问题 问答题 论述题

对肉用种禽为什么要进行限制饲养?限饲时应注意些什么?

答案

参考答案:

限饲的目的是控制营养的摄入,防止肉种鸡体内沉积过多的脂肪,使种鸡有一个正常的体型和适当的体重,以便生产更多的合格种蛋,而且限饲可节约大量的饲料,降低生产成本。

注意:

①应根据各品种类型制订切实可行的限饲计划。

②限制饲养前应将体重过大和体弱的鸡移出,按不同体重分级分圈饲养。

③限制饲养前必须进行断喙,防止发生啄癖。

④准确掌握每天的饲喂量。

⑤配置足够的食槽、饮水器、合理的鸡舍面积,使每只鸡都机会均等地采食、饮水和活动。

⑥限饲主要是限制能量饲料不使鸡过肥,而其它物质必须满足。

⑦限饲必须与舍内的光照管理相结合。

⑧经常观察鸡群动态,避免各种应激。

填空题
阅读理解

Imagine living in a city made of glass. No, this isn’t a fairy tale. If you could grab your diving gear and swim down 650 feet into the Pacific Ocean off the coast of Washington State, you would witness the secret world of glass reefs.

The reef you’d be looking at is made up of glass sponges(海绵). But how can animals be made of glass? Well, glass is formed from a substance called silica. The sponges use the silica found in ocean waters to build glass structures that will give them shape and support. Be careful! Some of the fragile creatures are up to 200 years old.

When sponges die, new ones grow on top of the pile of old ones. Over centuries, a massive and complex reef takes shape. Some sponges look like wrinkled trumpets, while others look like overgrown cauliflower or mushrooms.

Dr. Paul Johnson, who discovered the Washington reef in 2007, also found other surprises such as bubbles of methane(甲烷) gas flowing out of the seafloor nearby. The methane feeds bacteria, and the bacteria feed the glass sponges.

“It’s a new ecosystem we know nothing about,” said Dr. Johnson.

The reef of yellow and orange glass sponges is crowded with crabs, shrimp, starfish, worms, snails, and rockfish. The glass reef is also a nursery for the babies of many of these creatures and was called a “kindergarten” by scientists.

Many animals that live in the reef hang around for a long time, just like the sponges. Rockfish, for example, live for more than 100 years. Scientists are just beginning to study all the species that call the reef home.

The Washington coast isn’t the only place where a living glass reef has been found. The first was discovered in Hecate Strait off the coast of British Columbia in 1991. Scientists all over the world were stunned to see it.

小题1:Which of the following is the best title for the passage?

A.Man-made cities under the sea

B.The world under the sea

C.Glass “cities” under the sea

D.Creatures under the sea小题2:It can be learned that the glass reef _______.

A.is made up of a kind of materials called sponges

B.is a work of art made by some American scientists

C.is a new ecosystem people are not familiar with

D.was first discovered off the coast of Washington State小题3:Which of the following is TRUE according to the passage?

A.The sponges must feel soft.

B.Silica comes from animals’ body fluid.

C.Methane is harmful to glass sponges.

D.Glass sponges depend on the bacteria for a living.小题4:Why did scientists call the glass reef a “kindergarten”?

A.Because the babies of many sea creatures grow well there.

B.Because thousands of children visit it every year.

C.Because it is crowded with snails and rockfish, etc.

D.Because all the species call the reef home.小题5:What does the underlined word “stunned” in the last paragraph mean?

A.Greatly surprised.

B.Extremely scared.

C.Highly satisfied.

D.Very pleased.