The objective of this study was to investigate the impacts of replacing alfalfa hay with Artemisia sieberi leaves (ASL) on
growth performance, feeding behaviors, total tract feed digestibility, ruminal fermentation as well as blood cells, and bio-
chemical parameters. A total of 21 Kermani male lambs (average body weight (BW) of 25.2 ± 0.9 kg) were randomly divided
into three groups and offered the following treatments: (1) basal diet (65% concentrate and 35% alfalfa hay as forage source),
(2) ASL inclusion at 25% of forage source (8.75% of TMR, ASL25), and (3) ASL addition at 50% of forage source (17.5%
of TMR, ASL50). The experiment lasted for 64 days, including 14 days of adaptation and 50 days of data collection. Dietary
ASL inclusion decreased lambs’ feed consumption (6.7 and 2.8% reduction in ASL25 and ASL50, respectively, p < 0.05)
without affecting water intake, final BW, daily weight gain, and feed conversion ratio. Moreover, feeding behaviors, includ-
ing time spent for eating, ruminating, and chewing activities, were uninfluenced by the dietary ASL addition on days 25
and 50 of the experiment. Based on the data provided, the substitution of alfalfa hay with ASL resulted in an increase in the
digestibility of dry matter, organic matter, and neutral detergent fiber (p < 0.05). In addition, the ruminal fluid of ASL-fed
lambs had a lower molar proportion of acetate and a higher proportion of propionate compared to that of the control animals
(p < 0.05), whereas other volatile fatty acids (VFA) and total VFA were not different between the experimental groups.
Blood hematocrit, hemoglobin, red cells, white cells, and their differentiation, platelets, glucose, total protein, albumin,
globulin, triglyceride, calcium, phosphorus, aspartate aminotransferase, and alanine aminotransferase, urea, total antioxidant
capacity, and malondialdehyde remained unchanged when ASL was included in the diet. Regardless of the slight decrease
in dry matter intake, the lack of adverse effects of dietary ASL addition on growth performance, feeding behaviors, rumen
fermentation, and blood hemato-biochemical parameters, along with positive impacts of ASL on propionate production and
total tract feed digestibility, suggest that Artemisia sieberi leaves can be considered as a potential alternative feed resource
for small ruminants.