This work was carried out to study the effect of dietary energy and protein sources on digestibility, nutritive values, rumen parameters and weight gain. Twelve male goats, average body weight 20 kg were used in this experiment, which divided into four equal groups, fed on concentrate feed mixtures (CFM) and wheat straw ad libitum . The concentrate feed mixtures of tested rations were:
Ration 1 : 70% corn + 29% cotton seed meal + 1% additives (CFM1).
Ration 2 :23% corn + 29% cotton seed + 47% SBP + 1% additives (CFM2).
Ration 3 :70% corn + 29% broken horse bean + 1% additives (CFM3).
Ration 4: 23% corn + 29% broken horse bean + 47% SBP + 1% additives (CFM4).
The CFM was offered the give goat requirements while wheat straw offered ad libitum.
The results of two energy sources showed that sugar beet pulp (SBP) has crude fiber (CF), crude protein (CP) and ash contents higher than corn grains content. While nitrogen free extract (NFE) and ether extract (EE) were less than corn grains. Cotton seed meal (CSM) has higher CF, EE and ash content and lower CP and NFE in comparison with broken horse bean (HB).
Using of SBP instead of corn (CFM2) decreased (P<0.05) the digestibility of CP, EE and NFE while the total digestible nutrients (TDN) and digestible crude protein (DCP)% did not significantly affected. Broken horse bean (HB) caused significantly (P<0.05) increase in DM, OM, CF, NFE digestibility and TDN and DCP% in comparison with (CSM). The interaction between energy and protein sources had significant (P<0.05) effect on all nutrient digestibilities and nutritive values (%). The daily body weight gain did not affect by energy sources. It was high (P<0.05) for goats fed HB in comparison with which fed CSM. Generally, most results indicate that the best rations were contained CFM4 followed by CFM3 followed by CFM1 then CFM2.
Results of rumen parameters showed that, the pH value, ammonia nitrogen and total volatile fatty acids (TVFA's) concentrations not significantly (P<0.05) affected by energy source. On the other hand, the ammonia nitrogen and TVFA's significantly (P<0.05) affected by protein sources. The interaction between energy and protein sources was significant. The lowest pH and highest TVFA's were found in rumen liquor of goats fed CFM1 in comparison with fed others (CFM)s. The CSM increased (P<0.05) ammonia nitrogen concentration in comparison with HB.
Results of the study indicate that , replacing 67% of corn of CFM1 by SBP had deleterious effect on the digestibility, nutritive values and weight gain of goat when CSM was the protein source (CFM2). On the other hand, replacing of corn by SBP with using HB as protein source (CFM4) give the best results. All results indicate that HB was better than CSM meal.