Sheep - AgRIS

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aided intrauterine deposition into the uterine lumen by-passing the cervix or transcervical insemination adapted to the anatomy of the ewe's genetalia. A new diluent named egg yolk lactose raffinose citrate glycerol (EYLRCG) has been evolved for pellet freezing of ram semen giving more than 50% post-thaw motlity. It contains 18 ml eggyolk, 5g lactose, 8g raffinose, 2.2 g trisodium citrate dihydrate, 3.3 ml glycerol, 300 mg streptopenicillin and 100 ml triple glass distilled water. Ejaculates of good quality semen are diluted with EYLRCG to bring the sperm concentration to 1 billion spermatozoa per ml. Diluted samples are equilibrated at 5°C for 4 h and then frozen into 0.2 ml size pellets. Pelleting is done in a pitted anodysed aluminium tray floating over liquid nitrogen. Pelleted semetlaced in goblets and stored in canisters by lowering under liquid nitrogen in cryocans. Thawing of pellets is done in dry test tubes individually upto liquification at 50°C. In order to overcome the disadvantages of proper identifi.cation of stored pellets and lack of repeatition in freezing conditions, a protocol has been developed, for deep freezing of semen in straws at CSWRI, Avikanagar. The freezing protocol, based on programmable freezing and computer assisted sperm analysis technique, gives 70% post-thaw motility consistently in all the breeds tested. Ejaculates having 90% initial motility and sperm density exceeding 3 billion spermatozoa per ml are extended in egg-yolk tris glycerol diluent to bring the final concentration to 1 billion spermatozoa per ml. The diluted samples are filled in 0.25 or 0.5 ml size straws, equilibrated for 2 h at 5°C and frozen @ -5 to -125°C per minute in a programmable cell freezer. Thawing is done at 50°C for 10 seconds in case of 0.25 ml size straws and at 60°C for 10 seconds in case of 0.5 ml straws in a water bath. The application of computer assisted sperm analysis technique during various stages of cryopreservation enables precise and objective evaluation of sperm function. Apart from identifying motile and immotile spermatozoa, it helps also in computing the sperm velocity and track dimensions of the motile spermatozoa. Efforts are also being made to identify factors causing cryo injury to ram spermatozoa during cryopreservation by cryo microscopic technique in order to amelio rate the sperm plasma membrane from the deleterious effect offreeze thaw process. 7.3 Female reproduction Breeding ewes of indigenous breeds should be 1.5 to 2 years old depending upon their condition. Breeding too young ewes results in more wealclings and thus higher lamb losses. The ewes should posses a long preferably low set body, roomy hind-quarters, well formed pliable udder, active foraging habit and good mothering instinct. The ewes having poor milking capacity, overshot or undershot jaw, broken mouth, blind teat and meaty udder should be disqualified from the breeding programme. Body weight of an ewe at breeding should not normally be less than the adult body weight of that breed. The ewes should be prepared for mating when they are gaining weight, by giving them access to luxuriant pasture or feeding them a little grain for about 2-3 weeks preceding the beginning of the breeding season. After the ewes have been bred this extra feed can be stopped. The normal heat period in ewes lasts from 6 to 48 hours with an average of 24 hours. The normal oestrous cycle ranges from 16 to 19 days with an average of 17 days. The ewes come in heat usually about 2 months after lambing. <strong>Sheep</strong> can be bred naturally or through artificial insemination. The natural breeding is done by either flock mating, pen mating or hand mating. In flock-mating system artificial insemination makes possible the extensive use of superior exotic and outstanding crossbred/indigenous rams. On an average, a ram ejaculate measures about 1 ml and contains 3 to 4 billion spermatozoa of which about 80-90 per cent are alive, if the semen is from a healthy ram. Semen of higher concentration is usually slightly acidic in reaction, and that of lower concentration slightly alkaline. In fertile semen, spermatozoa have a whirling motion. Semen can be stored for artificial insemination in a chilled liquid form or deep-frozen in liquid nitrogen. Preserving semen in a liquid form allows short-term preservation while the deepfrozen form permits 'long-term preservation for indenfinite period without any significant decrease in semen quality. 411
7. 3.1 Puberty Puberty in the female is exhibited by the first estrous. The breed of the ewe affects the age and weight at puberty and sexual maturity. Ewe lambs in most of the mutton breeds reach puberty at the age of 10-12 months normally breeding during the first autumn. Larger, slower maturing breeds may mature at the age of 18-20 months. Awassi lambs on a good diet first display estrous at an average age of 274 days (Younis et al., 1978), but Rambouillet crossbred lambs in Rajasthan are about 615 days old before they display estrous (Kishore et al., 1982). This difference is largely due to the different growth rates resulting from different nutrition. The average age at puberty in Ossimi and Barki ewe lambs reared on high plane of nutrition was 347 days in Egypt whereas, it was 366 days on a low plane of nutrition (Ei-Homosi and El-Hafiz, 1982). The variation in age at puberty occurs in sub-tropics where the ewes are reasonably anestrous so that if a lamb fails to cycle in her first season she will not cycle until the next, several months later. Under Indian conditions, the ewes reach sexual maturity at 9 to 14 months of age, however, the full body growth is only attained between 18 to 24 months of age and the stage at which the mating is performed. Merino sheep mature more slowly than the Hampshire or Suffolk breeds, crossbred lambs generally mature earlier than pure bred lambs. Roy et al., (1962) recorded first estrous in young Bikaneri ewes of less than one year of age. Majority of the Nellore ewes attained puberty at 630-810 days of age (Gupta et al., 1987). The age at puberty has been reported to vary from 306-383 days in different exotic breeds (Martemucci et al., 1983). 7. 3.2 The Estrous Cycle Rhythmic sexual behaviour patterns develop in females during puberty. This change in behaviour in called estrous and it occurs with each estrous cycle in non seasonal breeders unless pregnancy intervenes. The combination of physiological events which begin at one estrous period and end at the next is termed as estrus cycle. Estrous occurs every 14-19 days with a mean of 17 days (Terrill, 1974). Similar duration has been observed for ewes in tropics by Narayanaswamy and Balaine (1976); Gaillard (1979) and Yenekoye etal., (1981). Cyclelengthsofupto 70 dayswererecordedforFulani ewes in Niger by Yenikoye et al. (1982). Visual signs of approaching estrous are, a swelling and redness of the vulva and restlessness or nervousness indicating a desire for company, but the most abvious sign is ridding and inturn being ridden. The breeding occurs only during estrous although the ram is capable of breeding at any time (Dhanda, 1970). Three types of estrous cycles commonly observed are: 1) One type is seen in sheep, goat, cow and sow during breeding seasons. The infertile cycle in these species culminates in spontaneous ovulation of mature follicles; corporalutea automatically formed, becomes functional and exists for a definite period oftime. 2) Rat and mouse are example of another type of estrous cycle in which ovulation is spontaneous, but the corpus leuteum which is formed is not functional unless mating occurs. 3) In third type maturation and ovulation of follicles fail unless the male copulates with the female, Rabbit is an induced ovulator. The main events of the estrous cycle of the ewe can be divided into those associated with the growth of follicle and those associated with the growth of the corpus luteum. The growth of the follicles takes place during proestrous and estrous. The period of the corpus luteum can be divided into two periods, metestrous and diestrous. The estrous cycle is usually dated from the first day of estrous. 1. Estrous Estrous is defined as the period of sexual receptivity during which ovulation occurs in most species and the corpus luteum begins to form. The psychic estrous is brought about by the action of estradiol on the central nervous system. Symptoms of heat are less pronounced in ewe than in cow or mare. The ewe in heat makes little effort to tease and mount. Because of weak 412
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1. Introduction ANNEXURE - IX-C SHE
Page 3 and 4:
2. Classification, Origin and Domes
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Nadu, Andhra Pradesh and Karnataka,
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different states it is estimated th
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Table 3.3 continued...... Country N
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een possible because of its substan
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(USA). The Rambouillet as purebreds
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ii) Marwari Deriving its name from
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Pradesh and Bihar, Bijapur, Gulbarg
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elatively tall with little hair exc
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4.2 Distribution of type breeds in
Page 23 and 24:
Table 4.1 continued...... Region/Br
Page 25 and 26: Table 4.2 continued....... SI. Bree
Page 27 and 28: 5. Genetics 5.1 Chromosome Profile
Page 29 and 30: esponsible for the formation of one
Page 31 and 32: the exercise these animals did not
Page 33 and 34: For understanding the inheritance o
Page 35 and 36: with a dense growth of relatively l
Page 37 and 38: produced on rations which contain i
Page 39 and 40: The Coefficient of Variation The co
Page 41 and 42: 5.6.3 Wool Production/Wool yield an
Page 43 and 44: 6. Breeding 6.1 Components of Sheep
Page 45 and 46: elationships. Certain coat colors a
Page 47 and 48: Selection on this basis means that
Page 49 and 50: ii) Independent Culling Method In t
Page 51 and 52: eflected by increase in average fle
Page 53 and 54: at 75 or 8-4 monthly intervals comp
Page 55 and 56: Based on the crossbreeding results,
Page 57 and 58: Table 6.8 Means and standard errors
Page 59 and 60: month post-weaning individual feedl
Page 61 and 62: ams) in November, 1975 for evaluati
Page 63 and 64: een heavily fed and therefore may h
Page 65 and 66: need for one or more "teasers" to d
Page 67 and 68: ii) Consistency The normal consiste
Page 69 and 70: collection frequencies per day in 3
Page 71 and 72: iv) Altitude High altitude and poor
Page 73 and 74: containing diluents enriched with a
Page 75: 6. Nutrients Although spermatozoa u
Page 79 and 80: Estrogen in large quantities inhibi
Page 81 and 82: The udder becomes firm and enlarged
Page 83 and 84: 7. 3. 8 Interlambing interval It is
Page 85 and 86: 8. Nutrition 8.1 Components of Shee
Page 87 and 88: allied to the various amino acids o
Page 89 and 90: animals. A deficiency of salt is sh
Page 91 and 92: seem to have most significance in s
Page 93 and 94: Table 8.2 Chemical composition of g
Page 95 and 96: Table 8.3 Nutritive value of fodder
Page 97 and 98: Mineral and vitamin Requirement If
Page 99 and 100: Table 8.5 Total digestible nutrient
Page 101 and 102: Table 8.7 continued....... c) Lacta
Page 103 and 104: shirinking due to reclaimation of l
Page 105 and 106: Sorghum-Berseem-Maize Improved vari
Page 107 and 108: 9. Housing and Management 9.1 Syste
Page 109 and 110: ) Shearing, skirtng and primary cla
Page 111 and 112: The availability of pastures which
Page 113 and 114: fodder as green or hay, concentrate
Page 115 and 116: 9.2.2 Lambs Efforts should be made
Page 117 and 118: Mortality in young lambs and other
Page 119 and 120: land and they depend on the forest
Page 121 and 122: age and fed intensively till they a
Page 123 and 124: Overnight teasing and drafting ridd
Page 125 and 126: The secretion of milk takes place d
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with coarse and hairy breeds showed
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11. Sheep Production System in Diff
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12. Wool Production and quality 12.
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crosses with Dorset and Merinos, Pa
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13. Meat Production 13.1 MeatProduc
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Table 13.1 Mutton (sheep) productio
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14.4 Utilization of milk Sheep are
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one crushing mills and about 360 bo
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16. Sheep Records It is essential t
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17. Diseases and their Control Morb
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Atropin sulphate 2.0 mg/kg. body we
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contents by neutralization tests wi
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prophylactic, foot and mouth vaccin
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