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FrangeÏ R., T. Gider, M. Kosec: Frequency of Boar Ejaculate Collection: its Influence on Semen Quality, Pregnancy Rate and Litter Size. Acta Vet. Brno 2005, 74: 265-273.The aim of this study was to determine the best collection frequency for boar ejaculate, based on semen quality, pregnancy rate and litter size. Over a period of 7 months, 480 ejaculates were obtained, at successive collection frequencies of one, two, three and seven times per week, from 12 mature boars of line 54. For each ejaculate, the volume, progressive motility, spermatozoa concentration, sperm morphology and total number of spermatozoa were determined. Two commercial semen extenders, Beltsville Thawing Solution and Merck, were used for semen dilution and preservation. Smaller ejaculate volumes (P < 0.05), lower sperm concentrations (P < 0.05), and lower total sperm counts per ejaculate (P < 0.05) were obtained at collection frequencies of 7 and 3 than at 2 and 1 times per week. Significantly lower progressive sperm motilities at 7 than at 3, 2 and 1 times per week were observed. 1586 sows were inseminated with semen obtained at the four collection frequencies. The conception in sows was highest when inseminated with semen collected once per week and was significantly (P < 0.05) lower when collected 7 times per week than at the other three collection frequencies. The number of delivered piglets was also highest in sows inseminated with semen collected once per week and significantly(P < 0.05) higher than at collection frequencies of 2 and 3 per week. No significant differences in the semen quality parameters measured or in pregnancy rate were found when using either of the two commercial preservation extenders.These results indicate that the sperm quality decreases with increasing collection frequency and is most pronounced at the collection frequency 7 × per week. Taking into account the fertility rate and litter size, together with the number of semen doses obtained per week, the most suitable ejaculate collection frequency in mature boars of line 54 is two or three times per week. , semen, frequency, sow, artificial insemination, pregnancy rate Boar

Haematological parameters [red blood cell count (RBC), white blood cell count (WBC), packed cell volume (PCV), haemoglobin concentration, mean cell volume (MCV), mean cell haemoglobin (MCH) and mean cell haemoglobin concentration (MCHC)] in resting Lipizzan horses were determined for 143 stallions, 104 mares and 25 foals. The mean RBC and WBC values in Lipizzans were in the lower part of the normal range for warm-blooded horses. The mean PCV, MCV and MCH values were higher, but the mean haemoglobin concentration and MCHC values were lower than reported for other warm-blooded horses. In foals, the mean RBC, WBC, PCV, haemoglobin concentration and MCHC values were higher, whereas MCV and MCH were lower than in older animals. Results indicating a significant decrease in WBC (P < 0.01) and an increase in MCV, MCH and MCHC (P < 0.05) with increasing age are consistent with some other reports on warm-blooded horses. The age-related variations in RBC and PCV were less marked. Contrary to some reports, RBC (P < 0.01), WBC and haemoglobin concentration (P < 0.001) were higher in Lipizzan stallions than in mares, but differences in MCHC, MCH and MCV were insignificant. The specific haematological values determined in Lipizzans are presumably a result of selection and should be taken into consideration when dealing with this race of horses.

The resazurin reduction assay depends on the ability of metabolically active cells to reduce the resazurin redox dye to resorufin. In the present study we applied and made a diagnostic evaluation of a spectrophotometric application of the resazurin reduction assay to assess the colour change of resazurin reduction in butanol extracted colour to evaluate boar semen quality. Forty-one samples of boar semen from various breeds were included in the study. The absorption peaks for resazurin and resorufin were found to be 610 and 575 nm, respectively. Absorbance at 610 nm, where the minimum overlap of the two peaks was observed, was used in further analysis. Spearman rank correlation analysis was used to determine the correlation between the resazurin reduction assay and various semen parameters. The highest correlations were observed with the concentration of motile spermatozoa (r = -0.841; p < 0.001), sperm concentration (r = -0.833; p < 0.001), sperm index (-0.826; p < 0.001) and concentration of viable spermatozoa (r = -0.763; p < 0.001). Sensitivity and specificity, at 94.1 and 91.7%, respectively, indicate that the present test is highly accurate in discriminating between the samples according to the sperm index. When motile sperm concentration was used to distinguish between good and poor samples, high sensitivity (93.6%) was also found, whereas the test was only moderately, 80%, specific. The stability of butanol extracts in terms of A610 at different times of measurement confirmed that the resazurin reduction could be spectrophotometrically measured within 7 days from the time of assay performance, making the assay much more useful. Based on these results, the assay could be used as an additional tool for evaluating the quality of boar semen.

Superoxide dismutase (SOD), total antioxidant capacity (TAC), and thiobarbituric acid reactive substances (TBARS) in seminal plasma were evaluated on the basis of receiver operating characteristics (ROC) analysis as predictors for distinguishing satisfactory from unsatisfactory boar semen samples after storage. SOD on day 0 correlated significantly with progressive motility (r = −0.686; P < 0.05) and viability (r = −0.513; P < 0.05) after storage; TBARS correlated only with motility (r = −0.480; P < 0.05). Semen samples that, after 3 days of storage, fulfilled all criteria for semen characteristics (viability > 85%, motility > 70%, progressive motility > 25%, and normal morphology > 50%) had significantly lower SOD levels on the day 0 than those with at least one criterion not fulfilled (P < 0.05) following storage. SOD levels of less than 1.05 U/mL predicted with 87.5% accuracy that fresh semen will suit the requirements for satisfactory semen characteristics after storage, while semen with SOD levels higher than 1.05 U/mL will not fulfill with 100% accuracy at least one semen characteristic after storage. These results support the proposal that SOD in fresh boar semen can be used as a predictor of semen quality after storage.

Total and differential leucocyte counts (lymphocytes, neutrophils, monocytes, eosinophils and basophils) were measured in 140 stallions, 101 mares and 25 foals of Lipizzan breed. The values fell in the normal ranges for warm-blooded horses. Differences between mares and stallions were not significant with the exception of foals, having higher white blood cell, neutrophil, lymphocyte, monocyte and basophil values in females than in males. Foals exhibited an age-related increase of total leucocyte count during the first 4 months of life, accompanied by a decrease in neutrophil and increase in lymphocyte and eosinophil counts. In mares and stallions, the total number of leucocytes, lymphocytes, monocytes and basophils significantly decreased but the number of neutrophils and eosinophils remained almost unchanged with age gain.

Summary Reasons for performing study: The success rate of artificial insemination following the freezing of stallion semen is limited; therefore, improving the stallion semen quality after the freezing and thawing process is a necessary objective. Objectives: To investigate the influence of glass bead column separation on the freezability of stallion semen. Hypothesis: Glass beads in a column separator remove damaged and dead spermatozoa in the ejaculate during centrifugation. Methods: In total, 50 ejaculates from 6 Lipizzaner stallions were studied. Each ejaculate was divided into 2 parts, one half processed following standard procedure and the second half used for the column separation procedure. After freezing, semen quality was evaluated using standard tests for motility, morphology and viability of semen. Results: Motility and progressive motility of the column‐separated (CS) semen were significantly higher (P<0.001) before freezing and immediately, 24 and 48 h after thawing. A significant increase (P<0.001) in the percentage of hypoosmotic positive spermatozoa was observed in CS samples. The percentage of total morphological changes in the separated samples before and after freezing was significantly lower (P<0.001) compared with samples prepared using the standard procedure. A substantial decrease (P<0.001) was found in the percentage of spermatozoa with damaged acrosomes. However, the percentage of spermatozoa with coiled tails was increased in the separated samples (P<0.001). Conclusions: Column separation before freezing has a positive effect on the quality of thawed equine semen. Potential relevance: The quality of CS frozen/thawed samples indicates their potential use for increasing insemination success in mares.

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