Last update: April 3, 2012 10:52:55 AM E-mail Print

 

THE FEEDING OF MERINO SHEEP

F. C. Hayward and P. J. Zeeman 

 

The Merino sheep in South Africa is run for the most part on natural grazing and veld grazing is often its only source of food. The optimal use of veld grazing remains the most economic way of providing food for animals. However, there is the problem that the nutritive value of the grazing and consequently the productive capacity of sheep vary during the changing seasons of the year. In years of normal distribution of rain we find that veld production records a peak in the summer months and a trough in the winter and early spring.

The usable production potential of natural grazing and the feeding requirements of a Merino ewe are seasonal. The inference to be drawn here is, inter alia, that if ewes are mated in the autumn, when the greatest sexual activity occurs in Merinos, the production potential of the grazing is at its lowest when the nutritional needs of the ewe are greatest. The grazing's production potential at any given point of time will therefore determine the extent to which it can satisfy the feeding requirements of the ewe at that stage.

The most critical stages of the ewe are:

(a) At mating time (stimulative feeding); and

(b) During late pregnancy and early lactation.

 

Stimulative feeding

Stimulative feeding may be defined as the provision of an improved ration to ewes in weak to fair condition two to three weeks before mating is to take place. This ensures that the ewe will be in the process of increasing her mass and will therefore conceive more readily. Stimulative feeding has no effect worth mentioning, however on the reproduction of ewes in good condition.

When an autumn mating-season is put to use, it can be clearly deduced that under normal conditions the usable production of natural grazing is such that it is unnecessary to provide stimulative feeding. When, however, the ewes are in poor condition just before mating time, energy-rich licks can be used to advantage provided enough roughage is still available in the grazing. This practice is especially applicable to a spring mating-arrangement when veld grazing is fairly poor.

 

Feeding during late pregnancy and early lactation

The feeding of the ewe for the last four to six weeks of pregnancy and the first four to six weeks of lactation is particularly important. The last six-week period of pregnancy sees the foetus increasing rapidly in size; the feeding needs of the ewe also grow in consequence and come to a climax about four weeks after she has lambed. The ewe's feeding during the last six weeks of pregnancy determines the viability of the lamb immediately after birth. For instance, it has been found that the post-birth growth-tempo is bound up with the mass of the lamb at birth. The larger the birth mass, the faster the subsequent rate of growth. Feeding at this time also determines the ewe’s capacity for milk production. Underfeeding during the late pregnancy and early lactation thus delays and hampers the lamb's rate of growth, adult wool production capacity and body mass as well as the attainment of puberty.

As previously noted, natural grazing is the cheapest source of feeding and it will pay to have reserve veld available at the times when the ewe's feeding requirements are higher. These periods are the times, as well, when supplementary feeding in the form of energy and protein licks can be applied to greatest advantage.

 

Examples of the composition of these licks are given in Table 1.

Examples of protein and energy licks (composition in mass units)

Kind of food

Lick No.

1

Lick No

2

Lick No

3

Lick No

4

Lick No

5

Yellow maize meal

Phosphate

Salt

Molasses

Lucerne meal

Fish or ground nut oil cake meal

Urea

Intake/ewe/day (gm)

65

10

15

10

-

-

 

-

200

30

10

15

10

35

-

 

-

200

50

10

15

10

-

15

 

-

200

60

10

15

10

-

-

 

5

200

50

10

15

10

-

10

 

5

200

 

When the grazing consists mostly of dry grass, licks numbers III, IV and V are recommended whereas licks numbers I and II are recommended for use chiefly in the case of shrubveld. The most important aspect of these licks is that their intake must be controlled and, if necessary, that must be done with the salt concentration. If the intake per sheep, per day is too high more salt must be added and vice versa.

When urea is added to licks it becomes necessary to take certain precautions, as it can be poisonous when taken in excess at once. The following points need special attention:

(a) Ensure that the urea is evenly mixed with the rest of the components.

(b) Prevent excessive intake resulting from a possible craving for salt, which the animals may feel.

(c) Take care that rain does not wet the lick and form pools in it. Urea is highly soluble in water and should the animals drink this water fatal results could ensue.

 

The feeding of rams

The needs of rams of all age groups in regard to feeding matter are greater than those of ewes mainly because they grow faster than ewes and therefore have a larger body mass. This aspect is generally recognised and there is a common tendency to overfeed rams. To ensure that they perform their function effectively they must re m good condition but not overfat.

Thus depending on the condition of the rams the feeding of flock rams can be improved as from six weeks before the mating season by supplementing grazing of good quality with food concentrate. If good grazing is not available a legume hay of good quality, such as lucerne hay should be made freely available.

In practice it amounts to this that the rams graze by day and are stalled at night, the food concentrate being available then. An appetizing food concentrate suitable for all age groups can be made up, as below:

2 parts of mealies;

2 parts of rolled oats;

1 part of wheat bran.

 

To every 100 parts of the above mixture 0,5 parts of bone meal and 0,5 parts of salt may be added. The quantity of food concentrate, which each ram receives, is determined by its body-mass and the following serves as a direction:

Body-mass (kg)

Concentrate (gm/day)

-27

27-36

45-54

54-64

64 and more

110

230

340

450

570

680-900

 

Published

Merino Breeders Journal 38 (2)