The relationship between the activity of enzymes-markers of fertility of succinate dehydrogenase and cytochrome oxidase with the content of lipoproteins in bull ejaculates was studied. The research was conducted at the Stepan Gzhytskyi National University of Veterinary Medicine and Biotechnologies Lviv and the Lviv National Production Center “Zakhidplemresursy”. Physiological indicators of the quality of bull ejaculates (volume, ml; sperm motility, scores; concentration, 109 cells/ml) and the activity of enzymes-markers of reproductive capacity of germ cells were studied. Freshly obtained bull ejaculates are characterized by a volume of 4.3 ± 0.18 ml, a concentration of 1.09 × 109 cells/ml and sperm activity of 7.4 ± 0.16 points. The activity of enzymes-markers of fertilization ability of germ cells shows a positive relationship with the content of very high density lipoproteins. In particular, for less than 30.0 units / h × 0.1 ml of semen enzyme activity revealed a minimum content of the fraction (22.1–23.4 %), which increases by 5.0–9.9 % with an increase to 50.0 units/h × 0.1 ml of semen and increases by another 14.6–25.4 % by more than 50.0 units/h × 0.1 ml of semen. Bull semen contains the main fractions of lipoproteins: chylomicrons (26.5 ± 2.20 %), very low density – 10.4 ± 0.44 %, low – 18.3 ± 1.84 %, high – 17.1 ± 1.09 % and very high density – 26.8 ± 1.94 %, and sperm show 24.7 ± 2.79 units/h × 0.1 ml of sperm succinate dehydrogenase and 36.7 ± 2.66 units/h × 0.1 ml of sperm cytochrome oxidase. With a proportional increase in the activity of succinate dehydrogenase, the content of low and high density lipoproteins in semen shows a negative correlation (η = 0.202–0.295) and with a very high density – positive (η = 0.490), and cytochrome oxidase with a high content of chylomitecron and negative chylomicron and lipoproin = 0.352 and 0.438) and from a very high density – positive (η = 0.674). With a proportional increase in the activity of enzymes-markers of the fertilizing ability of germ cells, the content of chylomicrons, low and high density lipoproteins decreases, and the content of very high density lipoproteins increases.