nd nutrient concentrtions of diets for lctting hyper-prolific sows nd herein distinguish etween primiprous nd multiprous sows. Acknowledgments The project ws funded y the Dnish Pig Reserch Centre nd the Fculty of Helth nd Medicl Sciences, University of Copenhgen. References Auldist DE, Morrish L, Thompson M nd King RH Response of sows to vrying litter size. In Proceedings of the Nutrition Society of Austrli, Septemer 1994, Newcstle, NSW, Austrli, p Bidoo SK, Aherne FX, Kirkwood RN nd Foxcroft GR Effect of feed intke during lcttion nd fter wening on sow reproductive performnce. Cndin Journl of Animl Science 72, Clowes EJ, Willims IH, Brcos VE, Pluske JR, Cegielski AC, Zk LJ nd Aherne FX Feeding lctting primiprous sows to estlish three divergent metolic sttes: II. Effect on nitrogen prtitioning nd skeletl muscle composition. Journl of Animl Science 76, Dourmd JY, Etienne M nd Nolet J Reconstitution of ody reserves in multiprous sows during pregnncy: effect of energy intke during pregnncy nd moiliztion during the previous lcttion. Journl of Animl Science 74, Dourmd JY, Étienne M, Vlncogne A, Duois S, vn Milgen J nd Nolet J InrPorc: model nd decision support tool for the nutrition of sows. Animl Feed Science nd Technology 143, Eissen JJ, Apeldoorn EJ, Knis E, Verstegen MW nd de Greef KH The importnce of high feed intke during lcttion of primiprous sows nursing lrge litters. Journl of Animl Science 81, Eissen JJ, Knis E nd Kemp B Sow fctors ffecting voluntry feed intke during lcttion. Livestock Production Science 64, Hnsen AV, Luridsen C, Sørensen MT, Bch Knudsen KE nd Theil PK Effects of nutrient supply, plsm metolites, nd nutritionl sttus of sows during trnsition on performnce in the next lcttion. Journl of Animl Science 90, Hnsen AV, Strthe AB, Kere E, Frnce J nd Theil PK Predicting milk yield nd composition in lctting sows: Byesin pproch. Journl of Animl Science 90, Hughes PE, Smits RJ nd Xie Y Reltionships mong gilt nd sow live weight, P2 ckft depth, nd culling rtes. Journl of Swine Helth nd Production 18, Kim SW nd Ester RA Nutrient moiliztion from ody tissues s influenced y litter size in lctting sows. 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9 Chrcteristics of hyper-prolific lctting sows Luci T Jr, Dil GD nd Mrsh WE Lifetime reproductive performnce in femle pigs hving distinct resons for removl. Livestock Production Science 63, Mosnier E, Etienne M, Rmekers P nd Père MC The metolic sttus during the peri prtum period ffects the voluntry feed intke nd the metolism of the lctting multiprous sow. Livestock Science 127, Pluske JR, Willims IH, Zk LJ, Clowes EJ, Cegielski AC nd Aherne FX Feeding lctting primiprous sows to estlish three divergent metolic sttes: III. Milk production nd pig growth. Journl of Animl Science 76, Quesnel H, Meunier-Slün M-C, Hmrd A, Guillemet R, Etienne M, Frmer C, Dourmd J-Y nd Père M-C Dietry fier for pregnnt sows: influence on sow physiology nd performnce during lcttion. Journl of Animl Science 87, Schenkel AC, Bernrdi ML, Bortolozzo FP nd Wentz I Body reserve moiliztion during lcttion in first prity sows nd its effect on second litter size. Livestock Science 132, Strthe AV, Bruun TS, Zerrhn J-E, Tuson A-H nd Hnsen CF The effect of incresing the dietry vline-to-lysine rtio on sow metolism, milk production, nd litter growth. Journl of Animl Science 94, Strthe AV, Strthe AB, Theil PK, Hnsen CF nd Kere E Determintion of protein nd mino cid requirements of lctting sows using popultionsed fctoril pproch. Animl 9, Trottier NL nd Ester RA Dietry nd plsm rnched-chin mino cids in reltion to tryptophn: effect on voluntry feed intke nd lcttion metolism in the primiprous sow. Journl of Animl Science 73, Vdmnd CN, Krogh U, Hnsen CF nd Theil PK Impct of sow nd litter chrcteristics on colostrum yield, time for onset of lcttion, nd milk yield of sows. Journl of Animl Science 93, vn den Brnd H, Heetkmp MJ, Soede NM, Schrm JW nd Kemp B Energy lnce of lctting primiprous sows s ffected y feeding level nd dietry energy source. Journl of Animl Science 78, Zk LJ, Cosgrove JR, Aherne FX nd Foxcroft GR Pttern of feed intke nd ssocited metolic nd endocrine chnges differentilly ffect postwening fertility in primiprous lctting sows. Journl of Animl Science 75, Zk LJ, Willims IH, Foxcroft GR, Pluske JR, Cegielski AC, Clowes EJ nd Aherne FX Feeding lctting primiprous sows to estlish three divergent metolic sttes: I. Associted endocrine chnges nd postwening reproductive performnce. Journl of Animl Science 76,