Publications by authors named "P S Ursem"

This study was done to determine the effects of processing techniques on the quality of semen from Dutch AI-bucks with the view on improving pregnancy rates after artificial insemination (AI) with liquid or frozen-thawed semen. Motility of spermatozoa was estimated under a microscope whereas the percentage live spermatozoa and the percentage live spermatozoa with intact acrosomes were determined by means of flow cytometry. Aspects of semen processing that were investigated are storage temperature of liquid semen (i), the effect of glycerol on liquid-stored semen (ii), removal of seminal plasma (iii) and type of extender (iv).

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The purpose of this study was to evaluate annual semen characteristics of pigeons (Columba livia). Ten selected male pigeons, aged 2 to 5 yr were housed under natural environmental conditions, and semen collection was conducted via a digital massage twice weekly throughout the year. The success rate of semen collection in a total of 920 attempts was 40% (371/920) over the whole year.

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Sperm preservation has become a routine procedure in dog breeding. In this study, the influence of prostatic fluid on sperm characteristics after preservation (either chilling or freezing) was investigated. The sperm-rich fractions of 20 ejaculates from five dogs were either extended without centrifugation or centrifuged and resuspended either directly in extender or in prostatic fluid before dilution with extender.

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The gubernaculum testis is the connective tissue organ that causes the testis to descend. How the process of testicular descent is regulated is not fully understood. Current hypotheses postulate that a nonandrogenic fetal testicular factor controls the first phase of descent, that is characterized by growth of the gubernaculum and transabdominal migration of the testis.

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An enzyme-linked immunosorbent assay (ELISA) was developed to monitor the antibody response to Corynebacterium parvum during cancer immunotherapy. Firstly, in sera from 176 clinically healthy individuals not treated with C. parvum, elevated ELISA extinction values were observed from the age of 11 years onwards for both sexes; these high values were probably due to preexisting antibodies to C.

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