Detection of Campylobacter fetus in artificial insemination bulls with a transport enrichment medium.

One hundred and five bulls from an artificial insemination unit were tested for the presence of Campylobacter fetus subspecies venerealis. The method involved the inoculation of preputial samples into a new transport enrichment medium prior to culture and immunofluorescence tests. Seventeen bulls (16%) were found to be either positive or suspected carriers of C. fetus at one or more sampling times. The average age of these 17 bulls was about two years greater than the average age of all the bulls in the unit. A combined treatment of vaccination and dihydrostreptomycin sulfate injection suppressed or eliminated the organism from carrier bulls. The use of transport enrichment medium has increased our capability and effectiveness to monitor the presence of C. fetus in artificial insemination bulls.     

Molecular epidemiology of Campylobacter fetus subsp. fetus on bovine artificial insemination stations using pulsed field gel electrophoresis

The presence of Campylobacter fetus subspecies fetus (Cff) on bovine artificial insemination (AI)-stations can have major economical consequences. More knowledge on the epidemiology of C. fetus is needed to control Cff infections at AI-stations. We assessed the epidemiology of Cff on AI-stations and the molecular relationship between Cff strains isolated from outbreaks on AI-stations. Thirteen Cff strains (two Cff strains per outbreak and one sporadic case) isolated from bulls housed on different AI-stations were selected and compared with ten unrelated bovine and ovine Cff isolates from different geographical regions. Molecular typing by pulsed field gel electrophoresis (PFGE) with the restriction enzymes SmaI, SalI and KpnI, yielded unique profiles for most unrelated strains but indistinguishable profiles for all isolates from the same outbreak. Computer aided analysis using a composite data set of SmaI, SalI and KpnI restriction profiles revealed separate clusters for outbreak strains. Thus, PFGE profiling of Cff strains is a valuable tool to discriminate between strains derived from separate outbreaks and to identify routes of infection.     

The distribution of mycoplasmas and ureaplasmas in the genital tract of normal artificial insemination bulls

Bull semen is commonly contaminated with mycoplasmas. To determine the source of contamination, semen and the genital tracts of 45 artificial insemination bulls were cultured for these organisms. The results indicate that mycoplasmas colonize the prepuce and the distal part of the urethra. Only rarely were they found in the ampullae or seminal vesicles. In 92% of the bulls with contaminated semen the same Mycoplasma species or Ureaplasma diversum was isolated from the prepuce and urethral orifice as was found in the semen. This suggests that the prepuce and distal urethra is the source of contamination. Colonization of the genital tracts with Mycoplasmas or U. diversum was not associated with histological changes.     

Effect of acrosomal defects on fertility of bulls used in artificial insemination and natural breeding

Four bulls that produced spermatozoa with a high percentage of abnormal acrosomes were individually placed in pens with females for 21 days. Frozen semen from 2 of the bulls was used for artificial insemination. One of the bulls was placed in a competitive mating situation with normal bulls at pasture. First service pregnancy rates were determined by transrectal ultrasonography 28 days after bull removal from breeding pens, or after the last artificial insemination. The results of competitive mating at pasture were determined from breeding observations, the phenotypic characteristics of calves sired, and blood typing for parentage. The results of these studies suggest that bulls that produce a high percentage of spermatozoa with indented acrosomes may have normal fertility when used in artificial insemination or in single sire mating; however, their fertility may be low when breeding competitively with bulls with normal spermiograms.     

Prevalence of bovine viral diarrhea virus infection in bulls in artificial insemination centers in Poland

This study was directed at the evaluation of the prevalence of bovine viral diarrhea virus (BVDV) infection in bulls in artificial insemination centers. Both serological and virological examinations were performed. Blood samples were tested in micro-seroneutralization test for BVDV antibodies. Virus isolation was performed in cell culture and BVDV antigen was detected in an indirect immunofluorescence assay with monoclonal antibodies. One hundred and seventy-five serum samples and 219 whole blood samples for virus isolation were tested. Neutralizing antibodies were found in 86% of the bulls. Persistent infection (PI) was detected in 0.9% of the analyzed blood samples.     

Growth hormone treatment of breeding bulls used for artificial insemination improves fertilization rates

To evaluate new therapeutical concepts for male subfertility, we tested the effects of exogenous recombinant bovine growth hormone (rbGH) on various endocrine and metabolic parameters both in blood and in seminal plasma of bulls. Sperm quality was assessed morphometrically and by monitoring the number of successful artificial inseminations (AIs) defined as non-return rates (NRR). Aliquots of 450 semen samples were used from each bull and each experimental period (4 wk before, 14 weeks during and 6 wk after treatment). Six out of ten sires (average age 8.4 years) were treated every two weeks with 640-mg depot formulated rbGH (Eli Lilly). Four bulls received vehicle only. Blood plasma bGH, IGF-I, insulin and glucose concentrations were increased with rbGH treatment. In seminal plasma there was no effect of rbGH treatment on fructose and citrate or on testosterone concentrations. With one exception, rbGH-treated bulls had greater IGFBP-3 concentrations in seminal plasma. Motility of spermatozoa after freezing and thawing was increased compared with pretreatment rates. Most interestingly, the number of successful AIs was increased by an average of 6.0% NRR when ejaculates from rbGH-treated bulls were used.     

Campylobacter fetus fetus abortions in vaccinated ewes

AIMS: To investigate the cause of an outbreak of ovine abortion in 1996 in a flock of 300 two-tooth (rising 2-year-old) ewes vaccinated against Campylobacter fetus fetus infection and to subsequently characterise the strain of C. fetus fetus isolated from aborted foetuses. METHODS: Standard bacteriological methods were used to identify C. fetus fetus isolates which were then antigenically typed and subjected to pulsed-field gel electrophoresis (PFGE) and compared to the vaccine strain. RESULTS: C. fetus fetus was identified as the causal agent of the abortions despite the ewes having been vaccinated before ram introduction and at the time of ram removal. Four isolates cultured from aborted material were indistinguishable when compared using antigenic typing and PFGE, but all differed from the vaccine strain. CONCLUSIONS: Within the limitations of the available typing systems, it is proposed that PFGE may be a useful tool to establish the distribution and strain variation of C. fetus fetus. CLINICAL RELEVANCE: This field case indicates the need for further study of non-vaccine C. fetus fetus strains which cause abortion in vaccinated ewes, and of the importance of these strains to the New Zealand sheep industry.     

The application of a transport and enrichment medium to the diagnosis of Campylobacter fetus infections in bulls

The use of a transport and enrichment medium (TEM) in the diagnosis of Campylobacter fetus infections in bulls is described. The medium significantly improved the diagnosis rate in samples which, because of the length of time between collection and receipt at the laboratory, were unsuitable for processing by direct culture. The TEM was able to support the viability, and subsequent multiplication, of C. fetus in some samples for up to 7 days before the TEM was incubated. The submission of paired samples of TEM, one containing unfiltered preputial washing (PW) and the other containing PW filtered through a 0.60 micron cellulose acetate filter, significantly increased the accuracy of diagnosis.     

Campylobacter colitis in ranch mink in Ontario.

Outbreaks of colitis, where Campylobacter jejuni and Campylobacter coli were the only pathogens isolated occurred in weanling mink (Mustella vision) on two commercial mink ranches in Ontario. Lesions were restricted to the proximal colon and were characterized by multiple 1 mm focal or 1 mm linear erosions/ulcers in the region 2 cm distal to the ileal-colonic junction. Histological changes included thickening of the colonic mucosa, inflammatory cell infiltrate in the lamina propria and submucosa, cellular debris and inflammatory exudate within cryptal lumens and multiple areas of mucosal erosion/ulceration. Four C. jejuni negative mink were challenged with 5.1 X 10(9) colony forming units of C. jejuni by oral inoculation. Three of four experimentally infected mink developed diarrhea by day 4 postinfection with lesions grossly and microscopically similar to mink in the naturally occurring outbreak. Examination of lesions by transmission electron microscope failed to show evidence of C. jejuni invasion of intestinal epithelium. Feeding uncooked slaughterhouse chicken offal was the likely source of C. jejuni in the naturally occurring outbreaks.     

Cytogenetic survey of Holstein bulls at a commercial artificial insemination company to determine prevalence of bulls with centric fusion and chimeric anomalies

OBJECTIVE: To determine prevalence of Holstein bulls with chromosomal anomalies, particularly the 1/21 centric fusion (CF), at a commercial artificial insemination (AI) company in the United States. DESIGN: Cross-sectional cytogenetic prevalence study. ANIMALS: All 606 Holstein bulls at a commercial AI company were cytogenetically screened to detect CF, chimerism, and other chromosomal abnormalities. PROCEDURE: Lymphocytes from heparinized blood samples were cultured by standard cytogenetic techniques, and chromosome spreads were prepared for microscopic examination. Chromosomal abnormalities were detected by examining 10 chromosome spreads per bull. Pedigree analysis was performed. RESULTS: None of the bulls had any type of CF. However, 6 bulls were identified as chimeras (i.e., contained lymphocytes with male [XY] and female [XX] chromosomes). One bull was sire or maternal grandsire to 85 of the bulls tested, and 739 of 1,212 (61%) sire and maternal-grandsire possibilities were accounted for by just 18 bulls. CONCLUSIONS AND CLINICAL RELEVANCE: Analysis of these results supports previous indications that CF is extremely rare in Holstein bloodlines available commercially via AI in the United States. However, chimeric bulls are more common, and they reportedly have decreased reproductive performance. Therefore, identification of chimeric sires in the AI facility reported here and the possibility of de novo onset of CF at any time indicates that early cytogenetic screening should be encouraged for prospective bulls intended for use in AI programs.