Influence of cows' milk productivity level on calving interval | Govju piena produktivitātes līmeņa ietekme uz starpatnešanās perioda ilgumu
2008
Jonkus, D., Latvia Univ. of Agriculture, Jelgava (Latvia). Faculty of Agriculture. Inst. of Agrobiotechnology | Kairisa, D., Latvia Univ. of Agriculture, Jelgava (Latvia). Faculty of Agriculture. Inst. of Agrobiotechnology
The aim of the investigation was to analyse the influence of cow's milk productivity on the length of the calving interval (CI) in dairy cows on the Training and Research Farm Vecauce of Latvia University of Agriculture, and to find out the optimum calving interval in cows of different productivity level. During the period of time from 2002 to 2007 974 cows were examined. The average age of cows was 2.6 lactations, and the average milk yield was 5489.2 kg per lactation with fat content 4.36 % and protein content 3.26 % that made 5667.1 kg of energy corrected milk (ECM). Milk productivity influenced the CI. In cows with 800 kg milk yield, a longer CI was observed, namely 503.6 days, while in cows with 5000 kg of milk yield CI was 369.9 (p is less than 0.05). In cows with the highest productivity level, the service period was longer – 221.9 days, and the number of insemination times were more (3.9) than in cows with a lower productivity level (p is less than 0.05). Evaluating indices of reproduction and productivity, it was stated that there is a positive correlation between ECM and IC (r=0.613) as well as ECM and service period (r=0.612, p is less than 0.01). The highest productivity of one IC day (24.9 kg) was in cows with IC up to 365 days.
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