Clinical evaluation of the CRIF 4.5/5.5 system for long-bone fracture repair in cattle

OBJECTIVE: To report clinical evaluation of the clamp rod internal fixator 4.5/5.5 (CRIF 4.5/5.5) in bovine long-bone fracture repair. STUDY DESIGN: Retrospective study. ANIMALS: Cattle (n=22) with long-bone fractures. METHODS: Records for cattle with long-bone fractures repaired between 1999 and 2004 with CRIF 4.5/5.5 were reviewed. Quality of fracture repair, fracture healing, and clinical outcome were investigated by means of clinical examination, medical records, radiographs, and telephone questionnaire. RESULTS: Successful long-term outcome was achieved in 18 cattle (82%); 4 were euthanatized 2-14 days postoperatively because of fracture breakdowns. Two cattle had movement of clamps on the rod. Moderate to severe callus formation was evident in 11 cattle 6 months postoperatively. CONCLUSIONS: Movement of clamps on the rod was recognized as implant failure unique to the CRIF. This occurred in cattle with poor fracture stability because of an extensive cortical defect. The CRIF system may not be ideal to treat metacarpal/metatarsal fractures because its voluminous size makes skin closure difficult, thereby increasing the risk of postoperative infections. CLINICAL RELEVANCE: CRIF cannot be recommended for repair of complicated long-bone fractures in cattle.

Financial analysis of various strategies for the control of Neospora caninum in dairy cattle in Switzerland

The present study was conducted to estimate the direct losses due to Neospora caninum in Swiss dairy cattle and to assess the costs and benefits of different potential control strategies. A Monte Carlo simulation spreadsheet module was developed to estimate the direct costs caused by N. caninum, with and without control strategies, and to estimate the costs of these control strategies in a financial analysis. The control strategies considered were "testing and culling of seropositive female cattle", "discontinued breeding with offspring from seropositive cows", "chemotherapeutical treatment of female offspring" and "vaccination of all female cattle". Each parameter in the module that was considered to be uncertain, was described using probability distributions. The simulations were run with 20,000 iterations over a time period of 25 years. The median annual losses due to N. caninum in the Swiss dairy cow population were estimated to be euro 9.7 million euros. All control strategies that required yearly serological testing of all cattle in the population produced high costs and thus were not financially profitable. Among the other control strategies, two showed benefit-cost ratios (BCR) >1 and positive net present values (NPV): "Discontinued breeding with offspring from seropositive cows" (BCR=1.29, NPV=25 million euros ) and "chemotherapeutical treatment of all female offspring" (BCR=2.95, NPV=59 million euros). In economic terms, the best control strategy currently available would therefore be "discontinued breeding with offspring from seropositive cows".

Simulating the impact of four control strategies on the population dynamics of Neospora caninum infection in Swiss dairy cattle

A dynamic deterministic simulation model was developed to assess the impact of different putative control strategies on the seroprevalence of Neospora caninum in female Swiss dairy cattle. The model structure comprised compartments of "susceptible" and "infected" animals (SI-model) and the cattle population was divided into 12 age classes. A reference model (Model 1) was developed to simulate the current (status quo) situation (present seroprevalence in Switzerland 12%), taking into account available demographic and seroprevalence data of Switzerland. Model 1 was modified to represent four putative control strategies: testing and culling of seropositive animals (Model 2), discontinued breeding with offspring from seropositive cows (Model 3), chemotherapeutic treatment of calves from seropositive cows (Model 4), and vaccination of susceptible and infected animals (Model 5). Models 2-4 considered different sub-scenarios with regard to the frequency of diagnostic testing. Multivariable Monte Carlo sensitivity analysis was used to assess the impact of uncertainty in input parameters. A policy of annual testing and culling of all seropositive cattle in the population reduced the seroprevalence effectively and rapidly from 12% to <1% in the first year of simulation. The control strategies with discontinued breeding with offspring from all seropositive cows, chemotherapy of calves and vaccination of all cattle reduced the prevalence more slowly than culling but were still very effective (reduction of prevalence below 2% within 11, 23 and 3 years of simulation, respectively). However, sensitivity analyses revealed that the effectiveness of these strategies depended strongly on the quality of the input parameters used, such as the horizontal and vertical transmission factors, the sensitivity of the diagnostic test and the efficacy of medication and vaccination. Finally, all models confirmed that it was not possible to completely eradicate N. caninum as long as the horizontal transmission process was not interrupted.

Isolation of Besnoitia besnoiti from infected cattle in Portugal

Besnoitia besnoiti, an obligate intracellular protozoan parasite belonging to the phylum apicomplexa, is the causative agent of bovine besnoitiosis. Besnoitiosis is responsible for significant losses in the cattle industry of Africa and Mediterranean countries due to the high morbidity rate, abortion and infertility in males. The acute stage of disease is associated with the proliferative forms (tachyzoites) and is characterized by fever, whimpery, general weakness and swelling of the superficial lymph nodes. During the following chronic stage, a huge number of cysts are formed mainly in the subcutaneous tissues. This process is non-reversible, and chronic besnoitiosis is characterized by hyper-sclerodermia, hyperkeratosis, alopecia and, in bulls, atrophy, sclerosis and focal necrosis that cause irreversible lesions in the testis. In this paper we report on the identification of large cysts in the skin of a cow and a bull in Portugal, which presented loss of hair and enlargement and pachydermis all over the body. The observation of a two-layered cyst wall within the host cell, the encapsulation of the host cell by a large outer cyst wall, and the subcutaneous localization of the cysts within the host, were characteristic for B. besnoiti. The parasites were isolated from the infected animals and successfully propagated in Vero cells without prior passages in laboratory animals. Morphological characterization of B. besnoiti tachyzoites and the amplification of the 149 bp segment from the internal transcribed spacer 1 (ITS1), aided with specific primers, confirmed the identification of B. besnoiti.

Ontogenesis of mRNA levels and binding sites of hepatic alpha-adrenoceptors in young cattle

Catecholamines affect hepatic glucose production through (alpha- and beta2-) adrenoceptors (AR). We studied mRNA abundance and binding of hepatic alpha-AR in pre-term (P0) calves and in full-term calves at day 0 (F0), day 5 (F5) and day 159 (F159) to test the hypothesis that gene expression and numbers of hepatic alpha-AR in calves are influenced by age and associated with beta2-AR and selected traits of glucose metabolism. mRNA levels of alpha1- and alpha2-AR were measured by real time RT-PCR. alpha1- and alpha2-AR numbers (maximal binding, Bmax) were determined by saturation binding of (3H)-prazosin and (3H)-RX821002, respectively. alpha1- and alpha2-AR subtypes were evaluated by competitive binding. alpha1A-AR mRNA levels were lower in P0 than in F0, F5 and F159 and alpha(2AD)-AR mRNA levels were lower in F159 than in P0, F0 and F5, while alpha2C-AR mRNA levels increased from P0 and F0 to F5 and F159. Bmax of alpha1-AR increased from P0 to F5, then decreased in F159. Bmax of alpha2-AR decreased from F0 to F159. Bmax of alpha1-AR was positively associated with mRNA levels of alpha1A-AR (r = 0.7), Bmax of beta2-AR (r = 0.5) and negatively with hepatic glycogen content (r = -0.6). Bmax of alpha2-AR was negatively associated with Bmax of beta2-AR (r = -0.4). In conclusion, mRNA levels and binding sites of alpha1- and alpha2-AR in calves exhibited developmental changes and were negatively associated with hepatic glycogen content.

Oxytocin release and lactation performance in Syrian Shami cattle milked with and without suckling

Oxytocin (OT) release and lactation performance in primiparous Syrian Shami cows were evaluated in response to two different machine milking regimes. Six cows were milked in the presence of the calves (PC) and subsequently suckled, whereas six cows were exclusively machine milked without the presence of their calves (WC) until day 91 post partum. Milk yield and milk constituents were determined weekly. The degree of udder evacuation was determined by the succeeding removal of residual milk. PC released OT during the milking process, whereas in WC no OT release was detected throughout the milking process. Consequently, the residual milk fraction was much lower in PC than in WC (11% v. 58%, P<0.05) and daily milk yield until day 91 post partum was higher in PC than in WC (12.6+/-0.3 v. 7.1+/-0.4 kg, P<0.05). In conclusion, Syrian Shami cattle are not suitable to be exclusively machine milked without the presence of their calves.

Ontogeny of mRNA abundance of nuclear receptors and nuclear receptor target genes in young cattle

After birth the development of appropriate detoxification mechanisms is important. Nuclear receptors (NR), such as constitutive androstane receptor (CAR), pregnane X receptor (PXR), peroxisome proliferator-activated receptor-alpha (PPARalpha), retinoid receptors (RAR, RXR), and NR target genes are involved in the detoxification of exogenous and endogenous substances. We quantified abundances of hepatic mRNA of NR and several NR target genes (cytochromes, CYP; cytochrome P450 reductase, CPR; UDP-glucuronosyl transferase, UDP) in calves at different ages. Gene expression was quantified by real-time RT-PCR. Abundance of mRNA of CAR and PXR increased from low levels at birth in pre-term calves (P0) and full-term calves (F0) to higher levels in 5-day-old calves (F5) and in 159-day-old veal calves (F159), whereas mRNA levels of PPARalpha did not exhibit significant ontogenetic changes. RARbeta mRNA levels were higher in F5 and F159 than in F0, whereas no age differences were observed for RARalpha levels. Levels of RXRalpha and RXRbeta mRNA were lower in F5 than in P0 and F0. Abundance of CYP2C8 and CYP3A4 increased from low levels in P0 and F0 to higher levels in F5 and to highest levels in F159. Abundance of CPR was transiently decreased in F0 and F5 calves. Levels of UGT1A1 mRNA increased from low levels in P0 and F0 to maximal level in F5 and F159. In conclusion, mRNA levels of NR and NR target genes exhibited ontogenetic changes that are likely of importance for handling of xeno- and endobiotics with increasing age.

Diagnostic significance of Neospora caninum DNA detected by PCR in cattle serum

A nested PCR that successfully detected Neospora caninum DNA in serum of cattle was used for investigation of selected abortion cases and in a study of healthy pregnant cows at an abattoir. N. caninum DNA was not detected in serum from antibody positive dams that aborted due to N. caninum, but was present in serum of some antibody negative dams that aborted due to other causes. N. caninum DNA was also found in the serum of about half of the animals that aborted of undetermined cause, but was not detected in cow sera from two beef cattle herds in Western Australia with no recent history of abortion. In the abattoir study of 79 dams and their foetuses N. caninum DNA was found in serum of 3 dams and in material from 11 foetuses. The majority of the cows and all foetuses were antibody negative. Our findings suggest that there is no obvious relationship between the presence or absence of N. caninum DNA in serum and the presence of antibodies to N. caninum in dams, the presence of N. caninum DNA in foetuses or abortion due to N. caninum. This is the first report of the detection of N. caninum DNA in serum of cattle rather than the white blood cell fraction. It indicates the presence of free tachyzoites and/or parasite DNA in circulation. The results suggest that persistent infection in the absence of antibodies is a possible outcome of N. caninum infection. Infection of foetuses in the absence of antibodies supports the possibility of persistent infection due to immunotolerance to an early in utero infection. It is therefore important to test for N. caninum DNA as well as antibodies for the detection of exposed and/or infected animals. However, the presence or absence of N. caninum antibodies or DNA did not support nor exclude N. caninum as the cause of abortion. Additional criteria are required for a positive diagnosis of abortion caused by N. caninum.

Phylogenetic relationships of German heavy draught horse breeds inferred from mitochondrial DNA D-loop variation

We analysed a 610-bp mitochondrial (mt)DNA D-loop fragment in a sample of German draught horse breeds and compared the polymorphic sites with sequences from Arabian, Hanoverian, Exmoor, Icelandic, Sorraia and Przewalski's Horses as well as with Suffolk, Shire and Belgian horses. In a total of 65 horses, 70 polymorphic sites representing 47 haplotypes were observed. The average percentage of polymorphic sites was 11.5% for the mtDNA fragment analysed. In the nine different draught horse breeds including South German, Mecklenburg, Saxon Thuringa coldblood, Rhenisch German, Schleswig Draught Horse, Black Forest Horse, Shire, Suffolk and Belgian, 61 polymorphic sites and 24 haplotypes were found. The phylogenetic analysis failed to show monophyletic groups for the draught horses. The analysis indicated that the draught horse populations investigated consist of diverse genetic groups with respect to their maternal lineage.

Microarray based study on virulence-associated genes and resistance determinants of Staphylococcus aureus isolates from cattle

Staphylococcus aureus is a common pathogen which can colonise and infect not only man, but also domestic animals. Especially, infection of cattle is of high economic relevance as S. aureus is an important causal agent of bovine mastitis. In the present contribution, a DNA microarray was applied for the study of 144 different gene targets, including resistance genes and genes encoding exotoxins, in S. aureus isolated from cows. One hundred and twenty-eight isolates from Germany and Switzerland were tested. These isolates were assigned to 20 different strains and nine clonal complexes. The majority of isolates belonged either to apparently closely related clonal complexes 8, 25, and 97 (together 34.4%) or were related to the sequenced bovine strain RF122 (48.4%). Notable characteristics of S. aureus of bovine origin are the carriage of intact haemolysin beta (in 82% of isolates tested), the absence of staphylokinase (in 89.1%), the presence of allelic variants of several exotoxins such as toxic shock syndrome toxin and enterotoxin N, and the occurrence of the leukocidin lukF-P83/lukM (in 53.1%). Two isolates were methicillin-resistant S. aureus (MRSA). One of them was a clonal complex 8 MRSA related to the epidemic MRSA strain Irish 01. The other one belonged to ST398/spa-type 34 resembling a newly emerging MRSA strain which has been described to occur in humans as well as in domestic animals. The presence of these two strains highlights the possibility of transfers of S. aureus strains between different host species.

Influence of prostaglandin E2 on parturition in cattle

A double-blinded, randomised, placebo-controlled field study of the influence of prostaglandin E2 (PGE2) on cattle at parturition was carried out. The extent of cervical opening and the intensity of labour were scored before administration of the compound and 10 minutes later; routine birth assistance was then continued by the veterinarian. Successful birth occurred more quickly in the cows treated with PGE2. The extent of cervical opening before the administration of the drug had a significant effect on the time to delivery, but the intensity of labour and a concomitant infusion of calcium did not have significant effects on this period. The less open the cervix before administration of the drug, the more the duration of parturition differed between the two groups, with the placebo group taking longer. A telephone follow-up inquiry found no significant differences between the cows postpartum; there were cases of mastitis and hypocalcaemia in both groups. The incidence of retained fetal membranes and the mortality of the calves were higher in the placebo group, but in neither case was the difference significant.

[Rumenocentesis: a suitable technique for analysis of rumen juice pH in cattle?]

In the United States, rumenocentesis has been recommended especially for early diagnosis of subacute rumen acidosis (SARA). The objective of the current study was to evaluate health risks due to the technique ofrumenocentesis and to measure pH in ruminal juice using a commercial indicator paper (Pehanon) and a pH electrode (reference method). After 11 dairy cows underwent rumenocentesis, the clinical status of those animals was evaluated daily, and cows were slaughtered as well as pathologically--anatomically examined on day 7. During the observation period, the following pathological clinical signs were evident: forced inspiration (3 cows), transient episode of hyperthermia (2 cows), increased tension of the abdominal wall (8 cows) and positive foreign body tests (3 cows). One cow had to be culled on day 7 because of severe generalised septic peritonitis spreading from the site of rumenocentesis. At slaughter, hematoma formation in the area of the puncture site was found in 9 out of 10 cows. It was concluded that the severe complications encountered with this technique do not legitimate rumenocentesis as a routine procedure for collection of rumen juice samples in cows under Swiss conditions. The correlation between the pH reference method and the commercial indicator paper was the high (r = 0.926).