Like other mammals, the reproduction of domestic sheep occurs sexually. Its reproductive strategy is very similar to other domestic livestock. The sheep are generally married by a ram, which has been chosen by a farmer or has established dominance through physical contests with other rams (in wild populations). Most sheep have breeding season (autumn tupping) in autumn, though some may multiply throughout the year.
Mostly as a result of human influences in sheep breeding, sheep often produce many sheep. This increase in the birth of the lamb, both in number and birth weight, can cause problems in labor and survival of sheep, which require the intervention of pastors.
Video Domestic sheep reproduction
Sexual behavior
Ewes generally reach sexual maturity at the age of six to eight months, and rams are generally at the age of four to six years (ram is sometimes known to impregnate their mother in two months). Ewes enters the oestrus cycle every 17 days, which lasts for about 30 hours. In addition to emitting the scent, they show readiness through the physical appearance toward the ram. The phenomenon of freemartin, a female cow that behaves masculine and has no functioning ovaries, is generally associated with cattle, but occurs at some level in sheep. Freemartin agencies in sheep may increase as the birth of twins (freemartins are the result of male-female twin combinations).
Rutting
Without human intervention, rams can fight during the habit of determining which individual can marry a mother. Sheep, especially the unknown, will also fight outside the breeding period to establish dominance; rams can kill each other if left to mix freely. During the routine, even usually friendly sheep can become aggressive against humans because of their elevated hormone levels.
Historically, aggressive goats are sometimes blindfolded or staggered. Today, those who raise rams usually prefer softer preventive measures, such as moving in clear lines to get out, never turning their backs on rams, and may water with water or a solution of bleach or vinegar to reduce costs.
Maps Domestic sheep reproduction
Pregnancy
Without ultrasound or other special tools, determining whether a sheep is pregnant is difficult. Ewes only begins to clearly show pregnancy about six weeks before giving birth, so shepherds often rely on the assumption that a ram will impregnate all the sheep in a herd. However, by placing a ram with a chest armor called marking harness that holds a special crayon (or raddle , sometimes spelled reddle), the males have been marked with a color. Dyes can also be directly applied to brisket ram. This measure is not used in clusters where wool is important, because the color of a yeast is soiled.
After mating, sheep have a pregnancy period of about five months. Within a few days after the coming birth, the parents begin to behave differently. They may lie down and stand erratically, scratch the ground, or act out of harmony with the normal flock pattern. The udis tree's grease will quickly fill up, and the vulva will swell. Vaginal, uterine or rectal prolapse may also occur, in which case a physical seam or retainer may be used to hold the orifice if the problem persists.
Artificial insemination and embryo transfer
In addition to natural insemination by rams, artificial insemination and embryo transfer have been used in many years of sheep breeding programs in Australia and New Zealand. These programs have become more common in the United States during the 2000s because of the number of veterinarians eligible to perform these types of procedures with proficiency has grown. However, ovine AI is a relatively complicated procedure compared to other livestock. Unlike cows or goats, which have a straight service that can be insominated in the vagina, men have a curved cervix that is more difficult to access. In addition, breeders to date can not control their estrus cycles. The ability to control the estrous cycle is much easier today because a safe product helps in aligning the heat cycle. Some examples of products are PG600, CIDRs, Estrumate and Folltropin V. These products contain progesterone which will lead to the induction of estrus in sheep (sheep) during seasonal anestrus. Seasonal anesthesia is when the baby does not have a regular estrus cycle outside the natural breeding season.
Historically, sheep's vaginal insemination only resulted in a 40-60% success rate, and is thus called "shot in the dark" (SID). In the 1980s, Australian researchers developed laparoscopic insemination procedures combined with the use of progestogen and pregnant serum gonadotropin (PMSG), resulting in a much higher success rate (50-80% or more), and had become the standard for artificial insemination. sheep in the 21st century.
The collection of natural cement is an integral component of the whole process. Once the semen is collected, it can be used immediately for insemination or slowly frozen for future use. The freshest semen is recognized as the preferred method because it lives longer and produces a higher level of conception. Frozen Cement will work but it must be the highest cement quality and the mains must be inseminated twice on the same day. The marketing of cement ram is a major part of the industry. Manufacturers who have prize-winning sheep have found this to be a good way to take advantage of the award of their most famous animal.
During embryo transfer (ET) small surgical procedures with virtually no risk of injury or infection when done correctly, sheep laparoscopy allows improved genetic imports, even breeds that may not exist in certain countries due to live animal import regulations. Embryo transfer procedures are used to enable producers to maximize females that produce the best sheep/children either for retention into swarms or sold to other producers. ET also allows producers to continue utilizing a female parent who may not physically be able to carry or feed a set of lambs. ET can allow producers to grow the herd quickly with individuals above the average of the same blood line. The main industries to utilize this technology in the United States are sheep breeders and exhibitors. This is a common practice in the commercial sheep industry of Australia, New Zealand, and South America.
The average success rate in Embryo Transfer in terms of recovering embryos can vary greatly. Each breed will respond differently to the ET process. Usually females are white-faced and indeed more fertile than the black ones. The range of zero to mid 20 in the case of a viable embryo recovered from the flush procedure can be expected. For an average year, 6.8 eggs can be transferred per donor with a 75% conception rate for the eggs.
Lambing
When birth is imminent, contractions begin to occur, and the swelling behavior of females may increase. A normal delivery may take one to several hours, depending on how many lambs are present, the age of the mother, and their physical and nutritional condition before birth. Although some breeds may regularly produce larger lambs (note standing about nine sheep at a time), most produce single sheep or twins. At some point, usually at the beginning of labor or soon after birth, sheep and sheep may be confined to a small jug of childbirth. These pens, typically two to eight feet long (0.6-2.4 m) in length and width, are designed to aid the careful observation of the female mothers and to unite the bonds between them and their sheep.
Obstetric ovine can be a problem. By raising female breeds that produce multiple offspring with higher birth weight for generations, sheep producers inadvertently cause some domestic sheep have difficulty breeding. However, it is a myth that sheep can not be sheep without human help; many mothers are born directly in the grasslands without help. This can be proved by the fact that they give birth in the wild. Balancing fertility with high productivity is one of the sheep breeding dilemmas. While most deliveries are relatively normal and require no intervention, many complications may arise. A sheep can be present in a normal way (with both feet and head forward), but it may be too big to slide out of the birth canal. This often happens when the big ram is crossed with the female parent (this is related to the breed, the male sheep is naturally larger than the female parent by comparison). The lamb may also present itself with one shoulder to the side, fully retreat, or just some prominent limb. Sheep can also be spontaneously canceled or stillborn. Reproductive failure is a common consequence of infections such as toxoplasmosis and foot and mouth disease. Some types of abortion in sheep can be prevented by vaccination against this infection.
In the case of such a problem, those present in lambing (who may or may not be excluding veterinarians, most of the shepherds are able to compete in a certain degree) may help the females in extracting or positioning the lambs. After birth, ideally break the amniotic sac (if it does not break during delivery), and start licking the sheep clean. Licking clean the nose and mouth, dry the lamb, and stimulate it. Lambs who breathe and healthy at this point start trying to stand up, and ideally do it between half and hour full, with the help of the mother. Generally after sheep stands, the cord is trimmed to about an inch (2.5 cm). Once trimmed, a small container (such as a film tube) of iodine is held against the sheep's stomach above the rest of the wire to prevent infection.
Postnatal care
Under normal circumstances, the sheep nurse upon standing, receives vital colostrum milk. Lambs who fail to breastfeed or are prevented from doing so by their parents need help to survive. If persuading a partner to accept nursing is unsuccessful, one of several steps can then be taken. Ewes can be held or tied to force them to accept sheep feeding. If a sheep does not eat, the stomach tube can also be used to force feed the lamb to save his life. In the case of a lamb denied permanently, a shepherd can then try to grow an orphaned sheep to another parent. Lambs are also sometimes nurtured after the death of their mother, either from birth or other events.
Scents play a big factor in sheep who recognize their sheep, thus disturbing the smell of newborn sheep by washing or over-handling can cause a baby to reject it. On the contrary, various methods of applying the female sheep's aroma to orphanages may be useful in the construction. If an orphan sheep can not be fostered, then it is usually what is known as a bottle of sheep - a sheep raised by the people and fed through the bottle.
After the lambs are stabilized, sheep marking is done - this includes ear tagging, docking, castration and usually vaccination. The ear tag with numbers is the main mode of identification when sheep are not named; it is also a legal means of animal identification in the EU: the number can identify individual sheep or just herd. When done at an early age, ear tagging seems to cause little or no discomfort to the sheep. However, using tags incorrectly or using tags that are not designed for sheep can cause inconvenience, in large part due to excess weight tags for other animals.
Ram sheep are not intended for castrated breeding, although some shepherds prefer to avoid procedures for ethical, economic or practical reasons. Ram lambs that will be slaughtered or separated from the male parent before sexual maturity are usually not castrated. In most breeds, sheep are propped up for health reasons. Tail can be issued just under the sheep's tail wing (shorter docking than this can cause health problems such as rectal prolapse), but in some long-tailed breeds, or not anchored at all. Docking is not required in short-tailed breeds, and this is usually not done on breeds where long tails are valued, such as Zwartbles. Although docking is often considered cruel and unnatural by animal rights activists, it is perceived by large and small sheep producers alike to be an important step in maintaining sheep's health. The long, hairy tail makes cutting more difficult, interfering with marriage, and making sheep particularly vulnerable to parasites, especially those that cause flies. Both castration and docking can be done with multiple instruments. The elastrator places a tight rubber band around the area, causing it to have atrophy and falling within a few weeks. This process does not bleed and does not seem to cause long suffering for the lambs, who tend to ignore it after a few hours. In addition to the elastrator, a Burdizzo, emasculator, chisel or a heated knife is sometimes used. After one to three days in the mulching pitcher, sheep and sheep are usually stable enough to allow reintroduction throughout the herd.
Commercial sheep farm
In large South American sheep producing countries, Australia and New Zealand sheep are usually raised in vast lands with much less intervention than breeders or ranchers. Merinos, and much of the land in these countries do not lend themselves to the mass interventions found in smaller breeding countries. In these countries there is little need, and there is no choice but to sheep outside the home because there is not enough structure to handle the large sheep there. The New Zealand Elephant produces 36 million sheep each spring, which averages 2,250 sheep per farm. Australian farmers, too, do not receive financial support provided by governments in other countries to sheep breeders. Inexpensive sheep breeding is based on large sheep per unit of labor and has a female parent capable of giving birth without supervision to produce a strong and active sheep.
Managerial aspects
For ranchers who intend to make strict repairs to their livestock, the sheep are classified and the inferior sheep are discarded before mating to maintain or improve the quality of the herd. Wrinkled faces (wool) have long been associated with lower fertility rates. Selected specimens or sheep are selected with the help of objective measurements, genetic information, and evaluation services now available in Australia and New Zealand. The choice of marriage time is governed by many factors including climate, market requirements and feed availability. Rams are usually mated to about 2.5% depending on the age of the sheep, plus consideration for the size and type of paddocks mating. The marriage period ranges from about 6 to 8 weeks in a commercial group. Longer mating time produces management problems with sheep and shear etc.
Good nutrition is very important for mothers during the last 6 weeks of pregnancy to prevent toxemia in pregnancy, especially in twin cushions. However, overeating can produce more than single sheep and large single dystocia. Cutting sheep before giving birth reduces the number of parent thrown (ie can not rise without help), and the number of lost sheep and lambs. Lambs are also helped to find udders and suck shaved daughters.
After shaving the males are usually placed in well-protected paddocks that have good feed and water. Attention to sheep's sheep varies depending on the type, size, and location of the property. Unless they are unlikely they will receive intensive care. In stations with large pastures there is a non-interference policy. On other properties, the mass is examined by the cattle ranch at various intervals to stand the dwarves and deal with dystocia. Manufacturers also occasionally secretly take pregnant mothers away from mothers who have children, to prevent false mothers.
Sheep are usually marked at the age of three to six weeks, but protracted prolonged seasons may require two signs.
Inbreeding depression
Inbreeding tends to occur in a limited size group and where only one or more rams are used. Associated with inbreeding is a decrease in progeny performance that is usually referred to as inbreeding depression. Inbreeding depression has been found for birth weight of sheep, average weight every day from birth to two months, and litter size.
Other countries
In the main countries of Argentine, Uruguayan, Brazilian, Peruvian, and Chilean sheep, ranchers also make use of feather testing and performance recording schemes as a means of increasing their livestock.
New research
In 2008, for the first time in history, researchers at Chiswick CSIRO research station, between Uralla and Armidale, New South Wales have used stem cells to develop ram and replacement bulls. This man then produces a decent semen from another man.
The approach in this sheep experiment involves the irradiation of the testes of ram while placing the stem cells from the second ram into the first testicle, ram A. In the following weeks ram A produces semen in the normal way, but uses stem cells from ram B and therefore produces semen carries the genetics of ram B rather than his own. Ram A therefore effectively becomes a replacement ram.
Decent semen is then implanted in females and many sheep born through this process prove normal and healthy. DNA testing has proven that up to 10% of sheep are cherished by replacement sheep and carry the genetics of the donor sheep.
References
External links
- Reproduction in ram
- Reproduction to the parent
- Seedling and sheep selection
- General ram management
Source of the article : Wikipedia
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