Roasted Flaxseed and Hydro-cooling Synergy: Impacts on Seminal Quality of Crossbred Bulls under Heat Stress

Abstract This study evaluated the effects of roasted flaxseed supplementation and surface water misting on semen quality and sexual behaviour of crossbred Karan Fries bulls during the summer season under tropical Indian conditions. A total of eighteen healthy Karan Fries bulls were randomly assigned to three experimental groups (n = 6 per group). Bulls in the control group (T1) received a standard ration without any supplementation. In the second group (T2), were supplemented with roasted flaxseed ( 1 kg/bull/day), while those in the third group (T3) received the same level of flaxseed supplementation along with periodic freshwater misting over the body surface. Physiological responses including body weight, rectal temperature, respiration rate, pulse rate, and circulating concentrations of testosterone and luteinizing hormone were monitored at fortnightly intervals over two consecutive periods. Sexual behaviour traits were also recorded at the same frequency. Semen was collected fortnightly and evaluated for ejaculate volume, colour, mass activity, sperm motility, concentration, viability, hypo-osmotic swelling test (HOST) response, and acrosomal integrity in fresh samples. Statistical analysis using one-way ANOVA revealed significantly higher rectal temperature, respiration rate, and pulse rate in bulls maintained under the control group, followed by those in T2 and T3 (P < 0.05). In contrast, bulls in T3 exhibited significantly reduced reaction time, dismounting time, and ejaculation time compared to the control group (P < 0.05). Measures of sexual performance, including libido score and mating ability, were significantly superior in T3 animals. Semen quality parameters such as ejaculate volume, sperm concentration, motility, livability, percentage of normal spermatozoa, HOST response, and acrosomal integrity were also highest in T3, followed by T2 and T1 (P < 0.05). Overall, the findings indicate that the combined application of roasted flaxseed supplementation and freshwater misting effectively alleviates heat stress, enhances sexual behaviour, and improves semen quality in Karan Fries bulls during the summer season in tropical environments.