Genetic Potential of Awassi Sheep for Growth and Meat Production
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International Journal of Advances in Science Engineering and Technology, ISSN(p): 2321 –8991, ISSN(e): 2321 –9009 Volume-7, Issue-1, Jan.-2019, http://iraj.in GENETIC POTENTIAL OF AWASSI SHEEP FOR GROWTH AND MEAT PRODUCTION 1HANI N. HERMIZ, 2JALAL E. ALKASS 1College of Agriculture, University of Salahaddin, Erbil, Kurdistan Region, Iraq. 2College of Agriculture, University of Dohuk, Dohuk, Kurdistan Region, Iraq. E-mail: [email protected] Abstract - Awassi sheep which is distributed over 30 countries possesses very desirable characteristics such as endurance to nutritional fluctuation, resistance to disease and parasites, and adapted well to different ecological conditions. The economic usefulness of sheep in meat production would be enhanced by increased frequency and rate of reproduction, more efficient growth to heavier market weights and more desirable meat qualities. Growth rate of Awassi lambs particularly under feedlot is extremely good and indicating that this breed is suited for such following system. Fattening traits displays a wide range which is attributed to genetic differences between flocks and individuals, and to several other influences including different fattening periods, rations and regimes, as well as to different ages and initial weights of lambs at fattening. Heritability estimates of body weight at different ages and some carcass traits are moderate to high, and those of feed intake and feed efficiency are moderate. Such estimates warrant effective selection schemes as well as upgrading of standards of feeding and management. Moreover, much work is needed to investigate the molecular genetics of this breed in different populations in the countries of origin. Keywords - Awassi Sheep, Genetic Potential, Growth, Meat Production. I. INTRODUCTION According to twenty one studies conducted earlier in Iraq using 40057 records, the overall mean of birth Awassi is the most common breed of sheep in the east weight ranged between 3.61 and 4.56 kg, and vary of Mediterranean. It is the main sheep breed in Iraq between 3.53 and 4.89 kg in the males, and between and Syria, the only native breed in Jordan, Israel and 3.26 and 4.32 kg in the females (Table 1). Also, the Palestine and represent an important contribution to birth weight of Awassi lambs raised in Jordon, Syria, sheep breeds in Turkey. Also Awassi possesses very Lebanon, and Turkey is almost within the range desirable characteristics as far as endurance to reported for the same breed raised in Iraq (Table 2). nutritional fluctuation, resistance to disease and Sex of lamb, type of birth, age and weight of dam, as parasites, tolerance to extreme temperature (Galal et well as month, season and year of lambing are among al., 2008). Additionally the breed has spread from its the factors that affect lamb’s birth weight. place of origin in South West Asia to all continents Weaning weight: including South America. In twenty one studies in Iraq using 20527 records The economic usefulness of sheep in meat production were reviewed and it was found that the overall mean would be enhanced by increased frequency and rate of weaning weight ranged between 15.517 and 24.25 of reproduction, more efficient growth to heavier kg, and vary from 16.10 to 23.84 kg in the males, and market weights and more desirable meat qualities from 14.89 to 22.359 kg in the females (Table 1). (Dickerson et al., 1972). Furthermore, most of the Also, it can be observed from table (2) that the people in the region prefer the local traditional highest weaning weights of lambs were recorded for carcass with its fat-tail. Therefore the price of meat Awassi in Syria and the lowest weight was found in from local breed is much higher than imported meat Jordon which attributed mainly to the differences in or from imported life animals. It is known that age at weaning as well as the availability of dam’s growth, feed efficiency and carcass characteristics are milk. The within sex differences are attributed among the major factors affecting meat production primarily to differences between farms in feeding and both quality and quantity (Aziz et al., 1994 a). management practices followed, as well as to This paper attempts to review the available literature differences in weaning age which usually varies on the growth performance and meat production of between 3 and 4 months. Differences in weaning Awassi sheep. weight due to sex of lamb, type of birth and age of dam are usually significant. II. BODY WEIGHTS AND GROWTH RATES Body weights at 6-months, yearling and maturity: In eight papers (Aziz et al., 1989; Badawi, 1989; Al- Birth weight: Azzawi et al., 1995; Hermiz and Assak, 1995; Al- Birth weight of lambs expresses the inherent ability to Anbari, 1998; Abdul-Rahman et al., 1999; Al-Rawi et grow within the uterine cavity, by utilizing the uterine al., 2000; and Idris, 2001) used 9244 records of lamb fluid to the maximum space available; this inherent body weight at six months of age and was found to be vitality of an individual is the earliest indication of varied between 17.469 to 33.54 kg. A review of 8 future growth of an animal (Raina et al., 1973). reports revealed that average yearling weight of Genetic Potential of Awassi Sheep for Growth and Meat Production 46 International Journal of Advances in Science Engineering and Technology, ISSN(p): 2321 –8991, ISSN(e): 2321 –9009 Volume-7, Issue-1, Jan.-2019, http://iraj.in Awassi sheep were 43.64 and 36.14 kg for males and Also, differences exist in the rate of growth displayed females, respectively (Table 3). Depending on 11 in settled systems and those raised in nomadic studies, Juma and Alkass (1996) reported that average systems (233.5 vs. 201.2 g/d), respectively, from birth yearling weight displays a wide range in both males to day 60, as the environment of the later are more (34.6-44.9 kg) and females (29.4-42.2 kg). Ewes and difficult to control (Kassem, 2005). rams usually attained their mature weights at the age Highest daily gain in weight of 285 g/d has been of 3 to 4 years, and sheep raised in commercial flocks attained when lambs, 5-6 months old and 28 kg in by local farmers are at least 10% lighter than those weight were fed atlib a concentrate mixture bred and maintained at state farms where animals are containing, 30% barley, 12% soybean meal, 15% date better fed and managed (Asker and El-Khalisi, 1964). palm and 40% wheat bran for 60 days (Al-Ani et al., Table 3 summarize adult weights from three studies 1988). In Jordon, the estimates of growth and being 63.4 and 46.2 kg for males and females performance of Awassi lambs fed different diets were respectively. 176 g/d (Al-Jassim et al., 1997), 242-297.9 g/d From the results presented in Table (4) it appears that (Abdullah et al., 2002), and 275 g/d (Muwalla et al., the weights of Awassi at 6-months, yearling and at 1994). At Al-Kraim Research Station in Syria when maturity are differ among countries raising this breed. Awassi lambs aged 6 months and fattened for 64 days Such variation could be mainly due to the genetic attained growth rate of 241 g/d (Kassem, 2005). make-up of individuals involved in these studies, as In Turkey, after weaning (60 days), the feedlot well as to different management systems practiced, performance of Awassi male lambs is extremely the availability of feed and to environmental good. It is not uncommon to obtain mean daily gains conditions especially temperature being exposed on of 340-350 g, indicating that the Awassi breed is these animals. suited to such fattening systems (Ozcan et al., 1994 Alkass et al., (1986) compared body weights of 120 a,b). When trying to optimize the energy and protein progeny of horned and polled Awassi rams. Ram levels provided to lambs, Gorgulu (1994) and group significantly influenced body weight at Gorgulu and Ozturkcan (1994) achieved daily gain of weaning, 6 and 8 months of age in favor of horned 225-329 g in lambs in the 8 weeks following lambing. sires. It has been hypothesized that polled genes to exhibit over dominance and/or epistasis for body III. FATTENING TRAITS weights in the heterozygous lambs (Table 5). This weight and subsequent weights of males (till 48 In 43 reports compiled in Iraq by Juma and Alkass weeks of age) and females (till 26 weeks of age), (2000) on fattening performance of 1113 Awassi however are noted to be suppressed by docking (Juma lambs, each fattening trait displays a wide range et al., 1973). which is attributed to genetic differences between Body weight gain: flocks and individuals, and to several other influences An investigation was carried out in Iraq to study the including different fattening periods, rations and growth of Awassi lambs from birth up to one year old regimes, as well as to different ages and initial by Juma et al. (1969). Results revealed that gain in weights of lambs at fattening (Table 6). weight during the suckling period (4 months) were Alkass and Al-Rawi (1982) conducted an experiment 166.0, 160.6, 134.2 and 122 g/d for single male, to compare some carcass traits of 66 progeny of single female, twin male and twin female, horned and polled Awassi rams. Ram group respectively. The corresponding gains in weight significantly influenced slaughter weight. Progeny of during the period that followed weaning were 61.9, horned-sires were heavier at slaughter than these of 46.3, 70.1 and 61.0 g/d.