Effect of Diet Physical Form on Performance and Diet Digestibility in Finishing Fat‐Tailed Lambs

This study was conducted in two experiments to evaluate the dietary physical form on dry matter intake (DMI), performance, carcass traits and nutrient digestibility from Kalkuhy (an Iranian fat–tailed breed) male lambs. Initial lamb body weight (BW) average was, 32 .81 ± 2 kg, and 110 ± 10 days of age. Three treatments (diet physical form) included T1: total mixture diet (TMR) mixed diet (MD), T2: TMR blocked diet (BD) and T3: TMR pellet diets (PD) that were compared in completely randomized design. Diets had similar composition (80% concentrate to 20% forage). Average DMI of lambs fed by BD was significantly greater than MD diet (P<0.05). Average daily gain of lambs fed by BD was significantly greater than lambs fed MD and PD diets (P<0.05). Hot carcass and fat-tail lamb weights fed the BD treatment were signifi-cantly greater than lambs fed MD treatment (P<0.05). Nutrient digestibility was not affected by treatments. Dry matter, organic matter (OM) and crude protein (CP) digestion were not significantly greater for BD. In conclusion, blocking the complete diet for finishing fat-tailed lambs did not change final weight, feed con-version ratio (FCR) and nutrient digestibility, but increased DM intake, which in turn resulted in an in-creased energy available for fattening. As a result, lambs fed the BD treatment had heavier fat- tails com-pared to lambs fed either the PD or MD treatments. Hence, TMR block diet (BD) use for fattening Kalkuhy (Iranian fat–tailed breed) male lambs when providing them ad libitum access to feed wasn’t recommended.