Bacteria detected in the genital tract, semen or pre-ejaculatory fluid of Swedish stallions from 2007 to 2017.

BACKGROUND: Although artificial insemination (AI) was developed as a means of controlling disease transmission, pathogens can still be transmitted to females in semen used for AI. In addition, bacteria can cause deterioration in sperm quality during storage. Semen becomes contaminated by the male's normal bacterial flora as it passes out of the reproductive tract but potential pathogens may also contaminate the semen. Therefore, semen samples from stallions to be used for AI are tested before the breeding season to minimize transmission of pathogens to inseminated mares. In Sweden, semen samples are tested at the National Veterinary Institute, Uppsala (SVA). For the present study, a retrospective analysis was made of potentially pathogenic bacteria isolated from samples submitted to the SVA from 2007 to 2017. RESULTS: In our study, Taylorella equigenitalis was found infrequently (53 out of 25,512 samples), representing 11 out of 2308 stallions. If T. equigenitalis was detected, the stallions were treated with antibiotics and re-tested later in the same year. Klebsiella pneumoniae and beta haemolytic streptococci were the most commonly found potential pathogens, whereas Pseudomonas aeruginosa was also isolated occasionally. There were considerable differences in the number of species isolated each year. CONCLUSIONS: Potential pathogens were identified in relatively few of the samples submitted to SVA during this period, with T. equigenitalis not being identified since 2015. Of the other potential pathogens, K. pneumoniae and beta haemolytic streptococci were the most common. The information is relevant for determining guidelines on the testing and treatment of stallions before breeding.

Sperm quality in frozen beef and dairy bull semen.

BACKGROUND: There is speculation that beef bull semen quality is inferior to that of dairy bulls although few scientific studies are available in the literature. The aim of this study was to evaluate sperm quality in beef bull semen and to determine which parameters could be indicative of fertility after insemination. Sperm quality, assessed by computer assisted sperm motility analysis and flow cytometric evaluation of membrane integrity, levels of reactive oxygen species, mitochondrial membrane potential, acrosome status and DNA fragmentation index, was evaluated in beef and dairy bull semen. RESULTS: For beef bulls, normal morphology (r = 0.62, P < 0.05) and WOBBLE (r = 0.57, P < 0.05) were significantly correlated with 56-day non-return rate, whereas sperm quality was not significantly correlated with the fertility index score for dairy bulls. Membrane integrity (46 ± 8.0% versus 40 ± 11%, P < 0.05), normal morphology (87 ± 6% versus 76 ± 8%; P < 0.05), and high respiratory activity (52 ± 13 versus 12 ± 4%; P < 0.001) were higher for dairy bulls than for beef bulls. The DNA fragmentation index was lower for dairy bull spermatozoa than beef (3.8 ± 1.1% versus 6.1 ± 2.9%; P < 0.01), whereas some sperm kinematics were higher. Multivariate analysis indicated that type of bull (beef versus dairy) had an impact on sperm quality. CONCLUSIONS: Different assays of sperm quality may be needed for appropriate analysis of beef and dairy bull semen. These finding could be important for cattle breeding stations when evaluating semen quality.

Testicular length as an indicator of the onset of sperm production in alpacas under Swedish conditions.

BACKGROUND: The popularity of alpacas (Vicugna pacos) is increasing in Sweden as well as in other countries; however, knowledge about optimal management practices under Swedish conditions is still limited. The wide age range reported when the onset of puberty can occur, between 1 and 3 years of age, makes management decisions difficult and may be influenced by the conditions under which the alpacas are kept. The aim of this study was to find out when Swedish alpacas can be expected to start producing sperm, by using testicular length and body condition score as a more precise indirect indicator than age. RESULTS: This study suggests that animals with a testicular length ≥3.8 cm would be producing sperm; however, if it is crucial to know that there is no sperm production for management purposes, the threshold level for testicular length used to differentiate between sperm-producing and non-sperm producing animals should be ≤1.6 cm instead. If only one variable is considered, testicular length appears to better than age alone to predict sperm production. Body condition score together with testicular length explains the individual onset of puberty and better guide management recommendations. CONCLUSIONS: Using a combination of these parameters (testicular length, body condition score and age) as a tool for decision making for alpaca husbandry under Swedish conditions is suggested.

Single layer centrifugation-selected boar spermatozoa are capable of fertilization in vitro.

BACKGROUND: Good quality spermatozoa are important to achieve fertilization, viable embryos and offspring. Single Layer Centrifugation (SLC) through a colloid (Androcoll-P) selects good quality spermatozoa. However, it has not been established previously whether porcine spermatozoa selected by this method maintain their fertility. METHODS: The semen was prepared either by SLC or by standard centrifugation (control) and used for in vitro fertilization (IVF) at oocyte:spermatozoa ratios of 1:50; 1:100 and 1:300 (or 4 x 10(3), 8 x 10(3) and 24 x 10(3) spermatozoa/ml) to evaluate their subsequent ability to generate blastocysts. In addition, sperm motility was assessed by computer assisted sperm motility analysis. RESULTS: Total and progressive motility were significantly higher in sperm samples prepared by SLC compared to uncentrifuged samples. Sperm binding ability, polyspermy, cleavage and blastocyst rates were affected by the oocyte:sperm ratio, but not by sperm treatment. CONCLUSION: The use of SLC does not adversely affect the in vitro fertilizing and embryo-generating ability of the selected spermatozoa compared to their unselected counterparts, but further modifications in the IVF conditions would be needed to improve the monospermy in IVF systems. Since SLC did not appear to have a negative effect on sperm fertilizing ability, and may in fact select for spermatozoa with a greater potential for fertilization, an in vivo trial to determine the usefulness of this sperm preparation technique prior to artificial insemination is warranted.