بقرة هولشتاين
بقرة هولشتاين Holstein cattle (وتعرف أيضا باسم بقرة هولشتاين-فريزيان أو بقرة فريزيان)، هي سلالة من الأبقار تشتهر بأنها من أعلى الحيوانات إنتاجا للحليب. في الأصل كانت تربى هولشتاين فيما يعرف حاليا بهولندا وبالتحديد في المقاطعات الشمالية شمال هولندا وفريزلاند. وكان هذا النوع من السلالات أبقار خاصة لقبيلتي باتاڤيان والفريزيان، واللتا استوطنتا في المنطقة الساحلية حول نهر الراين من 2000 سنة مضت.
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الخصائص الفيزيائية
التاريخ
المملكة المتحدة
الأعداد
التعريف
الانتاج
الولايات المتحدة
التاريخ
بقرة الرئاسة
الإنتاج
المورثات
الاستنساخ
البقرة الفريزيان البريطانية
While interest in increasing production through indexing and lifetime profit scores saw a huge increase in Holstein bloodlines in the UK, proponents of the traditional British Friesian did not see things that way and maintain that these criteria do not reflect the true profitability or the production of the Friesian cow.
Friesian breeders say that modern conditions in the UK, similar to the 50's through to the 80's, with low milk price and the need for extensive, low-cost systems for many farmers, may ultimately cause producers to re-examine the attributes of the British Friesian.
This animal came to dominate the UK dairy cow population during these years, with exports of stock and semen to many countries throughout the world. Although the idea of "dual-purpose" animals has arguably become outmoded, the fact remains that the Friesian is eminently suitable for many farms, particularly where grazing is a main feature of the system.
Proponents argue that Friesians last for more lactations through more robust conformation, thus spreading depreciation costs. There is the added advantage of income from the male calf, which can be placed into barley beef systems (finishing from eleven months) or steers taken on to finish at two years, on a cheap system of grass and silage. Very respectable grades can be obtained, commensurate with beef breeds, thereby providing extra income for the farm.
Such extensive, low cost systems may imply lower veterinary costs, through good fertility, resistance to lameness and a tendency to higher protein percentage and, therefore, higher milk price. An 800 kg Holstein has a higher daily maintenance energy requirement than the 650 kg Friesian.
Friesians have also been disadvantaged through the comparison of their type to a Holstein base. It is suggested that a separate "index" be composed to greater reflect the aspects of maintenance for body weight, protein percentage, longevity and calf value. National Milk Records (NMR) figures suggest that highest yields are achieved between the fifth and seventh lactations; if so, this is particularly so for Friesians, with a greater lift for mature cows, and sustained over more lactations. However, production index only takes the first five lactations into account. British Friesian breeding has certainly not stood still and, through studied evaluation, substantial gains in yield have been achieved without the loss of type.
التاريخ
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هولشتاين الحمراء والبيضاء
| R | r | |
| R | R R | R r |
| r | R r | r r |
الثور الأحمر rr is used on a carrier cow, Rr, then the Punnett square will give:
| r | r | |
| R | R r | R r |
| r | r r | r r |
| r | r | |
| R | R r | R r |
| R | R r | R r |
There is no chance of a red calf being born. There is, however, a 100% certainty that the calf will be a red carrier, Rr.
