Duration of economic use of cows with different somatic cells concentrations in milk during the first lactation

Petrozavodsk State University, 33, Lenin Str., Petrozavodsk, 185910, Russia

^* Corresponding author: kafedrazoo@mail.ru

Abstract

The work investigated the relationship between lifetime productivity, age and reasons for culling of Ayrshire cows with different levels of somatic cell count in milk during the first lactation. The study established the influence of high concentration of somatic cells in the milk of first-calf heifers on average per lactation on lifelong milk yield and the age of culling. It was revealed that heifers with an average somatic cell content of less than 300 thousand/mL in milk reached the age of highest productivity. At higher values, maximum culling was observed in the 1st– 2nd lactation. We obtained positive repeatability of the number of somatic cells in adjacent lactations. A study of the main reasons for the culling of cows with different numbers of somatic cells in milk showed that with a very high cell content, limb diseases and gynaecological diseases are most common. It has been substantiated that the prevention of udder diseases at the early stages of lactation contributes to a longer productive life of cows.