THE PERCENTAGE OF LAMBS.

Otago Witness, Issue 1891, 1 May 1890, Page 6

THE PERCENTAGE OF LAMBS.

The disparity in the namerical increase from breeding flocks, a disparity with a range of from 65 to 135 per cent.— or taking the extremes, about two to one— is sought to be \ accounted for in various ways, and as it suits the parties concerned in the lesser production. The most plausible excuses pleaded are exposed pasturage and the prevalence of inclement weather at or shortly after yeaning time while the lambs are but new born or weakly. If flockowners will persist in keeping breeding flocks on more or less unsuitable country without forethought or special provision for the ewes during the critical period of lambing down and for some time after, they must or should be aware beforehand of the inevitable consequences —a very low proportion of lambs to ewes supposed to be stinted. Bat in addition to those ordinarily assigned, there are other contributory causes which lower the standard production of breeding flocks, and to these influences it is desirable attention should be directed opportunely, at the time when the rams are about to be put in among the ewes for service. The ordinary practice, followed alike in the management of large and small ewe flocks, is to allot a certain number of rams for the duties, and place them all among the ewes at once. At first a comparatively small number of the ewes are " in blossom," fierce and continual fights for supremacy occur among the rams, wasting their strength and j vigour, and the ewes in heat are subjected to an ordeal that must impair their reproductive powers. Reasoning from suggested analogy, the over-frequent and varied copulation—inevitable under the circumstances — must cause sterility among no inconsiderable number of the ewes ; recurring impregnations neutralising each other, the females are prostituted. Meanwhile tho rams are becoming more and more fagged and wearied. The consequences are a seasonof prolonged impregnation, and ultimately the period _ for weaning extends over several weeks, and is at all times more or lees uncertain The evil consequences in large flocks could be minimised by simply putting proportionate numbers of the rams required in among the ewes at intervals of two, three, or four days, at the same time withdrawing for a spell those that were serving previously, and are therefore somewhat enervated. These latter, if fairly fed, can be returned to the flock with recruited energies after two or three days' rest, and will resume work quite as vigorously as when first put into the flock. Experienced men, acquainted with the old Home system of colouring daily rams at service among ewes, must be fully cognisant of the risks from the uncertainty of impregnation. It was the practice to stain the ram from the brisket down the belly, and so a ewe served was at once marked ; but it sometimes occurred that daily fresh marks over the previous ones were noticeable, and this was regarded as conclusive evidence of the impotenry of the ram, which was at once removed and replaced by another " coloured " differently. An unmistakeable clue was thus afforded as to the merits of the rams used and in all respects, for the ewes were earmarked according to stain, and at lambing time there could be no doubt regarding the paternity of the progeny. In this connection another important consideration arises. To quote Youatt:— "lf the marked ewes still continued to blossom and follow the ram it would show that the ewes had not been impregnated by him, and experience proved that if the first connection was not successful no other would, generally speaking, be so from the same ram." Thus there is conclusive evidence in support of the policy of putting the rams in detachments to the ewes, and of alternating them after a rest. Even in a small flock of say 200 ewes, for which three rams ought to suffice, two of them only should be put in on the first day and one of these should be withdrawn after a two-day service, his place being taken by the one reserved. The rested sheep would again replace the wearied one longest in service, and so on alternately. Again, success in breeding largely depends on the vigour of the rams. Over-worked rams, or those that have been over-taxed in previous seasons, are in a degree impotent, and at best beget small and weakly lambs. The age of a sheep ia no criterion of his potency. A young rake may permanently impair his energies before attaining to manhood, and the rule holds good in animal life. A shearling ram overworked is constitutionally and permanently impaired for breeding purposes, no matter what his outside appearance and condition may be. Age is therefore really no criterion to judge a sheep by ; and sheepbreeders in making their Beleetionß of stud rams would do well to ascertain particulars of the previous histories of the animals, and the exteut of the earlier duties. Early maturing breeds of sheep develop the generative powers sooner than the coarser bred, but their decadence is also more rapid, and this is especially noticeable in the rams. Full-mouthed rams of the improved breeds, generally speaking, have had their energies previously taxed to the utmost, season after season, and there- ! fore the cautious flock-master places little dependence on their abilities as sires. The suggested plan of repeatedly alternating the rams put to the ewe flock will, however, avert any dissappointing results sure to follow the rise of an incompetent or worn-out ram. Inevitably the trust-to-chance management of rams and ewes is followed in due time by prolonged and straggling yeaning— the beginning and end of which are notoriously matters of uncertainty to the common run of sheepbreeders, and afford an excuse for the almost universal inattention to the ewes when giving birth to the lambs. The duration of pregnancy varies certainly to some extent, but now that mutton and wool are improving in value, a higher average return of lambs should pay for the better supervision which would ensure it. With proper provision for ewes a fortnight before turning in the rams among them, or even during the while the rams are with them, the duration of yeaning time may be fixed approximately and circumscribed. Ewes given a fresh pasturage for say a fortnight before admitting the rams to them will come in season more or less simultaneously 10 days earlier than if left on their accustomed feeding grounds. With fresh pasture for the ewes, and the service of the rams properly supervised, lambing time should not extend over a fortnight to three weeks at farthest. Thus the period is contracted during which extra assistance I should be given the shepherd night and day to ensure thorough attention to the ewes during the parturition risks. As has already been intimated, the durat tion of pregnancy is subject to deviation. Com1 menting on this feature, Youatt quotes from a '

memoir presented by M. Tessier to the Royal Academy of Science, Paris, containing his observations on the period of pregnancy of almost every domesticated animal :—": —" Out of 912 ewes the shortest period was 146 days, and the longest 161, being a difference of 15 days; but more than three parts of them yeaned between the 150fch and 154 th days after impregnation, bringing the average as nearly as possible to 152 days, or five calendar months, or 21 weeks and five days." In whatever other details sheep management in the colony may be faulty, it may justly be asserted that the condition of the ewe flocks when the rams are put to them is invariably unexceptional, and as during pregnancy no attempt should be made to improve ifc, and gorging or the possibility of overfeeding should be carefully prevented, the breeders only requiring very moderate food and quiet, little difficulty should be experienced in reserving pastures and supplies of roots to be utilised while the ewes are suckling the lambs. To provide for all contingencies, such as bare pasturage and scarcity of roots, many of the most successful sheepbreeders in the province restrict the ewe flocks to limited pasturage, and during six weeks or so preceding the expected weaning time give a daily allowance of from Alb to lib p«*r head of chaffed sheaf oats. The "pasturage on sheltered paddocks is thus conserved until wanted for the ewes with lambs at foot; while the approval of the chaff food during the later stages of pregnanoy is unanimous on the part of extensive breeders consulted on the subject, and who not many years ago regarded the practice with positive disfavour. The ewes so fed are strong, and scarcely affected by the difficulties attendant on parturition, and they have a sufficient supply of milk for the support of the young lamb until it has gathered strength, and it becomes necessary to shift the flock and progeny to the reserved pasturage, or to provide supplies of succulent and nutritious food for the ewes to enable them to meet the steadily but gradually increasing demands on their resources by the growing lambs. Very few flock-masters regard as necessary any special provision for accommodation of ewes at lambing time, accommodation which would enable master or manager and shepherd to exercise sufficient watchfulness night and day for about three weeks over all the occurrences, and without considerable extra exertion. " Our sheep are not artificially fed," colonists say, " and we can trust to the natural efforts and instincts of the ewes to safely give birth to the lambs and succour them." To a certain extent the trust is not, for the reason given, misplaced; still there are many fatalities occasioned by the throes of parturition which could be averted by timely and experienced aid given. Ewes that have so lost lambs are frequently regarded as barren because they are only oasually looked after, whereaß had timely attention teen given one of twins could have been put to them, for ••mothering" or fostering a twin on a ewe other than its dam is a practice familiar to experienced shepherds. It may be truly averred that the low percentage of lambs in ordinary flocks is largely occasioned by fatalities at and during the two or three days subsequent to birth, and when to these shortcomings are added the usual number of barren ewes it is not surprising that unskilled, apathetic sheep-breeders content themselves with 70 per cent, of lambs from the breeding ewe flocks. . .