Text 7. Live Stock Improvement

The business of the breeder who sets out to improve his herd rather than merely to multiply it is to build up a certain combination of valuable hereditary characters – that is, to produce a good type of animal that will breed true to its good qualities. Obviously the first essential is a definite object, a clearly conceived ideal type. Our ideal animal should be that which will convert its food into meat or wool, milk, or work, as the case may be, with a maximum efficiency.

In certain cases it is easy to devise a simple and direct test of economic worth. It is so, for example, in the case of milk or of wool production because it is possible in both instances to determine both the yield and quality of the product and to take such determinations as a basis for selection. The usefulness of a work animal is more difficult to assess, because no final judgement can be reached until the end of its working life. With meat-producing animals, again, no complete or definite information can be obtained on such important points as the quality of the meat, or the proportion of carcass to offal, until the animal has been slaughtered. In general, however, any direct test is preferable to a mere inference based on the animals outward appearance, and there is an increasing tendency to apply such direct tests wherever possible. The efficiency of the animal in converting food into meat can be expressed as a ratio between its weight increment and its food consumption. Even on such a matter as the quality of the meat of a breeding animal, inferences can be drawn with some degree of certainty if a few of its litter brethren or its progeny be fattened and slaughtered.

It is important to note that improvement implies the closer adaptation of the animal to the environment in which it is expected to live, and that a breed or strain that has been improved in relation to one type of environment may have been less well adapted to another. For example, the type of sheep that has been bred for lowland conditions, which grows and fattens rapidly on abundant and nutritious food, lacks the agility of the mountain breeds to find its food on a mountain pasture, and its requirements for minerals to make bone, and for protein to make flesh, are so high that it cannot collect the necessary supplies of these nutrients from the poor herbage and hence its growth is stunted. As another example, the bacon type of pig which is intended to produce a lean carcass with the least possible consumption of food. If food is restricted in the early stages the development of lean tissue will be inhibited, and heavy feeding at a later stage will result in a large development of fat, so that the final product will not be what is desired. The expression of the animal’s hereditary merits thus depends on the provision of appropriate living conditions. The initial step in the improvement of each breed by one breeder after another, has been to collect a herd or flock of the best individuals of the local type, and so to get possession of all the qualities that it was deemed advisable to perpetuate in the improved breed.

Having started on a basis sufficiently wide to ensure the inclusion of all the characters desired, the breeder proceeds, by successive matings and selection of the progeny, to weed out undesirable characters, and to combine the good qualities first in an individual or two and finally in a true-breeding strain. This process has never been carried out to the point of complete or final success, yet so much progress has been made that it is important to survey the methods by which it has been achieved.

Лексические упражнения.

1. Выучите значение опорных слов:

to set out – намериваться; to multiply – приумножать; quality – качество, черта; definite – определенный; to convert into – превращать в; efficient – эффективный; carcass – (зд.) туша, убойный вес; offal – внутренности, требуха; slaughter – забивать (животное); in general – в общем; appearance – внешность; environment – окружающая среда; to supply – обеспечивать; to resist – сопротивляться; consumption of food – потребление пищи; hereditary merit – наследуемое качество; litter brethren – выводок; progeny –потомок; to stunt – замедлять(ся); initial step – первый шаг; provision – обеспечение; appropriate – подходящий, пригодный; condition – условие; to combine – совмещать; to weed out – (зд.) удалять, избавляться; point – пункт; success – успех.

2. Определите, к какой части речи относятся следующие слова:

hereditary, efficiency, usefulness, inference, certainity, abundant, agility, possession, sufficienty, inclusion, undesirable.

3. Образуйте существительные от следующих глаголов:

to produce, to select, to judge, to determine, to combine, to consume, to improve, to require, to intend, to restrict.

4. Заполните пропуски соответствующими предлогами.

1. Ideal animal will convert its food into meat or wool, or milk … a maximum efficiency.

2. … certain cases it is easy to devise a simple and direct test … economic worth.

3. The efficiency … the animal … converting food … meat can be expressed as a ratio between its weight increment and its food consumption.

4. When we speak … a highly productive dairy cow we really have … mind a type of animal that is capable … converting a large supply … nutrients … milk.

5. Ответьте на следующие вопросы:

1. Why is the usefulness of a work animal difficult to assess?

2. How can the efficiency of the animal in converting food into meat be expressed?

3. What is the bacon type of pig intended to produce?

4. What does the expression of the animal’s hereditary merits depend on?

5. What type of animal is capable of converting a large supply of nutrients into milk?

Грамматические упражнения.

1. Переведите на русский язык следующие предложения и определите их синтаксическую структуру и типы придаточных предложений:

1. The usefulness of a work animal is more difficult to assess, because no final judgement can be reached until the end of its working life.

2. The type of sheep that has been bred for lowland conditions, which grows and fattens rapidly on abundant and nutritious food, lacks the agility of the mountain breeds to find its food on a mountain pasture, and its requirements for minerals to make bone are so high that it cannot collect the necessary supplies of these nutrients from the poor herbage and hence its growth is stunted.

2. Переведите на русский язык следующее предложение и определите функцию выделенных слов:

Having started on a basis sufficiently wide to ensure the inclusion of all the characters desired, the breeder proceeds, by successive matings and selection of the progeny, to weed out undesirable characters, and to combine the good qualities first in an individual or two and finally in a true-breeding strain.

Упражнения для закрепления пройденного материала.