Historical

Although sheep flocks were established in New Zealand from 1840 onwards, it was not until the late 1860s that the natural increase of the sheep population exceeded the numbers required for flock replacement, the establishment of new flocks, and the needs of the local market for lamb and mutton. At this stage, the attention of pastoralists, particularly in the South Island, became focused on the serious question of finding a profitable method of disposal of fat sheep. The problem was not new. Australia and Argentina had long been faced with it, while the fact that the demand for meat in Great Britain had overtaken the home-grown supply, together with a decline in the price of wool, lent even greater urgency to finding a method of meat preservation, both to maintain British supplies and to bolster the failing pastoral economy of the colonies. Following on Australian experiences, meat canning works were established at Timaru, Oamaru, and Woodlands (in Southland) from about 1869. The combined capacity of these works was small and the quality of the product unreliable. It soon became clear that preservation by freezing was a more promising venture.

The pioneers of refrigerated transport from New Zealand were William Saltau Davidson and Thomas Brydone of the New Zealand and Australian Land Company. Davidson, while at the company's headquarters in Scotland, discovered that a successful shipment of frozen mutton had been made from Australia to London in 1880. He therefore determined to try an experimental shipment from New Zealand and for this purpose chartered the sailing ship Dunedin. After initial difficulties caused by the breakdown of the refrigerating plant, the ship sailed on 15 February 1882, and arrived in London on 24 May, the cargo being in sound condition. After word had been received of the success of the shipment, further cargoes were arranged in the same year. Freezing works were quickly established, the first being the New Zealand Refrigerating Company which was formed in 1881 and was in operation at Burnside, Dunedin, in 1882. The export trade in mutton and lamb developed steadily, and by 1889 the number of carcasses exported exceeded 1 million. In these early years, mutton carcasses made up the bulk of the shipments, but by 1900 the lamb trade was firmly established. The period from 1882 to 1900 was nevertheless full of difficulties for the trade. Prices declined, cargoes were frequently damaged, and freight rates were high and were only slowly reduced as the sailing ships were replaced by steamships.

Grading of carcasses by weight appears to have started about 1890 but the lines were mixed in quality and the weight standards adopted differed among the various freezing works. Failure to regulate shipping and to provide adequate cold-storage space resulted in seasonal gluts on the British market, with consequent low prices. These difficulties persisted until after the formation of the New Zealand Meat Producers' Board in 1922. The Board set about the tasks of controlling shipments, establishing uniform grading standards, negotiating reduced freight rates, advertising, and investigating new markets. These activities did much to foster the meat industry and to establish its present form and organisation.

Changes in the Breed Composition of Flocks

The introduction of refrigerated transport brought about many changes in the sheep industry. At this time, the Merino and its crosses were predominant, although most of the English breeds of sheep had been imported into New Zealand. In high rainfall areas, particularly in the North Island, the Merino proved to be unsatisfactory, mainly because of its susceptibility to foot troubles and to fleece rot and discolouration. Crosses with English breeds, notably the Lincoln, English Leicester, and Border Leicester, proved to be more successful and, after a number of generations of breeding, the Merino was almost completely ousted. From 1900 onwards the Lincoln gradually lost popularity in the North Island, largely because of difficulties in rearing the young stock. Its place was taken by the Romney Marsh breed, and today most of the North Island ewe flocks are of Romney breeding.

In the southern part of the South Island, the breed changes followed a pattern similar to that of the North Island. In the drier northern part of the South Island, crossing of the Merino with Lincoln and English Leicester rams seldom went beyond the first generation. The maintenance of these half-bred flocks was carried out in two ways: first, by the use of first-cross rams bred by mating Lincoln or Leicester rams to Merino ewes and, secondly, the breeding together of the half-bred sheep in successive generations. The latter method, combined with careful selection, gave rise to the Corriedale breed.

Although these changes in breed composition had started before 1882, they were hastened by the introduction of the lamb and mutton trade. From the viewpoint of meat production, ewes of the Halfbred, Corriedale, Lincoln, and Romney breeds were more satisfactory for breeding fat lambs than the pure-bred Merino ewe. The practice also arose of using sires of the specialised fat-lamb breeds for crossing with these ewes. In 1900 the popular breeds for this purpose were the Border Leicester, English Leicester, and Shropshire which together represented 28 per cent of the rams in use. The Southdown breed was of minor importance at this time but it increased rapidly in popularity and, in 1957, represented 24 per cent of the rams in use.

The main reason today for the widespread use of the Southdown ram for lamb production is the preference in the United Kingdom for light-weight carcasses with small joints and without excess fat. The Southdown, being a small, early maturing breed with good conformation, produces crossbred lambs which most nearly meet this requirement. Other breeds which are used to a limited extent are the Suffolk, South-Suffolk (a breed developed in New Zealand by interbreeding Southdown-Suffolk cross sheep), Border Leicester, Dorset Horn, Shropshire, and the recently re-introduced Dorset Down and Hampshire Down breeds. These breeds are larger than the Southdown and produce crossbred lambs which have a faster rate of growth, but are later maturing than Southdown cross lambs.

Stratification of the Industry

The development of the export trade in frozen meat has resulted in the evolution of a distinct pattern of organisation which is referred to as the “stratification” of the sheep industry. The pattern arose primarily through the establishment of specialised fattening farms on which rams of the fat-lamb breeds are used and all of their progeny slaughtered. As no ewe lambs are retained for breeding, the fat-lamb farmers have to replace their ewe flocks by purchase from breeding flocks located on the less fertile hill country. This stratification results in the full use of the fertile land for fattening rather than having much of it used for breeding and rearing replacement stock.

(a) The fattening farms. These farms are generally located on land which is of high fertility, either naturally, or produced by topdressing. Country of this type is usually flat to undulating in topography, and tends to be concentrated on the coastal plains and river valleys of both islands, e.g., the Waikato basin, the Poverty Bay flats, the Hawke's Bay, Manawatu, Canterbury, and Southland plains. These are typical areas of concentration of fat-lamb farming, although it is undertaken wherever suitable land is available. Climatic conditions vary widely from warm and moist in parts of the North Island, to fairly cold and dry in parts of the South Island. This influences the type of feed produced; in the North Island it is normal to rely on pasture as a sole diet, while in the drier areas of the South Island it is necessary to grow special crops, such as rape, for fattening lambs, and in colder areas to grow crops for supplementing the ewe flock feeding over the winter.

In the North Island, the ewes of the fat-lamb flocks are predominantly of Romney breeding. They are bought in either as five- or six-year-old cast-for-age ewes or as young ewes (about 17 months of age) surplus to requirements from hill country flocks. In the former case, they are retained for one or two seasons on the fattening farm and are then sold for slaughter. In the latter case they spend all of their breeding life in the fat-lamb flock before being sold for slaughter. Purchase of the ewes is either by private treaty or more commonly at the annual ewe fairs held in January and February. The rams used are mainly of the Southdown breed, although larger breeds such as the Suffolk and South-Suffolk are occasionally used.

In the South Island the same pattern is followed but the ewes available are more mixed in type (apart from Southland where conditions in many ways resemble the North Island). Halfbred, Corriedale, Romney crossbred, and threequarter-bred ewes are all included. Although the Southdown ram is widely used, Border Leicester, Suffolk, South-Suffolk, and Southdown × Border Leicester rams are common.

Fattening farms vary considerably in area and in the size of flock carried. A flock of 1,000–1,200 ewes is commonly regarded as a one-man unit. The average range in carrying capacity is from three to six ewes wintered, although figures of eight and more ewes to the acre are known. Lambing percentages are variable but average from 100 to 120 lambs per 100 ewes mated. The aim of the farmer is to sell a high proportion of these lambs fat off their mothers at carcass weights around 28–36 lb. In the North Island, cattle are normally purchased in the spring to control excess pasture growth and are fattened, if possible, by the autumn. On some properties, store wether lambs from the hill-breeding flocks may also be bought in for fattening. The amount of meat produced per acre on fattening farms averages about 120–140 lb per acre, while a level of 250 lb per acre has been shown to be a reasonable target to aim at on a well-managed farm.

It is estimated that there are approximately 14,000 fattening farms in New Zealand.

(b) The hill country farms. This type of farming is practised extensively over the wide range of hill country in both islands. In the North Island the sheep are mainly of the Romney breed. The stock carried consists of a mixed-age flock of breeding ewes, ewe hoggets for replacements, and rams. Where part of the property is of poor quality, wethers may also be carried. In the South Island, either Corriedale, Halfbred, or Romney cross sheep are run. In both cases, the products sold are wool (which usually represents 50 per cent or more of the total farm income), some fat wether lambs, store lambs for fattening and, of most importance, cast-for-age ewes and surplus two-tooth ewes which are purchased by fat-lamb farmers. Where wethers are carried, fat wethers will also be available for sale.

Thus, these farms are important not only because they supply breeding ewes to the fattening farms but also because they make a direct contribution to lamb and mutton production.

The Annual Cycle of Operations on a Fattening Farm

Although management practices on fattening farms differ throughout the country, it is proposed for the sake of brevity to describe the annual cycle of operations on a farm where pasture alone is used for feeding the flock. The essential problem on such a farm is to equate the variable seasonal production of pasture to the needs of the flock. Pasture growth is rapid in the spring, falls off during the dry period of summer to an extent which varies widely between districts, increases again with the advent of autumn rains, and then declines to a low level during the winter. The food requirements of the breeding ewe are also variable. Feed additional to that required to maintain body weight is needed before and during the mating period in the autumn, during the last month of pregnancy in the late winter, and during lactation in the spring. These requirements fit in well with seasonal pasture production because the increase needed for lactation coincides with the ample spring pasture growth and because a high proportion of the lambs are sold fat off the farm before the summer reduction in pasture growth. Special provision, however, must be made for the period of late pregnancy, either by saving pasture grown in the autumn for use in late winter or by conserving surplus spring growth of the previous year as hay or silage.

The ewes required to bring the flock up to the number which can be carried through the winter are bought in during late January and February. Replacement Southdown rams will usually have been purchased earlier. The date on which the rams are joined with the ewes varies considerably. It may be as early as late February in parts of the North Island to as late as mid-April in parts of the South Island, the date in each case being chosen so that the lambs will be born in time to ensure maximum utilisation of the spring growth of pasture. For efficient lamb production, it is important that the ewes be put on a rising plane of feeding commencing three weeks before the rams are joined and continuing for a further month. This practice is known as “flushing” and has the effect of increasing the proportion of twin lambs born. After the flushing programme has been completed, the ewes may be grazed on a low plane of nutrition without disadvantage. Opportunity is taken at this stage to spell the pasture on as large a part of the farm as possible. The grass thus saved is rationed out to the ewes during late July and August when pasture growth is at its lowest level and when the increasing food demands of the pregnant ewes need to be met. In June or July, the ewes are “crutched”, i.e., the wool around the hindquarters and flanks is removed so that the lamb, when born, may be able to suckle the ewe easily. The ewes may be drafted into groups according to their likely date of lambing. In this way the early lambing group can be given preferential treatment.

Lambing in the spring (August and September) is a busy time of the year for the farmer. The shepherd has to assist ewes which have difficulty in lambing, to foster lambs which have lost their mothers on to ewes which have lost their lambs, and to try to keep weakly lambs alive in bad weather. On some farms, ewes with twin lambs are drafted into separate paddocks from those with singles so that they can be given preferential treatment. Lambs are usually ear-marked and “docked”, i.e., they have their tails removed at about three weeks of age, the ram lambs being castrated at the same time. At this stage pasture is becoming plentiful, and consideration should be given to the purchase of cattle to consume the excess growth not required by the flock.

The time at which shearing takes place is variable. A common practice is to wait till the first draft of fat lambs has been taken in December, when the remaining lambs are weaned and the ewes shorn. After weaning, the ewes may be concentrated in one mob and used to graze out rough pastures, while the lambs are grazed on the best pasture. Lambs are sent to the freezing works as they become fat. Normally the last lambs are fattened in February, while the aged ewes which are not fit for further breeding, are sold off for slaughter as opportunity permits. Dipping, spraying, or dusting of sheep, to control keds and lice, is commonly done in February. The cycle of operations then starts again for the next season.

Production Increase

The production of lamb in New Zealand has increased from 37,800 tons in 1905 to 303,900 tons in the year ending 30 September 1964. In the latter year 20,900 tons, or 6·7 per cent, was consumed in New Zealand (18·1 lb per head of population). Of the remainder, 94 per cent was exported to the United Kingdom, 2 per cent to Canada, 1 per cent to Greece, and 3 per cent to other countries. In the 1963–64 season, 22,034,000 lambs were killed at works for export and for home consumption. The minimum carcass weight for export lamb is 20 lb, and the maximum weight 56 lb, the carcass being of a sheep under 12 months of age. Carcasses 57 lb and over are included in the wether mutton grades. From 1922 to 1960 the annual average carcass weight of lambs killed for export has varied from 31·1 lb to 355 lb, with a trend towards lower average weights in the last five years (1955–56 to 1959–60 averaged 32·1 lb). Usually the average carcass weight of South Island lambs is higher than North Island lambs.

The grading of lamb carcasses is based on two main considerations: quality and weight. In the North Island there are three quality grades: Prime Down Cross, Prime Crossbred, and Y. Carcasses of the Prime Down Cross grade must show considerable meatiness throughout, be short-legged and have a sufficiency of fat cover. There are two weight ranges within this grade: 20–28 lb and 29–36 lb. Prime Crossbred carcasses are longer-legged, show less meatiness, and may be slightly deficient in fat cover. There are five weight ranges in this grade: 20–28 lb, 29–36 lb, 37–42 lb, 43–50 lb, and 51–56 lb. Carcasses in the Y grade are poorest in conformation and fat cover. Averaged over the seasons 1955–56 to 1959–60, 21·1 per cent of lambs killed for export in the North Island graded Prime Down Cross, 40·9 per cent Prime Crossbred, and 38·0 per cent Y grade. In the South Island, lamb carcasses are graded into two grades only: Prime Canterbury and Y. From 1955–56 to 1959–60, 64·4 per cent of lambs killed for export in the South Island graded Prime Canterbury.

Meat classified as mutton may come from sheep of different types: (i) Hogget mutton carcasses are defined as not exceeding 56 lb weight, and are from either wethers or maiden ewes, showing not more than two permanent incisor teeth, i.e., in their second year of life. (ii) Carcasses of wethers which do not meet the above requirements. (iii) Carcasses of ewes which do not meet the requirements of (i). Heavy and overfat wether and ewe mutton carcasses are usually not exported in carcass form but the bone is removed and the flesh exported for use as manufacturing meat.

In 1905, 70,200 tons of mutton were produced in New Zealand. By 1915, production had increased to 122,500 tons and then tended to fluctuate around that level till the 1958–59 season when it increased to 168,400 tons, followed by 170,300 tons in 1963–64.

In this last season, 50·2 per cent was consumed in New Zealand (76·7 lb per head of population), while killings at works for export and for home consumption were 951,000 wethers and 4,600,000 ewes.

by Alexander Lindsay Rae, M.AGR.SC.(N.Z.), PH.D.(IOWA), Professor of Sheep Husbandry, Massey University of Manawatu.