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Feeding of Cactus to Sheep in times of Drought

GS Maré 

 

THE sheep-farming community in the more arid regions of our country have come more and more to realise that in order to tide them over periods of severe drought additional provision of stock feed must be made over and above what Nature provides.

Thus attention has naturally turned to plants which have great drought-resisting properties such as cactus and Australian Old man saltbush, both of which, but especially the spineless cactus, have been extensively established in different parts of the country.

 

Objects of the Experiments

Some of the immediate objects of the experiments carried out and which are here reported upon, were-

(a) to demonstrate the value of the wild variety of cactus as an emergency feed to sheep in times of drought;

(b) to determine the best and most economic method of preparing and feeding the cactus;

(c) to determine the quantity of additional feed required with the cactus (i) by dry sheep, (ii) by ewes rearing lambs;

(d) to ascertain the response of young sheep to a cactus ration.

The sheep used in the experiment consisted of Merinos, ewes and hamels, and Blackhead-Persian ewes. They ranged in ages from 2-tooth to old.

 

Salient Features of the Experiments

In March, 1927, seventy-one Merino hamels, 431 Merino ewes and 403 Persian ewes were transferred from Grootfontein to Graaff-Reinet. Subsequently, other 16 Merino hamels were sent.

The animals were immediately divided into the various experimental groups and placed on a cactus and lucerne-hay ration.

Unfortunately, the ewes were pregnant at the time of transfer and they commenced lambing shortly after arrival at Graaff-Reinet. The results were disastrous, only a small percentage of lambs reaching the weaning age, when they were transferred to Grootfontein. Receiving a ration of 12 ounces of chaffed lucerne-hay per day each, in addition to cactus prepared in four different ways, the ewes recovered remarkably after the lambs had been weaned, as is illustrated by the figures in Table 1:-

TABLE 1

 

Number of ewes mated

Nov – Dec 1927

Number of ewes lambed

Apr – May 1928

 

Percentage of lambs born

Merinos

Persians

386

378

287

341

74.4

90.0

 

It is well known that sheep will not show oestrus if they are low in vitality or under adverse feeding conditions. Since 74.4 percent of Merinos and 90 percent of Persians accepted the rams, it is evident that the flocks were in excellent health generally, and suffered no hardship.

By October, 1928, after the work had been in progress for 18 months, the position in regard to ewes and lambs was as follows:-

 

TABLE II

62 Merino ewes dead, i.e., 9.6 % per annum.

49 Persian ewes dead, i.e., 8.0 % per annum.

197 Merino lambs weaned, i.e., 51.0 %.

266 Persian lambs weaned, i.e., 71.3 %.

 

The Merino ewes cut just over 7 lb. of wool at 12 months' growth.

The disappointing feature in Table II is the high mortality in lambs during the period from birth to weaning, c.f. Table I.

At this stage of the experiment, two facts that had been established were (1) that the best results with spiny prickly pear are obtained by pulping the leaves and feeding them fresh to the sheep; and (2) that dry Merino sheep can be, successfully maintained on a cactus ration supplemented by 12 ounces of lucerne-hay.

 

Further Problems

Three other problems that now presented themselves were whether the supplementary feed could be reduced for the maintenance of dry sheep; whether lambs would grow normally on a cactus ration; and to what extent the ration of the ewe had to be increased during the lactation period to ensure an adequate milk supply.

It was, therefore, decided to continue the work for another 12 months, but on a much reduced scale.

Of the Merino ewes, 208 were retained at Graaff-Reinet, the balance together with the Persian ewes being transferred to Grootfontein. The lambs were also transferred, except for a representative 50 from each breed.

In regard to the lambs, a few general remarks must suffice: It was observed that although lambs born from the cactus-fed ewes were strong and healthy at birth and remained so for approximately a fortnight or three weeks, they increased slowly in live weight thereafter. The 100 lambs referred to above received liberal rations in conjunction with cactus for 1 months after weaning; they were transferred to Grootfontein in May, 1929, at the age of 12½ months (only one had died in these 7 months), when it was found that the lambs which had arrived at Grootfontein 7 months previously and had bee on good grazing for this period were 50 percent heavier than those fed at Graaff-Reinet.

It was definitely established that all the lambs transferred to good grazing recovered remarkably in a short space of time, but all attempts to stimulate normal growth on a cactus rations were futile.

For the period October, 1928 to October, 1929, the 208 Merino ewes received freshly pulped prickly pear and varying quantities of lucerne-hay, mealies and peanut meal according to the group into which they were placed. There were 4 groups of 52 each.

The supplementary feed in some of the groups proved inadequate, with the result that at mating time, November / December, 1928, the majority of ewes were in much lower condition than they were at the previous mating season. The group receiving 10 ounces of lucerne-hay as a supplement gave the best results.

The following Table gives the return for the lambing season under consideration :

TABLE III

Ewes mated

No. lambs born

Percent born

No of lambs reared

Percent reared

207

124

60.0

101

48.8

 

Just prior to and during the lactation period, the ewes received substantial increases in: supplementary feed. Also, as soon as the lambs would feed, arrangements were made in the paddocks for a separate supply of lucerne-hay for them.

This experiment was only a partial success. The ewes maintained their live weight during the lactation period, and in some groups a marked increase was observed. At shearing, they averaged 6 lb. of wool. The lambs, however, again failed to grow normally, their average live weight at the age of 5 months being 33.7 lb. For comparison, the following live weights of 5 months' old Merino lambs, reared on veld at Grootfontein, are given:-

In 1925, an excellent season, lambs weighed 45.0 lb.; in 1926, a poor season, lambs weighed 32.5 lb.

As far as the Merino hamels are concerned, they were fed in small groups, each group receiving corresponding rations to the larger groups of ewes. The losses in the case of the hamels amounted to 10.3 percent for the 2½ years.

The following table summarizes the losses and increases of sheep at Graaff-Reinet during the 2½ years:-

Table IV

 

Merino ewes

Merino hamels

Persian ewes

Merino lambs

Persian lambs

Transferred to Graaff-Reinet

Transferred from Graaff-Reinet

Deaths

Percent loss

431

346

85

19.5

87

78

9

10.3

403

354

49

12.2

-

294

117

28.5

-

265

76

22.3

 

In the above Table no account is taken of the initial lambing in March / April, 1921.

 

On the average Karoo farm under normal conditions, the returns as reflected in tables I, II and III above would be regarded as only a moderate success. The mortality in the ewes is high for normal conditions, and the yield of wool is rather low, whereas the percentage of lambs reared is disappointing. Under normal conditions, however, when a severe drought is in progress, the undertaking must be regarded as an unqualified success, especially from the humane point of view, for it is common knowledge that at various times farmers in drought stricken areas of South Africa have been obliged to kill all lambs at birth in order to give the mothers a better chance of surviving the adverse conditions. Statistics also reveal losses of 50 to 60 percent due to drought and exposure in several districts of the Cape Province during the year 1st August, 1921, to 31st July, 1928.

Considering the facts as set out above, and taking this experiment as the extreme of severity, the direct losses, which are below 15 percent over a period of 2½ years are not excessive.

No farmer will subject his stock to treatment as described above when grazing is available, nor will any farmer consider such a system of farming a profitable undertaking since the costs are prohibitive.

The experiment has, however, definitely proved that in case of emergency the farmer can with success resort to the feeding of spiny cactus.

It becomes clear, therefore, that in practice excellent use may be made of the prickly pear as an emergency ration if judiciously fed. If given in sufficient quantity, the problem of water, which is often most acute during droughts, becomes solved.

 

Published

Farming in South Africa 6