Investigation Of The Occurrence Status Of Hoof Disease Of Dairy Cow In A Large-scale Pasture And The Study Of Pathogenic Factors

Hoof disease is one of the three major diseases of dairy cow,which has a negative impact on milk production,reproductive performance and treatment costs,hindering the healthy development of dairy farming.At present,there are few studies on the occurrence of hoof disease in a large-scale pasture in southern China.In this study,a large-scale pasture in Jiangsu Province was selected to statistically analyze hoof diseases and related risk factors of lactating cows.By detecting the changes of serum and hoof hominess mineral content,serum oxidation,antioxidant indexes and endotoxin content in dairy cows,the pathogenesis of hoof disease is further explored.In order to improve the level of pasture feeding management,prevent and control hoof disease of dairy cow,it provides a theoretical reference.1.Investigation of the current status of hoof disease of dairy cow in a large-scale pastureThe current situation of hoof disease in lactating cows in a large-scale pasture in Jiangsu Province during July to November 2022 was investigated.and it was found that a total of 1719 dairy cows suffered from hoof disease,and 9 hoof diseases were occurred in the pasture,among which Digital dermatitis had the highest incidence,accounting for 56.8%of all hoof diseases.The average monthly in cidence of hoof disease in this pasture was 10.74%,with the highest incidence in August(17.69%).The incidence of hind hooves was significantly higher than that of anterior hooves(p<0.001),that of medial claws of anterior hooves was significantly higher than that of lateral claws(p<0.001),and that of lateral claws of hind hooves was significantly higher than that of medial claws(p<0.001).The incidence of hoof disease increased with the age of dairy cows,with the highest incidence of hoof disease in dairy cows older than 8 years old.The incidence of hoof disease in 4 and 5 parity was significantly higher than that in dairy cows of other parities(p<0.001).The incidence of hoof disease in dairy cows was concentrated within 30 days of lactation,and the incidence of hoof disease increased with the increase of milk production.Linear regression was used to analyze the risk factors of hoof disease,and the results showed that temperature and humidity index,stall use index,lameness and hock injury were the risk factors for hoof disease(p<0.05),among which hock injury was the most important risk factor for hoof disease in this pasture.Compared with the healthy group,dairy cows with Sole ulcers,Toe ulcers and Laminitis had significantly lower hardness in hoof hominess in apex of the sole(p<0.01).Analysis by 16S rRNA gene sequencing showed that Porphyromonas,Fusobacterium,Treponema and Bacteroides were abundant in Sole ulcers,Toe ulcers,White line disease,Digital dermatitis and Foot rot.The above results showed that the incidence of hoof disease in dairy cows in the large-scale pasture was high,there were many types of hoof disease,and a variety of factors were related to hoof disease.2.Study on the relationship between hoof disease and mineral elements and oxidative stress in dairy cowsAccording to the principle of similar age,parity and lactation period,20 dairy cows without hoof disease were selected as the healthy group,20 dairy cows with Digital dermatitis,White line disease,Sole ulcers and Toe ulcers were selected,and the lameness score was≥3 points as different types of hoof disease group.Compared with the healthy group,the contents of Cu,Zn,Mn and Se in the serum of dairy cows with hoof disease were significantly reduced(p<0.01),the content of Fe was significantly or very significantly increased(p<0.05 or p<0.01),the content of P was significantly increased(p<0.01),and the contents of Ca,Mg and Mo were not significantly changed.Compared with the healthy group,the content of Cr in the serum of dairy cows with White line disease,Sole ulcers and Toe ulcers was significantly reduced(p<0.01).Compared with the healthy group,the contents of Cu,Zn and Mn of hoof hominess in dairy cows with hoof disease were significantly reduced(p<0.01),and the contents of Mg and Fe were not significantly changed.Compared with the healthy group,the content of Ca in hoof hominess in dairy cows with White line disease,Sole ulcers and Toe ulcers was significantly reduced(p<0.01)and the content of P was significantly increased(p<0.01).Compared with the healthy group,the activities of T-AOC,CAT,SOD and GPX in serum of dairy cows with hoof disease were significantly reduced(p<0.01),the content of MDA was significantly increased(p<0.01),and the content of endotoxin in serum was significantly increased(p<0.01).The above results showed that the changes of mineral elements,the imbalance of antioxidant system and the increase of endotoxin levels in dairy cows were closely related to the occurrence and development of hoof disease.In summary,there was a high incidence of hoof disease and a variety of hoof diseases in the pasture.The occurrence of hoof disease was influenced by a variety of factors.Changes in mineral elements,imbalance of antioxidant system and increased endotoxin levels in dairy cows were closely related to the occurrence and development of hoof disease.