[Hematological indices in cows in asymptomatic stage of leucosis process]
2008
Smirnov, Yu.P. | Suvorova, I.L., Research and Development Veterinary Inst. of Nonchernozem Zone of Russian Federation, Nizhnij Novgorod (Russian Fedeartion)
At bovine leucosis-affected farms the influence of bovine leukemia virus on the content of lymphocytes, basophiles, and segmented neutrophils in blood in seronegative and seropositive animals at the asymptomatic stage (AS) of leukemia was studied. In healthy positive cows compared to conventionally healthy in the asymptomatic stage the content of lymphocytes (68.0%) and basophiles (0.19%) increased with segmented neutrophils (SN) reduced up to 20.5% saying about active impact of bovine leucosis virus on neutrophils in bone marrow, as well as chronic myeloleukemia. As is found the asymptomatic stage in seropositive cows at the age of 2.5-4-years runs more intensively (lymphocytes – 71.0%, leucocytes – 7.2%, segmented neutrophils – 18.7%) than animals at the age of 6-10 years (lymphocytes – 66.0%, leucocytes – 6.0%, segmented neutrophils – 22.5%). It is suggested that this should be associated with animal infection in antenatal life or early postnatal period at the background of immature immune system. An analysis of the content of lymphocytes with regard to reducing the number of SN in the leucogram of AS cows has shown that in the same number of leucocytes (6.5 thousand) a real relationship between increasing lymphocytes and reducing the number of SN is observed: 73.0% with the SN content less than 20% and 53% - with greater than 30%. This also confirms more intensive development of leucosis process in seropositive cows at AS of leucosis with the number of SN less than 20%. It is concluded that the animals with such parameters should be culled prior to the beginning of hematological and tumoral stages in order to obtain ecologically safe products
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