母羊营养会影响羔羊的性能、质量和适口性吗？.pdf

1、Can Ewe Nutrition Affect Performance,Quality and Palatability of their lambs?Min DuRegents Professor and Endowed Chair Department of Animal SciencesWashington State UniversityPullman,WA Lamb pregnancy lasts for about 148 days,and lambs are commonly slaughtered at around one year.In other words,one t

2、hird of its life is passed inside the uterus.All major developmental milestones are accomplished during the fetal stage.Why is the fetal stage so important for lamb production?Conception Birth Slaughter In the uterus Muscle mainly develops during the fetal stage.There is no increase in the number of

3、 muscle fibers after birth.For lambs,the formation of new muscle fibers largely stops after day 90-100 of gestation.Afterwards,growth of skeletal muscle is mainly due to the increase in the diameter and the elongation of existing muscle fibers.Fetal muscle developmentSkeletal muscle developmentFirst

4、 1 months Formation of new muscle fibers1 to 3 months of pregnancy,Formation of new muscle fibers Growth of muscle fibers3 months and after,Growth of muscle fibers Increase of muscle fiber formation during the fetal stage will increase later lean growth.Besides formation of muscle fibers,fetal muscl

5、e development also involves formation of fat cells and fibrogenic cells(connective tissues).Fat cells formed during the fetal stage and neonatal stage accumulate lipids during fattening stage,forming marbling.Excessive formation of connective tissue makes the meat tough.Fetal muscle developmentMid t

6、o late fetal stageLate fetal stageMature musclePrecursor cellsMyoblastsPrimary Muscle fiberFat cellsFibroblastPluripotentcellsMyoDMyf-5MyogeninSecondaryMusclefiberEmbryonic stageFetal muscle developmentConceptionEmbryonic stage0 1 2 3 4 5(Month)BirthFetal stagePrimary myogenesisSecondary myogenesisM