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Even morphologically normal mammalian sperm can suffer subtle chromatin damages. This study aimed to describe the relation between sperm morphology and chromatin integrity in the ram. Thus, weekly ejaculates (N=387) were collected for one... more
Even morphologically normal mammalian sperm can suffer subtle chromatin damages. This study aimed to describe the relation between sperm morphology and chromatin integrity in the ram. Thus, weekly ejaculates (N=387) were collected for one year from five Chios and four East-Friesian rams using an artificial vagina. Abnormalities of the head (pyriform, vacuolated, small, large, tapered, detached or misshapen head), the acrosome (knobbed acrosome or detached acrosome), the midpiece (distal midpiece reflex, Dag defect, segmental aplasia of the mitochondrial sheath, tail stump defect, bowed or bent midpiece, proximal or distal cytoplasmic droplet) and the principal tail piece (abaxial, coiled, bent or double/multiple tail) were microscopically (x1000) detected in eosin-nigrosin stained smears of fresh semen, as previously described by Barth and Oko (1989) for bull sperm. DNA-fragmentation index (DFI) and the percentage of cells with high DFI (%DFI) were determined using the SCSA^TM. Spea...
Teladorsagia circumcincta is among the most important gastrointestinal parasites in small ruminants and the predominant species in Southern European goats. Parasite control is largely based on metaphylactic/preventative treatments, which... more
Teladorsagia circumcincta is among the most important gastrointestinal parasites in small ruminants and the predominant species in Southern European goats. Parasite control is largely based on metaphylactic/preventative treatments, which is often seen as non-sustainable anymore. The reasons are increased consumer demand to reduce chemicals in livestock production and anthelmintic resistance against the common drugs. This study aimed at the development of a T. circumcincta-enzyme-linked immunosorbent assay (ELISA) specifically for goats. Samples were obtained from goats raised parasite-free or infected experimentally. Sampling continued during the following pasture season and housing period. The sensitivity for the use in bulk milk samples as an indicator of T. circumcincta infection levels in grazing goats was examined. The ELISA enables clear differentiation of negative and positive animals. With a specificity of 100% negative cut-off values for serum and milk were 0.294 and 0.228 ...
Research Interests:
Research Interests:
The objective of this study was to investigate the effect of microclimatic conditions on DNA integrity of bovine sperm. DNA fragmentation of frozen-thawed sperm was analyzed in monthly semen samples of nine AI bulls ejaculating in weekly... more
The objective of this study was to investigate the effect of microclimatic conditions on DNA integrity of bovine sperm. DNA fragmentation of frozen-thawed sperm was analyzed in monthly semen samples of nine AI bulls ejaculating in weekly routine for one year. The extent of DNA fragmentation was determined using the Sperm Chromatin Structure Assay (SCSA™) and quantified by the DNA fragmentation index (DFI) and the percentage of sperm showing high DFI values (%DFI) immediately (0h) and 3h (3h) after thawing. Microclimatic factors (ambient air temperature, relative humidity, dew point) were recorded in hourly intervals throughout the year. Their mean values were calculated for seven different time periods (up to day 56) preceding ejaculation (day 0). DFI (P<0.01) and its relative change between 0h and 3h (P<0.05) were related to the set of microclimatic parameters recorded the last 11 days and from day 49 to 43 prior to ejaculation, respectively. A significant relationship was detected between %DFI and microclimatic parameters of days 35-29 preceding ejaculation (P<0.05), while the degree of change of %DFI from 0h to 3h was related to microclimatic parameters recorded from day 28 to 22 before ejaculation (P<0.05). Dew point and relative humidity appeared to be the strongest and weakest predictors of DNA integrity, respectively. In conclusion, the results of the present study showed a lag effect of microclimate on DNA integrity of frozen-thawed bovine sperm. However, microclimatic parameters of a single time period before ejaculation could not be identified as the source of variation of different SCSA parameters.