Study of Some Effective Factors on Reproductive Performance of Holstein Cows in Tehran and Alborz Provinces

Document Type : Other

Authors

1 Islamic Azad University, Varamin-Pishva Branch, Iran

2 College of Agriculture & Natural Resources, University of Tehran, Karaj , Iran

3 Head Embryo Transfer Group, Animal Breeding Center of Country, Karaj, Iran

Abstract

        This study was carried out to determined the reproductive performance (calving interval, days open) of Tehran and Alborz provinces Holstein Cows and some factors affecting it, while using 90824 records which were collected by Animal Breeding Center from years2001to2011.mean and standard error of calving interval 401/75±70/52 days, days open 123/31±59/86 days were estimated. The effect of herd, lactation number and milk yield on reproductive performance were significant (p<0.001). The effect of sex of calf on reproductive performance was not significant. The most and the least days open related to spring and autumn calving respectively. Days open increase from the fourth lactation number. Milk yield was increase from years 2001 to 2011. The relation between milk yield and reproductive performance to large extent was significant (p<0.001)  

Keywords

Journal of Animal Environment
Volume 7, Issue 3 - Serial Number 3
November 2015
Pages 29-32

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