Evaluation of stallion semen.

This article outlines a basic method for conducting a stallion semen evaluation. After the removal of the gel fraction of the ejaculate, semen gel-free volume is determined, and any abnormality in appearance is noted. Concentration of sperm cells in semen can be determined with the use of either a hemacytometer or spectrophotometer after appropriate dilution of raw semen. The percentage of progressively motile sperm is evaluated promptly after collection of semen with the use of a phase-contrast microscope. The total numbers of sperm and progressively motile sperm in the ejaculate are calculated. The determination of seminal pH and the classification of sperm morphologic features are additional seminal characteristics evaluated during a semen evaluation. Sperm motion characteristics can be further evaluated with the use of computerized sperm image analysis systems and may add additional information concerning the quality of ejaculated sperm. Unfortunately, no single seminal characteristic has in itself been shown to be highly correlated with fertility, although various seminal characteristics are known to affect fertility. Therefore, to properly interpret the fertility of a semen sample, a complete and thorough semen evaluation must be performed.     

Cryopreservation of semen from a stallion with seminal vesiculitis

A 6‐year‐old Warmblood stallion was admitted for semen collection and cryopreservation. On the seventh and subsequent collection days semen samples were contaminated with purulent debris. A diagnosis of seminal vesiculitis was made following ultrasonography and endoscopy of the seminal vesicles. The stallion was treated with systemic and topical antimicrobial therapy and, although this did not cure the condition, subsequent ejaculates were suitable for cryopreservation.     

猪精液冷冻技术

<正>精液冷冻保存技术(Semen freezing)是将精液特殊处理后,通过液氮(-196℃)、干冰(-79℃)或其它冷源冷冻,超低温保存,使精液达到长期保存。精液冷冻保存技术的主要原理是精子在冷冻状态下,代谢几乎停止,生命保持相对静止状态,升温后又能复苏而不失去受精能力。     

Effective removal of equine arteritis virus from stallion semen

REASONS FOR PERFORMING STUDY: A method of removing equine arteritis virus (EAV) from equine semen used for artificial insemination is urgently needed. Recent medical studies suggest that a double semen processing technique of density gradient centrifugation followed by a 'swim-up' can provide virus-free sperm preparations for assisted reproduction. OBJECTIVES: To investigate the use of the double semen processing technique to obtain virus-free sperm preparations from stallion semen containing EAV. METHODS: Aliquots of an ejaculate from an uninfected stallion were spiked with virus and processed by the double processing technique. The sperm preparations were tested by PCR for the presence of EAV. The procedure was repeated using an ejaculate from a known shedding stallion, testing processed and unprocessed aliquots by PCR and virus isolation. RESULTS: Virus-free sperm preparations were obtained using the double sperm processing technique. The 'swim-up' step is apparently required to ensure complete virus removal. CONCLUSIONS: The double semen processing technique is potentially a useful and simple tool for the removal of EAV from the semen of shedding stallions. POTENTIAL RELEVANCE: The inclusion of density gradient centrifugation and 'swim-up' in protocols for the processing of semen for artificial insemination could help prevent the transmission of viral diseases carried in semen, such as EAV.     

In vitro evaluation of frozen-thawed stallion semen: a review

The article reviews methods used for in vitro evaluation of sperm, with particular emphasis on frozen-thawed stallion sperm. The techniques, limitations of the methods and correlations with fertility results are discussed. Very few studies have tried to find correlation between fertility of frozen stallion semen and laboratory tests. It is difficult and expensive to inseminate an adequate number of mares to achieve statistically significant differences. Significant, but low correlations have been demonstrated between the foaling rate and subjective motility of sperm incubated for 2 h and 4 h at 37 degrees C and hypoosmotic swelling test after 0 and 3 h of incubation. Significant correlations have been reported between the pregnancy rate and viability of propidium iodide-stained sperm assessed by flow cytometry as well as for glass wool and Sephadex filtration tests. No correlations have been detected between fertility and motility immediately after thawing. In spite of that, motility estimation by light microscope is the most commonly used method to evaluate frozen-thawed stallion sperm. Computer assisted automatic sperm analyzers have replaced light microscopy in research projects, but so far nobody has been able to demonstrate a correlation between fertility of frozen stallion semen and any of the motility parameters obtained by these instruments.     

Microsatellite analysis of cryopreserved stallion semen stored on FTA paper

The aim of this study was to establish and validate a method to permit microsatellite analysis of DNA profiles obtained from frozen-thawed stallion sperm cells. This would provide reliable and accurate verification of the identification of a semen donor. Ejaculates from 5 pony stallions were collected, processed and frozen in 0.5 ml plastic straws. Aliquots of 100 microl of the frozen-thawed semen thus obtained were either placed directly, or diluted (1:10; 1:100; and 1:1000) and placed on slides of FTA paper. Similarly, blood samples obtained from each of the stallions were placed onto slides of FTA paper. A punch was removed from each sample after drying Each sample was mixed with FTA purification reagent, Dithiothreitol and Proteinase K before incubation and processing. All samples were processed with a set of 13 microsatellite markers. Further analysis permitted a comparison of the DNA profiles of the frozen-thawed semen and the blood samples. A full profile of markers was obtained from the 1:10 and 1:100 dilutions of the frozen-thawed semen samples as well as from the blood samples. The DNA profiles from the frozen-thawed semen and blood samples obtained from the stallions matched in all cases.     

Isolation of Acholeplasma laidlawii and Mycoplasma equigenitalium from stallion semen

Forty semen samples from 40 stallions were examined for the presence of mycoplasmas. Mycoplasmas were isolated from 18 samples of semen, either immediately after collection or 3 months after storage at -20°C or in both cases. Ten of the isolates could be typed, nine as Mycoplasma equigenitalium and one as Acholeplasma laidlawii. Eight of the 18 isolates were lost during cultivation and storage; they were all glucose-positive and arginine-negative.