استاذ مساعد .
أحمد داوود إسماعيل احمد
Effect of Management Practices during Transition Period on Performance of Dairy Cattle
Effect of Management Practices during Transition Period on Performance of Dairy Cattle In this study 7956 dairy records of six Holstein Friesian farms were collected. Dairy cows were allocated in three main transition systems (TS I, TS II, and TS III) according to their management practice during their transition phase. In each transition system, dairy cattle were divided according to their body condition score into three groups. Low, medium and over condition (BCS values were 2-3; 3-4, and 4-5, respectively). Also, dairy cows were grouped into 4 groups according to length of days dry into short, medium, long, and very long dry period length (<30; 30-45; 45-60, and >60 days, respectively). Moreover, the dairy cows regrouped according to their lactation parity into 3 main groups, as dairy cattle were allocated into 1st; 2nd, and 3rd for lactation parity of 2-3; 4-5, and >5, respectively. Furthermore, different calving season of each cow was recorded and then dairy cows were allocated into 4 groups according to different calving seasons summer, fall, winter, and spring. The results of the experiments revealed that: TS I with periodical estimation and adjustment of BCS and efficient pre and post milking hygiene produced high dairy performance parameters and udder health condition (low SCC and SCS). Also, medium condition score cows produced milk as much as over condition score cows; however it improved udder health, reproductive parameters as well as decreased lameness, milk fever and ketosis affections among dairy Holstein transition systems. Medium days dry cows produced more milk and improved dairy performance as the same as those of long and very long days dry, unless it improved dairy cattle udder health as well as reproductive parameters (days to fist estrus and days open) especially in TS II. Moreover, both 1st (2-3 lactation parity) and 2nd (4-5 lactation parity) parity groups improved dairy cattle productive performance however it increased days to fist estrus and days open. Fall calving Holstein cows produced high milk yield performance on 305 and total milk yield bases compared with other dairy Holstein calved in different viii calving seasons. Fall and winter calving cows produced much milk as well as improved dairy cattle reproductive performance, as theses cattle decreased days to first estrus and days open values than those calved during summer and spring seasons.
، العدد .
Effect of Management Practices during Transition Period on Performance of Dairy Cattle,Transition Period,Dairy Cattle Performance
أحمد داوود إسماعيل احمد
الرعاية و تنمية الثروة الحيوانية، كلية الطب البيطرى
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