This study was conducted to determine the effect of different levels of whole and ground (8 and 15%) in late pregnancy on the performance of Karakul ewes. Thirty Karakul ewes, ages 2–3 years old and weighing 55 ± 2.5 kg, were randomly divided into five treatments and individually penned. Results revealed that there were no significant differences among treatments in the dry matter intakes or body weight changes of ewes and lambs (P>0.05). Crude protein and ether extract digestibility were significantly (P<0.05) higher in ewes fed whole and ground flaxseed compared to those fed the control treatment. The highest amount of crude protein and ether extract digestibility in ewes was observed with treatment with 15% whole flaxseed. The yield and composition of colostrum were not affected by experimental treatments (P>0.05), except for colostrum protein, which increased by using treatments with whole flaxseed (P<0.05). Glucose and cholesterol in blood plasma were significantly increased in ewes fed whole and ground flaxseed compared to the control treatment. (P<0.05), and the highest blood glucose and cholesterol levels were observed in the treatment of 15% whole flaxseed. The research showed that whole flaxseed (15%) can be used in late-pregnancy ewes’ diets without detrimental effects on performance and could be beneficial due to changes in glucose concentrations in plasma and colostrum protein. Manuscript profile

< p style="text-align: justify;">It was hypothesized that some of the variations in rumen and cecum fermentation parameters can form a share of individual differences resulting in feed efficiency, which may be altered based on the type of diet. This research aimed to determine the effects of dietary effect and feed efficiency of growing lambs (Kermani lambs) on their rumen and cecum indices and also microbial protein synthesis in gastrointestinal tract. Lambs (n=40; bodyweight (BW)=16±1.5 kg) were fed either a concentrate (CONC; 11.8% crude protein (CP), 18% neutral detergent fiber (NDF), 2.66 Mcal/kg metabolizable energy (ME); n=20) or a forage-based diet (FOR; 15.6% CP, 36.8% NDF, 2.15 Mcal/kg ME; n=20). Individual intake was recorded and residual feed intake (RFI) was determined over 42 days. The 8 highest (Low-RFI) and 8 lowest efficiencies (High RFI) records of lambs from each dietary group were selected (n=16; average BW=20±2.1 kg), and the samples of rumen and cecum fluid, and also urine were collected at the end of the trial. Data were analyzed as a 2 × 2 factorial design with RFI class (high vs. low efficiency), their type of diet (FOR vs. CONC), and their interaction in the defined model. Based on the results, high-efficiency lambs had a higher level (p < 0.01) of total volatile fatty acid (VFA), proportional concentrations of acetate, propionate, and ammonia nitrogen in the rumen in comparison to low-efficiency lambs. Higher (p < 0.01) amounts of allantoin, xanthine + hypoxanthine, total purine derivative (PD), microbial nitrogen and microbial protein were observed in the high efficiency than low-efficiency lambs. The low efficiency lambs had greater (p < 0.01) proportional acetate, cecal pH and cecal ammonia N compared to high-efficiency lambs. The RFI class × diet type interaction was significant (p < 0.01) for the majority of parameters of the rumen, cecum, and microbial protein synthesis. The results of this experiment exhibited that hindgut fermentation especially cecum played a key role in the efficiency of feed utilization in lambs which have consumed larger amounts of fermentable substrates. Manuscript profile