Study On The Formation Mechanism And Influencing Factors Of Bovine Ovarian Cyst And Its Prevention And Control

Cow ovarian cyst（cystic ovarian disease,COD）is one of the main causes of reproductive disorders.It often leads to prolonged calving intervals and causes serious economic losses to large-scale dairy farms.Therefore,this study is based on the COD survey of large-scale dairy farms.This study is based on clinical symptoms combined with rectal examination,B-ultrasound and comprehensive hormone detection diagnosis.This study is clarified the pathogenic factors and pathogenesis of COD in dairy cows through the analysis of biological characteristics and the expression of endocrine receptor signaling pathways.But it has clarified the COD of dairy cows.This research provides relevant theoretical and technical basis for more effective prevention and control of COD in dairy cows in the future.The research content includes:Test 1:For this experiment,a large-scale dairy cow experimental base in Beijing was selected.This experiment screened out cows with reproductive disorders through the collection and analysis of reproductive data.This investigation studies the relationship between different distributions,parities,seasons and COD of cows.The results of the survey showed that COD in dairy cows accounted for 12.46%of reproductive disorders.This test found that the second-born cows have the most COD,accounting for 50.69%of the total number of tests.This experiment found that summer childbirth is the season of high incidence of COD,with an incidence rate of 49.32%.Test 2:This test establishes an accurate B-ultrasound classification method for COD of different types of cows through clinical symptom observation,rectal examination and B-ultrasound image.The test results show that the accuracy of identifying follicular cysts and corpus luteum cysts is improved based on the diameter,thickness,shape and location of the cysts in the B-ultrasound image.Test 3:This experiment studies the relationship between the biological characteristics of the organism and the COD of dairy cows.This test measures and analyzes serum hormones,biochemical indicators,minerals,and follicular fluid hormones.The test results showed that the concentration of E₂,BUN,P,ACTH in the serum and follicular fluid of cyst cows was significantly higher than that of normal cows and the difference was significant（P<0.05）.However,the concentrations of Gn RH,P₄,INS,IGF-1,GLU,and TP were significantly lower than those of normal dairy cows and the difference was significant（P<0.05）.Test 4:To study the differential expression of COD gonadotropin and steroid receptor genes in dairy cows.The test results showed that compared with normal follicles,the m RNA expression of LHCGR and ESR1 in follicular cyst follicles were up-regulated and the difference was significant（P<0.05）.The expressions of FSHR and CYP17A1 m RNA were all down-regulated and the difference was significant（P<0.05）.However,the expressions of LHCGR,ESR2,3β-HSD and STAR m RNA in luteal cyst follicles were all up-regulated and the difference was significant（P<0.05）.The expression of CYP17A1 m RNA was down-regulated and the difference was significant.In this experiment,CYP19A1 was down-regulated between cysts and normal follicles,but there was no significant difference（P>0.05）.Test 5:To study the COD regulation technology of cows,and use different exogenous reproductive hormones to carry out regulation experiments on the recovery of ovarian function in COD cows.The test results showed that the cure rates of follicular cysts and corpus luteal cysts were 56.76%and 68.19%,respectively,and the conception rates were 47.62%and 53.33%.Conclusion:The occurrence of COD in dairy cows is closely related to the season and parity.Hormonal disorders and endocrine disorders are one of the main factors that cause COD.Exogenous reproductive hormone regulation programs can increase the cure rate and conception rate of COD.