| Dairy cow Laminitis can cause lameness,decrease milk production and reproductive performance,lead to solar hemorrhage/ulcers,white line disease,deformed hoof and other hoof diseases in dairy cows,causing huge economic losses.It is recognized as one of four major diseases of dairy cows.According to the characteristics of the disease,dairy cow laminitis can be divided into(sub)-acute,subclinical and chronic types,but the latter two are more common.In clinical practice,because dairy cows slowly respond to pain and the site of this disease is in the hoof capsule,early detection and accurate diagnosis of the disease are very difficult.In scientific studies,it has been confirmed that dairy cow laminitis is the hoof manifestation of systemic metabolic disorders.Numerous studies have explored the pathogenesis of the disease from the perspective of energy metabolism.The related study found that: laminitic dairy cows have obvious free fatty acid(FFA)metabolism disorders,and it is earlier than the lipid metabolism,and a variety of FFAs are involved in the occurrence and development of dairy cow laminitis.Related scholars proposed that specific FFAs may be the potential early diagnosis markers or effective treatment targets.But at present,the changes of FFA in different types of dairy cow laminitis are not clear.Based on this,this study screened dairy cows of subclinical laminitis and chronic laminitis,and detected changes in the types and levels of serum FFA,aiming to provide a valuable theoretical basis for the early diagnosis of dairy cow laminitis.According to the clinical diagnostic criteria of dairy cow laminitis,a healthy control group(CON),a subclinical laminitis group(SCL)and a chronic laminitis group(CL)were set up,each with 15 heads,a total of 45 heads.At the same time every day(from 8 am to 10 am),jugular vein blood was collected,and after the serum was separated,the serum triglycerides(TG),total cholesterol(CHO)and high-density lipoprotein(HDL)and low-density lipoprotein(LDL)were detected by an automatic biochemical analyzer;Gas chromatography-mass spectrometry was used to detect the type and content of serum FFA of dairy cows in each group.The experimental results found:(1)Determination of serum lipid metabolism parameters content in dairy cows with subclinical and chronic laminitis: CL compared with CON,the serum TG content was significantly increased(P < 0.05);the serum HDL content was significantly reduced(P < 0.05);there was no significant difference between the serum content of CHO and LDL(P > 0.05).CL compared with SCL,the serum TG content was significantly increased(P < 0.05);there was no significant difference in the serum contents of CHO,HDL and LDL(P > 0.05).Compared with CON,SCL had no significant difference in serum levels of TG,CHO,HDL and LDL(P > 0.05).(2)Determination of the types and content of serum FFA in dairy cows with subclinical and chronic laminitis: CON,SCL and CL all detected 18 identical FFAs.CL compared with CON,the levels of serum hexadecenoic acid(C16:1ω7)and heptatetraenoic acid(C17:4)were significantly increased(P < 0.05);N-pentadecanoic acid(C15:0),n-hexadecanoic acid(C16:0),octadecadienoic acid(C18: 2),n-octadecanoic acid(C18:0),eicosatetraenoic acid(C20: 4ω5,8,11,14),eicosatrienoic acid(C20: 3)and docosatetraenoic acid(C22: 4)serum levels were significantly reduced(P < 0.05).CL compared with SCL,the content of serum stearidonic acid(C18:1ω13)was significantly reduced(P < 0.05).SCL compared with CON,the serum levels of hexadecenoic acid(C16:1ω7)and hexadecenoic acid(C16:1ω9)were significantly increased(P < 0.05);serum levels of heptatetraenoic acid(C17: 4)was extremely increased(P < 0.01).In summary,the conclusion as follows:(1)Both subclinical and chronic laminitic dairy cows have lipid metabolism and free fatty acid metabolism disorders,both are closely related to the occurrence and development of laminitis in dairy cows.(2)When subclinical and chronic laminitic dairy cows have lipid metabolism disorders,and dairy cows with chronic laminitis have more serious disorders,serum triglyceride content can be used as an alternative parameters for differential diagnosis of the two.(3)When subclinical and chronic laminitic dairy cows have disordered free fatty acid metabolism,and dairy cows with chronic laminitis have more serious disorders,helicanoic acid and heptadectetraenoic acid are involved in the occurrence and development of laminitis in dairy cows,serum stearidonic acid content can be used as an alternative parameters for differential diagnosis of the two. |
