Effects of Crossbreeding on Reproductive Performance of Dairy Cattle
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چکیده
منابع مشابه
the effects of planning on accuracy and complexity of iranian efl students’ written narrative task performance
this study compared the different effects of form-focused guided planning vs. meaning-focused guided planning on iranian pre-intermediate students’ task performance. the study lasted for three weeks and concentrated on eight english structures. forty five pre-intermediate iranian students were randomly assigned to three groups of guided planning focus-on-form group (gpfg), guided planning focus...
15 صفحه اولthe effects of time planning and task complexity on accuracy of narrative task performance
هدف اصلی این تحقیق بررسی تاثیر برنامه ریزی زمانی، هم چنین افزایش میزان پیچیدگی تکالیف در نظر گرفته شده بصورت همزمان، بر دقت و صحت و پیچیدگی عملکرد نوشتاری زبان آموزان می باشد. بدین منظور، 50 نفر از دانش آموزان دختر در رده ی سنی 16 الی 18 سال به عنوان شرکت کنندگان در این زمینه ی تحقیق در نظر گرفته شدند و به دو گروه آزمایشی و کنترل بصورت اتفاقی تقسیم شدند. اعضای گروه آزمایشی هر دو تکلیف ساده و پی...
Grading and rotational crossbreeding of beef cattle. I. Reproductive performance.
Purebred Angus (A), Polled Hereford (PH) and Santa Gertrudis (SG) bulls were mated to grades, two-breed and three-breed rotational crosses of these breeds (seven herds) to produce three generations (G1, G2 and G3) of calves. The grade A and PH cows were higher in A and PH breeding, respectively, than grade SG cows were in SG breeding. Reproductive performance among grade and rotational-cross he...
متن کاملImproving Dairy Cattle Reproductive Performance
• A calving interval of 13.5 months is an achievable goal that will produce higher daily milk yield and higher milk yield over the length of the lactation. To achieve this goal average days to first service should be <80, yearly 21-day Pregnancy Rates should average >20% and culling for reproductive failure should not exceed 10%. • Management must set standard operating procedures for all aspec...
متن کاملEffect of Metabolic Stress on Ovarian Activity and Reproductive Performance of Dairy Cattle: A Review
Reproductive efficiency in dairy cattle has been decreased over the last 5 decades despite significant gains in genetic selection, improved reproductive technologies and nutritional care. In high-yielding dairy cattle, the negative energy balance (NEB) during the first week post-partum adversely affects ovarian activity, mainly follicle growth and steroidogenesis. Circulating levels of non-este...
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ژورنال
عنوان ژورنال: Journal of Dairy Science
سال: 1961
ISSN: 0022-0302
DOI: 10.3168/jds.s0022-0302(61)90019-4