| The gilts often have fewer litter size,lower survival rate and weaker maternity.With the increase of the production experience,the maternity becomes stronger and stronger,and it is also more and more stable.At present,the research about the maternity of sows mostly focuses on the influence of delivery housing on maternal ability,but the effect of pregnant feeding housing on maternal ability is rarely involved.As a kind of breeding method which can effectively improve the welfare level of sows,group housing during pregnancy has been popularized and applied gradually compared with the limited feeding housing.The purpose of this study was to study the effects of group housing and limited housing during pregnancy on reproductive performance,stress level,lipid oxidation and metabolism in placenta of Du Min gilts.Based on the premise that the enclosure affects the expression of sows’ maternal behaviors,the effects of different levels of stress on the feeding housing before and after delivery of Du Min gilts and the effects of maternal behaviors after delivery were studied.In the first part,Du Min gilts were divided into limited housing and group housing during pregnancy.At the stress levels,the levels of salivary cortisol and C-reactive protein in the group feeding group were significantly lower than those in the limited group(p<0.05),but in the later period of pregnancy,the levels of salivary cortisol and C-reactive protein were not significantly different from those in the control group.The levels of α-amylase in saliva of group housing was significantly higher than that of limited housing(p<0.05).In terms of reproductive performance,the litter weight of the Du Min gilts living in the group housing were significantly higher than that in the limited housing(p<0.05),and the total litter size,the number of live litter,the average weight,the number of dead births,the number of weak litter and the number of mummy have no significant difference between two groups(p<0.05).There was no significant difference in placental efficiency between the two groups(p>0.05).On the level of placental lipid deposition,the contents of total cholesterol and triglyceride in the group housing were significantly lower than those in the limited housing(p<0.05).There was no significant difference in the level of SOD and CAT between the two groups(p<0 05).The level of antioxidant activity in placental tissue was significantly lower than that in the limited housing(p<0.05),but there was no significant difference between the two groups(p<0.05).The level of SOD in the placental tissue was significantly lower than that in the control group(p<0.05).There was no significant difference between pre-pregnancy and late pregnancy(p>0.05).On the basis of part one,looseing delivery housing was adopted in the pregnant of group housing,and the gilts from limited pregnant housing will be divide into limited delivery housing and looseing delivery housing equally.On the 2nd and 8th day of lactation,the salivary cortisol level of gilts were significantly lower than that of the width group and the limit group.On the 8th day of lactation,the levels of C-reactive protein in saliva of the sows were significantly lower than that of the limit group(p<0.05).On the 8th and 15 th day of lactation,the level of amylase in saliva of sows was significantly higher than that of the limit group and the width group(p<0.05).The above results indicated that the stress level of pregnant sows had a certain effect on the stress level of lactating sows,and the effect lasted until the 15 th day of lactation.There was no significant difference in each index between the group width group and the limited width group at different time points(p>0.05),but there was significant difference in each index in the limit group at different time points(p<0.05).The total length of labor group was lower than the limit group(p<0.05),but there was no significant difference among the three groups(p>0.05),while on the first day and the 21 st day of lactation,the ratio of lying position in the sows was significantly higher than that in the limit group(p<0.05),but there was no significant difference among the three groups(p>0.05).On the 21 st and 35 th day of lactation,the length group width group was significantly higher than the width limited group(p<0.05),and the lactation frequency group width group was significantly lower than the width limited group(p<0.05).The ratio of the same behavior in the same group was significantly different in the three observation periods except for the group width group(p<0.05).In the group width group,there was a significant difference between the first day and the 21 st day of lactation and the 35 th day of the prostrate position in the group width group(p<0.05).In summary,compared with the feeding environment of pregnant group,pregnancy position feeding can increase the stress response of gilts in the early stage of pregnancy,increase the abnormal deposition of placental lipids,and reduce the content of immunoglobulin iga in colostrum.The effect of pregnancy term feeding on gilts continued during lactation.At the same time,due to the different feeding environment,stress level and behavior expression were different. |
