JIANG Qingrong;DELELESSE Debele Girma;GU Kuntao;DU Chao;MA Lu;WU Peng;WANG Jianping;BU Dengpan;College of Animal and Technology,Henan University of Science and Technology;Institute of Animal Science,Chinese Academy of Agricultural Science;College of Animal and Technology,Shihezi University;Dongying Shenzhou AustAsia Modern Dairy Farm Co.,Ltd.;

JIANG Qingrong%DELELESSE Debele Girma%GU Kuntao%DU Chao%MA Lu%WU Peng%WANG Jianping%BU Dengpan%College of Animal and Technology,Henan University of Science and Technology%Institute of Animal Science,Chinese Academy of Agricultural Science%College of Animal and Technology,Shihezi University%Dongying Shenzhou AustAsia Modern Dairy Farm Co.,Ltd.

low energy diet;;rumen-protected lysine;;colostrum quality;;growth performance;;rumen fermentation

This experiment was conducted to investigate the effects of diets with lowenergy level and rumenprotected lysine( RPL) for perinatal period on colostrum quality of cows,growth performance and rumen fer-mentation of pre-weaning calves. This experiment was used a 2 × 2 factorial design,including net energy for lactating cow( NEL,6.40 and 5.73 MJ/kg DM) and RPL( 0 and 40 g/d per head). Fifty-two Holstein cows in 3 parities were blocked by body score and predicted calving date and randomly assigned to 1 of 4 groups.Cows were fed in the four groups including a basal diet( B),a lowenergy diet( L),the basal diet supplemented with RPL( BL) and the lowenergy diet supplemented with RPL( LL),respectively. The experiment was lasted from day 21 before expected date of calving of cows to weaning of calves after calving. The colostrum was collected during the first milking time after giving birth,and the contents of total solids,protein,fat and lactose,immunoglobulin( Ig) G,IgMand IgA were measured. Body weight and body side were measured on birth( 1 days of age) and 60 days of age. Rumen liquid was collected on 60 days of age to measure pH,ammonia nitrogen( NH3-N) and volatile fatty acid( VFA) concentrations. The results showed as follows:1) diets with lowenergy level for perinatal period significantly decreased total solid,lactose and IgMcontents in the colostrum( P<0.05); RPL supplementation in diets for perinatal period had an increasing trend on lactose content in the colostrum( P = 0.068 2) and had no significant effects on others( P>0.05). 2) Diets with lowenergy level for perinatal period significantly decreased body weight,body height,body length and chest girth of female calves at 60 days of age( P<0.05),and significantly increased body weight of male calves at60 days of age and chest girth of male calves at birth( P<0.05). RPL supplementation in diets for perinatal period had a decreasing trend on body weight of male calves at 60 days of age( P = 0.073 0). 3) Diets with lowenergy level for perinatal period significantly decreased body structure index of female calves at birth( P <0.05),had an increasing trend on body structure index of female calves at 60 days of age( P = 0.059 6),had a decreasing trend on body structure index of male calves at birth( P = 0.099 1),significantly increased body structure index of male calves at 60 days of age( P < 0.05),and significantly decreased body length index of male calves at 60 days of age( P<0.05); RPL supplementation in diets for perinatal period had no significant effects on body structure index,body length index and chest girth index of female calves and body side index of calves( P> 0. 05). 4) Diets with lowenergy level for perinatal period significantly decreased total volatile fatty acids,acetic acid,propionic acid,isobutyric acid,butyric acid,isovaleric acid and valeric acid concentrations in the rumen liquid of calves( P<0.05); RPL supplementation in diets for perinatal period had no significant effects on rumen fermentation indexes of calves( P > 0.05). 5) No interaction was observed between dietary energy level and RPL supplementation on colostrum quality of cows,body weight and body side,body side indexes and rumen fermentation indexes of pre-weaning calves( P > 0.05). In conclusion,diets with lowenergy level for perinatal period decreases the colostrum quality of cows,body weight and body side,body side indexes and rumen fermentation of pre-weaning calves; RPL supplementation in diets for perinatal period has no harmful effect on the colostrum quality of cows,body weight and body side,body side indexes and rumen fermentation of pre-weaning calves; diets with lowenergy level and RPL supplementation for perinatal period cannot instead of basal diets with normal standardized energy level.[Chinese Journal of Animal Nutrition,2019,31(7):3164-3173]