| Pig production cost which is the key factor to determine the profitability of breeding pig farm is generally composed of feed cost,production cost of pigs weighted 17 kg,labor cost,medical and epidemic prevention cost and death loss cost.The pig production cost in China is significantly higher than that in Europe and America.In addition to the high feed cost,the high production cost of pigs weighted 17 kg due to the lower reproductive performance of sows is also the key factor to increase the pig production cost.Therefore,it is one of the effective way to reduce the production cost of pigs weighted 17 kg by improving the reproductive performance of sows.On the other hand,with the progress of genetic selection,the reproductive performance of sows has improved significantly,especially the nutritional requirements of primiparous sows are higher.Thus,it is necessary to re-evaluate the nutritional requirements of modern high-performance primiparous sows.Lysine(Lys)and Methionine(Met)play an important role in improving lactation reproduction and antioxidant capacity of sows,and growth and development of piglets.To improve the reproductive performance of sows by optimizing the nutrition level of modern high-performance primiparous sows will play a positive role for reducing the production cost of pigs weighted 17 kg.Therefore,the change rule and main influencing factors of pig production cost were analyzed and the relationship between sow reproductive performance and production cost of pigs weighted 17 kg was discussed in China from2009 to 2020.On this basis,the effects of optimizing Lys level and Met/Lys ratio in lactating diet on reproductive performance,multiple parities retention rate,and production cost of pigs weighted 17 kg were studied on modern high-performance primiparous sows.The main results are as follows:Part 1 Analysis on the composition and key influencing factors of pig production cost in ChinaIn order to analyze the change rule of pig production cost in China,data of The National Agricultural Product Cost and Income Data Compilation from 2009 to 2020were collected.The pig production cost,feed cost,production cost of pigs weighted 17 kg,labor cost and medical and epidemic prevention cost were adjusted to 120 kg body weight for comparison.Thus,the aims of the present study were to clarify the key components and influencing factors of pig production cost;and to analyze the influence of African swine fever(ASF)on the pig production cost。In addition,explore the relationship between sow reproductive performance and production cost of pigs weighted 17kg.The main results of this part are as follows:1.The pig production cost in China showed a general trend of rising first-then declining-and then rising during the period from 2009 to 2020.In detail,the pig production cost increased from 2009 to 2016,and then decreased from 2016 to 2018,and increased again from 2018 to 2020.Feed cost,production cost of pigs weighted 17 kg and labor cost,which accounting for more than 95%of pig production cost were the are the three main components of the pig production cost.Among the three main components,feed cost accounted for 36.48%～60.65%of the pig production cost,which showed a general trend of decreasing first-then increasing-and decreasing again.Production cost of pigs weighted 17 kg accounted for 23.74%～50.19%of the pig production cost,which was consistent with the change of the pig production cost.Labor cost fluctuated with a small variation and accounted for 9.25%～15.62%of the pig production cost.2.The top three components of pig production cost were labor cost,production cost of pigs weighted 17 kg,and feed cost,which increased by 122.98%,27.03%and 21.62%,respectively,before the outbreak of ASF from 2009 to 2018.Among them,labor cost increased from 113.64 yuan to 253.40 yuan,and piglet cost increased by 340.09 yuan increased to 432.02 yuan,and feed cost increased from 713.22 yuan to 867.43 yuan,an increase of 122.98%,27.03%and 21.62%,respectively.After the outbreak of African swine fever from 2018 to 2020,the piglet cost,death loss fee and medical and epidemic prevention fee were the top three three components of pig production cost.The production cost of pigs weighted 17 kg increased from 432.02 yuan to 1308.53 yuan,the death loss cost increased from 12.29 yuan to 18.26 yuan,and the medical and epidemic prevention cost increased from 18.69 yuan to 25.03 yuan,which increased by 202.89%,48.59%and 33.89%,respectively.3.Feed cost was affected by feedstuff price and feed conversion ratio of pigs.The feed cost,which kept consistent with the trend of corn price change showed a trend of rising first-then decreasing-and rising again during 2009 to 2020.When the feed conversion ratio of pigs was 2.6,2.7,2.8 and 2.9,respectively,the feed cost was 1131.07,1169.74,1211.39 and 1250.07 CNY,respectively.4.Labor cost was mainly composed of stuff’s salary,management cost,living expenses and other expenses.With the increasing of per capita breeding scale,the labor cost was gradually decreased.When the per capita breeding scale increased from 200 to1000,the labor cost/pig reduced from 234.00 to 46.80 CNY.5.The piglet cost in this study consists of two parts:the 7 kg weaned piglet cost and the 7-17 kg stage feeding cost.Gilt breeding cost was mainly affected by the successive mated rate and longevity of sows.Depreciation cost of equipment was mainly affected by feed consumption.Furthermore,gilt breeding cost and supplies consumption cost of sows were the key factors affecting the production cost of pigs weighted 17 kg.6.With the increase of weaning piglet,the production cost of pigs weighted 17kg decreased linearly.Each additional pig of weaning piglet reduces the production cost of pigs weighted 17kg by 15.89 CNY(y=-15.89x+896.7;r~2=0.9561;P<0.01).To sum up,feed cost,labor cost and production cost of pigs weighted 17 kg are the main components of pig production cost in China.Feed cost is mainly affected by feedstuff ingredient price.The labor cost is mainly affected by the per capita feeding scale.However,the production cost of pigs weighted 17 kg is mainly affected by the allocation gilt breeding cost and the annual material consumption cost of sow production.Increasing PSY of sows is the key to reduce the production cost of pigs weighted 17 kg.Part 2 Effects of lysine levels during lactating on reproductive performance and retention in high-performance primiparous sowsIn this part,a total of 160 dan-bred Landrace×Yorkshire crossbred lactating sows were randomly divided into 4 groups and fed with 4 SID Lys level lactation diets(0.84%(group 1),0.94%(group 2),1.04%(group 3)and 1.14%(group 4)for two consecutive lactation periods.Gestation sows were fed the same diet and the piglets was adjusted to13.2±0.29 after parturition.The changes of body weight and backfat of sows during lactation,the growth rate of piglets,the number of weaned piglets,the body weight and litter weight of sows,and the interval of estrus after weaning were measured.Blood and milk samples of sows at parturition and day 21 of lactation were collected to analyze plasma urea nitrogen,milk composition and amino acid composition of colostrum and milk.Multiple breeding cycle retention rate and production cost of pigs weighted 17kg in each group were calculated as well.The main results of this part are as follows:1.Lactation feed intake:Weekly and whole lactation feed intake of sows at parity 2was significantly higher than that of primiparous sows(P<0.05).Feed intake of lactation sows was not influenced by SID Lys level of lactation diet(P>0.05).However,there was an interaction between diet treatment and parity on feed intake of lactation sows(P<0.05).In the first breeding cycle,feed intake at week 1 of lactation sows in group 4 was significantly higher than that in group 1(P<0.05).While feed intake at week 1 of lactation sows in group 3 was significantly higher than that in groups 1 and 2(P<0.05).2.Body weight and backfat:There were significant differences in farrowing weight,weaning weight and weight loss,and backfat at farrowing and weaning(P<0.05)between the two parities of sows.While there was a trend of difference in weaning to estrus interval(WEI)among groups(P=0.09).Dietary treatments with different SID Lys levels had no significant effects on body weight,backfat,body weight and backfat loss of sows during lactation(P>0.05).3.Piglets performance:In terms of performance,the total born piglets,born alive piglets,and weaning piglets of sows at parity 2,and litter weight,individual weight at birth and weaning,average daily gain of piglet was significantly higher than that of primiparous sows(P<0.01).The pre-weaning survival rate(P=0.04),litter weight at weaning(P=0.04),individual weight(P=0.04)and average daily gain during lactation(P=0.03)increased linearly with the increase of SID Lys level.4.Plasma urea nitrogen and milk composition:Although dietary SID Lys levels and parity had no significant effects on plasma urea nitrogen and colostrum composition of sows during lactation(P>0.05),percentage of milk fat(P=0.03),milk protein(P=0.03),fat-free dry matter(P=0.03)and total dry matter(P=0.04)in milk were significantly increased with the increase of dietary SID Lys level(P<0.05).5.Amino acid composition of colostrum and milk:The levels of proline in colostrum was significantly increased in the second paritie compared with the first parity of sows(P=0.05),while the amino acid composition in milk was not affected(P>0.05).The levels of alanine,arginine,aspartic acid,glutamic acid,isoleucine,leucine,lysine,methionine,phenylalanine,proline,serine,threonine,tryptophan and valine in milk were significantly increased with the increase of SID Lys level in lactating diet(P<0.05).6.Plasma amino acid composition:The plasma levels of alanine,histidine,proline,serine and threonine in sows at parity 2 were significantly lower than those in primiparous sows(P<0.05).However,the plasma levels of alanine,proline,serine,threonine and valine decreased in sows at parity 2(P<0.05).Dietary SID Lys level did not affect plasma amino acid composition of sows at parturition(P>0.05),while plasma levels of alanine,lysine,methionine,phenylpropionic acid and valine of sows at weaning increased with the increase of SID Lys level(P<0.05).7.Sow retention rate:The retention rate of sows in group 2 was 81.62%,which was significantly higher than the other three groups after two consecutive lactation periods(P<0.05).8.Piglet cost:In the first breeding cycle,the cost of piglets in group 4 was the lowest,which was 496.40 CNY;in the second breeding cycle,the cost of piglets in groups 2 and 3 was lower,which was 474.4 CNY and 473.70 CNY,respectively.Therefore,it was recommended that SID Lys of dan-bred Landrace×Yorkshire crossbred sows during lactation be 1.14%,which can significantly improve the growth rate of piglets,litter weight of 21 days of lactation,and reduce the pig production cost.However,in the SID Lys of the second parity sow is 0.94%in the lactation period,the best piglet growth rate and litter weight at 21 days of lactation can be obtained,and the multiple litter retention rate can be improved,and the piglet cost is lower.Part 3 Effects of appropriate Methionine/Lysine ratio during lactation on reproductive performance in high-performance primiparous sowsOn the basis of part 2,a 2×2 experimental design was adopted,i.e.,two SID Lys levels were 1.14%and 1.24%,respectively and two Met/Lys levels of 0.31 and 0.41,respectively.It was divided into group 1(SID Lys 1.14%,Met/Lys 0.31),group 2(SID Lys 1.14%,Met/Lys 0.41),group 3(SID Lys 1.24%,Met/Lys 0.31),and group 4(SID Lys 1.24%,Met/Lys 0.41),respectively.Met/Lys 0.41).A total of 120 dan-bred Landrace×Yorkshire crossbred lactating sows were randomly assigned to 4 groups with 30 sows in each group.The feed intake of sows during lactation,weight and backfat changes at parturition and weaning,lactation performance of piglets and post-weaning performance of sows were determined.Blood and milk samples of sows at parturition weaning were collected,and milk composition,blood antioxidant indexes and methionine metabolites were determined respectively.Results of this part were as follows:1.Feed intake,body weight and backfat during lactation:Dietary SID Lys levels and Met/Lys ratio of lactating sows had no significant effects on total feed intake and average daily feed intake of lactating sows,as well as changes in body weight and backfat of sows at parturition and weaning and lactation period(P>0.05).2.Piglet performance:Compared with 0.31,diet Met/Lys ratio of 0.41 significantly increased the body weight of piglets at 7 and 21 days of lactation(P<0.05).Compared with SID Lys level of 1.24%,SID Lys level of 1.14%significantly increased the piglet body weight(P=0.04),litter weight(P=0.04)and litter weight(P=0.02)on day 7,and tended to increase litter weight on day 21(P=0.07).3.Sow weaning-rematch performance:There was interaction effect between SID Lys level and Met/Lys ratio on body weight and litter weight at 14 and 21 days,and daily gain at 1-21 days(P<0.05).Sows in group 2(SID Lys1.14%,Met/Lys 0.41)had the best performance among all groups(P<0.05).4.Plasma urea nitrogen and milk composition:Dietary SID Lys level and Met/Lys ratio had no significant effect on plasma urea nitrogen level at parturition(P>0.05).However,compared with dietary Met/Lys ratio of 0.31,the Met/Lys ratio increased to 0.41 significantly increased the plasma urea nitrogen level at weaning(P>0.05).Compared with SID Lys level of 1.14%,plasma urea nitrogen level was significantly increased in SID Lys level of 1.24%group(P=0.02).Dietary SID Lys level and Met/Lys ratio had no significant effect in composition of colostrum and milk(P>0.05).5.Plasma antioxidant indicators:Compared with SID Lys 1.14%,dietary SID Lys1.24%significantly increased T-AOC activity and GSH-Px activity in blood of sows at weaning(P<0.05).sows in Dietary Met/Lys ratio of 0.41 group had lower MDA,ROS,GSH-Px enzyme activities and 8-OHDG levels of sows at weaning compared with those in Met/Lys ratio of 0.31 group(P<0.05).There was a significant interaction between SID Lys level and Met/Lys ratio(P<0.05),the activity of GSH-Px in sows at group 2was significantly increased(P<0.05).In addition,Met/Lys of 0.41 tended to increase blood GSH content of sows at weaning(P=0.08).6.Sow retention rate:When Met/Lys was 0.41,the retention rate of primiparous sows was significantly increased(P<0.05).To sum up,this study draws the following conclusions:1.Feed cost,production cost of pigs weighted 17 kg and labor cost are the three main components of pig production cost.Corn price is the main factor affecting feed cost,and production cost of pigs weighted 17 kg is the most critical factor affecting pig production cost.more importantly,the production cost of pigs weighted 17kg can be reduced by improving sow reproductive performance.2.During first lactation,SID Lys level of 1.14%and Met/Lys ratio of 0.41 can reduce the oxidative stress state and production cost of pigs weighted 17 kg,and improve the antioxidant capacity of sows,growth performance of piglets,and sow retention rate in dan-bred Landrace×Yorkshire crossbred lactating sows.In the second parity,the second dan-bred Landrace×Yorkshire crossbred lactating sows SID Lys of 0.94%could increase the pre-weaning survival rate,litter weight at weaning,and multiple cycle retention rate,and the piglet cost is lower. |
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