The effect of rearing system on rumen development and non-carcass characteristics of Balouchi lambs were studied. Twenty-four male lambs were used in a completely randomized design. Eight lambs remained with their mothers throughout the experiment (NR) and 16 lambs divided 2 groups, ARWF, starter without alfalfa and ARF, starter containing 15% alfalfa and were housed individually. Glucose and BUN were not different significantly between groups. BHBA concentration was higher in artificial rearing whereas, NEFA was higher in natural rearing lambs. Neither DNA content and nor cell size were affected by rearing methods but RNA content and ribosomal capacity were affected by rearing system. ARWF lambs showed thickest keratinized layer than NR lambs and NR, thickest than the ARF but other rumen morphological characteristics were not affec by group. Differences between naturally and srtificially reared lambs in EBW and non-carcass organs weight except stomach weight and stomach and omasum capacity were not significant. The results of this study showed that rearing lambs have minimum development of rumen.

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