نوع مقاله : مقاله پژوهشی
نویسندگان
1 گروه علوم دامی، پژوهشکده کشاورزی، سازمان پژوهش های علمی و صنعتی ایران-تهران،ایران
2 دانشیار گروه علوم دام و طیور پردیس ابوریحان، دانشگاه تهران، تهران، ایران
3 گروه علوم دامی، پژوهشکده کشاورزی ، سازمان پژوهش های علمی و صنعتی ایران تهران، ایران
چکیده
کلیدواژه‌ها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
Introduction: Since cow culling is one of the main economic aspects in large industrial cattle farms, we decided to study the main removal or death reasons which can help determine management problems in herds. Removal is typically divided into two types, optional and non-optional (mandatory cull) where economic losses differ in these two types.
Materials and Methods: The data of culled cows from 20 industrial mega dairy farms (Holstein Frisian cows) located in 14 provinces in Iran during the last 15 years (2006-2020), belonging to 112096 culled cows were analyzed by T-Student methods of SAS software version 9.1.
Results and Discussion: The average herd size was 2069 Holstein-Frisian cows (max: 5301, min: 400 cows) and the annual culling rate of dairy cows was 23.5%. The main reasons for culling were fertility problems and abortion (21.3%), metabolic and digestive disorders (19.0%), and infectious diseases (14.0%). The data Analysis showed that fertility problems and abortion decreased from 21.7% in 2015 to 20% in 2019 (P<0.05). The Mobility problems (P<0.01), infectious diseases (P<0.01), and mammary system problems (P<0.01) in 2019 are lower than the average of 15 years. It can be concluded that by controlling infectious diseases and improving management, the life span of livestock has increased significantly which has led to farm's economic improvement too. Also, the optional removal of cows has helped the farmers have a proper intensity of breeding selection which led to excellent genetic gain too.
کلیدواژه‌ها [English]
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