Design and Construction of Sheep-drafting Yards

New Zealand Journal of Agriculture, Volume 81, Issue 1, 15 July 1950, Page 5

Design and Construction of Sheep-drafting Yards

By

J. E. DUNCAN,

Wool Supervisor, Department of Agriculture, Wellington.

OVER a period of years the volume of inquiries for plans and specifications of sheepyards and their accessories has shown that there is a constant demand for this information. Some inquiries are from young men just starting on their own, others from established farmers adding to or rebuilding their existing yards; but whatever the reason, the demand seems to be increasing. This is the first part of an article which aims to supply basic information covering most of the questions usually raised. The second and third parts will appear in the August and September issues of the “Journal.”

IT is out of the question to give a plan of a drafting yard and say: “This is the ideal yard for working a flock of 3000 sheep.” There is no “ideal” yard, simply because requirements and existing conditions vary so much from farm to farm. By listing and discussing some of the more important factors influencing the choice of a suitable type of yard and its construction it is hoped that the fundamentals will be covered to an extent enabling any farmer to use or modify the plans provided to fulfil his own requirements. SITE Choosing the best site for the yards is not always easy and a number of points must be considered: — Central position: Other things being equal the yards should occupy a central position on the farm to avoid long drives for the sheep. Whether it will be feasible to have them in a central position will depend on a number of the other factors affecting site. Question of attachment: When building a new set of yards, particularly if they will be the only set on the farm, the farmer usually desires to have them attached to the shearing shed and/or dip, so this will restrict the choice of position. However, where, as is often the case, there are other yards already on the farm, attached to the shed or elsewhere, there will be wider scope in selecting the site. If the farm is a large one, it is desirable to have yards where they will be

within easy driving distance of the main blocks or paddocks. Road droving should be avoided wherever possible because of the detrimental effects of dust on the fleece. The lie of the land is very important. Sheep work and draft best on a slight up-grade and it is easier for the man on the gate to see sheep approaching uphill. However, it is undesirable to have yards on a very steep slope, as the danger of smothering, particularly with lambs in a large yard, is greatly increased. If the forcing pens and the race and check pens run up a slight incline, it is quite satisfactory to have the rest of the yards on level ground. The size of the yards may be influenced by the lie of the land, as in many cases a good site, particularly in broken country, will be large enough for only a small set of yards. The orientation of the yards, particularly the drafting race, must be considered in conjunction with the site. It is claimed by some experienced sheep men that sheep always run best . toward the light, that is, into the sun; the drafting race should therefore point more or less north and south, with the crush pens south of the drafting gates. Of course it is seldom that both slope and orientation will work in exactly, and if there is direct conflict between them decision should rest on other considerations, such as the belief that sheep run better through a race toward their home paddocks. Good drainage is a necessity. In most cases where the yards are on a slope the natural drainage will be

good, but if they are entirely on level ground, an effort should be made to choose a site with a light porous type of soil. Gravel is best, but is not often available in the North Island. A poorly drained yard is very quickly churned into mud, and the sheep work reluctantly in it, quite apart from the fact that it will become, disease infected more readily than a dry yard. If the important conditions already outlined can be satisfactorily fulfilled, there are a number of other points which should be taken into consideration in selecting the site. Shelter and shade: If, in choosing the site, advantage can be taken of a hill or patch of standing bush, or even a plantation, to break the force of the prevailing wind or southerly gales, it is all to the good. It may be possible to find a suitable site where a few isolated trees, which will be very valuable for shade, can be enclosed in the holding yards. However, even after the yard has been built it is not too late to plant a few trees in suitable positions. One or two for shade in the large holding yards are much appreciated by sheep in hot weather. The planting of even single trees alongside the race is not recommended, as sheep tend to stop in the shady patch in hot weather, and moving shadows are apt to be troublesome. Quite apart from utility, trees very greatly improve the appearance of a bare dusty yard; in fact they assist in preventing dusty conditions by. preventing the soil from becoming parched. On the other hand too much shade in winter will keep the yard from drying out properly if the drainage is at all bad. In such a case it would be better, despite the trouble caused by falling leaves in autumn, to use deciduous trees, which will let in plenty of winter sun. As a temporary measure, until such time as a shelter belt can be grown, an exposed windy yard can be improved greatly by interlacing scrub, such as cut manuka, in the outer fence along the whole of the windy side. Such a windbreak is very valuable for sheltering dipped sheep when a cold wind springs up unexpectedly. Water supply: If the dip is included within the yards, a good water supply

is essential, but even in straight-out drafting yards it is desirable to have a good supply of drinking water available. Where the yards are on an isolated part of the farm and there is a lack of water the tail of the mob often has to be let out when the job in hand cannot be completed that day; a second muster is therefore necessary and time is lost simply because sheep could not be left in the yards without water. Water troughs should be available in all yards wherever possible. Sheep are frequently hot -and thirsty when yarded after a long drive, and it is quite probable that fewer losses would occur at dipping if sheep were not dipped when thirsty. In Australia - yards are often sprinkled with water to lay the dust and in some of- the larger yards a permanent sprinkler system is installed (Fig. 1). This practice could be adopted with advantage in some of the drier districts of New Zealand; the extent to which dust in wool mars its appearance and lowers its yield and hence its value is not generally appreciated. Even where sprinklers are used loose . accumulations .of dust and dried dung must be removed before the sprinklers are turned on or yards will become muddy. SIZE OF YARDS It is very difficult to arrive at any definite size of yards for a particular farm; size, as with type, will vary according to particular conditions. The number of sheep and the number of separate mobs likely to be yarded at any one time is thb ,first consideration, and is governed largely by the type of farming. If the size of the mobs to be handled is known, it is possible to estimate fairly closely the total area of yard space required. An average of 5 sq. ft. per sheep should be allowed; this average has been arrived at after measuring many existing yards of various types throughout New Zealand. Five square feet per sheep should allow ample room to work any but the largest sheep. In some Australian yards, designed of course for working the smaller types of Merinos, allowances as low. as 3 sq. ft. per sheep are common, and appear to give satisfaction in practice. Cost: Cost is frequently the limiting factor. A farmer may prefer yards capable of holding his whole flock at once, but has to be satisfied with. smaller ones, particularly where there are more than one set of yards on the place. Further, it is usually better economy to build the nucleus of a set of yards in lasting, first-quality materials than to attempt to build a larger set of poorer timber, which will later entail heavy replacement costs. If proper provision is made in choosing the site and the arrangement of the “nucleus”, it will not be difficult to enlarge the yards later when finance permits. With yards there is not the same need for providing in the first instance for future expansion of the flock as is the case when building a shearing shed, which cannot be added to so easily.

THE GENERAL LAYOUT Layout is the hardest of all matters connected with design of yards to pin down to any set of rules. There are so many different types of yards from which to choose, all of which give satisfactory service and all of which have special advantages claimed for them by their enthusiastic protagonists. Because drawings convey more than written descriptions, no attempt will be made at this stage to describe various yard layouts. The final section of this article will include a number of diagrams of fairly typical sheepyards with accompanying comments and descriptions. The most common shape is, of course, the rectangular yard, but there are many others, such as the wedgeshaped, the circular, the “bugle,” and many other “freak” yards. Fig. 2, page 8, shows in diagrammatic form only the component parts and is not to be taken as representing an ideal yard, although this plan would form a useful basis which could be modified to suit individual requirements. It is usual and very desirable to have one or more small holding paddocks alongside the yards. These have many uses and where they are provided the receiving and holding yards can. be smaller and less costly. Small holding paddocks are particularly useful at shearing time for holding sheep and allowing them to empty before entering the yards, and shed, thus reducing the fouling 'of these to a minimum. In general, large drafting yards embody the following subsections or divisions, but in small yards some of these will probably be omitted: — The receiving yards, into which the sheep enter, which usually, have a large capacity, sufficient to hold the

biggest mob of sheep usually dealt with at any one time. They usually communicate with The forwarding yards or pens, which are considerably smaller and consequently are useful for dealing with small mobs of sheep, as well as their function of leading up to The crush or forcing pen (s): These are usually one or two long, small pens, frequently tapering at one end, and holding about 50 sheep. They in turn communicate by a two-way gate with the mouth of the Drafting race: This race is long and narrow, just wide enough for the sheep to pass through in single file. Its purpose is to divide a mixed flock of sheep into any required number of smaller mobs, and for this purpose the race is fitted at its exit with one or more drafting gates, which guide the sheep into several Drafting pens: These are small pens, and there is one for each way the sheep can. be drafted. Where there are only two they frequently communicate direct with the holding yards, but in larger sets of yards one or more of these drafting pens communicate, via a gate, with The check pen(s): These vary in number, corresponding with the number of drafting pens. Since their purpose is to hold the sheep while they are being checked over for mistakes in drafting and for treatment, these pens must also be small, and each usually has the same capacity as its drafting pen. The check pens in turn usually open into much larger . Holding yards, which correspond in size to the receiving yards. In addition to the components mentioned there may be units such as a branding race and the sheep dip either with its own set of pens or sharing some sections of the general drafting yards.

Of course in a small set of yards it is not essential, or even necessary, to have all the subdivisions mentioned. The race and its immediately adjoining pens are the nucleus of a set of drafting yards, and in small yards they form the main part of the yards, the larger pens being few. Further, it must not be supposed that the various components listed earlier are necessarily arranged in a straight line. In practice this is often done, but provided the subdivisions follow in the sequence given, their actual arrangement is largely immaterial; for example,, in circular-design yards the receiving yards and holding yards may be next to one another. Other Factors Several other factors play a part in determining the final layout: — Use in conjunction with shed, etc.: Whether or not the yards have to be designed for use in conjunction with a woolshed and/or a sheep dip already in existence will affect the layout. Size of yards and land available: In special cases it may be found necessary to have an unorthodox layout to fit a given size of yards to the land available, because of the topography or area at one’s disposal. The alteration in the external shape of the yards must not be allowed to alter the sequence of the different components. The lie of the land: The drafting race is given first consideration and the rest of the yards are really built around it. Fencing, etc.: It will simplify construction to have as many straight unbroken sections of fence as possible. This will save the work and expense of putting in extra strainer and corner posts, stays, etc. In designing the yards try to make a fence or a pen serve a dual purpose wherever possible; for example, in a set of circular yards the fences nearly all do this. Frequently yards can be designed so that pens can be used for more than one purpose where sheep from the draining pens of the dip pass out into the holding yards, and where the run-through can be used for foot-rotting, dosing, lambpicking, etc. CONSTRUCTION When a new set of yards is to be built and the site has been , chosen the first step is to clear the area of any obstructions that are liable to injure the sheep and level off any very accentuated bumps in the ground. The site can be levelled quickly and at a reasonable cost with a modern bulldozer. From the plan (which it is assumed will have been drawn) distances should be measured and pegged off. Any logs and stumps close to the yards near gateways should also be cleared away. Several methods of construction are suitable, but one of the fundamentals in construction of yards is to have all fences of adequate strength, whatever the material.

The small sketches in Fig. 5 on page 10 will give some idea of the alternatives for yard fences. It is realised in mentioning some of these that cement and steel are for the time

being in short supply, but it is to be hoped that this is a passing phase. All-timber Construction Timber was the commonest material used in fence construction in the early days and is still largely used, although less is now being employed due to the increasing scarcity and cost of suitable timber. Provided good-quality wood of a lasting variety, for example, totara, was used, yards built of such timber would sometimes last half a century. Good timber yards entailed a fair amount of labour to erect, but once they were built replacement costs were low, both because replacements were not often necessary and because there was usually plenty of suitable timber at hand for the work. Unfortunately this is seldom the case today. In Massey Agricultural College Bulletin No. 12, “Farm Trees and Hedges”, by J. S. Yeates, the author states: — The durability of post timbers is a topic of endless argument. One man will put the useful life of a certain timber at two or three times the estimate made by another. Each man's estimate may be true for the particular posts and conditions he talks of. The trouble is that there are many reasons why timber of any given species may last longer at one time than another. Sap wood may be concerned in one case, heart wood in another; different varieties of the same species; rapidly-grown light timber or compact, slow-grown wood may be involved, and they may be used as posts on very different classes of soil; all these factors affect the length of life of posts. It will be understood from the above that estimates of the life of posts can

be expressed only as rough approximations. The durability of some common timbers (heart wood) as posts is shown below. More than 30 years: Puriri (Vitex lucens) — up to 60-80 years common Silver pine (Dacrydium colensoi) —also extremely durable Totara (Podocarpus totara and P. halli) Broadleaf (Griselinia littoralis) Hinau (Elaeocarpus dentatus) Maire (Olea cunninghami) False acacia (Robinia pseudacacia) From 15 to 30 years: Kaikawaka (Libocedrus bidwilli), in some districts Kowhai (Sophora tetraptera) Black beech (Nothofagus solandri), when mature Red beech (N. fusca) Hard beech (N. truncata) Matai (Podocarpus spicatus) Jarrah (Eucalyptus marginata) Cupressus macrocarpa (probably) From 10 to 20 years: Peppermint gum (Eucalyptus amygdalina) White stringy bark gum (E. eugenioides) Camden woolly butt (E. macarthuri) White or manna gum (E. viminalis) Blue gum (E. globulus) Blackbutt (E. pilularis) From 5 to 10 years: Rewarewa (Knightia excelsa) Rata (Metrosideros robusta) White manuka (Leptospermum ericoides) Kamahi (Weinmannia racemosa) Tanekaha (Phyllocladus trichomanoides) Kauri (Agathis australis), resinous timber Less than 5 years: Pukatea (Laurelia novae-zelandiae) Rimu (Dacrydium cupressinum) Miro (Podocarpus ferruginous) White pine (P. dacrydioides) Tawa (Beilschmiedia tawa) Taraire (B. taraire) Silver beech (Nothofagus menziesi) Insignis pine (Pinus radiata) Messmate, stringy bark gum (Eucalyptus obliqua) The possibility of using “live” posts should also be kept in mind, i.e., the use of trees such as poplars or willows which can be planted as large cuttings which will grow and serve as posts from the first. Preservative Treatment of Nondurable Woods As the durable woods are becoming increasingly scarce, many more farmers will soon be faced with an acute problem when replacements are necessary. There are several apparent solutions to this problem, but the one which will now be considered briefly is that of preservative treatment of non-durable woods. Almost without exception the durable timbers take a long time to grow. However, many of the non-durable timbers above can be grown to a size suitable for posts in a much shorter time. Their use untreated, for permanent fences, is not an economic proEosition due to their short life and igh replacement costs. However, by suitable treatment their life can be doubled or even quadrupled.

Ward of the New Zealand Forest Service quotes a case of creosotetreated white pine sleepers lasting for 14 to 30 years on the New Zealand railways and at the end of that time they were pulled up only because of mechanical failure, not because they rotted. He says: — The preservative is best injected into the wood under pressure, but for farm work, where pressure equipment is seldom available, creosote, introduced into posts by soaking them for some time first in hot and then in cold creosote, is an ideal preservative ... There is now at least one commercial process available to farmers in New Zealand by which they can have their own timber pressure treated with an effective and lasting preservative. The seasoned air-dry timber is loaded into a large steel cylinder where it is first subjected to a vacuum to remove the air from the wood cells, and then hot preservative is forced into the cylinder under high pressure so that it penetrates right through the wood, thus rendering sap and soft timbers more durable than the best heart grades, which are becoming increasingly scarce and dear. The cost of this treatment varies with the timber, but averages about £1 per 100 superficial feet— price which is economic if compared with today’s prices for heart timber; nor is heart timber always of the quality implied. Full information on preserving of timber can be obtained from the New Zealand Forest Service and from other .sources, but the following is a brief outline of the main points:— Short-lived posts are a continuing liability, not only because of replacement costs but because of recurring labour charges. The principle of preserving nondurable woods is to render them poisonous to decay organisms. As it is impracticable to get preservative into all parts of the wood, a complete protective envelope of treated

wood must be created. Any trimming, sawing, or cutting should therefore be done before, not after, treatment. Heart wood is usually difficult to impregnate, and best results are frequently obtained by using round whole posts. The sap wood soaks up the preservative and a complete protective envelope is formed round the heart wood. All bark must be removed to allow complete penetration, and any decayed wood should be removed before treatment, as there is the possibility that the decayed area may continue to spread afterward if deep seated.

The wood should be well seasoned before being treated. (If green timber is creosoted, or worse, if it is sealed up with a coating of tar or pitch, internal rotting is likely to result.) With seasoned timber there is better penetration of the preservative and less subsequent splitting. Deep cracks extending into untreated wood are a means of entry for decay organisms. Creosote is probably still the best all-round preservative for farm use, but brushing and dipping are inadequate methods of applying it and are false economy. The hot and cold dip method is the one generally recommended for farm use. Water-soluble preservatives are nearly all unsuitable for posts. For the hot dip the creosote must be heated to from 180 to 200 degrees F., and precautions must be taken to avoid unnecessary fire risks. Old oil drums are generally used as containers, but because their depth is insufficient, two handlings for each post are required, the butt ends and top ends being treated separately. If many posts are to be treated, the cost of a long horizontal tank is justified. Time in the hept bath (which comes first) varies from about 3 to 7 hours according to size and wood species. The time in the cold bath which follows should be not less than 14 hours, preferably more, say, overnight. J. S. Yeates estimates the cost of treatment (including labour) at between Is. sd. and 2s. 9d. per post. The New Zealand Forest Service has found that posts which untreated would have a life of 2 to 4 years after proper treatment by the hot and cold dip method lasted from 20 to 26 years Post-and-rail Fence Posts and rails form a strong and durable fence. The best method, but also the most laborious, is to have the rails on the inner side of the posts and checked into them so that the surface is flush. This helps to keep

the sheep- from getting bruised. The more common method, which gives a fence which is as strong and involves less labour than when rails are checked in, is to have the rails spiked or wired to the faces of the posts, the check being omitted. Round timber is best, as it will last longest and is least likely to bruise the sheep. •- The bark must not be left on, as it will lead to rapid decay due to water lodging under it and fungi getting a start there. Sawn timber, though more expensive, is preferable to split timber, because splinters become detached from the latter. Where split rails are used the smooth or sap side, if there is one, should face- inward, toward the sheep. “Stud” Fence The “stud” fence is not common in New Zealand, but is still used considerably in Australia. .. It is really a modification of the post-and-rail fence, the rails being , round saplings closely spaced (Fig. 5, above). Such a fence is very satisfactory if good durable saplings can be obtained for the rails. They are barked and trimmed and either spiked or wired and stapled to the posts. A fence of this type begins to show decay first where the rails make contact with the posts and with each other. In gates and in all woodwork exposed to the weather it is the joints that rot first because they catch and hold rain-water. It is a good policy therefore to apply some preservative, such as tar and creosote mixture or one of the proprietary copper compounds, to joints, even if it is not applied elsewhere on the score of economy. Slab Fence The slab fence is seldom put up now because it is extravagant of timber; in fact it is really a relic of the days when timber was very cheap.

Its only special virtue is its strength. The whole fence is composed of posts, or rather slabs, say 3in. x Bin., which are set in the ground like posts with 3in. or 4in. spaces between them. Sometimes a wire or a capping rail is run along the top to help prevent them from being knocked out of line. Timber and Wire Construction Normal Construction Timber and wire fencing for yards is done in the usual manner except that generally posts, battens, and wires are all more numerous,. for extra strength, than in the ordinary farm fence. When wire was readily available 8, 9, or even 10 wires were used. The lower ones were gauged close together to prevent lambs getting through. Often now fewer wires are used, but a . narrow strip of netting is run around the bottom of the fence to keep lambs in. Posts are spaced about every 10ft., and there are about 5 battens to a panel. Metal droppers may be used, but usually when wooden posts are obtainable at an economic price wooden battens are used. Wire and Netting For the outer fences of large receiving and holding yards considerable economy can be effected by using a light type of fencing. These fences are not subjected to the same strains and rough usage as those of the smaller pens and crushes, and the same strength is not required. The posts are put in in the usual way, but wire netting of one kind or another is used. With netting of the old light type 3 or 4 No. 8-gauge wires are required to give it rigidity, but with some of the heavier types of netting with locked or welded joints no supporting wires are needed. Occasionally sheep not noticing the netting in time have been injured by colliding violently

with it. This trouble could be avoided by having a single light rail along the centre. Wire and Paling Fence The wire and paling fence is quite useful for light duty and could be used successfully where there is plenty of suitable wood for making the palings. Only short lengths are required. The palings are interwoven by a double No. 8 wire at the top and a double No. 8 wire at the bottom. When the wires are tight the palings will not need stapling. The wires may be stapled to posts in the usual way, and where the posts are fairly well spaced it is advisable to drive in a stake in the centre of each panel and staple it to the wires to steady the fence. In practice, due to the weight of such a fence and its swinging in the wind, the wire tends to cut on the staples and often it is better to bore the posts and thread the wire through the holes. Construction Using Mainly Metal Standards and Droppers The particular sphere of usefulness of fences of standards and droppers is under ’ conditions such as are common in parts of Australia; that is, where suitable timber is unobtainable or prohibitively dear, where there is no gravel and sand suitable for concrete posts and freight on cement is high, and where there is considerable risk from fire and destruction by pests such as termites. Steel posts or standards also have the advantage of being quick to erect, since they are driven into the ground and the steel droppers can be rapidly clipped in position. The main disadvantages are cost and deterioration in a wet climate due to corrosion. At present the steel shortage virtually rules out this type of fence. It is possible that in some areas in the South Island, such as Central Otago, some of the conditions exist which justify the use of steel posts, and this type of construction could with advantage be used. Metal and Wood In certain instances it may be difficult and expensive to get timber suitable for posts, yet timber which would do for battens may be available. In such a case, if concrete posts are also out of the question, steel posts can be used with wooden battens. Steel Posts, Wire, and Netting It is unnecessary to go into details for using steel posts, wire, and netting, as steel posts and battens can be substituted for wooden in any of the cases where these are used. It is interesting to note in passing that dividing fences constructed of steel or concrete posts with panels of. galvanised iron have been used in some Australian yards. They are strong, durable, fireproof, and easily disinfected if necessary. They can also be arranged so that the sheep can see only in the direction in which . they are moving, which is an additional advantage. . Unfortunately, scarcity of materials and cost rule out this type of yard for the time being. Concrete construction will be dealt with in next month’s issue.