This should be enough to tide Ozzie over untol Saphira feels better
Don't be baaaaaaaaaaad Ozzie
Read and sleep
Many New Mexico livestock producers could profit by including sheep in their farm enterprises. Sheep are among the most efficient of all the domestic animals and have been for thousands of years. Different from cattle and swine, sheep are adapted to the most extreme environmental conditions. Sheep are very agile and graze easily in the most rugged of mountain terrain, where cattle choose not to feed. Furthermore, some sheep breeds are well suited to survive on sparse desert range that would not be used otherwise. Thus, sheep have the ability to convert the natural forage of these extreme habitats into protein for human uses. We use the proteins produced by sheep in the form of wool and lamb.
Sheep can use practically all types of forage, including crop residue and even ditch banks. An abundance of forage is one key to profitable sheep production. The successful producer also must have a genuine interest in business, management skills, and labor to care for the sheep.
Some Advantages of Producing Sheep
Sheep are easy to handle and generally require little input.
Sheep production does not require elaborate facilities and equipment.
Sheep consume roughage as their primary feed.
Sheep help control weeds.
Sheep provide two sources of cash income: lamb and wool.
Sheep require a minimum amount of supplemental feeding.
Sheep can provide a quick return on investment.
Disadvantages of Producing Sheep
A sheep enterprise must be well managed.
Sheep are subject to predation by coyotes, eagles, bobcats, lions, bears, domestic dogs, etc.
Sheep require better fencing than do cattle.
Internal parasites can create health problems when sheep are intensively grazed on irrigated pastures.
Choice of Breed
The most appropriate sheep breed depends upon environmental conditions, the producer's desired management intensity, and personal preference. For accelerated sheep production, it might be necessary to use three or more breeds to develop a ewe flock that exhibits acceptable levels of desirable traits. Accelerated flocks must be able to lamb out of season, produce large lamb crops, reach sexual maturity at an early age, and grow rapidly.
If producers want to overwinter ewes for spring lamb production, then local breeds such as range-raised, fine-wool ewes are an excellent choice. Breeds of sheep are generally classified according to the breed assets.
Fine-Wool Breeds
The fine-wool breeds are chiefly Rambouillet and Debouillet. The fine-wool breeds can withstand heat, cold, and drought, and produce satisfactorily under harsh conditions. They produce a more desirable, finer grading fleece that is more uniform than fleeces from other breed types. Additionally, they are more likely to breed out of season than are many other breeds.
Medium-Wool Breeds
The medium-wool breeds are white-faced crossbreeds that include the Columbia, Corriedale, and Targhee. These breeds are very productive when feed supply is ample. However, their breeding season is more restricted than that of fine-wool sheep, and their fleeces usually vary more in fineness of grade.
Meat-Type Breeds
Suffolk, Hampshire, Dorset, Southdown, and Shropshire are some of the more common meat-type (or mutton) breeds, and they are best adapted to farm-flock production. Except for the Dorset, these are more restricted in their breeding season than fine-wool sheep. These breeds are commonly crossed with commercial white-faced ewes to produce market lambs.
Wool from these breeds lacks the fineness and often the length of staple found in fleeces from the fine- and medium-wool breeds. Quite often, wool from these breeds is discounted on the market because of poor purity (they contain black fibers).
Other Breeds
One breed with potential for use in accelerated sheep-production management systems is the Finnish Landrace. The greatest and perhaps only contribution of this breed is its reproductive capability and early maturity. Finnish Landrace are small, white-faced sheep that produce little wool. Additionally, the carcass quality of this breed is somewhat below standard. Finnish Landrace are used in crossbreeding programs to increase lamb crop percentages and to initiate out-of-season lambing.
The Polypay is sheep breed developed at the U.S. Sheep Experiment Station in Dubois, Idaho. The breed was developed from Finnish Landrace, Dorset, Targhee, and Rambouillet to optimize reproductive efficiency while maintaining growth and carcass quality.
Sheep Management Systems
Sheep can be produced under many production systems in New Mexico. Here are some things to consider when designing a sheep production system:
Available forage. Plan to make maximum use of seasonal forage because feed costs often amount to 50 to 60 percent of the total cost of producing lamb and wool. Feed consumption is the greatest during late gestation and lactation; producers may be able to reduce feed costs by grazing ewes on pasture at these times.
Available labor. When sheep are added to other farming enterprises, it may be advisable, from a managerial standpoint, to lamb when labor is not needed for other activities.
Lamb prices. Lamb prices normally fluctuate during the year, and it may be more profitable to produce lambs for the expected high market. Typically, that is during the late spring and early summer.
Size of flock. Small flocks, from 10 to 50 ewes, often are not profitable because they tend to be poorly managed. The primary reason is that mechanization is not feasible, so return per hour of labor is not maximized. Small farm flocks generally are used simply to control weeds on irrigation ditches or maintained as a hobby.
Purebred Sheep Production
Purebred sheep supply genetics for the development of commercial sheep production systems. In general, depending on the breed and availability, it is more expensive to start a purebred sheep business than a commercial one. Purebred sheep are often more expensive to produce, and more expense is involved in advertising and marketing. Ordinarily, purebred sheep are fed at a higher nutrition level than are commercial flocks. A well-fed purebred flock is more productive and more attractive to prospective buyers than are sheep maintained on lower nutrition levels.
To grow to maximum size, ewe and ram lambs must be born early. On most purebred sheep operations, breeding occurs in July and August. This usually results in a suboptimal lamb crop percentage because most ewes are more fertile during September and October.
A purebred sheep operation produces stud rams, commercial rams, and replacement ewes, usually for a price above their commercial value. Managing such an operation requires a thorough understanding of genetics, nutrition, reproduction, and health.
Commercial Sheep Production
Many management alternatives are available to the commercial sheep producer. One major distinction among these
alternative production systems is the season in which lambing occurs.
Fall lamb production. For fall lambing, an abundant supply of fall and winter forage, small-grain pasture, alfalfa stubble, or other crop residue is necessary.
For ewes to lamb in October and November, breed them in May and June. The ewe flock must be of those breeds that tend to breed out of season. The fine-wools, Dorset, and crossbred ewes that are at least 50 percent fine-wool are best suited for fall lamb production.
Even so, the lamb crop percentage from May and June breeding is likely to be low. Ewes may need hormone therapy to induce estrus and ovulation (see section on reproduction, page 11). Furthermore, farm labor often is busy elsewhere during fall lambing when the ewes need attention. Occasionally, fall-born lambs are weak and small because of heat stress during the summer gestation period.
Winter lambing. One advantage of winter lambing is that labor requirements of other agricultural enterprises are generally low at this time, so more attention can be diverted toward the ewes. This program is best for the producer who has an abundance of homegrown forages. Under this production system, slaughter lambs of market weight and condition are ready to be sold during May and June, when lamb prices are normally high.
For winter lambing, breed the ewes in late July, August, and early September. Since this is somewhat earlier than normal, it may be necessary to flush the ewes to increase ovulation rate. After the ewes are bred, graze them on good pasture that will satisfy their nutritional requirements until about four to six weeks before lambing. Prior to lambing, supplement the ewes with high-quality hay and possibly with grain to meet their nutritional needs. Lambs born in the winter should be creep-fed as soon as possible with grains and high-quality legume hay.
If feed and pasture are available, lambs can be weaned at about 60 days. It is generally more economical to feed lambs directly than to feed nursing ewes. Many producers keep the lambs in a drylot and put the ewes back on pasture. This helps to prevent internal parasite problems in the lambs.
Spring lamb production. Spring lambing coincides with the natural breeding and lambing seasons. When ewes are bred from late September through November and lamb in late February through April, a higher percent lamb crop can be expected. With ideal conditions, the lamb crop should be 150 to 160 percent. The ovulation rate in sheep is normally at its peak in late September through November. Temperatures at this time are typically not high enough to decrease ram fertility or to cause embryo loss. Normally, spring temperatures are mild and death loss associated with weather conditions is minimal. But newborn lambs must be offered some protection from spring winds. In this type of system, ewes are bred when ovulation rates should be high, so that flushing, teasing, or control of environmental conditions has less effect on conception rate or length of lambing season. Ewes must have adequate feed and should not be on a declining plan of nutrition when bred.
After breeding, the ewe's nutritional requirements are at the lowest level and they can be maintained on various crop residues and pastures, if available. Before they lamb and during early lactation, the ewe's nutritional requirements are the highest. Ewes may need a protein and energy supplement at that time. In some areas, spring pasture may partially satisfy their nutritional needs. But some irrigated pastures have a high water content and the forage is "washy." The ewes may need supplemental feeds in addition to the pasture if they are to lamb and produce milk most efficiently.
If pasture is available, it may be feasible to separate the lambs from the ewes daily and put the lambs in a drylot or on pastures separate from the ewes. Generally, best results are obtained when the lambs are not pastured with the ewes.
Accelerated lambing. Accelerated lambing is lambing more than once a year. This takes intensive management and is not recommended for the sheep producer who has not yet achieved maximum production from a conventional once-a-year lambing program. Accelerated lambing may increase the number of lambs raised over a given period, but it adds to the production cost and requires more feed, labor, and facilities.
In a carefully controlled environment, sheep can be bred every six months. However, breeding every eight months for three lamb crops in two years is more practical than a six-month lambing schedule.
Accelerated lambing also may be used to gain an additional lamb crop from ewes before they are culled. Ewes that are old or dry in the spring can be rebred for fall lambing in their last year. The advantages of accelerated lambing include increased lamb production, having lambs available for market at different seasons, year-round use of labor and facilities, and, theoretically, increased income per ewe.
Accelerated lambing necessitates the use of fine-wool or Dorset ewes and an understanding of exogenous hormones. Excellent management, disease control, and exact nutritional requirements are fundamental to the success of such a program.
Early weaning is essential in an accelerated lambing program because it is difficult to breed ewes that are lactating. Most commonly, lambs are weaned at 30 to 45 days. An excellent nutrition and health program must be incorporated into the plan to get these lambs as large as possible before weaning.
Confinement systems. Sheep can adapt to a complete confinement system of production. The confinement may vary from a drylot to small pens with slatted floors. The object is to produce market lambs in a small space using mostly feeds harvested from the farm. The advantages are that lamb production can be increased on a small area using automated feeding equipment.
This program requires intensive year-round management. Confinement rearing is best associated with an accelerated lambing program for maximum use of facilities and labor. One system of confinement that has possibilities is the confining of range sheep before lambing. Ewes are hand-lambed in lambing sheds and the lambs are weaned early, within 30 to 45 days. The ewes are then returned to the range and the lambs are finished in a drylot. This program is particularly successful where predation makes it almost impossible to raise lambs under range conditions.
Seasonal-Use Production Systems
Many farmers in New Mexico could make excellent use of sheep on a seasonal basis if a year-round sheep production system is not suitable. An abundance of high-quality, fine-wool range ewes are sold every fall. Generally, these ewes are five to six years old. From a reproductive standpoint, this is an ideal age. Ewes of this age should have a high percentage of twins.
Select range ewes carefully. Cull those with bad udders and exceptionally bad mouths. Place the ewes on pastures or crop residue. Flush the ewes from three weeks before until three weeks after introducing the rams. The flushed ewes, if properly conditioned and bred for spring lambing, should have the potential to produce lamb crops of 140 to 160 percent.
The management alternatives for this type of a production system are numerous. If spring pasture or feed is not available, or if facilities are not available to lamb the ewes, there may be a demand for bred ewes in the spring or for ewes with young lambs. If pasture is not available for the ewes after lambing, the lambs can be weaned early for feeding in a drylot, and the ewes can be sold.
A seasonal-use program is a good way to market farm-produced roughages and keep labor busy in the off-season. The biggest objection to bringing range-raised sheep onto a farm is that they often are wild and sometimes difficult to manage.
If there is an abundance of winter pasture and crop residue, pasturing feeder lambs can be profitable. This is more speculative than other seasonal-use programs because market values can change, with potentially devastating results.
Selection and Breeding
Since life began, animals best adapted to their environment have survived and produced the largest number of offspring. For example, most breeds of sheep that originated in the British Isles survived only if they were born in the spring when the temperature was mild and feed was available. That is natural selection.
Selection should be a part of all breeding sheep production enterprises. It is effective for almost all the important economic traits in sheep. No selection program, however, can improve all these economically important traits at once. Generally, the more traits involved in selection, the less improvement will result for a single trait. The first step in any selection program is to identify the traits of greatest economic importance. They may be growth rate, carcass merit, fleece traits, or reproductive efficiency.
The improvement that can be made depends on:
Accurate measurement of the trait.
Complete records on the flock.
The amount of selection pressure applied.
The amount of variation of the trait or different traits among individuals within the flock. If the sheep do not vary genetically, then no improvement can be made. If they vary greatly, then improvement will be rapid when producers select only the individuals that excel in the expression of important traits.
The heritability of the trait. Variation in any economic trait is caused by genetic differences and environmental differences. Variation that results from differences in heredity is broadly defined as heritability.
Researchers have estimated the heritability (the ability to "pass on" traits to offspring) of the economically important traits (table 1). Generally, if the heritability estimate is less than 20 percent, progress is slow. A heritability estimate of 20 to 40 percent is considered medium. A heritability estimate greater than 40 percent is high.
Purebred breeders should be committed to improving the economically important traits of their breed. Their breed serves as a source of genetic material for crossbreeding and for improving the industry.
On the other hand, commercial sheep producers might find it more profitable to crossbreed. Some economically important traits that can be improved only slowly within a breed can be improved more rapidly with effective crossbreeding. An example is rate of reproduction. By most estimates, the heritability of reproductive traits is low. However, hybrid vigor (expression of a trait above the average of the dam and sire for that trait) exists for rate of reproduction. Generally, crossbred ewes exhibit a higher reproduction rate, produce more milk, and their lambs are stronger at birth.
Table 1. Heritability of traits in sheep.
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Trait Percent
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Birth weight 0.15
Weaning weight (60 days of age) 0.20
Weaning weight (120 days of age) 0.25
mature body weight 0.40
Rate of gain (post-weaning) 0.40
Face cover 0.35-0.55
Skin folds 0.20-0.50
Grease fleece weight 0.25-0.60
Clean fleece weight 0.25-0.60
Clean yield 0.30-0.40
Staple length 0.30-0.65
Fleece grade 0.20-0.60
Multiple birth 0.10
Milk production 0.10
Ewe productivitya 0.20
Loin-eye area 0.35
Fat thickness over loin eye 0.30
Carcass weight 0.35
Retail cut weight 0.45
Dressing percentage 0.10
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aPounds of lamb weaned per ewe exposed to a ram.
Source: Sheep Production Handbook. 1996. American Sheep Industry Association, Inc. Production, Education, and Research Council.
Crossbreeding
Crossbreeding is not an immediate cure-all. The results will be disappointing with poor quality parent stock or with a breed or breeds that are not adapted to the environment. For a successful crossbreeding program, use breeds that contribute the highest combination to the economically important traits. For example, if a producer wants to market lambs, then ewes from breeds that excel in the following characteristics should be selected:
Reproductive efficiency.
Desired time and length of breeding season.
Conception and lambing rate.
Milk production.
Maternal instincts.
Crossbred ewes with these characteristics could then be mated to rams of another breed to produce market lambs. Traits to look for in the ram breeds are:
High fertility.
Growthiness.
Carcass quality.
Sexual aggressiveness.
How to Select for Increased Fertility
Identify lambs that were born as twins or triplets and select replacement lambs from this group. Twin lambs from young ewes have a greater potential for twinning than do twins from older ewes.
If additional replacements are required, select single ewe lambs from young ewes.
Select rams that were twins or from ewes that had high twinning records. Scrotal circumference should be 28 cm for 12-month-old rams and 32 cm for
mature rams.
Ewe lambs that exhibit estrus are typically more fertile and have a greater lifetime production of lambs than ewe lambs that do not reach puberty the first year. Selecting early maturing ewe lambs also emphasizes early season lambing, which might be advantageous in some management systems.
A crossbreeding program such as this would be most successful on farms where feed supplies are usually controllable and sheep are a primary source of farm income. The fine-wool breeds should be a primary source in the development of any ewe breed intended for a crossbreeding program. These breeds are particularly well adapted to New Mexico rangelands, produce the highest quality wool, are produced within the state, and have the ability to breed out of season.
If the objective is to accelerate market lamb production, it might be practical to introduce a newer breed such as the Finnish Landrace. If out-of-season breeding is not desired, the medium-wool, white-faced breeds could prove satisfactory. However, to produce market lambs, breed ewes to rams noted for their growthiness and carcass desirability. Suffolk and Hampshire generally have an advantage in desirable characteristics.
Improving Economically Important Traits
Growth rate. Consumer preference for heavier lambs with less body fat has created considerable change within the sheep industry to increase size and weight. Lambs that grow rapidly reach market weights at younger ages, which generally means they require a shorter feeding period and have less risk of death loss with improved feed efficiency.
Growth rate is easy to measure. Lambs can be weighed at weaning time or at a later age. Most producers with commercial flocks weigh lambs at weaning. A ewe's milk production greatly influences her lamb's weaning weight, but lamb weaning weight is still a valuable trait to select for because the maternal trait of producing more milk can be transmitted to replacement ewe lambs.
The heritability of growth rate is higher for post-weaning weights. Therefore, placing lambs in a controlled feeding program after weaning is useful in growth rate selection. Producers who use such performance testing programs select ram lambs after they have been weaned and place them on a uniform feeding test for approximately 90 days.
Weights at birth, at weaning, and at 12 to 16 months of age are related, but it is important to maintain a relatively low birth weight to minimize dystocia (birthing problems) and lamb mortality. Therefore, select primarily for the growth traits of weaning weight or post-weaning weight, but try to maintain low birth weights.
If weaning weight is selected for, correct the weight for age, sex, type of birth, type of rearing, and age of the dam. Use the adjustment factors in table 2.
>When selecting individual animals within a flock, simply select within sex and within twin and single groups. By listing twins and singles separately and selecting within contemporary groups, type of birth is adjusted for automatically. Twins should be given preference in selection.
Reproductive efficiency. Sheep have the potential for multiple births, especially in farm flocks. Therefore, select twins for replacements when possible. With good management, mortality of twins should not be much higher than that of singles.
Measures of reproductive efficiency include age at puberty, fertility, lambing rate, and length of breeding season. Reproduction in sheep is strongly influenced by environment. By most estimates, the heritability of reproductive rate is low, but breed differences exist. Fine-wool breeds are highly fertile and have been used successfully in crossbreeding programs to improve reproductive rate. Breeds that have been used under intensive management systems to increase lambing rate include the Finnish Landrace, Border Leicester, and Suffolk.
Another aspect of reproductive efficiency is frequency of lambing. Fine-wool breeds, Dorset, and fine-wool crossbred ewes have been used successfully in accelerated lambing programs. To increase reproduction rate, select for number of lambs born within a given year or frequency of multiple births. Older ewes twin more frequently than younger ewes. This is environmental rather than genetic. The heritability of barrenness in sheep is low. However, to maintain a high productive level within a flock, cull ewes that fail to lamb.
Carcass merit. Most of the measurable carcass traits are medium to highly heritable, thus it is possible to improve carcass traits through selection. It is more difficult, however, than selecting for traits that can be measured accurately on the live animal.
Among market lambs of the same size, carcass merit is most influenced by cutability (the ratio of lean meat to fat). Fat is the primary factor in evaluating the carcass yield grade (measure of cutability) and eventual value to the consumer. The amount of fat in the carcass at a given weight is closely related to the growth curve of the lamb. Lambs that grow rapidly and reach market weight at an earlier age generally have a higher cutability (lower yield grade). Therefore, one practical method of selecting for increased carcass merit is to select for rate of gain.
More exact methods of selecting for carcass merit can be used if carcass traits of related individuals or groups can be measured. Carcass weight per day of age, loin-eye area, fat thickness at the 12th rib, percentage of closely trimmed retail cuts, and leg-loin index all are used in measuring carcass merit in progeny groups. Sire progeny group summaries can be compiled from progeny data. Ultrasound technology can be used to estimate fat thickness and loin eye area. This technology will allow selection for carcass merit in potential sires.
Wool traits. Wool can account for as much as a 20 percent of the total gross income. Of all the economically important traits in sheep, those related to wool are the easiest to improve. Generally, wool traits are highly heritable and easy to measure. Traits that most directly influence the value of a fleece include fleece weight, fiber diameter, and length of staple. Weight of the fleece, particularly clean fleece weight, is usually the most valuable trait. Ordinarily, clean fleece weight is associated with grease fleece weight (actual weight of the fleece when shorn).
To increase flock wool production, select sheep that produce the most wool. Beware, however, of selecting entirely on pounds of wool produced because ewes that are dry or have singles rather than twin lambs may have an advantage in wool production but not in economic return. Milk production is negatively correlated with wool growth, particularly when feed is limited. Keep records on lamb production and wool production. Furthermore, if selection is placed entirely on pounds of wool, it is conceivable that the coarser fleeces may be selected.
Staple length has an important effect on the monetary value of a fleece. Ordinarily, this trait is highly correlated with pounds of wool produced, and heavier fleeces typically have a longer staple length. Measure length of staple and fleece weight at shearing time, and select replacements based on a combination of these two economically important traits.
The grade of a fleece is also economically important. Fine-wool fleeces ordinarily bring higher prices per pound than do coarse-wool fleeces. The grade, or fiber diameter, of wool primarily depends on the breed of sheep. When selecting replacements, also emphasize uniformity of grade throughout the fleece. Fleeces with a high degree of variation in grade are undesirable and have a lower monetary value. To detect such variation, examine fleeces of ewes and rams before shearing. Cull ewes that have belly-type wool extending up the sides.
Other fleece traits that should be given attention are color, softness of handle, uniformity of length and of fiber diameter, and freedom from other defects. Cull sheep with a lot of black fiber, hair, or kemp.
How to Select for Desirable Wool Traits
Record grease fleece weight and staple length of each fleece at shearing.
If possible, obtain clean fleece weight.
Rank fleeces according to weight of fiber produced and staple length.
If possible, rank sheep within a given grade of wool, within a given age classification, and within a group in which the number of lambs raised is known.
Minimizing Genetic Defects
Fortunately, sheep have few inherited defects that reduce their survival or producing ability. A discussion of the major genetic defects follows.
Jaw defects. Jaw defects are present in almost all breeds of sheep and are associated with failure of the incisor teeth to properly meet the dental pad. A jaw is undershot if the incisor teeth extend forward past the dental pad; it is overshot if the teeth hit in back of the dental pad (this condition is known as parrot mouth). Cull sheep with either of these genetic defects. If the sire and dam can be identified, remove them from the flock.
Rectal prolapse. Rectal prolapse is a serious defect most commonly associated with the meat-type sheep. It is most common among lambs fed a high-concentrate ration. It is believed that this weakness is due to inheritance. This condition is sometimes corrected by surgery, but affected animals often continue to prolapse after surgery. Cull from the flock breeding sheep in which this occurs.
Inverted eyelids. Inverted eyelid (entropion) is widespread among most breeds of sheep. This trait is highly heritable. Inverted eyelids are a "turning in" of the margin of the eyelid. This condition causes extreme irritation, and, if left unattended, can eventually cause blindness. The condition may be noted at birth and treated at that time. One method of treating this condition is to clip a metal suture to the center of the affected eyelid. Gather enough skin under the clip in a vertical direction to hold the lid away from the eye. The clip can be left in place for several days. Mark the affected lambs and do not allow them to enter the breeding flock.
Cryptorchidism. Rams with one or both testicles retained in the abdomen are cryptorchids. The condition usually is inherited as a simple recessive trait. There seems to be some association between this condition and the polled characteristic found in some fine-wool rams. Purebred breeders should make every effort to eliminate this condition.
Skin folds. Skin folds are highly heritable. They once were considered desirable in some fine-wool breeds because they provide more surface area to grow wool. This condition is no longer considered advantageous, and most purebred breeders are trying to breed smooth-bodied sheep. Excessive skin folds are positively associated with lower fertility and overall productivity. Additionally, folds are difficult to shear and are subject to insect attack.
Face covering. The amount of wool growing on the face is also highly heritable. Cull sheep with excessive amounts of wool growing below the eyes and on the lower part of the face because face wool can obscure vision. Ewes that have trouble seeing are generally not as productive as open-faced ewes.
Fleece defects. Some inherited fleece defects include the incidence of belly-type wool growing high on the side of the sheep, hairiness or hairy wool, and colored wool. Through a rigid selection and culling system, the potential for genetic defects can be minimized.
Reproduction in Sheep
In their natural state, sheep are seasonal breeders; offspring are born at the time most favorable for their survival. In some domestic sheep, the breeding season has been altered both naturally and through the use of hormones.
Normal Breeding Habits of Sheep
Age of puberty. Ewes typically reach puberty at 5 to 12 months, depending on breed, nutrition, and date of birth.
Anestrous period (reproductive inactivity). This is the period when ewes normally do not demonstrate estrus (heat). Three types of anestrous are observed in ewes: seasonal (influenced by length of day), lactation (influenced by the sucking stimulus of lambs), and postpartum.
Length between estruses, or heat periods. The normal cycle for ewes is approximately 17 days between heat periods. However, it can vary from 14 to 19 days.
Duration of estrus, or heat period. The heat period usually lasts 30 to 35 hours, with a range of 20 to 42 hours. Ovulation occurs late in the period.
Gestation period. The normal gestation period of ewes is approximately 147 days, ranging from 144 to 152 days. The medium-wool breeds and meat-type breeds ordinarily have a shorter gestation period than do the fine-wool breeds. High temperatures and high nutrition levels may shorten the gestation period two or three days. Ewes bred to white-faced, wool-breed rams may have a slightly longer gestation period than those bred to black-faced, meat-type rams.
Breeding ewe lambs. Ewe lambs that breed and lamb as yearlings generally have a greater lifetime production than ewes that have their that first lamb as 2 year olds. Since the onset of puberty depends largely upon body weight, ewe lambs should be provided adequate levels of nutrition to reach at least two-thirds of
mature weight before breeding. Also, lambs born in winter or early spring are more likely to exhibit heat the first year than are lambs born later. Separate ewes that lamb as yearlings from
mature ewes, and manage and feed them so that the yearling ewes can grow to their maximum potential size.
Ewe lambs and yearlings are normally rather shy breeders. For best results, breed them separate from older ewes. In some cases, it may be better to use rams of smaller breeds on young ewes to minimize the chance of lambing difficulties.
Effects of Environment
Sexual activity in sheep is primarily controlled by the ratio of daylight to dark. Estrus becomes more frequent as the days become shorter. In general, fertility is highest and most efficient when ewes are bred in September, October, or November; ewes bred at this time generally produce the highest percentage of multiple births.
High temperatures are detrimental to fertility, embryo survival, and fetal development. This is the biggest objection to fall lamb production. High temperatures at breeding can reduce conception rate. Heat stress during gestation impairs fetal development and can cause lambs to be significantly smaller at birth.
Psychological Stimulation
The introduction of a ram near the end of the anestrous period appears to psychologically stimulate ewes. It brings about earlier ovulation and estrual activity. The ram can be either fertile or surgically sterilized. Rams should be kept with the ewes for about 10 to 14 days and removed from the flock before breeding begins. Then, at the beginning of the breeding season, rested fertile rams that are intended to sire the lamb crop can be introduced. The stimulation does not occur when rams are placed with ewes earlier, or when rams are simply left with the ewes continuously.
Effect of Nutrition
Nutrition has a direct bearing upon reproductive performance. Ewes kept in acceptable condition before breeding normally produce more lambs if they are flushed, or given the chance to gain weight before and during the breeding season. They can be flushed with rested pastures or by supplementation. Begin flushing three weeks before breeding and, if possible, continue through the first cycle (approximately 17 days).
Flushing ewes is most effective when they are mated early in the breeding season. Since ovulation rate is near a maximum during the middle of the season, flushing at this time is not as beneficial. The results of flushing are quite variable. Sometimes, when farm flock ewes are already on a high nutrition level before the breeding season, flushing may not affect ovulation or lambing percentage.
Nutrition affects total lifetime productivity of sheep by influencing
mature size. Well-developed ewes consistently have higher lamb crop percentages than smaller ewes. Fat ewes, however, are typically less fertile, do not respond to flushing, and may experience more embryonic death loss.
Ewes grazed on legume pastures, such as alfalfa and clover, may at times be less fertile. Under some conditions, the estrogen content of these legumes is related to reproductive disorders. Breeding dates may be delayed and conception rate reduced when ewes are on pastures that have a high estrogen content. However, the estrogen content of legumes declines during the later stages of maturity.
Effect of Lambing and Lactation
Both lambing and lactation suppress estrous cyclicity in ewes. Generally, the postpartum anestrous phase lasts through lactation, even though the uterus typically returns to normal two to three weeks after lambing. Most ewes that lamb in late winter or spring do not exhibit estrus until the following breeding season. However, ewes that lamb in the fall usually exhibit a fertile heat four to eight weeks after lambing, or approximately two weeks after weaning.
Effect of Disease and Parasites
Heavy infestation of internal parasites can reduce the body condition of breeding ewes and may reduce reproductive performance. To minimize negative effects, follow a regular parasite control program and vaccination schedule. A local veterinarian should be able to provide sufficient information to develop a flock health program.
Effect of Ram
Infertile, diseased, or disinterested rams often cause poor lambing rates. The average number of ewes that can be mated to a ram are as follows: well-matured ram lambs, 15 to 30 ewes; yearlings to five-year-old rams, 25 to 50 ewes. However, in many of the low-rainfall areas of New Mexico, the average number of ewes per ram may be 30 to 40 percent lower than these values. These rates depend upon season, temperature, sex drive, and body condition. Rams six years and older that are in good physical condition may still be suitable for pasture or hand breeding.
Rams vary in their sexual behavior. Some rams mate repeatedly with the same ewes, even though several other ewes in heat are present. Some rams prefer black-faced or white-faced ewes when both groups are in the same flock.
Temperature has a pronounced effect on the ram's semen quality. Rams may be completely sterile or show lower fertility during late summer as a result of the heat. If the temperature exceeds 90F for an extended period, especially if the humidity is high, fertility of most rams is reduced. Rams must be in good physical condition for successful reproduction. Malnutrition, internal parasites, or disease can cause sterility or depress the ram's desire to mate. Common diseases, such as those affecting the feet or any of the external breeding organs, can make it impossible for a ram to breed ewes.
The formation and development of sperm requires six to seven weeks. Therefore, after recovery from sickness or heat stress, it takes six to seven weeks for a ram to produce sperm capable of fertilization. An infertile ram in a one-sire flock can cause complete lambing failure. Also, a single dominant infertile ram in a large flock incorporating several rams can prevent fertile rams from mating and result in a lower lambing rate.
It is important to fertility test rams, particularly in one-sire flocks. Semen testing by qualified veterinarians is recommended to farm-flock producers, especially when only one or two rams are being used. If semen testing is not possible, the use of a marking harness can be beneficial. If several of the ewes return to heat, it may be necessary to substitute another ram.
Using Hormones to Control Reproduction
Reproduction in sheep can be controlled by artificially inducing estrus, ovulation, and fertilization. The use of hormones is effective if management, genetic selection of breeds, and strains of breeds allow for out-of-season breeding. For accelerated lamb production or out-of-season breeding, use sheep that most normally fit the desired reproductive pattern. To further alter the reproductive process, regulate conditions such as light, temperature, nutrition, association with the ram, and other environmental factors that affect reproduction.
Hormones, along with practical selection and management practices, are useful to:
Synchronize estrus during the breeding season.
Increase the ovulation rate and incidence of multiple births.
Induce fertile mating during anestrus.
Induce early puberty.
In general, three types of hormones are used alone or in combination to achieve these objectives.
Progestogens. These are female sex hormones. They include those produced naturally as well as artificially. Progesterone is produced after ovulation by the corpus luteum, which forms on the ovary. Exogenous progestogens are used during the breeding season to synchronize estrus and ovulation. They also may be used during the anestrous period to help prepare the uterus for pregnancy and to sensitize the animal to be more responsive to hormones that cause estrus and ovulation. They can be administered by ear implant, daily injection, daily feeding, or by insertion of an impregnated sponge (pessary) placed in the vagina.
During the normal breeding season, progestogens can be used to synchronize estrus when used for a 10- to 12-day period. Estrus and ovulation usually occur between the second and fifth day following the end of treatment. However, fertility is usually suboptimal on the first cycle after progestogens are administered. Higher fertility is obtained from breeding at the second estrus. When ewes have been synchronized, they generally remain well synchronized through at least the first three post-treatment estrous periods.
Estrogens. Estrogens also are female sex hormones. They are produced naturally by the ovary or they can be produced synthetically. The estrogen concentration in the blood is highest just before and during estrus. The follicles on the ovary from which eggs are developed and released are the main source of estrogens in the female. The estrogen level, therefore, drops rapidly near the end of estrus, when ovulation occurs. Estrogens are responsible for behavioral estrus (or heat). In combination with progesterone, they sensitize the animal to respond to ovulating hormones. They also influence uterine development and the preparation of the uterus for pregnancy.
Gonadotropins. Gonadotropins are hormones that cause ovulation. They are produced by the pituitary gland as well as by certain other tissues. The gonadotropin that is used most successfully in controlling reproduction in sheep is follicle stimulating hormone. Additionally, human chorionic gonadotropin (HCG) has been used to induce ovulation.
Synchronizing Estrus
Some farm-flock producers find it advantageous to plan their breeding season so that all ewes lamb at approximately the same time. This can be largely achieved by treating ewes with progesterone for 10 to 12 days to synchronize estrus. When the progesterone is removed, the ewes exhibit estrus and can be bred at this time. However, for the largest lamb crop, breed the ewes following the second estrus after progesterone treatment. An injection of gonadotropin can contribute to multiple ovulation. Therefore,
pregnant mare serum gonadotropin (PMSG) can be given as the progesterone treatment is terminated, and again 16 to 18 days later.
Accelerated Lambing or Out-of-Season Lambing
Accelerated lambing means lambing more often than the conventional once-a-year approach. Since ewes are
pregnant for five months and nurse lambs for only about three months, they can be considered idle four months of the year. It is possible to lamb ewes every eight months (in some cases, every six months). On the surface, this seems like a logical approach to efficient sheep production, but that is typically not the case. Even with use of hormones, the success of most accelerated lambing programs depends entirely upon the competence of management. Because of the increase in disease, stress, and death loss associated with lambing, accelerated lambing is likely to reduce the length of the ewe's productive life and increase feed, labor, and managerial expenses.
An accelerated lambing program necessitates that lambs be weaned early. The recommended hormone treatment is the same as for estrous synchronization in that progesterone should be administered for 10 to 12 days and followed immediately with an injection of 500 to 750 international units of gonadotropin, and again 16 days later. If the ewes are in an anestrous period, it is sometimes helpful to administer 2 milligrams of estradiol two days before the start of progesterone treatment.
Producers who lamb outside the natural season can expect some loss in reproductive efficiency. Only outstanding managers and those who can afford to experiment should try accelerated lambing.
Artificial Insemination
The use of artificial insemination (AI) in sheep has been the subject of research for a number of years in the United States. Currently, frozen ram semen is available commercially. Additionally, transcervical techniques for AI have allowed some commercial producers to introduce AI into their breeding programs, but it is not commonly used by seedstock producers.
Sheep Nutrition
Feed represents the largest single cost in all types of sheep production. Rations must be formulated to support optimum production, must be efficient and economical to feed, and must minimize the potential for nutrition-related problems.
A producer must know the animal's nutritional requirements during the different phases of production, the nutrient composition of available feedstuffs, and how to provide the available feedstuffs to meet the animal's requirements.
Nutrition of the Ewe
A ewe's nutritional needs are not static; they vary largely with her stage of production. For 16 to 20 weeks of the year, the ewe's energy needs are very critical (such as during breeding, immediately before lambing, and while lactating). Feed levels can be lowered to reduce the feed cost during the early stages of gestation and when ewes are dry.
Maintenance of the ewe is generally thought of in terms of her nutritional requirements when dry, because at that time her requirements are the lowest of the year. However, wool production is a continuous process that must be considered as part of the nutrient requirements throughout the year.
One of the most reliable sources of information regarding sheep nutrition is The Nutrient Requirements of Sheep (sixth edition, 1985), which was produced by the National Research Council (NRC). Table 3 illustrates the requirements of sheep of different biological types and in different physiological stages of production. Use the data only as guidelines, not as rigid standards. In any flock, sheep are of different sizes and in different stages of production, and it is not always possible to know at each feeding the exact nutrient composition of the feed. However, if the producers follow the NRC guidelines, the flock's nutritional requirements will be met as closely as scientifically possible at this time.
The energy requirements are a function of the animal's basic metabolic rate. However, several factors affect maintenance requirements.
Age. Yearlings tend to have about a 20 percent higher energy requirement than adult sheep.This is probably due to the yearling's additional requirements to support growth. This is of particular importance to producers who breed ewes to lamb first at 12 to 18 months of age.
Exercise. Grazing sheep may use from 10 to 100 percent more energy than do sheep in drylot conditions. However, the magnitude of increase depends on the distance sheep must travel to feed and water, and on the topography of the range.
Climate. Temperature, wind velocity, and humidity can jointly affect energy requirements. The length and density of the fleece also affects energy requirements. Wool plays an important role in protecting sheep from both heat and cold. The insulating properties of wool help to cool the sheep in the heat of summer and keep body temperatures warmer in winter. Without wool, a sheep's energy requirements would be higher.
Body Condition. It takes more feed to maintain a fat sheep at a constant weight than it does a thin sheep. Keeping the sheep excessively fat is not only expensive because of the feed, but also it is detrimental to the ewe's reproductive capabilities and overall production efficiency. A ewe should lose 5 to 7 percent of her body weight during lactation and recover this weight loss during the dry period. Additionally, the ewe should gain body weight during gestation in proportion to the weight of the fetus and accompanying fluids.
In most sheep production situations, it is most economical to increase body condition of the ewes during the nonlactation period and "milk it off" in lactation, especially when low-cost pasture is available from early to mid-gestation.
Reproduction Requirements. Reproductive efficiency depends largely upon proper nutrition before and during the breeding season. Large-bodied ewes tend to produce more lambs per ewe. Do not confuse ewes of large size and scale with ewes that look large because they are fat. Usually, excessively fat ewes have lower conception rates and higher embryonic mortality. Furthermore, extremely poor body condition is not conducive to efficient fertility and reproductive performance. Ewes that have not had a properly balanced diet, including adequate phosphorus and vitamin A, may have a poor lamb crop percentage.
Flushing. Flushing can improve the ewe's body condition just before and during the breeding season. Generally, the practice is thought to increase ovulation rate. Flushing has more effect early in the breeding season. It is also beneficial late in the season, as it tends to increase the opportunity for all ewes to become pregnant. Flushing may be achieved by moving the ewes to a better pasture shortly before breeding. The provision of a supplemental energy source (that is, 3/4 to 1 pound of whole corn per head per day) and(or) the introduction of ewes to fresh pasture also can enhance the potential for ewes to respond to flushing. The length of the flushing period can vary, but it probably should begin 21 days before the breeding season and continue through one estrous cycle (17 days) into the breeding season if possible.
Requirements During Gestation
During early gestation a ewe's nutrient requirements are only slightly higher than they are for maintenance. Ewes in good condition at the end of the breeding period can loose some weight without hindering normal production. This is particularly true of sheep that have recovered most of their lactational weight loss during the later phases of lactation. If the weight loss is entirely recovered before breeding, lack of gain for the first 60 to 90 days of gestation should not have a negative affect on subsequent production.
The last six weeks of gestation is the most critical period in ewe nutrition. Approximately 70 percent of the fetal growth occurs at this time. Nutrient restrictions during this period may result in lighter lambs at birth, increased postnatal lamb losses, lower levels of milk production, and possibly pregnancy disease (ketosis). In late pregnancy, ewes require approximately 50 percent more feed than they do earlier in gestation. If protein is limited during late gestation, lower birth rates and lighter ewe fleece weights can be expected. Very often inadequate phosphorus intake occurs during this period, especially with ewes on pasture or with ewes consuming hay.
Ewes in late pregnancy sometimes have difficulty consuming enough feed because of the space occupied by the fetus, particularly when they have twins or triplets. If the ewe is fed a high-roughage ration, she may not be able to consume enough to supply the necessary daily energy requirements. For ewes in late pregnancy consuming high roughage rations, it is generally advisable to feed supplemental grain.
Requirements During Lactation
During the first few weeks following lambing, a
lactating ewe requires about the same feed as in late gestation, provided she is nursing a single lamb. The requirements shown in table 3 are for a
lactating ewe that is producing 3 pounds of milk per day.
If the lamb does not consume all the milk produced daily, the ewe produces less milk and uses any excess energy to store fat.
Ewes suckling twin lambs normally do not deposit fat because the nutrient supply (primarily energy) does not meet the requirements of the
lactating ewe. For maximum rate and efficiency of lamb gains, separate ewes nursing twin lambs from those nursing singles and feed accordingly. It is practically impossible to provide high-producing ewes nursing twin lambs enough feed during lactation to prevent loss of body weight. From a practical standpoint, these ewes must have reserves of body fat to maintain high levels of milk production. It is imperative that high-producing ewes are of acceptable body condition prior to lambing.
Assessing Nutritional Status
To assess the nutritional status of ewes, a subjective scoring system based on external body fat has been developed. The amount of fat cover is then used to estimate body energy reserves. The scoring system has a range of one to five, with one being extremely thin and five being extremely fat. The advantage of this system is that it is easy to use and is fairly reliable within a flock.
To score a ewe's body condition, use your fingertips to feel the fat cover over the vertebrae and ribs. However, the best area to estimate body condition is over the loin (vertebrae between the last rib and hip bone). In this area, palpate the spinous (vertical) and transverse (horizontal) processes of the spine to provide the most reliable estimate of body condition. The following illustrations (figs. 1-9*) show how to palpate this area and they describe the body condition scores.
Essential Nutrient Requirements of Sheep
Of primary importance in sheep nutrition are water, energy, protein, minerals (with salt, calcium, and phosphorus the most critical components), and vitamins (with vitamin A of primary concern).
Energy. Insufficient energy limits performance of sheep probably more than any other nutritional deficiency. An energy deficiency may result from inadequate amounts of feed or from feeds (generally forages) that do not contain enough protein to sufficiently "unlock" the energy in the feedstuff. The major sources of energy for sheep are hay, pasture, silage, and grains. Milo, barley, corn, oats, and wheat also can be used to raise the energy level of the diet when necessary. Energy deficiencies can cause reduced growth rate, loss of weight, reduced fertility, lowered milk production, and reduced wool quantity and quality.
Protein. In sheep rations, the amount of protein is much more important than quality of protein. However, since the sheep is a ruminant,
mature sheep use effectively the naturally occurring protein and nonprotein nitrogen (urea) in their diets. Common sources of natural protein supplements include cottonseed, soybean, sunflower, linseed, and peanut meals. These oilseed meals contain from 40 to 50 percent protein and are excellent sources of supplemental protein. High-quality legume hays can contain from 12 to 20 percent protein and provide adequate protein for most classes of sheep when fed as a complete ration. Grains, however, are low in protein. They generally contain only 8 to 11 percent protein. Additional protein is necessary in high-grain, lamb-finishing rations for maximum performance.
Nonprotein nitrogen sources should not be fed to young lambs. Young lambs are not functioning ruminants until they are approximately 2 months old, depending upon how soon they have access to grain and forage. However,
mature sheep can be fed low levels of nonprotein nitrogen. In general, supplemental nonprotein nitrogen is beneficial only when adequate energy is available. Urea should never make up more than one-third of the ruminally degradable protein in the diet. Additionally, nonprotein nitrogen sources should not be used when lambs are limit-fed. Urea can be toxic if consumed in large amounts over a short time, especially when the diet lacks ruminally available energy. Furthermore, urea is very unpalatable.
When supplementing range sheep in New Mexico, it is important to consider the quantity of available forage in the pasture. If adequate forage is present, but the standing forage is dry and brown (containing < 5 to 6 percent crude protein), it may be necessary to supplement with a high-protein feed (> 35 percent protein). However, if the amount of available forage is insufficient or if the forage is still somewhat green (> 6 percent protein), a lower-protein supplement should be fed to provide additional energy, if needed.
lactating ewes have the highest protein requirement and may require supplemental protein if the range forage contains less than 10 to 12 percent crude protein.
Water. Water is essential for all livestock. Producers must plan for an adequate supply of clean water when designing any type of sheep enterprise. The quality of the water is also important. Sheep will not consume enough water if it is stagnant or of poor quality.
Ordinarily, sheep consume two to three times as much water as dry matter. Abundant, clean, ice-free water is a must in lamb feedlots. Without water, lambs may eat less. Water running through a low trough or water dripping into the trough can help to start the lambs drinking and eating.
Minerals. Approximately 13 different minerals are essential in sheep nutrition. Most of these requirements are met under normal grazing and feeding habits in New Mexico. Those that are most deficient are salt (sodium chloride) and phosphorus.
Salt is essential for many body functions. When sheep are deprived of salt, they generally consume less feed and water, produce less milk, and grow slowly. Animals that are deprived of adequate salt may try to satisfy their needs by chewing wood, licking dirt, or eating toxic amounts of poisonous plants. Inadequate salt intake may cause decreased feed consumption and decreased efficiency of nutrient use. When adding salt to mixed feed, add 0.3 percent to the complete diet or 1 percent to the concentrate portion. In general, supplemental salt should be provided to range ewes at a level of 8 to 11 g of salt per head per day. Provide loose salt rather than salt blocks. Sheep tend to bite instead of lick salt blocks; as a consequence, their teeth may break or wear down prematurely.
Almost all pastures and hays contain an abundance of calcium, but grains are lower in calcium. When lambs are fed on a high-concentrate diet, calcium supplementation may be necessary.
In New Mexico, pastures and hay are generally low in phosphorus. In grains, however, the amount of phosphorous is moderate to high. Since any efficient sheep operation uses a high percentage of roughage or pasture, it is good insurance to assume that the sheep need phosphorus supplementation. Phosphorus deficiency causes slow growth, reduced appetite, unthrifty appearance, listlessness, abnormal bone development, and poor reproductive performance. It may be beneficial to provide phosphorus supplements year-round for the breeding flock.
When purchasing commercial mineral blocks or loose forms of mineral supplements, look at the calcium-to-phosphorus ratio. The narrower this ratio, the better. However, it is important to make sure that the ratio is not inverted (more phosphorous than calcium). If producers prefer to mix a mineral supplement, mix 50 percent salt with 5 percent cottonseed meal and approximately 45 percent bone meal or dicalcium phosphate. Provide this supplement free choice and year-round in a feed box protected from rain and moisture.
mature sheep require all the fat-soluble vitamins: A, D, E, and K. They do not require supplemental B vitamins, which are synthesized in the rumen. Normally, the forage and feed supply contain all essential vitamins in adequate amounts, except vitamin A, which is sometimes deficient in dormant forage. However, sheep can store vitamin A for a considerable time. If ewes have been pastured on green forage or have had access to high-quality legume hay, vitamin A is not usually deficient.
In some areas, lambs may develop white muscle disease. This is thought to be caused from a deficiency of vitamin E, selenium, or both. Treatment is most effective with early diagnosis and injection of a vitamin E-selenium material (see page 26).
Creep Feeding. The objective of any farm sheep enterprise should be to develop thrifty, fast-gaining lambs that can be marketed at an early age. Creep feeding may help accomplish this objective.
The most efficient conversion of feed to weight gain occurs during the first 100 to 120 days of a lamb's life. Lambs can easily gain 1 pound per day in their first 70 to 80 days. In well-managed flocks of efficient, fast-gaining breeds, it is common for lambs to reach weights of 110 pounds at 120 days of age.
Young lambs gain 1 pound for every 3 to 4 pounds of feed consumed. By comparison, old-crop feeder lambs require 5 to 6 pounds of feed per pound of gain. There are several potential advantages to using a creep-feeding program:
Increased weight gains, especially for multiple-birth lambs.
Highly efficient feed conversion.
Early marketing.
Early growth and development of the lamb lessens the stress of early weaning.
When practical, start lambs on creep feed as soon after birth as possible. Ordinarily, lambs do not consume much feed until they are 3 to 4 weeks of age. However, the small amount consumed at earlier ages is critical for establishing rumen function in the lamb. Most studies have shown that if the intake of the creep ration does not average 1/2 pound per day from 20 days of age to weaning, then no increase in lamb performance is realized from creep feeding.
Locate the creep feeders where the lambs will use them. In a drylot, place the feeders in a convenient, dry, well-bedded, protected area. In pasture areas, place the feeders relatively close to water tanks, resting areas, or salt and supplement feeders.
To get lambs started on a creep, make sure the starter ration is palatable. Soybean meal in the starter ration increases palatability and provides additional protein. However, soybean meal is expensive. High-quality alfalfa hay, alfalfa pellets, and oat grain also are very palatable.
The creep ration does not have to be complex. It should provide at least 15 to 16 percent natural protein. A simple creep ration containing 80 percent grain sorghum, 10 percent oats, 10 percent oilseed meal, with alfalfa hay free choice should be adequate. Depending on the cost of grain, corn can be substituted for grain sorghum, and wheat or barley can replace half the grain sorghum. In general, young lambs prefer coarse, rolled grains and pelleted feeds. The cost of preparation can make the ration costly, but rate of gain and feed efficiency are increased by pelleting complete feeds, concentrates, and roughages. Pelleting also allows the producer to include different additives, standardize the grain-roughage ratio, and lessen feed waste. Do not feed dusty, moldy, wet feeds. If practical, give any feed left in the creep feeder daily to the ewes, and provide the lambs with fresh feed every day. Add antibiotics to creep rations according to a veterinarian's recommendations to provide some protection against low-level infections.
Individual management systems differ, but often it is feasible to discontinue feeding the ewes grain after the lambs are approximately 6 weeks old and are eating adequate amounts of the creep feed. It is more efficient to feed the grain directly to the lambs because they will convert the feed to gain more efficiently than the ewes can convert feed to milk to lamb gain.
Some producers wean lambs when they are 60 days old. Early weaning of 40 to 50 pound lambs can be successful, provided the lambs are consuming adequate amounts of feed. Research has shown that the ewe's milk production reaches a peak at about four weeks following lambing, and steadily declines to about half as much by the 10th week of lactation. About 74 percent of all milk is produced in the first eight weeks of lactation.
Feeding Lambs. If the farm enterprise is geared to producing marketable lambs in the shortest possible time, creep feeding the lambs early in life is essential to early weaning and to subsequent rapid development in the feedlot. The size o
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I hope, hope, HOPE it's all gone by tomorrow, but if not, you'll have to entertain Ozzie for a little while longer. *sniffle* I'm soooo sorry.
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) We'll keep an eye on ozzie.
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