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C.E. Terrill


Prospects for the future expansion of sheep and goat production are excellent. These small ruminants produce food and fibre at relatively low cost from feed materials and on land that often cannot be used in any other way. Their high and increasing efficiency is due not only to their ability to use low quality feed stuffs and sparse natural forage but also to their early puberty, short gestation period, high prolificacy, rapid growth rate and good marketability within one season on forage alone.

Sheep and goats do not compete with people, pigs or poultry for food because they can produce on forage alone and require little grain or concentrates for good production. Small ruminants produce about twice as much meat per animal unit in the tropics as cattle (Terrill, 1983). In recent years they have failed to compete with cattle in the use of surplus grain. Eventually surplus grain will decline so that hopefully the prices for grain to farmers will exceed the real cost of production. As this occurs the feeding of grain to dairy and beef cattle, pigs and poultry will likely decline because of increased feed costs. People will probably not maintain present consumption of meat at much higher consumer prices even when populations are increasing faster than production. Meat from small ruminants should be available at lower prices because of their greater efficiency on non-grain diets, than beef or pork and possibly poultry. Expanding meat production from small ruminants will offset some of the decline expected in total meat production.

Small ruminants compete well with other livestock in quality of meat produced. Meat from small ruminants is generally more tender than grass-fed beef because the animals can be marketed at a much younger age. Lamb meat is more established in marketing systems than is goat meat, but both are quite delicious, especially under one year of age. In many countries lamb and mutton are preferred, while some prefer goat meat, but almost everyone will eat sheep and goat meat if the price is relatively low. Sheep and goats can supply high efficiency and low cost of production.

Small ruminant production can be started with very little capital expense except for land and often the cheaper land is suitable. Small farmers can start with a few head and increase numbers through reproduction, as also can large farmers who can supplement income through use of sheep and goats to utilize otherwise wasted forage and crop residues found on any farm. Equipment needed requires only minor expenditure and can often be improvised. Fences, where needed, are expensive but electric fences will sometimes be adequate and feasible.

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Small ruminants are well suited to marginal land, abandoned crop land, eroding land and land not usable for other crops. Unproductive land covered with brush and scrub trees can be gradually cleared by sheep and goats followed by establishment of productive pastures. This not only increases food production but lessens hazards from fires and erosion. Erosion can often best be slowed and prevented by reseeding and improving pastures on such land, thus improving the ground cover even with grazing at higher rates.

Sheep and goats tend to complement each other in grazing natural pastures. Sheep prefer finer plants and grass areas while goats prefer browse and brush. Both complement cattle because cattle need the fast growing coarser grasses found on the better land with ample rainfall. Sheep, goats and cattle should all be grazed together or on the same land where this is ecologically desirable and economically feasible, particularly on larger farms.


The greatest potential, which sheep and goats have, in contrast to other food commodities, is their high ceiling on biological efficiency. This is the opportunity or potential for further increase in yield of product per unit of production. An increase of two times the current level of less than one lamb weaned per female per year is attainable under the most extensive conditions with very little additional cost providing the increase is obtained by genetic selection and that the number of females is reduced according to the increase in young weaned. Increases of three to six times are feasible under more intensive conditions but with higher costs per female for facilities and feed. Increases of eight to twelve times are possible with genetic capability already partially demonstrated. However, six times current biological efficiency of one offspring per female per year might be considered as a practical ceiling. That is weaning three lambs twice every year. Other crops such as poultry, dairy, beef, corn and soyabeans are nearing their practical ceiling now. In these crops increasing biological efficiency will require ever increasing costs, while with small ruminants an approximate doubling of efficiency, with practically no increase in costs, is attainable within about 35 years of genetic selection alone with some gain every year and under almost any environmental conditions.

Forty to fifty years ago in the Western United States we thought that one lamb was sufficient for a ewe to wean under extensive conditions and the average was 0.6to 0.7lambs weaned per ewe. Now we favour increased prolificacy under extensive conditions and have improved our stock so that 100 to 130 percent lambs weaned per ewe mated is now achieved under extensive conditions. One group which selected for total weight of lambs weaned of ewes mated in the best adapted breed is now averaging over 120 percent lambs weaned of ewes mated, as compared to about 100 percent in the lesser adapted breeds (Terrill, 1982). Finn sheep crossbreds (1/2Finn) are averaging about 130 percent under the same conditions. These increases did not require additional feed although some was available through range improvement, through improved management and because of some increase in annual rainfall from about 225 to 300 mm., but number of adult ewes was not reduced. In fact they have increased from about 2000 to 3000 head.

Productivity is still far below the ceiling even under extensive range conditions. This year I saw a few ewes, each suckling triplets, under extensive conditions on a high mountain range in Utah. It is important that the gains be made by genetic selection with direct emphasis on total weight of lambs weaned per ewe so that all aspects of reproductive efficiency from conception through pregnancy, parturition, lactation, survival to weaning, growth rate to weaning and weaning weight are all improved together. High survivability can probably he obtained only with well adapted stock. Slightly better gains were obtained from a better adapted breed (Terrill, 1982). It is not necessary to increase the feed supply but good management is essential to ensure that each ewe received adequate feed for her needs.


The predictability of first lambing results for lifetime lamb production was reported by Terrill (1949) where ewes having twins at two years of age had a lifetime advantage of 21 percent in kg of lamb weaned per ewe mated and ewes having single lambs had an advantage of 2 percent above the flock average. This predictive value of early lambing records pays off in two ways. First by culling the ewes with low early records the production in subsequent years is higher. This gives an immediate phenotypic gain from selection while costs are actually reduced as ewes with lower productivity are not maintained. Second, there is a genetic gain in the offspring which appears to be at least 0.5to 0.9percent per year (Terrill, 1982).

Fortunately ewe lambs can reveal a great deal about their lifetime ability to wean more total weight of lambs while they are still lambs. Hulet et al., (1969) found that Rambouillet, Targhee and Columbia lambs exhibiting estrus in their first winter (12percent) accumulated 20, 11 and 19 kg more lamb per ewe, respectively, over five production years than those which did not show estrus.

Whiteman and Dzakuma (1981) and Dzakuma et al., (1982) found that ewes joined to lamb at one year of age had lifetime lambing averages of 1.33,1.49 and 1.60 lambs per ewe where the first lambing was 0,1 and 2, respectively. The ewe lamb record is a better predictor of lifetime lamb production than is the yearling record and also seems a better predictor of genetic advantage. These advantages likely result from less resistance to stress by the ewe lamb so that a smaller proportion complete the reproductive process and thus give greater phenotypic spread between those with higher and lower genetic merit.

The predictive value of early reproductive performance is not the only asset that small ruminants have that leads to rapid improvement in efficiency. More important is the ability for male generations to turn every year. Even though selection on the mothers' record is less accurate than selection on progeny records there is obviously more progress from turning generations every year rather than every third year. The selection of twin or triplet male offspring of lamb or kid mothers provides a genetic advantage probably greater than that of selection based on a limited number of female progeny of a limited number of sires tested. In turning sire generations every year, the genetic gain in one year is taken advantage of in each succeeding year.

Simple on-farm selection of females that wean offspring from lambing at one year of age and retaining only ewes that wean offspring each year will probably increase lamb production phenotypically by about 5 percent or more per year for a one time gain and up to 0.5 to 1 percent or more per year in genetic or cumulative gain. Also mothers weaning twins or lambs weaned as twins would always be favoured. These increases are practically without cost as many offspring must be marketed annually. No records or individual identification are needed as only females suckling offspring at weaning time would be retained. If ewes were lambing throughout the year, some records would be necessary and of course identification and records will permit greater gain.

If within flock selection of sires were also involved in selection for lambs weaned (number × weight) of ewes mated, the genetic gain might be increased to as much as 3 percent per year. This would involve some individual identification and keeping of records as male offspring born from lamb mothers would be used exclusively in breeding, thus turning the male generations every year. Male young would be selected on their own birth type which would be part of their mother's record. Selecting among all twin male offspring from lamb mothers should favour the heaviest males at a given age. The same would apply to single lambs if no twins were born from ewe lamb mothers. All males kept because of probable genetic superiority in total weight of lambs weaned of ewes mated, whether used in breeding or not, could be sold at 7 to 9 months of age as breeding males. The producer would not need to maintain any males for the entire year. Such males should bring well above market prices from those who prefer to purchase males, by new producers, to use to avoid inbreeding and by those who do not prefer to make male selections within their own flocks.


Predicted economic gains are shown in Table,1. These are based on average records for 1981–83 (Economic Indicators of the Farm Sector, USDA, 1983). Adjustments were made to better represent small farms. No government incentive payments were included. No labour costs ($12.80 to $13.55per ewe and increasing at about 3 percent per year), were included as small farms would probably use family labour and would be paid from net returns. No interest charges ($9.64 to $10.58 per ewe) were included as it was assumed that such farmers would not borrow money. Anyway, Table 1 will serve as a guide to developing an economic balance sheet by each farmer each year and possibly by each country ea-year. Economic gain will be the strongest incentive to expanding small ruminant production and efficiency.

Costs can be expected to increase as a matter of course. In the USDA data, they increase at 2.26 percent per year and this increase was projected in Table 1. Thus a 1 percent per year increase in efficiency was not sufficient to maintain a positive net return for 10 years. Constant receipts were predicted as it is difficult to expect that prices could be lower. Total per capita meat production is declining in the United States so that meat prices should be expected to increase, but this may not result in increased farm prices as the costs of processing and distribution will also increase and these costs are often passed back to the farmer.

Selection in both sexes among offspring of lamb mothers could be expected to give a gain of almost 3 percent per year in gross receipts and a cumulative gain of about 15 percent per year in net returns after being phased in during the early years. The rapid increase in net returns will provide the main incentive for adopting this breeding programme. The net returns after ten years are still insufficient to give a fair return for labour and nothing for management, but this is because of the base value being so low. The prospective 15 percent per year increase in net returns is probably greater than could be expected for any other farm enterprise.

If research and development by public institutions were applied to increase the rate of genetic progress up to 5 percent per year, then net returns per year to farmers would increase over 30 percent per year. There would be a lag period of about ten years. This kind of help to farmers is far preferable to a subsidy to offset low prices or as a repayment to farmers for the benefits received by the non-farming public from an economic system that forces farm prices lower and farm costs higher with time. If such a repayment is made to farmers it should be based on slaughter animals only or it might result in increased animals maintained to obtain the government payments. Government payments on adult animals slaughtered is especially desirable because this encourages rapid disposal of the low or non-producing females.

Gains of up to 3 to 5 percent per year in efficiency of production by small ruminants could continue for many years without levelling off because of a practical ceiling. I expect that under the most rigorous environmental and extensive conditions, an average of two lambs weaned per ewe is attainable as some females wean twins under such conditions now. Such a goal would not be reached before about 20 to 30 years or longer anyway unless additional gains per year are made through research. Also any producer could stop at any given level, but I suspect when they see how this procedure increases income that they will go as far as they can.

Other means of increasing lambs weaned of ewes mated such as flushing, use of high fertility breeds, cross breeding, immunogenic methods, and control of reproduction all can add to gains from selection. Selection should not be thought of as an alternative to these other methods but rather as a basic part of management, with other methods being used for additional gains where they are practical. Selection and use of these methods tend to enhance each other but selection is most essential. These other methods are more costly, generally give one time gains, do not lead to improvement in adaptability, and have much lower ceilings than selection. Furthermore, they are often not acceptable to farmers. This is demonstrated by overall gains of less than one percent per year in efficiency in recent years, which indicates that farmers or research scientists are actually not doing enough to increase efficiency sufficient to offset increasing costs.

One procedure that can be facilitated by selection for weaning rate is the practice of lambing more often than once per year. If ewes are put on a regime of lambing every eight months and selection for weaning rate is applied to this, the ability to lamb every eight months can also be improved genetically, because only offspring from successful matings will become replacements and twin ram lambs from ewe lamb mothers born from the most difficult mating month could be used exclusively to bring rapid gains in ability to mate any time of the year. This might not be practical for farmers but would be well suited to research stations who could pass the gains on to farmers through sale of rams.


The advantages of sheep and possibly goats for using crop residues are well known and are generally well utilized for ewes with lambs, dry ewes and finishing lambs. The advantages of sheep and possibly goats for using by-products and particularly wastes have not been well recognized. Ewes to produce lambs can be kept in close confinement at or near the source of the by-product or waste and probably also near the source of supplemental feed. The saving in less processing, drying and transportation of the waste material may make its use feasible. Furthermore, the ewes can be bred back as quickly as possible and the lambs can be weaned at 60 to 90 days to be finished on clean feed. Cull ewes can also be finished on clean feed so that there is no trace or residue from the waste in the slaughter animals. Research on contamination hazards from the waste, on needed supplementation, and pilot plant trials should preceed actual application.

Information on industrial food processing wastes, non-food industrial wastes, forest residues, animal wastes, crop residue and acquatic plants have been presented by the Committee on animal nutrition entitled “Underutilized Resources as Animal Feedstuffs”, National Academy Press, Washington, D.C. (1983).


Hundreds of millions of hectares of land, suitable for grazing by sheep and goats, is unused because of unprofitability, predator losses, or because the land in protected in reserves, wilderness areas, park land and for other purposes. Some land owners leave the land unused because of the mistaken impression that this is conservation. Brush fires near the California coast could be prevented if the land were grazed by sheep and goats to prevent the accumulation of excess combustible material and to lead to the establishment of a grass cover. Abandoned marginal crop land is often more subject to erosion than if it were cropped. Erosion on almost any land in humid areas can be reduced by reseeding to grass or other forage crops to be grazed by ruminants. Managed grazing by ruminants not only reduces erosion, but enhances conservation and adds economic and esthetic value. Reclaimed land from strip mining can sometimes be restored to full use through grazing by small ruminants.

Sheep and goat owners rarely allow overgrazing contrary to the common accusations. Most producers expect their children and grandchildren to continue the enterprise so that permanancy of the enterprise is given a high priority. New entrants into sheep and goat production may not know how to manage properly and have to learn from experience, but undergrazing by these people is more common because this gives greater individual performance. Nomadic people who live in desert areas use all of the forage available but the plants present have adjusted to this kind of use over thousands of years and quickly respond to rain. Disinterested or uninformed managers may overgraze, but the situtation rarely occurs with owner-managers who are also concerned with the care of the sheep and goats. Overgrazing in the United States has occured with feral horses, donkeys and wild deer where emotional appeals have prevented harvesting of surplus animals. In any event, overgrazing is revealed by decreased production per head and per hectare (and these are generally increasing for most countries in the world for sheep and goats).


Potential for increasing forage production from both natural and introduced plants is high in many developed countries and possibly in some developing countries, especially in the humid tropics. Even in arid and semi-arid areas, the range responds to good management that allows plants, desired by small ruminants, opportunity for regrowth and reproduction. Poor management of grazing land seems more likely in countries such as the United States where range lands have generally only been grazed for about 150 years and many plants, sensitive to heavy use by small ruminants, are still there.

Big increases in carrying capacity will probably occur in temperate humid areas like the Northwestern Coast and land east of the Great Plains in the United States. In such areas unimproved pasture land may support only about 2 sheep or goats per hectare while after reseeding and fertilization this number might be increased to 8 or 12. In the past it has often been unprofitable to improve pastures because of low market prices. Now with the possibility of steadily increasing efficiency through selection, pasture improvement may become profitable even with low prices. Increases in weaning rates enhance the utilization of improved pastures by allowing more lambs to reach heavier weights.


The heavier lamb is generally the more profitable lamb, unless there is price discrimination or unless high cost feed is used to obtain part of the gain. Of course lambs should go to the market when they reach the desired level of fatness for slaughter, when they stop gaining, or when the return from additional unit of gain is balanced with added cost. Even high cost, feed or labour is justified if the added returns exceed the cost. Overhead and fixed costs per head have to be paid regardless of market weight so that heavy market weights will generally increase efficiency.

Increases in rate of gain, feed efficiency and decrease in feed and other costs will generally increase efficiency. Management will generally increase efficiency, more than purchased feed. Forward creep grazing, grazing lambs on the best pastures separately from their mothers, creep feeding when ewes are in confinement, all may lead to better gains and heavier market weights with little increase in out-of-pocket feed costs. I saw little lambs being grazed separately and ahead of their mothers by nomadic people in Pakistan. Creep feeding on pasture may not always be profitable as the lambs or kids may substitute more expensive creep feed for lower-cost pasture.

Selection for increased rate of gain and heavier market weights should be done along with selection for more lambs weaned per ewe. The use of an index involving total weights of lambs weaned at a standard age will place selection pressure on both weaning weight and weaning rate, but in accordance with their relative economic importance. Too often in the past selection on rate of gain has favoured the single lambs and may even have led to a reduction in weaning rate.

An index consisting of the total weight weaned at a standard age of weaning is very simple and easy to use. Individual identification of both parents and offspring is essential. Weights may be estimated somewhat adequately if scales are not practical but checking by holding a lamb on bathroom scales is desirable. Portable scales may be available from extension agents. If prices of small lambs are different than from large lambs, the weight should be multiplied by estimated or actual price and then value (price × weight ) would be used as the index.


Dzakuma, J.M., Whiteman, J.V., McNew, R.W. 1982. J. Anim. Sci. 54: 540–543

Hulet, C.V., Wiggins, E.L. & Ercanbrack, S.K.1989. J. Anim. Sci. 28: 246.

Terrill, C.E.1949. Paper presented to Western Section, American Soc. Anim. Science.

Terrill, C.E.1982. Proc. World Congress on Sheep and Beef Cattle Breeding, 1:115–123.

Terrill, C.E.1983. Reproduction des ruminants en zone tropicale. Pointe-a-Pitre (F.W.I.), 8–10 Jun. Ed. INRA Publ., 1984.

Whiteman, J.V., Dzakuma, J.M. 1981. Animal Science Res. Rep., Oklahoma Agr. E.S.M.P.-108: 14–17.

TABLE 1. Economic benefits from increasing efficiency of sheep production by selection

5 years
10 years
Increase in total weight of lambs marketed per ewe (at 1% per year) from selection   
Receipts:sale of market lamb at $1.13/kg50.8553.4556.17
 sale of cull ewes at $.31/kg4.124.334.56
 sale of wool 3.4kg at £2.02/kg6.876.876.87
Total receipts:61.8464.6567.60
Expenses (increase at 2.26% per year):42.8247.8853.51
Replacements of 0.2ewe lambs and 0.1 ram lambs at market price:15.2515.2515.25
Net returns:3.771.52-1.16
Increase in total weight of lambs marketed per ewe at 3% per year from selection   
Receipts:sale of lambs50.8557.2566.35
 sale of cull ewes4.124.845.38
 sale of wool6.876.876.87
Total receipts:61.8468.7678.60
Net returns:3.775.639.84
Increase in total weight of lambs marketed per ewe at 5% per year from selection   
Receipts:sale of lambs50.8558.9275.20
 sale of cull ewes4.124.776.08
 sale of wool6.876.876.87
Total receipts61.8470.5688.15
Net returns:3.777.4319.39

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