Factors of early embryo mortality incidence in dairy cows

Petrozavodsk State University, Institute of Biology, Ecology and Agricultural technologies, 185910 Lenin str. 33, Petrozavodsk, Russia

^* Corresponding author: bolg@petrsu.ru

Abstract

Early embryo mortality (EEM) is considered to be one of the causes of dairy cows’ productivity reduction. The aim of the research was to study the factors of EEM expansion and the ways to its minimization in order to determine the possibilities of maintaining cows’ productivity. About 4 thousand Ayrshire cows were studied. EEM was registered in 21.7% cows. Low level of EEM was observed in first lactating cows (12.1%), the highest level (27.3%) was registered in old cows (seven lactations and more). Cows with higher productivity are more susceptible to this abnormality: 12.3% of cows with 4500 kg and less of milk yield and 26.5% of cows with milk yield of over 7000 kg. Less cases of embryo mortality are registered during spring and summer seasons of calving (12.0-16.3%) in comparison with autumn and winter ones (19.1-25.7). EEM is observed 1.7 times more in case of deficient feeding than in case of full feeding. Frequency of EEM varied from 5.6 to 44.4% in daughters of different bulls. It is possible to reduce the level of EEM in dairy cows by implementing complex measures of disease prevention and optimization of paratypic, physiological and hereditary factors.