[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.

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.

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.

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.