پروار بره‌های با ابعاد دنبه کوچک و مقایسه آنها با دنبه بزرگتر بر عملكرد رشد صفات لاشه بره‌های نژاد گوسفند لری

محورهای موضوعی : فصلنامه زیست شناسی جانوری

بهروز یاراحمدی ^{1 *} , محسن محمدی ساعی ² , میرحسن بیرانوند ³ , امین کاظمی زاده ⁴

1 - بخش تحقیقات علوم دامی مرکز آموزش و تحقیقات کشاورزی و منابع طبیعی لرستان ، سازمان تحقیقات، آموزش و ترویج کشاورزی، خرم آباد، ایران.
2 - بخش تحقیقات علوم دامی مرکز آموزش و تحقیقات کشاورزی و منابع طبیعی لرستان ، سازمان تحقیقات، آموزش و ترویج کشاورزی، خرم آباد، ایران.
3 - بخش تحقیقات علوم دامی مرکز آموزش و تحقیقات کشاورزی و منابع طبیعی لرستان، سازمان تحقیقات، آموزش و ترویج کشاورزی، خرم آباد، ایران
4 - بخش تحقیقات علوم دامی مرکز آموزش و تحقیقات کشاورزی و منابع طبیعی لرستان، سازمان تحقیقات، آموزش و ترویج کشاورزی، خرم آباد، ایران

تاریخ دریافت : 1403/06/24 تاریخ پذیرش : 1404/01/24 تاریخ انتشار : 1404/04/11

کلید واژه: بره‌هاي نژاد لري, دنبه کوچک, خصوصيات پرواري, ضریب تبدیل خوراک, صفات لاشه,

چکیده مقاله :

این مطالعه باهدف پروار بره‌های با دنبه كوچك در مقایسه با بره‌هاي با دنبه بزرگ بر عملکرد رشد و صفات لاشه بره‌های نژاد لری انجام شد. تعداد 30 رأس برۀ نر بر اساس اندازه دنبه انتخاب شدند. بره‌ها با وزن حدود 30 کیلوگرمی و سن سه ماه از شیرگیری، انتخاب و به دو گروه 15 رأسی تقسیم شدند. بره‌های گروه آزمایشی شامل بره‌هایی كه عرض دنبه آنها بين 5/19-5/15 سانتي‌متر و طول دنبه 22-17 سانتي‌متر و گروه شاهد بره‌هایی که دنبه آنها دارای عرض بیش از 5/19 سانتي‌متر و طول دنبه 22 سانتي‌متر بودند. در پايان ميزان عملکرد رشد اندازه‌گيري شد. در انتهاي مرحله پروار 90 روز تعداد 8 رأس از هر گروه ذبح شدند. با استفاده از آزمون t مستقل مقایسه دو گروه انجام شد. بالاترين افزايش وزن در بره‌های با دنبه کوچک با ميزان 210 گرم در روز و كمترين دنبه بزرگتر با ميزان 182 گرم در روز بود. ضریب تبدیل خوراک در بره‌های با دنبه کوچک در مقابل دنبه بزرگتر (21/7 در مقابل 35/8) وضعیت بهتری داشت. بالاترين راندمان لاشه و درصد گوشت لخم مربوط به بره‌های دنبه كوچك بود. ازنظر چربي كل لاشه بين دو گروه تفاوت معني‌دار وجود داشت و بره‌هاي دنبه كوچك با 29/17درصد كمترين و دنبه بزرگ‌ها با 63/23 درصد بيشترين را داشتند. بره‌های دنبه کوچک و بره‌های شاهد از نظر درصد گوشت لخم معني‌دار شد(05/0p <) . قیمت هر كيلوگرم افزايش وزن برای بره‌های با دنبه کوچک 65/13 درصد ارزان‌تر از بره‌های  با دنبه بزرگتر بوده و از این نظر، ارزش اقتصادی بالاتری داشتند. بر اساس نتايج، بره‌های با دنبه كوچك به علت ضريب تبديل خوراک مناسب، افزايش وزن روزانه بالاتر و صفات لاشه مناسب‌تر به همراه هزينه توليد هر كيلوگرم افزايش وزن و لاشه پائين‌تر جهت پروار قابل توصيه است. 

چکیده انگلیسی:

This study was conducted with the aim of fattening lambs with small fat-tail compared to lambs with large fat-tail on growth performance and carcass traits of lambs of the Lori breed. 30 male lambs were selected based on the size of the tail. The lambs weighing about 30 kg and three months old of weaning were selected and divided into two groups of 15. The experimental group lambs included whose fat-tail width was between 15.5-19.5 cm and fat-tail length 17-22 cm, and the control group included whose fat-tail width was more than 19.5 cm and fat-tail length was 22 cm. At the period end ADG, FI, and FCRwere measured. At the end of the fattening of 90 days, 8 heads from each group of small tail and large fat-tail were slaughtered. The lambs were compared with the independent t-test.The highest ADG in lambs with small fat-tail was compared to larger fat-tail (210 vs.182gr/d).The FCR was better in lambs with small fat-tail compared to larger fat-tail (7.21 vs. 8.35). The highest carcass  efficiency percentage and lean meat percentage were small fat-tail lambs. In terms of total carcass fat, there was a significant difference between the two groups and small tail lambs had the lowest( 17.29 vs. 23.63%). There was significant difference between small tail lambs and control lambs in terms of lean meat percentage (P<0.05). The results showed that the price of each kilogram of weight gain for lambs with small tails was 13.65% cheaper than larger fat tails. Overall, lambs with small fat-tail size are recommended for fattening due to the suitable FCR, higher ADG and more suitable carcass traits along with the  cost weight gain and lower carcass.

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