Extended lactation in high-yielding dairy cows. I. Effects on reproductive measurements
نویسندگان
چکیده
منابع مشابه
Fertility in High Yielding Dairy Cows
Introduction Genetic progress coupled with improved nutritional management has resulted in many more cows that can produce over 8,500 litres per 305 day lactation. This upward trend in production over the past 30 years has been accompanied by a steady decline in fertility, with first service conception rates often falling below 40%. Over the same period, there have been considerable changes to ...
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Protection of the mammary gland against mastitis-causing pathogens is mediated by many factors in thegland and blood circulation. The professional phagocytic cells of bovine udder, polymorphonuclearneutrophils (PMN) and macrophages, comprise the first line of defense against invading mastitis pathogens.Most researchers now accept that the PMN is a key factor in the cows’ defense against intrama...
متن کاملPostpartum reproductive function: association with energy, metabolic and endocrine status in high yielding dairy cows.
This study evaluated the effect of metabolic, endocrine and energy status on onset of ovarian cycle, days open (DO), and conception at first service in 90 multiparous Holstein cows, housed at a research farm. Dry matter intake, milk yield and body weight were measured daily from Week 2 antepartum (a.p.) to Week 20 postpartum (p.p.). Milk composition was determined four times per week and milk a...
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Dairy cows have shown a steep increase in milk production, which is unfortunately characterized by a dramatic decline in reproductive performance. In these modern high yielding cows authors worldwide mention a higher number of puerperal problems, such as retained placenta, acute metritis and abnormal vaginal discharge. All of which are known to negatively influence reproductive capacity of thes...
متن کاملthe effects of high non fibrous carbohydrates diet on milk production, inflammation and molecular mechanism of innate immunity in lactating dairy cows
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: 2019
ISSN: 0022-0302
DOI: 10.3168/jds.2018-15115