نوع مقاله : سایر
نویسندگان
1 گروه علوم دامی، دانشکده کشاورزی، دانشگاه آزاد اسلامی واحد ورامین- پیشوا
2 گروه علوم دامی، پردیس کشاورزی و منابع طبیعی دانشگاه تهران، کرج، صندوق پستی: 4111
3 گروه انتقال جنین، مرکزاصلاح نژاد دام کشور، کرج، صندوق پستی: 936-31585
چکیده
کلیدواژهها
عنوان مقاله [English]
نویسندگان [English]
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)
کلیدواژهها [English]