This study was designed to determine the degree and type of bacterial contamination in boar semen (79 ejaculates from Large White and Landrace boars) and its consequences for sperm quality during storage (27 extended semen samples, 16°C for five days) under practical conditions of artificial insemination (AI). The results revealed the presence of aerobic bacteria in 99% of the ejaculates (from 80 to 370 ×10⁶ colony-forming units/mL). Most of the ejaculates contained two or three bacterial contaminants, while the Staphylococcus, Streptococcus, and Pseudomonas bacterial genera were most frequently isolated. Also detected were Enterobacter spp., Bacillus spp., Proteus spp., Escherichia coli, P. fluorescens, and P. aeruginosa. In general, the growth of certain bacterial types isolated prior to semen processing (Enterobacter spp., E. coli, P. fluorescens, and P. aeruginosa) was not discovered on different days of storage, but fluctuations (with a tendency towards increases) were found in the frequencies of Bacillus spp., Pseudomonas spp., and Staphylococcus spp. isolates up to the end of storage. Semen preserved for five days exhibited decreases in sperm motility and increases in the average number of total aerobic bacteria; this was associated with sperm agglutination, plasma membrane disruption, and acrosome damage. We inferred that, due to the different degrees and types of bacterial contaminants in the boar ejaculates, the inhibitory activity of some antimicrobial agents used in swine extenders (such as gentamicin sulfate) may be limited. Because such agents can contribute to the overgrowth of certain aerobic bacteria and a reduction in the quality of stored semen, procedures with high standards of hygiene and microbiological control should be used when processing boar semen.

Red deer farming has started to play a greater role in modern agriculture and today is an interesting alternative for pig or cattle breeders. With regard to the low effort and high efficiency of maintenance, it may be expected that keeping these animals in fenced enclosures will be more popular over time. This trend is warranted by the fact that the demand on two main deer products: venison and antlers, is constantly rising, due to the quality of deer meat and prices of antler hunting trophies. Several countries of the world have already realized the scale of advantages to be derived from deer farming and today are world leaders in this area. Despite this expansion, the market still remains opened for deer products. Poland is a country with the climatic conditions, vast plain areas and varied vegetation that are fully sufficient to undertake large-scale deer farming, and to become a European leader. Therefore the aim of this review is to detail deer farming within the Polish framework and environmental conditions, and to illustrate its potential in sustainable modern agriculture and the economy.

Doi:10.3906/biy-1412-76 Storage temperature of boar semen and its relationship to changes in sperm plasma membrane integrity, mitochondrial membrane potential, and oxidoreductive capabilit