Lepesheva, . A, Bolgov, . E MULTIPLE FACTORS OF EARLY EMBRYONIC LOSSES IN DAIRY COWS // Proceedings of Petrozavodsk State University. 2018. No 3 (172). DOI: 10.15393/uchz.art.2018.124


General Biology

MULTIPLE FACTORS OF EARLY EMBRYONIC LOSSES IN DAIRY COWS

Keywords:
embryo mortality
milk yield
productivity
insemination
cow		 Summary: The aim of the research was to study the factors of early embryo mortality (EEM) expansion and the ways of its minimization to determine the possibilities of maintaining cows’ productivity. About 4 thousand Ayrshire cows were studied. The influence of paratypical, physiological and hereditary factors on EEM was taken into account. An indirect method, based on the recording of durations between intervals of contiguous cow inseminations was used to register EEM. EEM was registered in 21,7 % cows with a high variation factor (39,5 %). The low level of EEM was observed in the cows with the first lactation (12,1 %), the highest level (27,3 %) wasregistered in old cows (seven lactations and more). The lowest level of EEM was registered in cows after the first insemination in 2,5–3,5 months after the first calving (10,8–7,4 %); the highest one – in 4 months and later (44,4 %; P < 0,01). Cows with higher dairy productivity are more susceptible to this abnormality: 12,3 % of the cows with 4 500 kg and less of the milk yield and 26,5 % of the cows with the milk yield over 7 000 kg. EEM is observed 1,7 times more in case of deficient feeding than in case of full feeding. The 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 the disease prevention and optimization of paratypic, physiological and hereditary factors.



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