Establishing a surveillance programme for Salmonella Dublin in Austrian dairy herds by comparing herd-level vs. individual animal detection methods.

Due to its increasing occurrence in cattle farms in various countries, leading to significant economic losses in affected livestock, Salmonella enterica subspecies enterica serovar Dublin (S. Dublin) has become a highly investigated pathogen in cattle production. In Austria, there have been occasional human cases of S. Dublin as well as an increase in laboratory-confirmed cases in cattle, indicating the need for a screening programme to determine the current status in Austria. The aims of this study were, firstly, to determine the seroprevalence of S. Dublin in dairy herds through bulk milk screenings in two federal states (Salzburg, Tyrol) of Austria. Secondly, the study aimed to identify the infection status of the herds through individual animal and herd level detection, comparing microbiological, molecular and serological detection methods. The results of the study will allow the development of a sampling strategy for a surveillance programme in Austria. A total of 6973 dairy farms were tested through serological bulk milk screening. The seroprevalence for the federal state of Tyrol was 14.8 % and for Salzburg it was 18.2 %, resulting in an average seroprevalence of 16.5 %. At an individual animal level, 205 (11.3 %) animals tested positive for shedding of S. Dublin in the faeces through microbiological detection, and 268 (17.0 %) animals had positive values (ct value ≤ 38) by qPCR. The association between microbiological and molecular detection was statistically significant (p < 0.001), with a calculated kappa value of 0.65 ± 0.27 (p ≤ 0.001), assuming a substantial level of agreement. In 17 herds, where an individual animal tested positive for shedding of S. Dublin, environmental sampling and testing were carried out. At a herd level 16 (94.1 %) out of the 17 participating herds, tested positive for S. Dublin either microbiologically or by molecular assay in boot swab samples. Bulk milk samples from 14 out of the 17 participating herds were analysed for antibodies to S. Dublin and 12 samples (85.7 %) were positive. In total 111 (18.9 %) out of 587 blood samples tested positive for S. Dublin antibodies, demonstrating a statistically significant correlation (p < 0.001) both with microbiological (κ = 0.32 ± 0.49; p ≤ 0.001) and molecular (κ=0.23 ± 0.06; p ≤ 0.001) findings. It was possible to identify S. Dublin by culture from boot swabs in 14 (82.4 %) out of 17 herds and by molecular assay using qPCR in 15 (88.2 %) out of 17 herds, indicating a suitable sample type for screening on a herd level-basis for acute infections, but not for identifying chronic infections or asymptomatic carriers. Other environmental samples, such as sponge-sticks, are only suitable to a limited extent for the detection of S. Dublin. The results of this study demonstrate a moderate S. Dublin prevalence in dairy herds in the selected Austrian regions, signalling further screening and management programmes for the future.

Investigating the Prevalence of Paratuberculosis in Hungarian Large-Scale Dairy Herds and the Success of Control Measures over Four Years.

Paratuberculosis (PTB) is a severe, slow-developing, untreatable disease of ruminants. Worldwide, the disease affects more than 50% of herds in the dairy industry, and causes substantial economic losses for dairy producers. Diagnostic tests show limited sensitivity, especially in the early stages of the disease. Our study aimed to investigate the seroprevalence of Mycobacterium avium ssp. paratuberculosis (MAP) in large-scale dairy herds in Hungary, in association with the self-reported presence or absence of screening and intervention measures against MAP transmission. We processed data from 42 large-scale Holstein Friesian farms in Hungary between 1 January 2018 and 31 December 2021. An average of 32,009 (min.: 31,702; max.: 32,207) animals were blood sampled yearly (127,372 in total during the four years), corresponding to 15% of the Hungarian dairy cattle population. All female cattle older than 2 years were blood sampled on the farms enroled in the study. The samples were tested using a commercial ELISA (IDEXX paratuberculosis screening Ab test). Farm managers were interviewed about their on-farm diagnostic and intervention approaches using a uniform questionnaire, including questions on the level of awareness, frequency of ELISA and PCR testing, and their strategies for culling adult animals and reducing transmission to newborn calves. By comparing the annual rate of change in seroprevalence and the amount of change observed during the four-year period, we concluded that test-and-cull strategies implemented in parallel with newborn calf management that aimed at preventing MAP transmission were superior to test-and-cull strategies alone; moreover, fortifying culling decision making via additional ELISA and PCR tests is superior to using a single ELISA result. For farms that carried out a complex program with both "test-and-cull" and proper newborn calf management, there was a proportional reduction in apparent seroprevalence at an average of 22.8% per year. Fifteen of the sampled farms had no measures in place to control paratuberculosis. On these farms, the seroprevalence increased by 12.1% per year on average.

Mycobacterium avium subsp. paratuberculosis in Sheep and Goats in Austria: Seroprevalence, Risk Factors and Detection from Boot Swab Samples.

This study aimed to investigate the prevalence of Mycobacterium avium subsp. paratuberculosis (MAP) in small ruminants in Austria by testing 22,019 serum samples with ELISA for the presence of specific antibodies. Furthermore, detailed investigations in five MAP-infected goat herds were carried out by ELISA, qPCR and bacterial culture. The found animal-level apparent MAP seroprevalence was 2.0% for goats and 0.7% for sheep (calculated true prevalence 3.5% and 1.2%, respectively). Herd-level apparent MAP seroprevalence was 11.1% for goat herds and 8.9% for sheep flocks. Significant risk factors for seropositivity in goat herds were: herd size, animal trading, farmed as a dairy herd, Animal Health Service membership and cohabitation with farmed game. For sheep flocks, seroprevalence was significantly higher in flocks with animal trading and where cattle or goats were kept in the flock, respectively. The overall apparent within-herd MAP seroprevalence in the five goat farms investigated was 21.8% (11.7%-28.0%, calculated true seroprevalence 38.6%) and an overall rate of MAP shedding of 12.3% was detected (5.0%-24.7%). It was possible to identify MAP by culture using boot swab samples in each herd. The results indicated a moderate MAP infection rate in small ruminants in Austria.

Association between calf rearing technology and farm-level paratuberculosis infection in Hungarian dairy farms.

The ruminant paratuberculosis (PTB) is a global problem. The disease causes significant economic loss, primarily in dairy farms, due to premature culling, reduced slaughter value, and production losses. Newborn and young calves are the most susceptible to being infected, and the chance of infection decreases with increasing age. Animals are most commonly infected orally. The study aimed to assess the factors that have a greater association with PTB prevalence in Hungarian cattle farms and could play a major role in the eradication process. We visited 26 large-scale Hungarian dairy herds (having preliminary data on PTB and testing positive during the last two years). We assessed 10 management aspects that may influence the spread of PTB. Farms were evaluated, and answers were dichotomised based on whether the given management practice was advantageous or disadvantageous in controlling the spread of MAP. By summing up the obtained values, a 'Hygiene score' was achieved that would rank the farms based on their awareness in MAP control. In the visited herds, the average apparent animal-level PTB prevalence was 8.3 % (min. 2.0 %, max. 19.5 %). There was a significant negative correlation between the 'Hygiene score' and the apparent MAP seropositivity of the given farm. Taking the calf away immediately after birth was associated with an average 55 % decrease in the odds of seropositivity as compared to the longer time spent with the dam. Discarding of colostrum from previously PTB+ cows after calving was associated with a 48 % decrease in the odds of seropositivity as compared to farms where the colostrum or milk of PTB+ cows was not discarded but fed to the calves. In conclusion, calf management is key in controlling paratuberculosis where immediate removal of the calf from its mother and the feeding of MAP-free colostrum and milk are essential elements.

Individual faecal and boot swab sampling to determine John's disease status in small cattle herds.

Individual faecal samples were collected from adult animals in 275 cattle farms previously positive for Mycobacterium avium subsp. paratuberculosis (MAP). In addition, boot swab samples were collected in 30 randomly chosen farms. Faecal samples were tested for MAP by a combination of bacterial culture and PCR. A logistic regression and the Pearson Correlation were used to calculate the relation between the number of MAP­positive cows and boot swab results. In 66.9% of all previously tested herds, no positive individual faecal sample was detected, indicating possible fadeout of the infection. In 9 (30.0%) of the 30 selected farms, at least one MAP­shedding animal was detected in faecal samples individually collected, while only 5 (16.7%) of these farms were found positive when the boot sampling method was used. The sensitivity of the boot swab sampling increased up to 92% (95% CI: 41%­99%), if at least 12 animals were faecal MAP­shedders in a herd. The current study shows possible fadeout of JD in a substantial percentage of previously infected herds. Furthermore, in small herds, a relatively high within­herd prevalence of MAP­shedding animals is needed to assure reliable positive boot swab results.

[Etiology, therapy and prophylaxis of bovine parturient paresis (hypocalcaemia)]. / Wesen, Ursachen, Therapie und Prophylaxe der hypokalzämischen Gebärparese beim Rind.

Due to the sudden increase of calcium demand at the onset of lactation many high yielding dairy cows experience a certain level of hypocalcaemia following parturition. The incidence of hypocalcaemia (parturient paresis) increases with age but also depends on many other factors such as the acid-base status and the availability of calcium as well as other minerals and trace elements. Hypocalcaemia can easily be treated by supplementation of calcium parenterally or orally, nonetheless, prophylaxis of the condition should be the main focus in modern dairy farming, in order to avoid its negative effects. Oral administration of calcium around parturition is the simplest way of prophylaxis, but results in a high work load and requires exact knowledge of the date of parturition. The latter also applies for the parenteral administration of vitamin D3, which should be injected 1 week before parturition. Additionally, repeated treatment with vitamin D increases the risk for calcinosis. Reducing the calcium concentration of the ration fed during the late dry period also decreases the risk for hypocalcaemia by activating the mechanisms for calcium homeostasis within the body. The induction of a mild (compensated) metabolic acidosis to increase the sensitivity of parathormone receptors and enhance intestinal calcium uptake may also be employed to prevent milk fever. For this purpose, a DCAD (dietary cation anion difference) diet is fed during the late dry period, in which the concentrations of strong cations (potassium and sodium) as well as strong anions (sulfate and chloride) are altered. This may either be achieved by reducing the potassium concentration (partial-DCAD) or by adding anionic salts (full-DCAD). This method, especially the full-DCAD variant, requires a substantial level of surveillance and monitoring. Suitable prophylactic measures for the prevention of hypocalcaemia must be chosen individually for each farm, depending on the incidence of hypocalcaemia as well as personnel and structural resources.

Evaluation of host-based molecular markers for the early detection of human sepsis.

We have identified 24 molecular markers, based on circulating nucleic acids (CNA) originating from the human genome, which in combination can be used in a quantitative real-time PCR (qPCR) assay to identify the presence of human sepsis, starting two to three days before the first clinical signs develop and including patients who meet the SEPSIS-3 criteria. The accuracy was more than 87 % inside of the same patient cohort for which the markers were developed and up to 81 % in blind studies of patient cohorts which were not included in the marker development. As our markers are host-based, they can be used to capture bacterial as well as fungal sepsis, unlike the current PCR-based tests, which require species-specific primer sets for each organism causing human sepsis. Our assay directly uses an aliquot of cell-free blood as the substrate for the PCR reaction, thus allowing to obtain the diagnostic results in three to four hours after the collection of the blood samples.

[Two-stage control of paratuberculosis: Herd-status surveillance as the basis for operational measures to reduce the prevalence. - Experiences from Lower Saxony, Hesse, Thuringia and Tyrol]. / Zweistufige Paratuberkulosebekämpfung in der Praxis: Überwachung auf Herdenebene als Basis für betriebliche Maßnahmen zur Prävalenzsenkung.

Economic losses caused by paratuberculosis (Johne's disease) can be high in infected herds. A universally accepted concept for the surveillance or control of paratuberculosis in cattle herds has not yet been established.In the course of the program for the reduction of MAP (Mycobacterium avium subsp. paratuberculosis) infections in Lower Saxony, Germany, dairy farms are obliged to test bulk tank milk samples for the presence of MAP-antibodies every 6 months. In case of a non-negative result, testing is required at the single animal level. Farmers can than decide whether they join a program to control MAP-infections in their herd. Within the voluntary certification program for paratuberculosis in Hesse, Germany, the MAP-herd status is evaluated using boot swab sampling. On positive farms, animals are tested at 6-month intervals by milk or blood serology with timely culling of positive individuals. The program for the abatement of paratuberculosis in cattle herds in Thuringia, Germany, is based on a yearly fecal examination for MAP-shedding of all adult cattle within a herd. Fecal MAP-positive animals should be culled as soon as possible. The basis of the surveillance and control program for MAP in Tyrol, Austria, is the biennial survey of the MAP-herd status by boot swab sampling. Farms with a MAP-positive boot swab result have the option to have their adult animals tested for MAP by single animal fecal sampling. On the basis of the results of these samples, farmers can decide whether they wish to join the MAP-control program.The programs presented above show that a two-stage approach consisting of the evaluation of the MAP-herd level, followed by the testing of single animals, represents a feasible approach for the surveillance and control of paratuberculosis in cattle herds.

Testing of milk replacers for Mycobacterium avium subsp. paratuberculosis by PCR and bacterial culture as a possible source for Johne's disease (paratuberculosis) in calves.

Johne's disease (paratuberculosis) is caused by Mycobacterium avium subsp. paratuberculosis (MAP) and can lead to severe economic losses in the affected cattle herds. The transmission of the disease occurs mainly orally, by the ingestion of MAP, which is shed in the feces and milk of infected animals. Calves show a high susceptibility for the infection compared to adult animals. The use of milk replacers can, therefore, contribute to the prevention of the transmission of the disease to calves in MAP-positive herds by preventing the ingestion of the bacterium with milk from infected animals. The objective of this study was to test milk replacers for calves for the presence of MAP by bacteriological culture and PCR. Therefore, commercially available milk replacers for calves were purchased from 15 different companies. All of the products were tested for MAP by solid culture and real time quantitative PCR (qPCR) targeting IS900 and F57. During the present study, MAP could not be detected by qPCR or solid culture in commercially available milk replacers for calf rearing. The results of the present study underpins that the use of milk replacers for calf rearing might contribute to the reduction of MAP intake by calves in JD positive herds. Additional studies, including more products with a higher diversity, are needed to further elucidate the presence or absence of MAP in milk replacers for calves.

Lymphatic fluid for the detection of Mycobacterium avium subsp. paratuberculosis in cows by PCR, compared to fecal sampling and detection of antibodies in blood and milk.

Johne's disease (JD), caused by Mycobacterium avium subsp. paratuberculosis (MAP), can cause considerable economic losses in affected herds. Early diagnosis of JD is hampered by the chronic nature of the disease with a slow subclincal progression. The aim of the present study was to challenge the hypothesis that lymphatic fluid is of diagnostic value in the early stages of the disease. Lymphatic fluid from 122 animals was collected and tested for MAP by nested PCR for IS900 and compared to the results of testing for MAP in feces (culture), blood and milk (ELISA) in 110 of these samples. MAP was detected by PCR in 27.1% of the lymph samples. Agreement between the tests was poor: 6.9% of the lymph positive cows were also positive in all other tests applied, and 69.0% had negative results in fecal culture, blood and milk ELISA. Resampling of 25 cows after 8 to 12 and 16 to 20 months revealed 20.0% lymph positive animals at the first, 5.5% at the second and 27.8% at the third sampling, respectively. Only one cow showed positive lymph-PCR results at more than one sampling date. Lymph-positive cows had a 7.2 times greater likelihood of being culled within 8 to 12 months after sampling, compared to negative cows, mainly due to other health issues than JD. It can be concluded, that lymphatic fluid might be promising for the detection of early MAP-infection in cows, but further studies to elucidate the potential of this diagnostic approach are needed.

Examples and suggestions for the control of paratuberculosis in European cattle.

Paratuberculosis, or Johne's disease (JD), is caused by Mycobacterium avium subspecies paratuberculosis (MAP), is found in ruminants worldwide and can cause considerable economic losses in cattle. Control efforts and programs for JD in cattle are very diverse among European states, in Austria clinical JD is rated as a notifiable disease since 2006. The voluntary control programs established in many European countries, show different aims, measurements and acceptance. Most control programs for JD are based on a test and cull strategy, combined with hygienic precautions. Unfortunately, the willingness to participate in such programs by farmers and veterinarians is limited due to high costs, intensive workload, long duration and limited success. To overcome this drawback and to harmonize the control of MAP in Europe, a basic program with defined minimum standards is suggested. This "minimal program" for the control of JD in cattle consists of 3 steps. Step 1 includes diagnostic evaluation of every case of diarrhea in adult cattle and culling of animals with clinical JD. Step 2 is the implementation of basic management measures, adapted to the potentials of the individual farm. Step 3 consists of regularly evaluation of the MAP-herd status with the focus on MAP-shedding animals. This basic control program can be performed with reasonable costs and work load in most cattle herds and might serve as an international minimum standard for MAP-control in cattle. Such a program can also pose an incentive to decrease MAP-infections for those not willing to participate in more sophisticated control programs.

The collection of lymphatic fluid from the bovine udder and its use for the detection of Mycobacterium avium subsp. paratuberculosis in the cow.

The objective of the current study was to evaluate the feasibility of lymph collection from the bovine udder and to investigate if the lymphatic fluid might be of diagnostic value in cows infected with Mycobacterium avium subsp. paratuberculosis (MAP), the etiologic agent of paratuberculosis. Lymph fluid collection was attempted from 58 cows, and the reactions of the cows as well as the level of difficulty of the procedure were recorded in 56 animals. Lymph samples (51 in total) were tested for the presence of MAP by nested polymerase chain reaction. Collection of the lymphatic fluid caused no or mild signs of discomfort in 94.6% of the cows; in 51.8% of cows, lymphatic fluid was attained on the first attempt, while sample collection was unsuccessful in 12.1%. Mycobacterium avium subsp. paratuberculosis was detected in 43.1% of all lymph samples. The bacterium was present in 66.7% of cows with clinical Johne's disease, in 42.8% of asymptomatic cows with a positive or suspicious enzyme-linked immunosorbent assay (ELISA) result in blood, and in 38.7% of cows with a negative ELISA result in blood. The present study shows that the procedure was well tolerated by most cows and can easily be performed on farm. The current report of the isolation of MAP from lymph fluid suggests that the present approach could be used for the early detection of Johne's disease in cattle.

A novel real-time PCR assay for specific detection and quantification of Mycobacterium avium subsp. paratuberculosis in milk with the inherent possibility of differentiation between viable and dead cells.

BACKGROUND: Mycobacterium avium subsp. paratuberculosis (MAP) is the etiological agent of paratuberculosis (Johne's disease) in ruminants and is suggested to be one of the etiologic factors in Crohn's disease in humans. Contaminated milk might expose humans to that pathogen. The aim of the present study was to develop a novel real-time PCR assay providing the additional possibility to detect viable Mycobacterium avium subsp. paratuberculosis (MAP) based on the MAP-specific Mptb52.16 target. The design included an internal amplification control to identify false negative results. FINDINGS: Inclusivity and exclusivity tested on 10 MAP strains, 22 non-MAP mycobacteria, and 16 raw milk microflora strains achieved 100%. The detection limit in artificially contaminated raw milk was 2.42 × 101 MAP cells/ml milk. In a survey of naturally contaminated samples obtained from dairy herds with a known history of paratuberculosis, 47.8% pre-milk and 51.9% main milk samples tested positive. Real-time PCR-derived MAP-specific bacterial cell equivalents (bce) ranged from 1 × 100 to 5.1 × 102 bce/51 ml; the majority of samples had less than one bce per ml milk. Expression of the chosen target was detected in artificially contaminated raw milk as well as inoculated Dubos broth, thus confirming the real-time PCR assay's potential to detect viable MAP cells. CONCLUSIONS: Concentrating the DNA of a large sample volume in combination with the newly developed real-time PCR assay permitted quantification of low levels of MAP cells in raw milk and pasteurized milk. The selected target - Mptb52.16 - is promising with regard to the detection of viable MAP. Future studies integrating quantitative DNA- and RNA-based data might provide important information for risk assessment concerning the presence of MAP in raw milk and pasteurized milk.

Consecutive excretion of Mycobacterium avium subspecies paratuberculosis in semen of a breeding bull compared to the distribution in feces, tissue and blood by IS900 and F57 quantitative real-time PCR and culture examinations.

Paratuberculosis (Johne's disease) has emerged as one of the most important diseases in cattle. The role of infected bull semen in the spread of infection remains unclear, as the correlation between the amount of excreted Mycobacterium avium subsp. paratuberculosis (semen and feces) and the infection load (blood and tissues) has not been defined. The aim of the present study was to study by culture, and a quantitative real-time polymerase chain reaction, the presence of bacteria in consecutive semen, blood, and fecal samples collected from one infected Piedmont breeding bull during a 380-day period. Five out of seven blood samples and all nine semen samples were positive in the real-time quantitative polymerase chain reaction with 10¹ to 10² and 10² to 104 copies of IS900/F57 per ml, respectively. In all, there were 9 fecal culture positive samples with too numerous to count colony forming units and positive real-time quantitative polymerase chain reactions ranging from 105 to 107 copies of IS900/F57. After the bull was euthanized, Mycobacterium avium subsp. paratuberculosis was cultured from various parts of the small and large intestines, liver tissue and lymph nodes and from the epididymis and vesicular glands. The results demonstrate a wide extraintestinal distribution of the bacterium and that breeding bulls should be considered a source of paratuberculosis infection due to their contact with other breeding bulls and a high number of heifers and cows through the natural mating process.

Laparoscopic-assisted implantation of a urinary catheter in male sheep.

OBJECTIVE-To evaluate a laparoscopic technique for implantation of a urinary catheter in the right paramedian area in male sheep and to determine feasibility, benefits, and risks for this technique. DESIGN-Evaluation study. ANIMALS-6 Healthy male sheep (mean +/- SD body weight, 42.16 +/- 11.95 kg [92.75 +/- 26.29 lb]). PROCEDURES-Each sheep was anesthetized and positioned in dorsal recumbency. A 10-mm laparoscope was inserted in the right paramedian area between the xiphoid and preputial orifice. After creation of capnoperitoneum, grasping forceps were inserted in the left paramedian area at the level of the teats and used to immobilize the urinary bladder. A pigtail balloon catheter was implanted transcutaneously in the right paramedian area between the preputial orifice and teats and directed into the urinary bladder by use of laparoscopic guidance. The catheter was removed 10 days after implantation. Fourteen days after initial surgery, a second laparoscopy was performed to evaluate pathologic changes. RESULTS-Inadvertent insertion of the first trocar into the rumen of 1 sheep was the only intraoperative complication encountered. Laparoscopic-assisted implantation of the urinary catheter was successfully performed in all sheep. No postoperative complications were detected. CONCLUSIONS AND CLINICAL RELEVANCE-Laparoscopic-assisted implantation of a urinary catheter in the right paramedian area was successfully performed and may be a feasible method for use in sheep. This method can be considered as an alternative to tube cystotomy performed by laparotomy.

Influence of milking technique and lactation on the bovine teat by means of ultrasonographic examination.

The teats of Brown Swiss and Austrian Simmental cows, divided into two groups, one milked by means of an automatic milking system, the other using a conventional milking parlour, were examined monthly by ultrasonography. Aim of the study was to compare the effects of two different milking machines upon the structures of the bovine teat canal and wall by ultrasonography and thereby evaluate ultrasonography as a research tool for visualisation of different influences on the bovine teat. Length and thickness of the teat canal and teat wall thickness were measured and analysed. During lactation, teat canal length and thickness increased in both groups, teat canal length decreased in conventional milked cows at the end of lactation. Shorter and narrower teat canals were observed in automatic milked cows. Differences between the groups in teat canal length and thickness were determined in early lactation. During lactation teat wall thickness showed a slight increase. Automatic milked cows displayed thinner teat walls than cows milked in the milking parlour. Teat morphology was influenced by the number and duration of lactations, milk yield, quarter of the udder and time and date of examination. It was concluded that the effect of the two different milking machines caused significant differences in bovine teat morphology and that ultrasonography proved to be an appropriate method for visualising influences of the milking technique on the bovine teat.

Ultrasonographic measurement of the bovine teat: breed differences, and the significance of the measurements for udder health.

The objective was to measure teat canal length and diameter, teat diameter and teat wall thickness by ultrasonographic scanning in order to determine the differences in bovine breeds, and to study the influence of teat canal length and diameter on the occurrence of mastitis. A total of 269 lactating dairy cows of four different breeds (Brown Swiss, Simmental, Simmental crossbred with Red Pied, and Holstein-Friesians) from seven Upper Austrian dairy farms were examined. Average teat canal length of Brown Swiss animals was shortest (15.7 mm) followed by Holstein-Friesians (17.2 mm) and Simmental (18.3 mm). These differences in teat canal length were highly significant (P < or = 0.001). There was no significant difference in teat canal length between pure-bred and crossbred Simmentals. Differences of teat canal diameter between breeds were significant (P < or = 0.05). Brown Swiss animals had the largest diameters (2.0 mm) and Holstein-Friesians the smallest (1.7 mm). Differences in teat diameter between Brown Swiss, Holstein-Friesian and Simmental were also significant. No differences were found between the pure-bred and crossbred Simmental cows. The narrowest teats were in Holstein-Friesians and the widest in Simmental. Holstein-Friesians also exhibited the thinnest teat walls while the Simmental had the thickest ones. Teat canal length and diameter were correlated with udder health. Teat canals of healthy udders tended to be longer (17.4 mm) and narrower (1.8 mm) than teat canals of infected udders (15.8 mm, 2.1 mm; P < or = 0.001). A logistic regression model showed significant effects of teat canal length, teat canal diameter and lactation number on udder health.