بررسي مقايسه اي عملكرد پروار و خصوصيات لاشه بره‌هاي لري بختياري و آميخته‌هاي رومانف × لري بختياري

Comparison of feedlot performance and carcass characteristics of Lori-Bakhtiari and Romanov×Lori-Bakhtiari crossbreed lambs

هدف از اين آزمايش بررسي مقايسه اي عملكرد پروار و خصوصيات كمي لاشه بره هاي لري بختياري و آميخته هاي رومانفΧلري بختياري بود. به همين منظور از 44 راس بره لري بختياري 100 روزه و 44 راس بره آميخته رومانف با لري بختياري 100 روزه در قالب طرح كاملا تصادفي به روش فاكتوريل 2Χ2Χ2 با دو گروه ژنتيكي(لري بختياري و آميخته رومانفΧلري بختياري)جنس (نر و ماده) و سال (1395 و 1396) استفاده شد. افزايش وزن روزانه، جيره هاي مورد مصرف،، ضريب تبديل خوراك و نيز ويژگي هاي كمي لاشه دام ها اندازه گيري شد. نتايج نشان داد كه ميانگين افزايش وزن روزانه قبل از شيرگيري و نيز وزن در سن 100 روزگي (پايان شيرگيري) در بره هاي آميخته رومانفΧلري بختياري بيشتر از بره هاي لري بختياري بود(p <0/05). اما ميانگين افزايش وزن روزانه طي دوره پروار، وزن دوره پروار، مصرف خوراك، وزن لاشه و درصد دنبه بره هاي لري بختياري بيشتر از آميخته هاي رومانفΧلري بختياري بود(p <0/05). بره هاي نر ، ميانگين افزايش وزن روزانه دوره پروار بيشتر و ضريب تبديل كمتري نسبت به بره هاي ماده داشتند(p <0/05). درصد دنبه و چربي لاشه بره هاي نربيشتز از ماده ها بود(p <0/05). نتايج اين مطالعه نشان داد كه عملكرد قبل از شيرگيري بره هاي آميخته از بره هاي لري بختياري بهتر ولي عملكرد دوره پروار آن ها كمتر است. لذا به نظر مي رسد پروار بره هاي لري بختياري مناسب تر از آميخته ها در استان چهارمحال و بختياري باشد. كليدواژه‌ها

The aim of this experiment was to compare the feedlot performance and carcass characteristics of Lori-Bakhtiari and Romanov×Lori-Bakhtiari crossbreed lambs. Forty-four Lori-Bakhtiari lamb and Forty-four Romanov×Lori-Bakhtiari lambs were used in a completely randomized design and using a factorial method (2×2) during two consecutive years. The average daily gain and daily feed intake were determined by individual weaning of each animal and then feed conversion ratio was calculated. Carcass characteristics of lambs were measured. The results showed that average daily gain during fattening period (212.1vs. 179.6 g), final fattening weight (52.12 vs. 48.26 kg), feed intake, carcass weight and fat tail percentage in Lori Bakhtiari lambs were greater than Romanov× Lori Bakhtiari crossbred lambs. The average daily gain before weaning (298.4 vs. 266.8 g), the average daily gain during fattening period (217.2 vs. 161.9 g), and feed conversion ratio (7.62 vs. 9.75) in male lambs was better than female lambs (p < 0.05). Fat tail percentage and total carcass fat content in male lambs were higher than that of female lambs (p < 0.05). It is concluded that, Romanov×Lori Bakhtiari crossbred lambs had higher performance than Lori Bakhtiari lambs before weaning. However, fattening period performance and carcass weight in Bakhtiari lambs were higher compared to Romanov×Lori Bakhtiari crossbred lambs. In addition, energy spent per kg of carcass and live weights in Bakhtiari lambs was lower than Romanov×Lori Bakhtiari crossbreds. Therefore, it can be concluded that the indigenous Bakhtiari sheep breed is more useful for fattening than that of Romanov×Lori Bakhtiari crossbreds in Chaharmahal and Bakhtiari province.