The Investigation of Main Pathogens Causing Dairy Cattle Recessive Mastitis in Eastern Hebei

[Objective]This paper aimed to determine the main pathogens causing dairy cattle recessive mastitis in eastern Hebei and provide certain reference for local veterinarians and cow farmers to prevent and cure the disease.[Method]512 cows from 5 different farms in eastern Hebei were selected,and LMT,milk ph test and somatic cell direct counting methods were combined and used to conduct recessive mastitis＇ s epidemiological investigation,as well as isolate and identify the pethogens.[Result]The results indicated that the incidence of recessive mastitis is 60.7%（311 / 512）,bacteria isolation rate reached 87.8%（273 /311）.Total 81 isolates,belonging to 3 classes and 5 types were identified in milk samples of positive milk area from 273 cows with recessive mastitis.Among which,19 isolates were Streptococcus,accounting for 23.45%.Staphylococcus had 31 isolates,accounting for 38.27%.Enterobacter had 3,accounting for 3.7%.Other unshaped had 28 isolates,accounting for 34.6%.[Conclusion] The main pathogens caused dairy cattle recessive mastitis in eastern Hebei were Streptococcus agalactiae and Staphylococcus aureus.

Novel SNPs in IL-17F and IL-17A genes associated with somatic cell count in Chinese Holstein and Inner-Mongolia Sanhe cattle

Background： Bovine mastitis is the most common and costly disease of lactating cattle worldwide. Apart from milk somatic cell count（SCC） and somatic cell score（SCS）, serum cytokines such as interleukin-17（IL-17） and interleukin-4（IL-4） may also be potential indicators for bovine mastitis. The present study was designed to investigate the effects of single nucleotide polymorphisms（SNPs） in bovine IL-17 F and IL-17 A genes on SCC, SCS and serum cytokines in Chinese Holstein and Inner-Mongolia Sanhe cattle, and to compare the m RNA expression variations of the cows with different genotypes.Results： A total of 464 lactating cows（337 Holstein and 127 Inner-Mongolia Sanhe cattle） were screened for SNPs identification and the data were analyzed using fixed effects of herd, parity, season and year of calving by general linear model procedure. The results revealed that SNP g.24392436 C ＆gt; T in IL-17 F and SNP g.24345410 A ＆gt; G in IL-17 A showed significant effects on SCC and IL-4 in Holstein（n = 337） and on IL-17 and IL-4 in Sanhe cattle（n = 127）. The homozygous GG genotype of SNP g.24345410 A ＆gt; G had significantly higher m RNA expression compared with the heterozygous AG genotype.Conclusions： The results indicate that IL-17 F and IL-17 A could be powerful candidate genes of mastitis resistance and the significant SNPs might be useful genetic markers against mastitis in both dairy and dual purpose cattle.