Test№ 13 feeding of farm animals. Feeding dairy cows.

A cow`s food consists of concentrates and roughage. The concentrates are foods in which the nutritive energy is high in proportion to their weight and bulk, and they are from 75 to 100 percent digestible. In roughages , the nutritive energy is lower in proportion to weight , the digestibility being from 30 to 75 percent.

The concentrates consist of grains and highly digestible materials produced from grains , while roughages are whole plants ,with the exception of the roots. Pasture and silage are also usually included under the head of roughage. In numerous experiments with cattle , the nutritive properties of grain and hay have been studied by feeding each kind of food separately for long periods. Cattle can not be kept alive for more than a year or so on grain alone.

In order to keep high-producing cows in good health and obtain maximum milk production , one should feed them both hay and grain – the hay to provide some nutritive energy , but particularly certain nutritive essentials necessary to keep animals in good health ; the grain –to provide a large amount of nutritive energy in such concentrated form that the cows can consume and digest enough of it for heavy milk production.

Text № 14

Importance of hay for calves.

Since green-coloured , sun-cured hay is the richest source of vitamin D among common feeds and is also high in vitamin A , it is very important that calves have access to good hay as soon as they will eat it. At about 2 weeks of age a handful of such hay should therefore be placed each day where the calf can get it. Little will be eaten at first , but even this may be important in supplying needed vitamins and thus preventing rickets and other trouble.

As the calf grows and its paunch develops , more hay will be eaten ,until at 6 months of age it should be eating 3 to 5 lbs.a day. The best way to feed hay is in a rack. All uneaten hay should be removed daily and fed to other stock , for calves do not like hay which has been picked over.

From the standpoint of the amount of protein ,calcium, and vitamins A and D

supplied ,leafy, fine-stemmed legume hay is the best for calves. Sometimes young will eat so much of such hay that its laxative properties will cause them to scour. This can be avoided by limiting the amount or by starting them on mixd legume-and-grass hay.

In general ,the leafier the hay is, the higher will be its value for calves. Therefore second-cutting clover or alfalfa hay is preferred to the first cutting.

Text № 15 biology of bacteria.

Bacteria are remarkable for the extreme simplicity of their structure , the primitive and rapid method of their reproduction and distribution.

They are to be found practically everywhere in nature. The air over the sea and on mountain –tops is more free of bacteria than the air of towns .The air of inhabited buildings has a high bacteria content. The bulk of bacteria are saprophytes which live upon dead organic material of plants and animals. A comparatively small number have acquired the power of living as parasites on the bodies of living plants or animals and only some of these produce diseases , being termed pathogenic. Organisms are also to be found on the external surfaces of the body and in the mouth ,nose, alimentary canal etc., but these are usually harmless and are known as commensals. These commensals may , under certain circumstances ,e.g.lowered resistance ,injury ,etc.become pathogenic. Normally , the fluids and tissues of the body are bacteria-free.