-An experiment was conducted to determine the effect of varying dietary supplemental inclusion levels of onion and garlic mixture on semen quality characteristics of Koekoek breeder cocks aged 35-41 weeks. The experimental diets were isocaloric and isonitrogenous but with different supplemental inclusion levels of onion and garlic. A complete randomized design was used for the experiment. The three dietary supplemental levels based on garlic and onion supplemental inclusion levels were Q 0 (0 g onion and 0 g garlic per 600 g DM feed), Q 1 (2.5 g onion and 2.5 g garlic per 600 g DM feed), and Q 2 (5 g onion and 5 g garlic per 600 g DM feed) with each treatment having three replicates. A quadratic type equation was used to determine the onion and garlic levels for optimum semen quality characteristics. Daily supplementation with 5 g onion and 5 g garlic per 600 g DM feed increased progressive motile cells (%), actual life sperm count (×10 6 /nl), and live sperm (%) by 221.20%, 301.51%, and 352.43%, while 2.5 g onion and 2.5 g garlic per 600 g DM feed reduced them by 28.67%, 12.69%, and 19.00%, respectively. However, daily supplementation with 2.5 g onion and 2.5 g garlic per 600 g DM feed increased sperm count (×10 6 /nl) by 12.82%, whereas daily supplementation with 5 g onion and 5 g garlic per 600 g DM feed reduced it by 10.26% in Koekoek breeder cocks. Dietary onion and garlic supplemental inclusion levels of 3. 009, 3.191, 4.621, 6.601, 6.719, 2.327, 2.385, and 2.247 g per 600 g DM feed supported optimum progressive motile cells (%), immotile sperm cells (%), actual dead sperm count (×10 6 /nl), actual live sperm count (×10 6 /nl), live sperm (%), acrosome morphology defects (%), acrosome detachment (%), and acrosome swelling (%), with probability values ranging from 0.003 to 0.783, whereas minimum progressive motile cells (%) increase was achieved at an optimum onion and garlic supplementation levels of 3.009 g per 600 g DM feed. These findings have a lot of implications on the use of supplemental onion and garlic inclusion levels to enhance reproductive efficiency in Koekoek breeder cocks.
