Effects of Days Dry and Days Open on Holstein Milk Production
نویسندگان
چکیده
منابع مشابه
Genetic Relationship between Milk Production, Calving Ease and Days Open at First Parity in Holstein Cows
Data containing 14,188 lactation and reproductive records of Korean Holstein cows at first parity distributed across 3,734 herd-year-season groups were analyzed to get genetic (co)variance estimates for milk yield, fat yield, calving ease, and days open. Milk and Fat yields were adjusted to 305 d. Heritabilities and genetic correlations were estimated in two different animal models on which wer...
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The primary objective of this research was to determine if, with appropriate methodology, unbiased estimates of days dry (DD) effects on subsequent lactation milk yield can be obtained from field data, particularly when DD is correlated with cow effects. Another objective was to ascertain relevant sampling properties of designed trials for estimation of DD effects. Simulated records were used t...
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the objective of this study was to estimate genetic parameters coupled with genetic and phonotypic trends for age at first calving (afc), open days(od) and milk yield(my) of first lactation in iranian holstein cows. records of reproduction and production for genetic evaluation from 1984 to 2005 for afc, od and my were 71736, 20126 and 20126, respectively. single and two-variable animal models w...
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Effects of twinning on lactation and days open in Holsteins were studied from calving records compiled by member surveys of Eastern Artificial Insemination Cooperative. Records of cows with 305-day mature-equivalent records from the Northeast Dairy Records Processing Laboratory were grouped according to whether the twin calving was associated with dystocia. Records of each cow that had a twin c...
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پژوهش حاضر با هدف بررسی اثر جیره حاوی کربوهیدراتهای غیرالیافی زیاد و بروز التهاب در گاوهای شیرده در دو آزمایش جداگانه انجام شد. در آزمایش اول 20 رأس گاو مبتلا به ورم پستان از دو گروه کم تولید و پرتولید (هر کدام 10 رأس) و 20 رأس گاو سالم از دو گروه کم تولید و پرتولید (هر کدام 10 رأس) انتخاب شدند. همه گاوها در دوره دوم و یا سوم شیردهی و در روزهای 80-120 پس از زایش بودند. میانگین تولید شیر در گروه...
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ژورنال
عنوان ژورنال: Journal of Dairy Science
سال: 1972
ISSN: 0022-0302
DOI: 10.3168/jds.s0022-0302(72)85439-0