| This experiment was conducted to study the nutritional intake level of gilts during pregnancy on reproductive performance, metabolic Status and milk composition. Forty-four crossbred sows (Landrace×Yorkshine) with similar age and body weight (255±10d age,150±9kg weight) were chosed. Single factorial trial arrangement was performed in this study, after mating gilts were fed0.75M,1.0M,1.25M,1.5M(M:Maintenance requirements of nutrient).Base on1M energy requrement during the early pregnancy(1to30pregnancy), combined with dietary energy concentration, the different nutritional intake bettwen gilts of four groups were through feeding intake regulation.To meeting the nutrient needs of fetal growth,nutrient intake increased to20%in the middle geatation basis on the prophase, and increase to25%in the late gestation basis on the metaphas. all sows fed the same diet during0-90days pregnancy(DE3.0Mcal/kg,0.6%/kg SID-Lys),and after pregnancy90d change to another (DE3.2Mcal/kg, SID-LysO.64%). All sows were fed ad libitum during LactationThe results showed that:1) Nutrient intake during pregnancy did not influence total number born, but1.5M group has a trend (P=0.081) to reduce the number of piglet born alive. Number of effective pigs born alive (P<0.90kg) per litter, and litter weight at farrowing in1.25M group was significantly higher than in0.75M (P<0.05), and had a trend to higher than in150%NRC group (P=0.083, P=0.090), was not significant different between the1.0M group (P>0.05). Litter weight in1.25M group on21and28lactation days was significantly higher than in the other group (P<0.1). As nutritie intake improved during pregnancy, birth weight of piglet was significantly increased, the relationship between digestible energy intake X (MJ/d) and weight of birth piglet7(kg) was:Y=0.932+0.014X(R2=0.454, P<0.01)2) As nutrite intake improved during pregnancy, total weight gain, net weight of sows and breeding-weaning body weight gain of sows was increased significantly (P<0.01), lactation weight loss also increased (P<0.01). 3) As nutrition intake improved during pregnancy, sow backfat thickness gradually increased. Average farrowing backfat of1.5M group was23.4mm,significantly higher than the other groups (P<0.01), Average farrowing backfat of0.75M was14.5mm, significantly lower than the remaining groups (P<0.01),1.25M backfat thickness was significantly higher than the1.0M (P<0.05), the trend of lactation backfat loss was the same with gestational backfat growth.4) Nutrite intake during pregnancy had different effects on reproductive performance factor. According to sow weight gain during pregnancy and reproductive performance regression we found that when the total weght gain of sow during gestation was67kg, average daily digestible energy intake was6.87Mcal/d, sow would own best litter size at farrowing and most number of piglet born alive per litter. when the total weght gain of sow during gestation was74-78kg, digestible energy intake was7.24-7.54Mcal/d, sows would have the best farrowing litter weight, and weaning litter weight.5) As nutrition intake of sow during pregnancy increased, lactation feed int ake decreased, Regression relationship between digestible energy (Mcal/d) intak-e during lactation Y and digestible energy intake (Mcal/d) during pregnancy X was Y=18.07-0.743X, R2=0.572, P<0.01.6) On30,90day of pregnancy, as the intake of nutrition increase, blood urea nitrogen concentration gradually improved,at farrowing urea nitrogen concentration of0.75M,1.5M group was significantly higher than other groups(P<0.05), urea nitrogen concentration of0.75M group at weaning was significantly lower than the other groups(P<0.05). on30,90,day of pregnancy and at farrowing serum free fatty acid concentration of0.75M was significantly higher than the rest of the group (P<0.05),but was significantly lower others at weaning. Free fatty acid concentration of1.5M group was significantly higher than the other groups at weaning (P<0.05).7) Fat and Protein content in colostrum was higher as dietary nutrition level was increased during gestation, but percentage of milk fat and protein in1.25M group on28lactation days was highest, regression relationship between nutrition levels and milk fat, protein content was Quadratic (P<0.01). We can draw following conclusing base on the results:1) Under our experimente condition, the optimum reproductive performance and milk quality of gilts which breeding weight is150kg could be met by provided daily DE7.99Mcal/d,SID-Lys15.9g/d during prgnancy2) Excessive nutrient intake during pregnancy (9.59Mcal/d DE, SID-Lys19.18g/d) could decrease farrowing performance of sow, and account for deficie-ncy feed intake during lactation which cause excessively loss of body reserves that affect lactation performance.3) Low nutrient intake during pregnancy (4.80Meal/d DE, SID-Lys9.59g/d) caused giIts catabolic status, lower piglets birth weight, and account for seriouly shortage of sow body reserves which affect lactation performance. |
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