Abstract: [Objective] To study the effects of different levels of coated ammonium chloride（Menoam）on the health of Jersey Cows in perinatal period.[Method] Pre-perinatal Jersey cows with similar parity and body condition were divided into 4 groups：CON Group,Group A,Group B and Group C. CON Group was fed the basal diet,and the DCAD value was +165.64 mEq/kg DM,Group A was fed the basal diet+200 g Menoam,and the DCAD value was -43.94 mEq/kg DM. Group B was fed the basal diet+250 g Menoam,and the DCAD value was -112.51 m Eq/kg DM. Group C was fed the basal diet+300 g Menoam,and the DCAD value was -175.37 m Eq/kg DM.[Result] （1） Compared with the CON Group,the feed intakes of groups A,B and C increased significantly（P<0.05）and the dry matter intake of Group B was the highest（2）With the increase of the addition amount of Menoam,the urine pH value of Jersey cows in the pre-perinatal period gradually decreased,and the differences among the groups were significant（P<0.05）,and the urine pH value of Group B was the appropriate range.（3）As the dietary DCAD value decreased,the blood calcium levels of Group A,B and C showed an upward trend,and the differences among the groups were significant（P<0.05）.（4）Compared with the CON Group,the incidences of milk fever,retained fetal membranes,endometritis and abomasal displacement in Group A,Group B and Group C all decreased,and the incidences of retained fetal membranes and abomasal displacement in Group B were the lowest.（5）The average colostrum yield of CON Group,Group A,Group B and Group C were 9.20 kg,9.28 kg,9.20 kg and 9.10 kg,respectively,and there was no significant difference among the groups (P>0.05).The Brix degrees degrees of colostrum in CON Group，Group A，Group B and Group C were 32.0%，33.0%，31.8% and 32.1%，respectively. There was no significant difference among the groups (P＞0.05)，but there was a significant difference in the Brix degree between group A and group B (P < 0.05).[Conclusion] Adding Menoam to the diet of Jersey cows in the perinatal period can increase DMI，reduce the DCAD value，effectively regulate the urine pH value，improve blood calcium level and reduce the incidence of diseases of Jersey cows in the perinatal period. Under the experimental conditions，it is appropriate to add 250 g Menoam to the diet of Jersey cows in the early perinatal period and adjust the DCAD value to -112.51 mEq/kg DM.

Key words: Jersey cow, coated ammonium chloride（Menoam）, health