A comparison of the effect of short-acting and long-acting cloxacillin-based dry-cow therapy on somatic cell counts after calving in cows also given internal teat sealants

AIM: To compare, in cows treated with an internal teat sealant, the effect of short-acting and long-acting cloxacillin-based dry-cow therapy on somatic cell counts (SCC) after calving.

METHODS: Cows from a spring-calving, pasture-based dairy farm in the Manawatu-Whanganui region of New Zealand were randomly allocated to receive either a short-acting cloxacillin and ampicillin dry-cow therapy and internal teat sealant (n=291) or a long-acting cloxacillin and ampicillin dry-cow therapy and internal teat sealant (n=288) at the end of lactation. Cows were managed on-farm with routine husbandry procedures through the dry period and following calving. A multivariable logistic regression model was used to determine the association between length of action of dry-cow therapy and the proportion of cows with a SCC >150,000?cells/mL at the first herd test after calving.

RESULTS: Age of cow, mean SCC for the preceding season and interval from calving to the first post-calving herd test were all associated with the proportion of cows with an individual SCC >150,000?cells/mL at the first herd test (p<0.001) Treatment with the short-acting dry-cow therapy was not associated with decreased odds of cows having a SCC >150,000?cells/mL at the first herd test compared with treatment with long-acting dry-cow therapy (OR=0.724; 95% CI=0.40–1.30).

CONCLUSIONS AND CLINICAL RELEVANCE: In this herd, which routinely used internal teat sealants, the use of short-acting cloxacillin-based dry-cow therapy did not result in an increased proportion of cows with elevated SSC post-calving. This was a single farm, single year study but indicates that in this herd, changing from a long-acting to a short-acting antimicrobial may have no impact on the prevalence of subclinical mastitis.     

Isolation and identification of antifungal and antialgal alkaloids from Haplophyllum sieversii

Bioassay-guided fractionation of the hexane/ethyl acetate/water (H/EtOAc/H2O) crude extract of the aerial parts of Haplophyllum sieversii was performed because of preliminary screening data that indicated the presence of growth inhibitory components against Colletotrichum fragariae, Colletotrichum gloeosporioides, and Colletotrichum acutatum. Fractionation was directed using bioautographical methods resulting in the isolation of the bioactive alkaloids flindersine, anhydroevoxine, haplamine, and a lignan eudesmin. These four compounds were evaluated for activity against C. fragariae, C. gloeosporioides, C. acutatum, Botrytis cinerea, Fusarium oxysporum, and Phomopsis obscurans in a dose-response growth-inhibitory bioassay at 50.0, 100.0, and 150.0 microM. Of the four compounds tested, flindersine demonstrated the highest level of antifungal activity. Additionally, flindersine, eudesmin, and haplamine were screened against the freshwater phytoplanktons Oscillatoria perornata, Oscillatoria agardhii, Selenastrum capricornutum, and Pseudanabaena sp. (strain LW397). Haplamine demonstrated selective inhibition against the odor-producing cyanobacterium O. perornata compared to the activity against the green alga S. capricornutum, with lowest observed effect concentration values of 1.0 and 10.0 microM, respectively.     

Dimensionality-driven insulator-to-metal transition in the bechgaard salts

Optical experiments were conducted on a series of organic linear chain conductors with different values of the interchain single-electron transfer integral tb, which quantifies the degree of anisotropy. Electron-electron interactions together with Umklapp scattering resulted in a correlation gap and an insulating state for small tb. An insulator-to-metal transition was observed when tb exceeded a critical value, on the order of the correlation gap Egap. The absence of a plasma edge on the insulator side of the transition for polarization perpendicular to the chains suggests that the electrons are confined to the chains. The optical features of the metallic state, when contrasted with the magnetic properties, are suggestive of spin-charge separation.     

Role of sweetclover and phacelia in agriculture ecology improvement for droughty left-bank areas of Saratov region

Ecological pollution and physical degradation of soil depend strongly on anthropogenic action on it. The role of such legumes as biennial yellow sweetclover, annual white sweetclover, and plants of Boraginaceae family—lacy phacelia and blue curls—in improvement of physical and chemical soil properties was investigated. An ecologically safe way for soil fertility increase under droughty conditions is offered. Use of both species of sweetclover and one species of phacelia tanacetifolia as green manure in crop rotations are recommended.     

Impact of the use of biofertilizers on cotton ( Gossypium hirsutum ) crop under irrigated agro-ecosystem

High nitrogen fixing, phosphate solubilizing, phytohormones producing isolates of Azotobacter, Azospirillum, Acetobacter and Pseudomonas were used as inoculants for cotton. Important cultures were selected on the basis of their effect on root/shoot length and chemotactic behaviour. Selected bioinoculants were earlier tested for their beneficial properties like nitrogen fixation (ARA), ammonia excretion, IAA production etc. These bio-inoculants were further tested for phosphate solubilization property. Various chosen strains were tested with Desi (HD 123) and American (H 1098) cotton under field conditions (as for wheat). Plant height and boll weight were determined at the time of harvesting whereas survival rate of inoculated bacteria was determined after 30, 80 and 130 days respectively. In the year 2000–01, on the basis of boll number and boll weight plant^?1 AVK 51 (36; 76.2?g plant^?1), HT 57 (27; 56.9?g plant^?1), AC18 (33; 61.5?g plant^?1), Ala 27 (36; 61.4?g plant^?1) and Pseudomonas (34; 71.3?g plant^?1) were identified as significant both for American and desi cotton varieties. Highest survival rate was observed with Mac 68 (33.4 × 10⁵) followed by HT54 (31.5 × 10⁵) after 30 days of sowing, which decreased after 80 days and remained constant up to 130 days. This trend was observed with all the cultures. Similar results were observed in 2001–02. 25?kg ha^?1 N saving was observed with A. chroococcum (AVK51) bioinoculant for cotton crop.     

Echocardiographic evaluation of dogs receiving 1:1 thiopental/propofol in a clinical setting

The purpose of this study was to compare the echocardiographic Doppler blood pressure and heart rate effects of 1:1 thiopental/propofol with thiopental and propofol, when used as anesthesia‐induction agents. Seven healthy dogs (six Beagles and one Pembroke Welsh Corgi), ranging in age from 1 to 9 years and weighing 14.2 ± 2.4 kg (mean ± SD), were used during the study. In a cross‐over study design with a minimum drug interval of 3 days, each dog received propofol, thiopental, or a mixture of propofol–thiopental IV until each dog received all the three anesthetic agents. An initial dose (propofol 4.9 ± 0.8 mg kg^?1; thiopental 12.9 ± 2.4 mg kg^?1; propofol–thiopental 2.3 ± 0.3 mg kg^?1 (P)?5.7 ± 0.8 mg kg^?1 (T)) of each anesthetic agent was titrated IV until intubation was accomplished. Echocardiographic Doppler blood pressure and heart rate variables were recorded prior to anesthesia and at 1, 5, and 10 minutes after induction of anesthesia. anova and the Bonferroni's t‐test were used to evaluate the groups for differences. Alpha was <0.05. There was no significant effect of treatment on systolic or diastolic ventricular wall thickness, septal thickness, left atrial diameter, or systolic left ventricular diameter. There was a tendency for diastolic left ventricular diameter to decrease over time. There was a tendency for heart rate to increase with a significant difference at the 10‐minute time period between propofol (109 ± 26 beats minute^?1) and thiopental (129 ± 23 beats minute^?1). At the 10‐minute recording period, heart rate following the propofol/thiopental mixture (110 ± 34 beats minute^?1) was closer to that following propofol than to that following thiopental. With all induction agents, indirect blood pressure tended to decrease over time (p = 0.005); however, there was no difference between the groups. The changes observed were not considered to be of clinical significance. The propofol/thiopental mixture produces similar changes in echocardiographic variables when compared to propofol or thiopental, and could be substituted for propofol for induction of anesthesia in dogs.     

Expression of genes encoding chitin-binding proteins (PR-4) and hevein-like antimicrobial peptides in transgenic tomato plants enhanced resistanse to <Emphasis Type="Italic">Phytophthora infestance</Emphasis>

The resistance of transgenic tomato plants containing genes of chitin-binding proteins from Amaranthus caudatus (ac) and A. retraflexus (RS-intron-Shir) and hevein-like antimicrobial peptides (amp1 and amp2) from Stellaria media is analyzed. Lines expressing genes ac, amp1, and amp2 are characterized, unlike the untransformed control, by enhanced resistance to a isolate Phytophthora infestans obtained from potato leaves.     

Antifeedant and toxicity effects of thiophenes from four Echinops species against the Formosan subterranean termite, Coptotermes formosanus

Over 220 crude extracts from repositories generated from plants native to Greece and Kazakhstan were evaluated for termiticidal activity against the Formosan subterranean termite, Coptotermes formosanus Shiraki (Isoptera: Rhinotermitidae). Emerging from this screening effort were bioactive extracts from two Greek species (Echinops ritro L. and Echinops spinosissimus Turra subsp. spinosissimus) and extracts from two Kazakhstan species (Echinops albicaulis Kar. & Kir. and Echinops transiliensis Golosh.). Fractionation and isolation of constituents from the most active extracts from each of the four species has been completed, resulting in the isolation of eight thiophenes possessing varying degrees of termiticidal activity. 2,2':5',2"-Terthiophene and 5'-(3-buten-1-ynyl)-2,2'-bithiophene demonstrated 100% mortality against C. formosanus within 9 days at 1 and 2 wt% concentrations respectively. In addition, all but two of the eight compounds tested were significantly different from the solvent controls in the filter paper consumption bioassay.     

The effect of elemental Zn boluses on concentrations of Zn in serum and faeces of South American camelids

ABSTRACT

Aims: To monitor the effect of using long-acting Zn boluses on the Zn status of a group of South American camelids, using measurements of concentrations of Zn in faeces and serum.

Methods: As part of a facial eczema (FE) prevention programme, 15 camelids were treated with long-acting Zn boluses designed for preventing FE in sheep. Based on bodyweight, 13 alpacas (Vicugna pacos) received two boluses (26.4?g Zn/bolus) and two llamas (Lama glama) received three boluses. In order to monitor Zn status, measurements were made of concentrations of Zn in serum and faeces immediately prior to bolus treatment (Week 0) and 4, 6, 8 and 10 weeks later. Gamma glutamyl transferase (GGT) activity in serum was measured at Weeks 0 and 8.

Results: Two alpacas regurgitated the boluses; in one case the animal was quickly re-treated but this was not possible in the second animal. Mean concentrations of Zn in faeces were higher at all time points compared to Week 0 (p?<?0.001). Peak concentrations were measured at Week 8, and concentrations >120?mg/kg fresh weight (FW), suggested as being protective in calves, were only measured in all (13/13) treated camelids at Week 6. Mean concentrations of Zn in serum differed between weeks of sampling but changes were not consistent, and concentrations did not exceed 18?μmol/L following treatment. There was no evidence of a natural sporidesmin challenge during the study period and activity of GGT in serum of all animals was <45?IU/L.

Conclusions: Treatment with Zn boluses significantly increased concentrations of Zn in faeces but not in serum, but peak concentrations in faeces were only detected 8 weeks after treatment.

Clinical Relevance: The delay in achieving concentrations of Zn in faeces which were associated with protection against FE in calves, combined with the difficulties of administering boluses to camelids, means that we do not believe that Zn boluses should be used as the primary method for preventing FE in camelids. We recommend that FE prevention in camelids should focus on minimising spore production in pasture through the use of fungicides, grazing management and alternative forages, with boluses only used when it is thought that these methods are unlikely to provide sufficient protection against FE. Such use should always be under the guidance of a veterinarian and monitoring of serum GGT activity should be used to ensure that FE control is being achieved.