Forty-five Najdi ram lambs were equally and randomly allotted to five dietary groups with three replications per diet to evaluate the effect of feeding olive cake in complete diet on nutrient digestibility, growth performance and carcass characteristics. The diets were: a whole-mixed control diet (C) containing 12% wheat straw and four diets; namely O, ON, OU and OUE, where crude olive cake, 3% NaOH-treated olive cake, 5% urea-treated olive cake (U) and ensiled U, respectively were incorporated to replace the wheat straw of C diet. The results showed that the digestibility of DM, CP, EE and NFE and TDN were higher (p<0.05) in OUE diet as compared to the control diet; there were no changes (p>0.05) in the corresponding values between O, ON and OU diets. The nutrient digestibilities, body weight gain, feed efficiency and Longissimus area were significantly (p<0.05) lower in ON diet as compared to other experimental diets. Average daily DM intake and weight gain were higher (p<0.05) in lambs fed O, OU and OUE diets than those fed C diet. The moisture and protein contents in the soft tissue from ON treatment were lower (p<0.05) than those tissues from C, O, OU and OUE treatments. In conclusion, these results indicated that crude olive cake is a better substitute of wheat straw when fed to growing lambs.

One hundred-fifty lactating, multiparous cow at post-peak of lactation were used to examine the effect of dietary yeast supplementation on milk production, milk composition and ruminal fermentation. The cows were randomly allocated to three groups of fifty cows each: a control group fed on a basal diet without yeast supplementation and two groups fed on basal diets supplemented with one of two commercial sources of yeast cultures, given at the rates of 15 g/head/d (YC 1 ) and 50 g/head/d (YC 2 ), respectively, as per manufacturers' recommendation. Daily milk production was recorded for all cows, while milk samples were taken randomly from ten cows per group for two consecutive days at two-week intervals for chemical analysis of the milk. Rumen fluids were also analyzed for ammonia nitrogen and volatile fatty acids. The results indicated that cows consuming diets supplemented with yeast culture tended to decrease their dry matter intake and to increase their milk yield. Cows fed YC 2 supplemented diet produced more milk and 4% fat corrected milk than those fed either YC 1 -supplemented diet or the control. The highest milk fat percentage was obtained in cows fed YC 2 supplemented diet while the highest percentages of protein, lactose, total solids and solids not fat were recorded in cows fed YC 1 . Rumen ammonia nitrogen concentration decreased significantly after yeast culture supplementation. Molar proportion of volatile fatty acids did not change significantly with yeast supplementation.

Thirty-six Naeimi ram lambs were equally and randomly allotted to four treatment groups with three replications per treatment to determine the simple and additive effects of monensin and zeranol on growth performance, carcass characteristics and nutrient digestibility. The treatment groups were: basal diet-fed lambs (C), monensin-fed lambs (M) where the basal diet was supplemented with 33 mg monensin per kilogram DM, lambs implanted with 12 mg zeranol (Z), and monensin-fed lambs implanted with zeranol (MZ). Lambs fed monensin-containing diet consumed 10.5% less (p<0.05) DM/100 kg weight and were 8.3% more (p<0.05) efficient in converting feed than lambs fed control diet. Zeranol implanted lambs tended to grow 35.2% (p<0.05) faster, consumed 5.1% more (p<0.05) feed and were (p<0.05) 21.9% more efficient in their feed conversion than control lambs. Responses of lambs to monensin and zeranol implants were not additive. Except for Z treatment, there were no marked differences in all carcass characteristics among the various treatment groups. Z-lambs produced 12.7% heavier (p<0.05) carcasses compared with those from C treatment. Also fat parameters, namely, kidney and pelvic fat (KP), body wall thickness and fat thickness, indicated trends for higher finish in Z treatment lambs (p<0.05) than for those lambs from other treatments. Except for CF and ADF, no significant differences in nutrients digestibility were noticed between various treatments; feeding monensin resulted in 24.5% and 8.5% depressions (p<0.05) in CF and ADF digestibility, respectively in comparison to C treatment. Nitrogen retention as percentage of total N-intakes was averaging 7.5 and 20.2% higher (p<0.05) in lambs implanted with zeranol than those fed the M and C diets, respectively.

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