BREEDING EWES.

Press, Volume LXVII, Issue 20224, 30 April 1931, Page 7

BREEDING EWES.

WINTER MANAGEMENT. CHAMBER OF COMMERCE BULLETIN. The monthly Agricultural Bulletin (No. 22) of the Canterbury Chamber of Commerce, prepared by Lincoln College, is on the subject of the winter management of breeding owes.. It is as follows: — The object of this bulletin is to oxplain some of the commoner controllable food factors that affect tbo health of breeding ewes, and consuquently the lambing percentage. Individual Variations in Sheep. If all sheep were alike in resarl to food productivity and constitution, many of the troubles of winter management would be overcome. Keseareh, however, has clearly shown that a wide range of variation exists among individuals of the . same breed, and that such variation becomes more apparent in a flock consisting of different .breeds. Tbo possession of certain peculiarities by. different individuals and different breeds constitutes individuality, and its widespread occurrence in a flock adds considerably to the problems of flock management. Their- elimination from a flock is a practical impossibility; but the culling out near lambing timo of ull ewes that do not appear to Lo doing well, and giving them a more adequate or suitablo food supply, is a prnctico worthy of greater consideration in flock management. - Condition of Ew.js. The following graph, illustrates flio reflection of tho food supply on the condition of properly aud improperlymapaged ewes duriug tho seven months prior to lambing:—

Iho graph shows that, disregarding tho irregularity at flushing time, there is, in the caso of healthy ewes, a gradual improvement in condition until lambing is complete. If, however, ewes are over-fat at mating time, the accomplishment of this procedure becomes very difficult when consideration is given to weather conditions and tho normally redueod winter food supply. Under natural conditions of flock managofiient the graph lino will alter according to the available food, as influenced by weather conditions. Under intensive sheep farming conditions any marked deviation in tho graph lino can generally bo minimised by modifying tho food supply and shelter.

Food Requirements of Breeding Ewes. 1. Prior to Mating.—The period between weaning and mating is usually characterised by marked iinpiovoiiicnt in the condition of owes, and when mating time is reached many ewes arc too fat. That too fat or too thin animals are bad breeders is common knowledge. Fewer owes return to the ram and a better percentage of lambs is obtained if ewes are lit, thriving, and active at flushing time. In the absence of a special flushing food, tho fit, thriving and active ewe will respond better to a change of pasture than tho very fat animal, and ewes should therefore not .be allowed to get too fat before flushing time. 2. During Flushing and Mating.— The practice of flushing ewes prior to and at mating tiruu principally depends upon tho stimulating effects .of good food on general body functions. It can be safely said that this, steam-' ing-up process is a practical means of getting tho maximum number of ewes in lamb, and the maximum number of lambs from each ewe. .Mushing, however, signifies not the fattening of ewes, but the stimulation of the development of heat in ewes, and tends to prevent a scattered lambing. In this connection it is worthy of note that a well-balanced food can only bring out the latent possibilities in an animal, and the beneficial results following the use of additional foods or minerals can only help the body jn so far as . they will stimulate it to work at its best. A luscious, succulent green food, such as good grass, clover, green oats, etc., gives the best stimulating effect on ewes coming off bare pasture, while ewes on luscious food may bo flushed by. changing to dry food.

Of more than passing importance in respect of the value of minerals on fecundity (i.e., the number of youi'g produced), is tho widespread belief among farmers and others that the addition of iodine to the food beneficially affects tho lambing percentage, irrespective of the iodine requirements of the animal body. Research in connection with this matter, nt present iD progress at the Canterbury Agricultural College, shows that even very small doses of iodine have a harmful effect upon fecundity. Tho attention of farmers who use iodino for ewes at mating timo without having regard to the iodine needs of the animal and the dose, is directed to the following table, •which sets out the results of mating iodine-dOsed and non-iodine-dosed ewes. The quantity of iodine, administered as potassium iodide solution once a week for approximately four months prior to mating, was equivalent to six-tenths of a grain of potassium iodide per ewe per day. This dose was chosen as being that sometimes used in the feeding of iodin.e to sheep.

Besults of Canterbury Agricultural College Experiment with lodine. lodino Non-lodine Ewes. Ewes. Ewes put to ram .. 48 44 Lambs produced ..41 45 Twins • ■ • .5 Dry ewes . • .. 9 4 Percentage of lambs produced .. .. 85 102 t The conclusions to be drawn from the results of the experiment above are: . ~ 1. That excess of iodine produces harmful effects, particularly at mating time. 2. That its beneficial effects on fecundity have not yet been demonstrated. 3. That farmers would be well artvised to cease using it unless goitre has been diagnosed in their animals.

4. That, if any iodine is necessary for sheep, the proper dose has Jiot yet been determined. 3., After Mating.—The practice of allowing in-lamb ewes all they will eat immediately aJter the rams are takan out is a wrong one, since the increasing needs of early pregnancy are not great. It is during this period fhat there are many failures in tho regulation of the food supply of in-lamb ewes. It is possible to given consideration to this point without interfering with the growth of wool. 4. Before Lambing.—lt is when the ewes are near lambing that 105533 most commonly encountered. If, howover, improvement iu condition is gradually maintained in tho flock, the only factor that is likely to i>e responsible for losses is bad weather. The effects of' unfavourable weather can be reduced if shelter is provide;! and hand feeding resorted to. Emphasis must be laid upon the nece.«ity for hand feeding during bad weather or inaccessibility of food, as veterinary research conducted at Canterbury Agricultural College shows that many of the losses during and following bid weather are associated, in the majority of cases, with varying periods of starvation or shortage of food, In-lamb ewes, particularly those carrying two or more big lambs, arc very susceptible to a check in the food supply during tho four to six weeks before lambing. During this period tho nature and bulkincss of the food, sudden changes of food, and need for exercise require consideration. Common Diseases of In-Lamb Ewes. 3. Ante-partum paralysis (dopiness).- —This is a nutritional disoase of heavy in-lamb ewes, characterised by .fatty changes affecting the livor, and not infrequently the kidneys, r.nd definitely associated in the majority of cases with ewes going back in condition as lambing time approaches. The affected animal • invariably carries two or more big lambs. Tin common symptoms ar« those of excitement, dullness, impaired vision, loss of fippe-

tite, impaired gait or lameness, weakness, paralysis, and death. Although the actual causo of this disease remains obscure, veterinary rosearch conducted at this College has evolved a practical method of prevention which can bo practised by tho majority of intensive sheepfarmcr*. Prevention. (a) Food.—Tho lower iino oi: ihe graph illustrates the condition of breeding ewes that remain healthy during the seven months prior to iarnbing. Tho fact, as illustrated by the upper line of tho graph, that "many ewes are in better condition at Hushing and mating time than at lambing time, is an all too common a causo of losses. Tho whole question of preventing ante-partuni' paralysis depends upon not only allowing ewes an adequate and suitable ration during tho latter part of the pregnancy period, but also regulating the foo:l supply in the early part. When gradual improvement in the condition of tho flock is being maintained during t.hu critical period, ante-partuin paralypis, bearing trouble, premature abortion*-,' and shortage of milk ut lambing time arc reduced to a 'minimum and losses are negligible.

The' belief that ewes when heavy iulamb require Jess food than during the earlier part of the year has not Lioen borne out experimentally. The truth is that ewes heavy iu-lamb, to remain free of diseaso and do well to the.ir progeny, require a less bulky but more nutritious and laxativo diet. Excessive quantities of dry, innutritious, indigestible, fibrous material predispose to uulhriftiness, constipution, straining, bearing trouble, and shortage of milk. Periodic access to a green, succulent, laxativo feed, according to requirements, not only guards against impairment of health, but is a very valuable means of oncijuraging milk secretion. Green feed, . young grass, etc., are extremoly valuable iu this respect, and access for nn hour or so once a day prior to lambiug is one of the best practical ways of keoping ewes fit and well. Koots and green grass have a similar effect. The fact that old ewes are the commonest subjects of this complaint is not surprising when an examination is made of their teeth. Excessive root feeding is a starvation diet *or old, toothless ewes if the roots are offered intact. Heavy root feeding in nny type of breeding ewe. is always attended with risks.

Although tho practice of wowing green feed and its utilisation off and on before and after lambing hu3 much to commend it, yet profitable iambings can be assured by using other foods of a less forcing nature. Tho use of concentrates such as oat 3hoaf chaff, peas, linseed, wheat, crushed oats, etc., are specially indicated for periods of bad weather when access to other foods is impossible, and the use of cereal straw, hay, lucerne, silag-s, etc., apart from their feeding vilue, gives the necessary amount of bulk in the stomachs of the animal. Having regard to the Jjiiueral requirements of rapidly growing lamba in the womb of the mother, and the fjict that the jirncril •teoutdat of herbages reaches its lowest ebb in the winter, care 6hould be taken to supplement the ration of the ewe with the necessary bone-forming minerals, if mineral deficient foods are used. For general purposes free access to a iick containing finely-pulverised bono flour or bone dust and salt should bo permitted. All sheep do not require licks containing many different ingredients. Bulletin No. 6 gives in tabulated form tho percentage of the various mineral ingredients in different foods, and a perusal of it will give a good indication as to whether or not mineral supplementation or the addition of minerals to the ration is necessary. In many areas where top-dressing is not carried out, or is impracticable, the value of bone flour in the food or as a lick cannot be over-estimated. - (b) Exercise.—The beneficial effects of sufficient exercise for breeding ewes has been recognised from time immemorial, and in areas where food is plentiful and ewes become too fat and lazy, daily exercise constitutes . a successful eombafive measure against disease. One mile daily,'or, preferably, half a mile twice a day, should be sufficient. The value of exercise, how-

ever, as the sole preventive for this disease cannot bo accepted in the light of recent College research, and more harm is done by giving excess of exercise to low-conditioned ewes than is generally believed. Daily forced exercise is the best method of detecting early cases of this disease. 2. Bearing Trouble (prolapse of the vagina).—This consists in the protrusion, or pushing backwards, of tho vagina by the womb and its contents, and is most noticeable when the animal is lying down. Animals of a lazy temperament, those possessing a roomy, wide polvis, and those receiving an abundance of bulky, innutritions food, arG the most susceptible subjects. Excessivo distension of the first stomach- or rumen of heavy in-lamb ewes with large quantities of bulky food causes pressure upon an equally distended womb, and thus the condition develops. Constipation, a not infrequent complication of pregnancy, and dry feed consumption, is also a common cause. Irritant substances, such as turpentino in salt licks, cause bearing trouble through irritation and straining. In 'determining the bulkfiicss of the food and preventive measures for this disease, it should be remembered that the optimum total bulk per sheep per day depends largely upon tho rata of passage of the food through the animal. The value of succulent feeds, or the addition of treacle or molasses to the concentrates, or the administration of a laxative medicine, therefore, becomes apparent. 3. Premature Birth of Lambs—Miscarriages among ewes are most common towards the latter part of the gestation period. Apart from mechanical injuries and fright, common causes of this complaint are improper food, sudden change of . food, mineral deficiency, and periods of starvation and underfeeding. Death of the lamb or lambs in the womb of the mother is not unusual, and it is noteworthy that slipping of dead lambs and antepartum paralysis are frequently met with in the same flock. Under-feeding during the pregnancy period is regarded as an important - factor in causing abortions, dead lambs in the womb, and weak or dead lambs at birth. Access to roots without j sufficient 'straw, hay or lucerne is not infrequently associated with ewes slipping lambs or giving birth to weak, delicate lambs. In areas where abortions are common, free access to bone flour should be permitted during the whole of the gestation period, as research has shown that pregnant animals may not show obvious signs of mineral deficiency themselves: but lack of the mineral ingredients nfTects not only the nutrition and life of tho lamb in the womb, but also its vitality and constitution after birth. 4. Shortage of Milk at Lambing. — The advisability and practicability of steaming up ewes at lambing time as a means of preventing • losses and stimulating milk production is, tor many reasons, a problem for the individual farmer. If, however, results following the adoption of this practice among dairy cows are applicable to sheep, and there is no reason to believe they are not, it is sufficient to say that the feeding of extra succulent or other foods prior to and at .lambing time will result in: (1) An increased milk yield; (2) Milk richer in fat; (3) A steadying of the lactation curve. j Copies of this Bulletin may be obtained from the Secretary, Canterbury Chamber of Commerce, P.O. Box 187, i ChnstchurcL