EN
The aim of the study was to evaluate the morphology structure of sperm cells and quality of individual male deer obtained in the Lublin Upland during the 2015/2016 hunting season. The comparison included two separate periods of the hunting season resulting from varying physiological processes related to the estrus period of this species. In the first study with regards to the estrus period, males were characterized by an average of 1.6 grams less testicle weight, while body weight was 1.9 kg higher. Increasing the mass of the testicles in the reproductive season proceeded simultaneously with the increase in the share of properly developed sperm cells to the level of 70.6%. During the pre-estrus period, the percentage of spermatozoids with main and secondary defects accounted for almost 60%. Between the compared periods, an approximately 6.8% body weight loss occurred. The highest percentage of properly developed spermatozoids was present in deer aged 4 and 5 years. Regarding the greatest body weight loss in these two age groups, it is indicated that this age is the climax in terms of potential accession to the breeding and effective mating of females and the possibility of fertilization. Analysis of the relationship between body weight and testicle weight showed low and statistically insignificant correlation coefficients (rxy = 0.331-0.393) between those features.