Prevalence of Chlamydiaceae and Mollicutes on the genital mucosa and serological findings in dairy cattle

It was the aim of this project to obtain information on the prevalence of Chlamydiaceae and Mollicutes and their potential importance for reproductive problems in cattle. Cervical or vaginal swabs were taken from 644 animals in 196 farms and blood samples were collected from 375 cattle. Out of the animals, 6.8% had aborted within the last 12 months, 2.6% showed clinical vaginitis and 11.6% clinical endometritis. Chlamydiaceae were detected and identified by PCR followed by restriction fragment length polymorphism (RFLP) analysis. For the detection and identification of Mollicutes cultivation procedures, biochemical differentiation and serological identification were used. Sera were tested for antibodies against Chlamydiaceae and Mycoplasma (M.) bovis by ELISA and against M. bovigenitalium by Western blot analysis. Chlamydophila (Cp.) abortus was found in three cervical swabs. Cp. pecorum was detected in 9% of cervical or vaginal swabs. The majority of Cp. species found was Cp. pecorum and thus fertility problems caused by Cp. abortus are limited. M. bovis was found in only one genital swab. M. bovigenitalium was rarely diagnosed (3% of cervical and 2% of vaginal swabs). M. bovigenitalium was found more often in cattle having aborted (4/32 animals) than in cattle without history of abortion (5/220, p<0.05). Ureaplasma (U.) diversum existed in 12% of cervical and 36% of vaginal swabs and was found in 8 out of 17 animals with vaginitis. Out of the animals tested, 44.9% were seropositive for Chlamydiaceae, 14.8% for M. bovis and 27.3% for M. bovigenitalium.     

Female genital tract abnormalities of Zebu cattle slaughtered at Bahir-Dar Town, north-west Ethiopia

A study was conducted to assess the type and prevalence of abnormalities occurring in the female reproductive tracts of 201 Zebu cattle of Fogera type (161 cows and 40 heifers) slaughtered at Bahir-Dar town, north-west Ethiopia. Out of the 201 female genital tracts collected and examined, abnormalities were recorded in 74 (36.8%). The most common abnormalities encountered were ovariobursal adhesion (5.5%), endometritis (3.9%) and cystic ovaries (3.5%). Other abnormalities recorded were ovarian hypoplasia, vaginitis, cervicitis, tortuous cervical canal, mucometra, vaginal cyst, parovarian cyst, hypoplastic cervical rings, cervical cyst, freemartins, closed external cervical os, uterine and oviducts adhesion, cystic uterine tube, remnant of retained fetal membrane and cyst in the uterine wall. The prevalence of the abnormalities was significantly (p < 0.05) higher in parous than in nulliparous cows. Moreover, evidence of ovarian cyclicity was found in 51.6% and 30% of non-pregnant parous and nulliparous cows examined, respectively. This study revealed that reproductive tract abnormalities seem to be an important problem with possible subsequent infertility in Fogera-type Zebu cows in the study area.     

Immunofluorescence tests for the detection of antibodies against Corynebacterium pyogenes and streptococci in blood serum and vaginal mucus of cattle]

Bacteriological tests were applied to cattle with endometritis and vaginitis. Included were cervical mucus samples and immunofluorescence tests to detect in that mucus as well as in blood serum antibody to Corynebacterium pyogenes and Streptococcus haemolyticus. The results pointed at intensive contact of the animals with the above pathogens and to their frequent occurrence in cervical mucus of cattle afflicted with endometritis and vaginitis. They also supported the assumption of localised antibody formation in the sexual organs or female cattle.     

Pre-breeding Ovaro–Uterine Ultrasonography and its Relationship with First Service Pregnancy Rate in Seasonal-Calving Dairy Herds

The objectives of the study were to characterize an ultrasound reproductive tract scoring (URTS) system to assess suitability for breeding in dairy cows, to describe the prevalence of these scores in commercial dairy herds and to examine their relationship with subsequent fertility. Ultrasound examinations (7797) were performed on 5751 Holstein–Friesian cows prior to breeding in 62 seasonally calving herds over 2 years. Data recorded from images of both ovaries and the uterus were combined into a six point scoring system and the prevalence of cows with cystic ovarian follicles and uterine abscesses and adhesions was recorded separately. The prevalence of ovulatory cows which had completed uterine involution (score 1), or had mild (2) or moderate endometritis (3) was 62.5%, 21.7% and 2.2%, respectively. The prevalence of anovulatory cows with moderate endometritis (4), ovulatory cows with pyometra (5) and anovulatory cows which had completed uterine involution (6) was 3.3%, 2.2% and 8.1%, respectively. The interval between calving and examination differed between cows with each of the scores 1, 2, 5 and 6 (61, 46, 53 and 50 days, respectively, p < 0.05) but not between cows with scores 3 and 4 (37 and 35 days, respectively). Ovulatory cows which had completed uterine involution (score 1) had a higher likelihood of pregnancy to first service than ovulatory or anovulatory cows which had not completed uterine involution (p ≤ 0.10). The prevalence of cows with cystic ovarian follicles or abscesses or adhesions of the reproductive tract was 3.9% and 1.2%, respectively. In conclusion, 29% and 11% of cows in seasonally calving and breeding dairy herds had not completed uterine involution or were anovulatory prior to the mating start date, respectively. Both conditions, detected using a URTS system, significantly reduced first service pregnancy rate in these pasture-based dairy herds.     

The resemblance of clinical attributes between mastitic cows with no growth on bacterial milk cultures and those with gram-positive bacteria cultured

The clinical attributes of 40 dairy cows which had mastitis but no growth of bacteria from the milk were analyzed and compared to the attributes in 102 cows with only gram-positive and 61 cows with only gram-negative bacteria cultured from the milk. Cows with no bacteria cultured from the milk did not differ significantly from cows with gram-positive bacteria cultured, but 9 of 12 attributes were significantly different between cows with no bacteria cultured and cows with gram-negative bacteria cultured. Discriminant analysis was used to classify cows as members of the gram-positive or gram-negative culture groups. The discriminant equation was then applied to the cows with no bacteria cultured, and 78% of cows with no bacteria cultured were classified as members of the gram-positive group. Most mastitis in cows with no bacteria grown from the milk was probably due to gram-positive bacteria. If antibiotic therapy is used in cows with persistent mastitis and a negative culture in the belief that the culture is a false negative, treatment with antibiotics effective only against gram-negative organisms would not be appropriate.     

Cloacal flora isolated from wild black-bellied whistling ducks (Dendrocygna autumnalis) in Laguna La Nacha, Mexico.

Cloacal swabs from 110 adult black-bellied whistling ducks trapped at Laguna La Nacha, Tamaulipas, Mexico, were cultured to determine the prevalence of normal and potentially pathogenic bacteria. Twenty-five gram-negative enterobacteria and four gram-positive cocci were isolated. The most common isolates included Escherichia coli (54%), Staphylococcus spp. (29%), Streptococcus spp. (22%), Aeromonas hydrophila (15%) Enterobacter cloacae (14%), and Micrococcus sp. (14%). The implications of whistling ducks as possible reservoirs of pathogenic bacteria are discussed.     

Investigation of purulent vaginal discharge in cows, with particular reference to Haemophilus somnus

The relationship between vaginal discharge, site of inflammation in the reproductive tract and species of bacteria isolated was examined in cows that were either normal, subfertile, or had had an abnormal parturition. Microbiological and cytological examinations were performed on uterine swabs from 221 cows and cervical swabs from 107 cows. There were 167 subferitle cows, 144 of which had failed to conceive to 3 or more services (FTC) and 23 of which had not had a visible oestrus since calving (NVO). Metritis was diagnosed in 22% of the FTC cows, 48% of the NVO cows, and 12% of the cows with abnormal parturition. Fifty percent of cows with metritis had purulent vaginal discharge. However, only 25% of a total of 91 cows with vaginal discharge had metritis; the remainder had cervicitis. Fifty-four percent of subfertile cows had cervicitis without metritis. Mixed infection with aerobes and anaerobes was significantly correlated with uterine inflammation and was found in 20% of cows with metritis. The rate of isolation of H.somnus from inflamed uteruses (22%) and inflamed cervixes (39%) was significantly greater than the isolation rate from normal uteruses (8%) and cervixes (10%). No bacteria were isolated from 50% of inflamed uteruses and 37% of inflamed cervixes. The number of subfertile cows with or without metritis that subsequently conceived was not significantly different.     

Isolation of Haemophilus somnus from dairy cattle in kwaZulu-Natal. An emerging cause of 'dirty cow syndrome' and infertility?

Haemophilus somnus was consistently isolated from vaginal discharges of dairy cows submitted from field cases of vaginitis, cervicitis and/or metritis in the KwaZulu-Natal Midlands during the period July 1995 - December 2000 and from the East Griqualand area in November/December 2000. The purulent vaginal discharges, red granular vaginitis and cervicitis, and pain on palpation described in these cases was very similar to that reported in outbreaks of H.somnus endometritis syndrome in Australia, Europe and North America. In all the herds involved in these outbreaks, natural breeding with bulls was employed. Although there was a good cure rate in clinically-affected animals treated with tetracyclines, culling rates for chronic infertility were unacceptably high. Employment of artificial insemination in these herds improved pregnancy rates in cows that had calved previously, but many cows that had formerly been infected failed to conceive.     

Chlamydiaceae in riverine buffalo (Bubalus bubalis) and cows (Bos taurus) in Egypt with and without signs of reproductive disease

Abstract

AIMS: To obtain information and compare the prevalence of Chlamydiaceae in riverine buffalo (Bubalus bubalis) and cows (Bos taurus) in Egypt with and without clinical signs of reproductive disease.

METHODS: Vaginal swabs and blood samples were collected from animals attending Governmental Veterinary Clinics without (buffalo n=39, cows n=20) and with (buffalo n=63, cows n=53) signs of reproductive disease. Serum samples were tested for antibodies to Chlamydiaceae using complement fixation testing (CFT). Vaginal swabs were tested for Chlamydiaceae following inoculation into Vero cells and 6-day-old embryonated chicken eggs, using modified Giménez and immunoperoxidase staining, PCR analyses targeting the omp2 gene, and Restriction Fragment Length Polymorphism PCR (RFLP-PCR) for species identification.

RESULTS: Antibodies to Chlamydiaceae were detected in 30/39 (77%) and 50/63 (79%) buffalo without and with signs of reproductive disease, respectively, and 10/20 (50%) and 39/53 (74%) of cows with and without signs of reproductive disease, respectively. Positive samples from PCR analysis were identified in 31/39 (79%) and 37/63 (59%) buffalo without and with signs of reproductive disease, respectively, and 12/20 (60%) and 46/53 (89%) of cows without and with signs of reproductive disease, respectively. Using RFLP-PCR, 57/68 (84%) of samples from buffalo, and 47/58 (81%) from cows, were identified as Chlamydophila psittaci and the reminder as Cp. abortus. From the CFT and PCR results there was no significant difference in the prevalence of positive samples between species, or between animals without or with signs of reproductive disease.

CONCLUSION: The presence of anti-Chlamydiaceae antibodies in 77% of the animals with signs of reproductive disease and the detection of Chlamydiaceae in 72% of vaginal swabs of the animals suggest a pathogenic role by Chlamydiaceae in riverine buffalo and cows. The main Chlamydiaceae found in the genital tract of cattle in Egypt were Cp. psittaci and Cp. abortus.

CLINICAL RELEVANCE: Chlamydophila spp. should be included in diagnostic algorithms for reproductive disorders, in order to assess the real burden of Chlamydophila associated disease in buffalo and cattle and to evaluate the potential value of vaccines.     

Effects of the intensity of a post partum examination on the fertility performance of high yielding dairy cows

Two methods for a scheduled post partum examination were compared on a commercial dairy farm. In Group 1, all cows (n = 601) were examined by rectal palpation between day 20 and 26 post partum for signs of endometritis (vaginal discharge, enlarged uterus). In Group 2, all cows (n = 652) were examined by external inspection for vaginal discharge as a sign for endometritis. In both groups all cows with endometritis were treated twice with prostaglandin F2 alpha (25 mg of dinoprost) in a 14-day interval. The proportion of cows with signs of endometritis was 33.3% and 17.2% in Group 1 and Group 2, respectively (p < 0.05). In Group 1, the conception rate (39.0% vs 49.3%) and the proportion of cows pregnant (60.5% vs 72.6%) were lower for cows with endometritis than for cows without endometritis. In Group 2, no significant differences were found in reproductive performance for cows with and without signs of endometritis. No significant differences in reproductive performance were found for cows with endometritis between the two groups. Also, for cows without endometritis no significant differences in reproductive performance were found between the groups. It is concluded that the post partum examination by rectal palpation was more sensitive in finding cows with endometritis. However, with regard to the reproductive performance the more sensitive method was not more effective than the method based on systematic external inspection.     

Normal bacterial flora from vaginas of Criollo Limonero cows

In order to describe the normal bacterial flora in vaginas of Criollo Limonero cows, 51 healthy multiparous cows, at least 90-day postpartum, were selected. Duplicated swabs (N = 102) were taken from the vaginal fornix of cows to perform aerobic and anaerobic cultures as well as conventional biochemical tests. Out of 102 swabs, bacterial growth was obtained in 55 (53.9%) while the remaining 47 (46.1%) did not exhibited any bacterial growth. Of the 55 bacterial growths, 23 (41.8%) were aerobic whereas 32 (58.1%) were anaerobic. Likewise, 29 (52.72%) of bacterial growths were pure and 26 (47.27%) were mixed. Under both aerobic and anaerobic conditions, Gram positive bacteria were predominant (81.82% and 73.08%, respectively) over Gram negative bacteria (18.18% and 26.92%, respectively). Isolated bacteria were Arcanobacterium pyogenes (22.92%), Staphylococcus aureus (15.63%), Staphylococcus coagulase negative (17.71%), Erysipelothrix rhusiopathiae (6.25%), Bacteroides spp. (13.54%), and Peptostreptococcus spp. (7.29%). In conclusion, normal vaginal bacterial flora of Criollo Limonero cows was predominantly Gram positive and included A. pyogenes, S. aureus, coagulase negative Staphylococcus, E. rhusiopathiae, Bacteroides spp., and Peptostreptococcus spp. In Criollo Limonero cattle, adaptive aspects such as development of humoral and physical mechanisms for defense, and bacterial adaptation to host deserve research attention.     

Ability of hematologic and serum biochemical variables to differentiate gram-negative and gram-positive mastitis in dairy cows

Medical records of 142 dairy cows with clinical mastitis were examined to determine whether hematologic or serum biochemical results could be used to distinguish between mastitis episodes caused by gram-negative bacteria (n = 78) from those caused by gram-positive bacteria (n = 64). Signalment, historic information, hematologic and serum biochemical results, milk culture results, and outcome (discharged from hospital or died) were obtained from the medical records. Cows with gram-negative mastitis had significantly (P < .01) lower blood leukocyte, segmented neutrophil, monocyte, and lymphocyte counts and had higher blood hemoglobin concentrations and hematocrits than did cows with gram-positive mastitis. Serum urea nitrogen was the only serum biochemical result associated with pathogen type, and it was higher in cows with gram-negative mastitis than in those with gram-positive mastitis. Mortality rate (25% overall) did not differ between groups. Logistic regression indicated that routine hematologic analysis (segmented neutrophil count, monocyte count, and hemoglobin concentration) was an accurate predictor of gram-negative mastitis, with a sensitivity of .93, a specificity of .89, and an overall accuracy of 91%. The values for sensitivity and specificity were higher than those previously reported for clinical tests differentiating mastitis episodes caused by gram-negative bacteria from those caused by gram-positive bacteria. Our results indicate that routine hematologic analysis is useful for predicting pathogen type in dairy cows with clinical mastitis, thereby facilitating treatment decisions.     

Comparison of External and Internal Pelvic Measurements of Belgian Blue Cattle from Sample Herds in Belgium and the United Kingdom

Measurements describing pelvic conformation of pedigree Belgian Blue cows were obtained from a sample of nine herds in Flanders, Belgium, comprising 111 adult breeding cows, and from 11 herds in the United Kingdom comprising 108 similar cows. All herds in the Belgian sample (111 cows) managed parturition by elective caesarian section as did seven herds (56 cows) in the UK sample; the remainder of UK herds (52 cows) allowed cows the opportunity to calve naturally per vagina before resorting to caesarian section. The data described the external and internal measurements, and pelvic area characteristic of this breed, irrespective of the different selection pressures applied over a number of years to this breed through variation in farm management and market forces present in either country. From these data, generalized linear models were constructed to predict pelvic area; they correctly identified cows with either small or large pelvic areas. There were no significant differences in pelvic conformation between cattle bred either in Belgium or the UK, although those cows bred in herds where natural calving was allowed to take place had significantly larger internal pelvic height (p < 0.05) and area (p < 0.05) than other Belgian Blue cows. The correlation coefficients between internal pelvic height and width and external pelvic measurements were significant (p < 0.001). These results might facilitate the selection of breeding cows with larger pelvic area so that a higher proportion of cows can calve naturally than currently occurs. However, selection for other traits such as relatively low birth weight combined with higher weaning weight should be carried out at the same time.     

Shedding of Coxiella burnetii in ewes in two pregnancies following an episode of Coxiella abortion in a sheep flock.

Coxiella burnetii infection in pregnant sheep typically causes abortion or the birth of weak lambs. Two C. burnetii-related abortions in a group of 34 pregnant ewes were reported at their first lambing in our research institute. The seroprevalence of C. burnetii infection and bacteria shedding were investigated using an ELISA and PCR, respectively, during the course of two subsequent pregnancies. None of the ewes examined seroconverted from negative to positive at the time of the second and the third parturition and most of the ewes that were seropositive at the abortion episode remained positive throughout the investigation. The two successive pregnancies resulted in the birth of healthy lambs without PCR evidence of Coxiella infection from placenta and vaginal swabs taken postpartum. PCR assay performed on vaginal swabs taken from all animals 1, 5 or 12 days after the second lambing were also negative for Coxiella. However, one ewe that had previously experienced C. burnetii shedding at the first lambing excreted the bacteria in the genital tract after the third parturition. The bacteria could not be detected by PCR in milk and faecal samples taken up to 12 days after both parturitions.     

Safety of a progesterone-releasing intravaginal device as assessed from vaginal mucosal integrity and indicators of systemic inflammation in postpartum dairy cows

A clinical trial was conducted to investigate the animal safety of a progesterone-releasing intravaginal device (PRID). Anestrus cows at a mean of 63 +/- 3.5 d in milk were randomly assigned to an ovulation-synchronization protocol that included placement of either a PRID or a placebo intravaginal device (PID) or no such treatment. At enrolment and at device removal 7 d later, blood samples were collected. The outcomes of interest included the vaginal reaction to the device, the vaginal mucosal integrity, and the results of bacterial culture of swabs of the vaginal mucosa. In addition, the leukocyte and haptoglobin responses were measured. Although only 5% of the PRID-treated animals compared with 19% of the PID-treated animals had a copious purulent vaginal discharge at the time of device removal, there was no significant difference in the proportions; furthermore, there was no evidence of vaginal mucosal damage associated with either device. The total blood leukocyte count was significantly lower in both the PRID-treated cows and the PID-treated cows after device removal compared with the start of treatment (P < 0.05) and compared with no treatment (P < 0.001); there was no difference in leukocyte response between the 2 device-treated groups. The decrease in leukocyte count was attributed to a significant reduction in the numbers of circulating neutrophils and lymphocytes, a pattern consistent with the luteal phase of the bovine estrus cycle. There was no significant difference in the circulating haptoglobin concentration between the 3 groups of cows. Culture revealed commensal bacterial growth in the vagina of all the cows.     

Relationship between haemoglobin types and productivity of Thai indigenous and Simmental × Brahman crossbred cattle

The relationship between the haemoglobin (Hb) type and reproduction and body weight was estimated in two different cattle breeds including 59 Thai indigenous and 51 Simmental × Brahman crossbred cows. Haemoglobin type was measured using cellulose acetate electrophoresis. Five haemoglobin types were present in indigenous cattle: HbAA (35.59%), HbAB (28.81%), HbAC (20.34%), HbBB (11.6%) and HbBC (3.39%). In the Simmental × Brahman crossbred cattle, three haemoglobin types, 50.98% HbAA, 45.10% HbAB and 3.92% HbBB, were present. The results revealed that Thai indigenous cows with HbAB type were heavier at birth, however, the best growth performance was recorded in HbAC animals. In contrast, calves carrying HbBB type were the lightest animals at birth and were the youngest group at first calving. This group of Thai indigenous cows was more than 4 months younger at first calving than the heifers with HbAA type. Simmental × Brahman crossbred cows with HbAA type were significantly (P < 0.05) heavier than the animals with HbAB type at birth as well as on days 200, 400 and 600 of age. Whereas, the animals with HbAB type gave birth to their first calf at a significantly (P < 0.05) younger age than those with HbAA type.     

Comparison of Two Doses of the GnRH Antagonist, Acyline, for Pregnancy Termination in Bitches

Gonadotropin-releasing hormone (GnRH) antagonists are particularly useful when a rapid inhibitory effect on the gonadal axis is required. The aim of this study was to test the efficacy and clinical safety of a low and high dose of the third generation GnRH antagonist, acyline, on pregnancy termination in female dogs. The effect of the antagonist on the progesterone (P₄) serum concentration was also described. Twenty-one mid-pregnant bitches were randomly assigned to a single subcutaneous (SC) dose of a placebo (PLACE; n = 7), a low (ACY-L; 110 μg/kg; n = 6) or high (ACY-H; 330 μg/kg; n = 8) dose of acyline. The animals were followed up for 15 days. All ACY treated but no placebo-treated animals terminated their pregnancy by abortion (p < 0.01). The ACY-L and ACY-H groups interrupted their pregnancy 7 ± 1.9 and 6.4 ± 1.3   days after treatment, respectively (p = 0.7). A significant interaction between treatment and day was found (p < 0.01) for P₄ serum concentrations when PLACE was compared with both ACY groups. No difference was found for this hormone between both ACY groups (p > 0.05) where P₄ diminished throughout the study. The decreasing rate varied among animals and was closely related to the time of abortion when P₄ reached basal concentrations. In PLACE animals, gestation progressed normally and P₄ did not change throughout the study (p > 0.05). None of the bitches presented side effects. It was concluded that acyline safely terminated mid-pregnancy by permanently decreasing P₄ serum concentrations.     

Supplementation with Calcium Salts of Linoleic and trans-Octadecenoic Acids Improves Fertility of Lactating Dairy Cows

Objectives were to evaluate effects of feeding a calcium salt rich in linoleic and trans -octadecenoic acids (LTFA) on synthesis of prostaglandin F_2α based on its metabolite (PGFM), uterine involution and pregnancy rates in lactating dairy cows. Five hundred and eleven Holstein cows were blocked according to parity, body condition score and milk yield in the previous lactation. Primiparous and multiparous cows were randomly assigned to one of the two treatments consisting of calcium salt (2% diet dry matter) of either palm oil (PO) or LTFA from 25 days prepartum to 80 days of lactation. Cows were time-inseminated at 70 ± 3 days postpartum. Feeding LTFA tended (p = 0.08) to decrease the incidence of puerperal metritis (15.1% vs 8.8%). Primiparous cows supplemented with LTFA showed larger increase in plasma PGFM concentration at day 1 postpartum (17018 vs 6897 p m ). Pregnancy rate after first insemination tended (p = 0.07) to be greater at 27 days after insemination (37.9% vs 28.6%), and was greater (p = 0.05) at 41 days after insemination (35.5% vs 25.8%) for cows fed LTFA compared with PO. These results indicate that unsaturated fatty acids fed in a rumen inert form have the potential to modulate reproductive events and improve pregnancy rates in lactating dairy cows.     

Pathological changes in the reproductive organs of cows and heifers culled because of infertility

The reproductive organs of 20 Estonian Holstein Breed (EHF) cows and three heifers, culled because of infertility, were studied by palpation per rectum and ultrasonography. In addition, pathoanatomical and pathohistological studies were carried out after slaughtering. The pathohistological study revealed that small cysts often (12 animals) existed in culled cows, whose diameter was less than 2.5 cm. These cysts were frequently accompanied by changes in secondary and Graafi follicles, rete ovarii, ovarian stroma, and the endometrium. Three cows had follicular cysts in the ovaries, which were 25-35 mm in diameter. Two cows revealed luteal cysts in the ovaries; one of them had vaginal prolapse. Four animals (one heifer and three cows) manifested tumours or tumour-like malformations: ovarian endosalpingiosis, germ and stromal cell tumour, oviductal myolipoma, and haemangiosarcoma in the uterine blood vessels. One heifer had been culled because of two abscesses in the vaginal wall close to the cervix and another had chronic endometritis. The research findings indicate that the most common cause of infertility in the culled cows was cystic degeneration in ovaries (85%), accompanied by pathological changes elsewhere in the reproductive organs. We claim that these changes are responsible for the low pregnancy rate after the treatment of ovarian cysts. The second most common reason was genital tumours (15%). In heifers, infertility is rare and its causes are heterogeneous.     

Reservoirs of Staphylococcus aureus in meat sheep and dairy cattle

The objective of the study was to investigate reservoirs and transmission of S. aureus in ewes and lambs in 3 meat sheep flocks. Repeated sampling of milk, teat skin, nasal- and vaginal mucous membranes was performed and samples were analysed for S. aureus. For comparison, samples were also collected from cows and young heifers in 3 dairy cattle herds. Selected isolates were compared by pulsed-field gel electrophoresis (PFGE). S. aureus was detected in 8 (1.5%) of 520 milk samples from ewes and in 38 (6.4%) of 588 milk samples from cows. From body site swabs, S. aureus was found in 394 (32.6%) of 1208 samples from sheep and in 67 (16.0%) of 420 samples from cattle. The proportion of S. aureus-positive nasal swabs from ewes and cows were 56.7% and 13.9%, respectively. From lambs, 58.2% of the nasal swabs were S. aureus-positive. In each flock, one S. aureus pulsotype predominated. Identical S. aureus pulsotypes were found in milk and from body sites. Paired S. aureus isolates from the nasal cavity of (i) ewes and their lambs, (ii) twins and (iii) from repeated swabs of individual ewes were compared by PFGE, and in the majority of cases the two isolates were identical. The results contribute new knowledge indicating frequent transmission of S. aureus between the dam and her lambs and within animals in a flock. In contrast to cattle, S. aureus is frequently present in the nose of sheep which may represent the primary reservoir of S. aureus in sheep flocks.