Quiz 30: Sheep and Goat Breeds and Breeding

Biology

715130-30-1RQ AID: 5766 | 28/10/2016 ________________________________________________________________________ Sheep are produced for two main reasons. One reason is for their wool and secondly for the meat. Both these traits are heritable in nature and so various breeds of sheep have been developed to meet the demand for wool and meat in the market. ________________________________________________________________________ Sheep are divided into two types - the Ewe breed and the Ram breed. The Ewe breed is the one which is raised only for their wool. The Ram breed is reared for its meat. Based on the type of wool they are of the following types: 1) Fine wool breeds 2) Medium wool breeds 3) Long wool breeds 4) Crossbred-wool breeds 5) Hair type sheep Each of these breeds has its own strengths and drawbacks. The characteristics of each of these breed type is discussed below. ________________________________________________________________________ Fine wool breeds : They constitute 50% of the world's sheep population. They live in the dry and semi arid climatic conditions. The breed is very popular for its flocking impulses. They have a long life and have enduring nature. Some examples of this breed are Merino and Rambouillet. The wool has very small fibers. The diameter of the fiber is less than 22 microns. The fleeces of these sheep are too short in length. This sheep's wool is the most valued in the market because it does not cause itching to the skin when it comes in contact. ________________________________________________________________________ Long wool breeds : The ancestors of this breed are known to be the British Isles. They inhabit the wetlands unlike the fine wool breeds. They are seen in countries like United Kingdom, New Zealand and Falkland Islands. Some examples of this breed are Border Leicester, Lincoln and Romney. The wool of this sheep has a diameter of more than 30microns. Wool is long and has staple length. This breed's long fleeces are in demand by weavers and hand spinners. ________________________________________________________________________ Medium wool breeds : They only constitute 15% of the sheep population in the world. All sheep that are bred for meat usually have medium wool. This breed is also known as 'mutton type'. Their wool is intermediate between fine and long wool sheep in diameter and length. Two famous names in this category are Cheviot and Dorset. ________________________________________________________________________ Two strains of Cheviot are known - Cheviot and North Country Cheviot. Cheviot was first brought to United States in 1838. And North Country Cheviot was brought to United States in 1944. Both these sheep have a stylish appearance, with a high head, ears upright. They don't have wool on head and legs and hence they do not suffer from wool blindness. img ________________________________________________________________________ Cross-bred wool breeds : This breed was a result of crossing fine wool breed with long wool breed. The aim of this crossing was to obtain wool which had the length like that of long wool breed and a quality of the wool like that of fine wool type. The fleece of a cross bred wool type is graded between 56 - 62 hanks. ________________________________________________________________________ Some examples of this breed are Columbia, Corriedale, Polypay and Targhee. Columbia is found in majority among the cross bred wool breeds. Corriedale is chosen by breeders because of its open face. The fleece of Corriedale is known to the best. The yearly fleece weight average goes up to 17 pounds. Polypay has some good traits like high proliferation rate, short gestation period and early puberty. ________________________________________________________________________ Hair-type sheep breed : This breed is a minority. It constitutes only 10% of the sheep population. They are more popular in the temperate climates of North America and Europe. They do not have any wool or fleeces. Their body coat looks similar to a goat. Some examples of this breed are Dorper, Katahdin and St. Croix. ________________________________________________________________________ Dorper exists in two forms - Dorper black head and Dorper white head. It is mainly reared for mutton. It can adapt to a wide range of climatic conditions. It has tolerance towards heat and insects. They have long breeding season due to which the lambing rate goes up to 180%. And their lambs grow very fast. ________________________________________________________________________ Another breed by the name Texel also belongs to this category. Texel is known for its muscling and high carcass. The wool produced by Texel is medium wool type.

Unlike the sheep, goats are raised for three reasons - meat, fiber and milk. And the breed of goat preferred for each of these products is different. The characteristics and uses for each breed are explained below. Meat goats : The main breed reared for meat or mutton are Spanish and Boer. Spanish: It is the popular breed for meat. They have a small built and can breed off season also. Due to their high survival rates and endurance levels they are excellent at range. They exist in a variety of shades and have different shapes of the ears. They are very good at range and can be easily managed with low inputs. Boer: It is another breed produced for meat, and slowly gaining popularity after the Spanish. This breed is known for its fast growth rate and lean meat. A yearling male weighs about 100 lb and a yearling female weighs about 85 lb. But an adult male Boer weighs 250lb while an adult female weighs 140 lbs. Boers have head with cherry red color and white body. Their ears are long and drooping. Dairy goats: among the dairy goats 6 breeds are well known in the industry. The features, strengths and production values are summarized in the table below: img Fiber goats: These goats are only raised for their fiber. Two popular breeds in this category are Angora and Cashmere. Angora : Angora is domestic breed of goat. It derives its name after the capital city of Turkey, Ankara. The goat produces a shining fiber called "mohair". One single goat generates 4-5 kgs of hair in one year. They are shorn twice in one year. The fleeces grow very fast. They are mostly seen in semi arid and arid regions like Texas. The horns of the Angora take a curve to the sides. Mature buck weighs about 150-200 lb. And a does weighs about 90-110 lb. Their dense coat makes them susceptible to parasites. Their nutritional requirements are very high because of the fast growth of the fleece. Mohair's development curtails if the diet is not of good quality.

The first step of a breeding programme is selection and assessment. Looks or appeal of the animal is not the only criteria for selection. The animal should be selected as per the objectives mentioned below: When a producer is selecting a sheep for wool production he should consider 3 things. 1) The quantity of wool - Quality is judged by looking at the density of the fleece. Density is measured by observing number of fibers per square cm. 2) The quality of wool - It should be very fine in its diameter according to the ISI standards. The staple length should be more than or equal to 3.5cm. The growth of the fleece should be uniform on the whole body of the sheep 3) The condition of the wool - Condition of the wool is assessed by observing the amount and distribution of yolk, existence of foreign particles and shade of the fleece. Almost all characteristics related to wool are heritable. And sheep should be selected based on their individual performance which can bring out genetic improvement. Selection and assessment of sheep for mutton : When a sheep is being reared for its mutton the traits one should see are symmetrical blocky body, balance of the body, thick flesh, body constitution and quality, weaning weight and number of lambs per gestation. All these traits of mutton sheep are also highly heritable. Hence, selection of a parent with the right traits will bring a significant improvement in the progeny traits. The table shows the percentage of heritability for economically important traits. img

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