PROPER SIZE OF MERINOS.

Press, Volume XII, Issue 1550, 25 October 1867, Page 3

PROPER SIZE OF MERINOS.

[From the " Rural New Yorker."] We often bear accounts of heavy merino fleeces shorn from carcasses of under 701b. in the full-grown ewe, 1001b. in the full-grown ram, both being in good ordinary condition. A large proportion of wool to carcass is, of course, a prime .point of excellence, but it is bought too dearly if it is bought at the expense of a proper sized carcass. It is a demonstrable fact that a small spherical body, like the body of a sheep, presents more surface in proportion to weight than a larger one, and consequently that, other things being equal, the smaller sheep must proportionally produce more wool. We have seen runts on which its production appeared too great to be natural in a well-balanced, healthy organization. It seemed as if the system abnormally devoted its energies to the formation of the pabulum of wool (the special substances which constitute and tend to the growth of wool) to the partial exclusion of those secretions which enter into the composition of muscles, bones, and other structures of the body; and hence, while the wool grew as fast or faster than orij the ordinary full-sized sheep the carcaas remained dwarfish, unthrifty, and deficient in constitution. We have seen sheep that were very small or very large for their species, which were strong and hardy; but this is rather the exception than the rule. The common observation of mankind has always discovered and recognized the fact that the average or medium size in any variety of animals is the size which indicates the best constitution — i.e., that development of the general organs and functions which best fits them to perform their mechanical duties, utilise food, resist disease, and withstand hardship. But if excessively email or excessively large animals for their species do happen to possess the full average vigour of constitution, it is not therefore expedient to breed from them. These peculiarities are very likely to reproduce themselves, especially in the male sheep. A very small stock ram generally gets undersized progeny—a verylarge one, oversized progeny. This is peculiarly the case where these characteristics of a. stock ram are inherited and not accidental. Such a course of breeding, persisted in, permanently changes the average size of the flock. Unless there is a special reason for this—as, for example, to .better adapt the flock to meagre or rich pasturage —it is not generally advisable. And where such a motive exists, it is more expedient, if practicable, to select a variety whose natural size is adapted to the surroundings than it is to select an unadapted variety, and then by changing their size, adapt them to such surroundings. Why? Because we believe, as we have already said, that the natural size of a species is the size in which it exhibits most vigour; and secondly, because it is most convenient. Why create a new subvariety, or family, by breeding, to meet a local want, when other already adapted varieties are equally attainable ? The proper size of the merino, with the conditions above laid down, depends upon the quantity and quality of the aliment—summer and winter feed—which can be profitably bestowed

on it in the locality where it is to be kept.- Oα the rich grain lands of Western New York and Southern Ohio, for example, where sheep art only an incident in convertible husbandry —where all the varieties of feed ! are superabundant—the largest variety is called for It is so called for, because it can as well be kept as smaller ones, and because it will produce a given amount of mutton, with a less percentage of offal than a smaller variety. And it will pay quite as well for'what it consumes. The advantage of greater surface for the production of wool, in the small sheep, is probably nearly or quite counterbalanced by its increased consumption to support parts of the carcass which are not saleable products, namely the offal —for it requires food to grow offal, in proportion to its amount, as well as mutton and wool. Adding the superior proportion of mutton in the large sheep, the balance stands in its favour, in the situations to which it is adapted. On light or meagre soils and pasturage, or those habitually exposed to periodical droughts, smaller varieties' of the merino are called for. Sheep, it is well known, consume food in proportion to their weight. It follows then that when pasturage is scanty a smaller sheep has not to travel so far to obtain its necessary supply as a larger one. And if the large sheep is for this purpose required to travel beyond what is necessary for healthy exercise, the labour thus incurred both wastes its valuable products (wool and mutton), and creates a demand for additional food. How long would the high-fed and heavy infantados of Vermont retain their present size, condition, and weight of fleece, if forced to travel fifteen of twenty miles a day over the burning plains of Australia, or half that distance over the prairies of Texas, when scorched by drought, to obtain even a moderate supply of food ? And turning our eyes to other breeds besides the merino, how long would the great splendid mutton varieties of England contrive even to live under such circumstances ? Many persons suppose that small sheep are hardier per se than larger ones. We doubt this. But it is made to appear so to superficial observation, because the physical causes —meagre food, privation, and hardship—which in the natural course of things render varieties small, inure them to euch surroundings; and it is this and not their small size which renders them capable of enduring greater hardship and privation. The size is but a coincident effect, of the same cause. We have already, however, noted one apparent exception. The small sheep is not compelled to waste so much strength in securing its food, and can therefore better encounter the consequences of extremely meagre pasturage. But this is rathej; a mechanical advantage than a result of superiority of constitution. If the small sheep travelled as far the result would be the same. It follows, from the preceding views, that we would determine the proper size of merinos, first by selecting a variety, if it can be found, adapted in this particular to the keep; and second, that in choosing animals from any variety, we would consider good medium sized ones preferable to either runts or monsters. We have two varieties of merinos in the United States which, when unmixed with each other, will meet the wants of most localities. The mixture forms an admirable class of sheep—but we have always urged at least a portion of those who specially breed sheep to sell to the founders of new flocks to preserve these varieties entirely distinct, in order specially to meet the wants of different localities. We can indeed suppose cases where larger, and possibly smaller, varieties of merinos might be desirable. In breeding to secure either object we would " hasten slowly," and not, so to speak, disturb the equilibrium of the constitution by sudden and violent changes. This is especially important if it be true, as many breeders and physiologists suppose, that the progeny inherit to a great extent a part of their organs aud structures from one parent and a part from the other. Thus, it has been claimed, for example, that while the sire controls in much the greater degree the size of the progeny, the dam exerts the predominating influence in transmitting the characteristics of the viscera, and one of those characteristics is size. If then this theory is sound, it would follow that the coupling of a large male and a small female would generate offspring whose viscera were disproportioned in size to the general frame, and like results would follow coupling large females with small males. Such results would obviously be injurious. The ram does, undoubtedly, as we have already said, far most control size. The proofs are visible to all eyes. The other hypothesis has not, so far as we know, received any ocular demonstration. But waiving all speculations "on the subject, we are prepared to believe on general physiological principles that any sudden and violent changes in the Size and structures, produced by breeding, must derange to some extent the animal machinery and adaptation to : each other of the different parts. Wβ could, we think, furnish proof of this, patent to all eyes. But this is not the topic now chiefly under consideration, and we have not space or time to pursue the investigation at present.