Ja'far Al-Khaza'leh 1,* and Belal Obeidat 2
1Department of Nutrition and Food Processing, Faculty of Agricultural Technology, Al-Balqa Applied University, P.O. Box 19117, Al-Salt, Jordan; 2Department of Animal Production, Faculty of Agriculture, Jordan University of Science and Technology, Irbid 22110, Jordan
*Corresponding author: jkhaza@bau.edu.jo
This study aimed to assess the impact of supplementing Awassi lambs fed low-quality forage with barley grain (BAR) or soybean meal (SBM) on growth performance. Twenty-four lambs were randomly assigned to the three different diets: 0 g BAR or SBM (CON; n=8), 300 g BAR /head /day (BAR; n=8), or 300 g SBM/head/day (SBM; n=8) of the basal diet. The experiment included a 70-day growth period (10 days of pen adaptation and 60 days of feeding), followed by a 10-day digestibility period (5 days of metabolic cage acclimatization and 5 days of data collection). Forage intake was greater (P<0.002) in the group supplemented with SBM than in the other diets. The SBM-containing diets had the highest dry matter (DM) and crude protein (CP) intake and digestibility, followed by the BAR-containing diet, then the CON diet. Lambs fed the SBM diet had higher intake and digestibility of neutral detergent fiber (NDF) and acid detergent fiber (ADF) than those fed BAR or CON diets. SBM supplementation significantly improved nitrogen balance. Lambs fed the SBM diet showed the greatest growth performance, followed by those fed the BAR diet, whereas the CON diet resulted in the lowest growth performance (P<0.0001). The interaction between diet and sampling time significantly affected rumen fluid pH (P<0.0001). In conclusion, supplementing low-quality forage with barley grain or soybean meal improved nutrient intake, digestibility, and growth performance, with soybean meal producing greater responses than barley grain under the conditions of this experiment.