1. This study was conducted as three trials. 2. In the first trial, zinc, manganese, copper and iron concentrations were determined in dietary raw materials collected from various regions of Turkey. 3. In the second trial, 200 Hisex Brown laying hens, 30 weeks of age, were divided into two groups. The first group served as controls and were fed on a standard commercial layer diet. The second group were fed on a commercial layer diet that was not supplemented with trace minerals and vitamins. Egg production, egg weight, specific gravity, food consumption and food efficiency of the birds in each group were determined. In the unsupplemented group, egg production (0.75 vs 0.83) and food intake (114 vs 122 g) were lower than the those of the control group (P < 0.05). Food efficiency was 2.42 (kg food/kg gain) in the group consuming the unsupplemented diet and 2.36 in the controls. 4. In the third trial, as in Trial 2, Hisex Brown laying hens, 62 weeks of age were used. In the unsupplemented group, the mean egg weight was significantly lower than that of controls (68.0 vs 69.6 g) (P < 0.01). 5. At the end of the second and third trials, egg samples collected from experimental groups were hard boiled in water. The levels of zinc, manganese, copper and iron in the egg yolk were determined. The zinc level of the egg yolk from the control group of second trial was higher (23.5 mg/kg) than those of the unsupplemented group (13.6 mg/kg).

| INTRODUC TI ONNutritional management strategies in increase grain proportion to meet demand for energy should cover risk for and prevention of subclinical ruminal acidosis (SARA). It is characterized by increased total volatile fatty acid (VFA) concentration and propionate fraction and decreased ruminal pH (5.2-5.8) and acetate fraction. Meanwhile, ruminal lactate concentration exceeds 5-10 mM (Keunen et al., 2002).Ruminal pH kinetics parameters (i.e., minimal pH level and time below critical pH level) are diagnostic markers for SARA. The degree of severity of acidosis is more related to time below critical pH level, rather than the mean pH level (Keunen et al., 2002). To maintain normal flora and biological processes in the rumen as well as prevent SARA, daily mean ruminal pH should not be less than 6.16 and time for pH less than 5.80 should not be longer than 5.24 hr in high-producing cows (Zebeli et al., 2008).

Mistletoe (Viscum album L. subsp. album) is known as an obligatory hemiparasite of trees and is consumed by herbivores in some places, especially during periods of forage shortage and drought. This experiment was conducted to determine nutrient composition and nutritive value of mistletoe with respect to vegetation stage. Mistletoe samples were collected from three different tree species [almond (Amygdalus communis L.), plum (Prunus domestica L.), and willow (Salix alba L.)] at three different vegetation stages (April, July, October) naturally growing in Central Turkey. Five samples were taken at each vegetation stage for each tree species. The samples were incubated in rumens of two 2-year old fistulated Holstein cows. Nutrient data and nutritive value indices were subjected to 2-way ANOVA using the GLM procedure. Crude protein and NDF concentrations and metabolisable energy level of the samples were in the ranges of 52.5-68.6, 291-330, and 7.8-8.4 MJ kg À1 DM, respectively. There were also significant differences in DM, crude ash, Fe, Cu, and Zn levels among trees. As the vegetation progressed, there were linear decreases in DM, CP, and NDF and linear increases in ADF, Ca, Cu, and Zn levels. There were significant interaction effects for tree species by vegetation stage in terms of DM, ADF, and Zn. In vitro dry matter and organic matter digestibility coefficients were between 0.84 and 0.87 and between 0.52 and 0.55, respectively. It was also observed that degradation of V. album was almost completed after the first 48 h. The soluble and readily degraded portion of DM (fraction ''a'') increased, whereas the insoluble but degradable portion of DM (fraction ''b'') decreased with advancing vegetation stage. Effective degradability of dry matter (EDDM) also increased significantly as the vegetation progressed. Gas production from fraction ''b'' varied by tree species and the stage of vegetation. A significant interaction of tree species by vegetation effects on EDDM and gas production was also noted. After 48 h, cumulative gas production and fraction ''b'' ranged from 52.71 ml to 58.85 ml and from 48.8 ml to 75.4 ml, respectively. In general, the mistletoe was low in protein, moderate in fibre, and high in minerals. In conclusion, as long as a lack of deleterious effects on health and performance is This experiment was funded by shown in feeding trials, mistletoe has potential to be used as a dietary component in ruminant feeding.

An investigation of the dry matter degradability (DMD) and effective dry matter degradability (EDDM) was performed for barley, wheat, rye, corn, triticale and oat samples, using the Nylon-bag technique. Gas production (GP), metabolizable energy (ME) and in vitro organic matter digestibility (IVOMD) were also studied by using Hohenheim gas test. The DM from barley, wheat, rye and triticale was digested rapidly in the rumen, and, at the 48 h of incubation, degradability was found to be approximately about 80%. The higher degradability observed for these grains than for oats and corn was attributable to the structure of these grains. In contrast, DM of corn and oats was degraded very slowly and reached 66.7 and 66.5 at 48 h, respectively. Effective degradability values of barley, wheat, rye, corn, triticale and oats were determined to be 61.4, 69.0, 64.0, 41.7, 66.7 and 58.6% in 5% rumen outflow rate, respectively. At the end of the 48 h incubation, total gas productions in barley, wheat, rye, corn, triticale and oats were estimated to be 83.6, 87.2, 87.5, 83.5, 85.8 and 63.9 ml/200 mg DM, respectively. The mean ME values of these grains calculated from cumulative gas amount at 24 h incubation were 11.8, 12.1, 12.3, 10.9, 12.4 and 10.2 MJ/kg DM, respectively. In vitro digestible organic matter of barley, wheat, rye, corn, triticale and oats were estimated to be 85.0, 87.3, 88.2, 79.5, 89.0 and 72.6%. Percentage overall EDDM (k=5%) of barley, wheat, rye, triticale and oats was positively correlated with in vitro GP at 6 h, cumulative GP at 24 h and total GP at 48 h (p<0.05). As a result, in situ dry matter degradation of grains showed great differences depending on the chemical compositions. In situ EDDM of grains may be predicted from in vitro gas production parameters.

This study was conducted to determine the chemical composition and nutritive value of Prangos ferulacea, a plant found in the Mediterranean and Middle-east regions, where it is used as animal fodder. Samples of mature plants were collected from S.E. Turkey. Metabolizable energy (ME) values were estimated from in vitro gas production measurements and from chemical composition. ME concentrations of the whole plant, leaves and stems were estimated to be 12AE2, 11AE9 and 12AE7 MJ kg )1 dry matter (DM) respectively, which compares favourably with high-quality forages commonly used in ruminant feeding. The DM degradability of the whole plant, leaves and stems increased up until 48 h of in situ incubation, 866, 915 and 784 g kg )1 DM respectively, but changed little between 48 and 72 h. In vitro DM and organic matter digestibility of the whole plant, leaves and stems were 0AE769 and 0AE806, 0AE773 and 0AE790, and 0AE740 and 0AE840 respectively. The results show that P. ferulacea may be regarded as a high-energy forage, but further research is needed on its intake characteristics and the levels of animal performance that can be achieved from its inclusion in the diet.