Dairy Cattle Feed Upcycling, Adaptogenic Nutraceuticals and Precision Reproduction: Advanced CASA Sperm Kinematic Profiling and Sexual Drive in Rams

This study capitalizes on computer-assisted semen analysis (CASA) to evaluate a precision nutritional strategy integrating agro-industrial feed upcycling and functional phytogenic supplementation in rams. Black Belly rams (n = 15) sustained on an upcycled basal diet derived from dairy-cow feed rejections were assigned to a non-supplemented control group (CONT) or supplemented with Withania somnifera (WITH) or Lepidium meyenii (LEPI) at 400 mg kg−1 LW d−1. The 64-day trial was conducted from May to July in arid northern Mexico. Sexual drive, seminal quality, and high-resolution sperm kinematics were evaluated using CASA. Body and testicular measurements, ejaculate volume, and most categorical motility traits remained comparable among treatments (p > 0.05). However, phytogenic supplementation enhanced selected seminal and sexual-drive variables (p < 0.05). Crucially, longitudinal treatment × time interactions (p < 0.05) showed that while the CONT group experienced a seasonal decline in local mobility (LOCMOB), it increased from 1.47% to 2.01% in the WITH group, representing a 37% relative increase over time. Moreover, both WITH and LEPI increased LIN and STR by the end of the experimental period (p < 0.05), demonstrating more linear and efficient sperm trajectories. These findings highlight the productive value of upcycled dairy-cow feed rejections and demonstrate that strategic supplementation with W. somnifera or L. meyenii can refine sexual drive, seminal quality, and sperm kinematic efficiency. This integrated bio-circular strategy provides actionable insights for sustainable small-ruminant production under challenging arid summer conditions.