Ectomycorrhizal inoculation with Pisolithus tinctorius increases the performance of Quercus suber L. (cork oak) nursery and field seedlings

Mediterranean ecosystems are characterized by large arid areas where the patchy distribution of trees offers little protection against harsh climate conditions for seedling establishment. Climate change is predicted to result in an increase in these arid regions, with pronounced effects on vegetation. Production of seedlings with developed ectomycorrhizas is a promising strategy for minimizing the initial transplant shock, thereby increasing plant survival and growth during the first, most critical years of a plantation. One important species in the Mediterranean basin is Quercus suber (cork oak), which occurs, together with other evergreen oak species, in an agro-silvo-pastoral system that represents an example of sustainable land use in Europe. In this study, a Pisolithus tinctorius isolate was used for ectomycorrhizal colonization of cork oak nursery seedlings, and the effects on aboveground plant growth and leaf structural and physiological parameters were investigated. Ectomycorrhizal development resulted in a significant increase in leaf area, dry weight, nitrogen content, and photosynthetic pigments, and mycorrhizal plants showed a higher photosynthetic capacity and water use efficiency. Nursery-inoculated plants established in the field showed increased survival and growth during the first year after transplant. These results indicate a potential for further enhancing the use of mycorrhizal inoculation as a cultivation practice in forest nurseries. Considering the difficulty of soil restoration under limiting environmental conditions, nursery inoculation with ectomycorrhizal fungi can be an important advantage for improving the quality of seedling stock and its performance after out-planting in the field, benefiting the regeneration of arid regions and the reintroduction of inocula of ectomycorrhizal fungi into these areas.     

Evaluation of electrical nerve stimulation for epidural catheter positioning in the dog

ObjectiveTo evaluate the accuracy of epidural catheter placement at different levels of the spinal cord guided solely by electrical nerve stimulation and resultant segmental muscle contraction.Study designProspective, experiment.AnimalsSix male and two female Beagles, age (1 ± 0.17 years) and weight (12.9 ± 1.1 kg).MethodsAnimals were anesthetized with propofol and maintained with isoflurane. An insulated epidural needle was used to reach the lumbosacral epidural space. A Tsui epidural catheter was inserted and connected to a nerve stimulator (1.0 mA, 0.1 ms, 2 Hz) to assess positioning of the tip at specific spinal cord segments. The catheter was advanced to three different levels of the spinal cord: lumbar (L2–L5), thoracic (T5–T10) and cervical (C4–C6). Subcutaneous needles were previously placed at these spinal levels and the catheter was advanced to match the needle location, guided only by corresponding muscle contractions. Catheter position was verified by fluoroscopy. If catheter tip and needle were at the same vertebral body a score of zero was assigned. When catheter tip was cranial or caudal to the needle, positive or negative numbers, respectively, corresponding to the number of vertebrae between them, were assigned. The mean and standard deviation of the number of vertebrae between catheter tip and needle were calculated to assess accuracy. Results are given as mean ± SD.ResultsThe catheter position in relation to the needle was within 0.3 ± 2.0 vertebral bodies. Positive predictive values (PPV) were 57%, 83% and 71% for lumbar, thoracic and cervical regions respectively. Overall PPV was 70%. No significant difference in PPV among regions was found.Conclusion and clinical relevancePlacement of an epidural catheter at specific spinal levels using electrical nerve stimulation was feasible without radiographic assistance in dogs. Two vertebral bodies difference from the target site may be clinically acceptable when performing segmental epidural regional anesthesia.     

Cellular structure and chemical composition of cork from the Chinese cork oak (Quercus variabilis)

Quercus variabilis Blume, the Chinese cork oak, is an oak species with a thick cork outer bark. The cork is exploited at a limited scale in China and considered of lower quality than the commercial cork from Quercus suber. We studied an industrial cork granulate feedstock of Q. variabilis in relation to cellular structure and chemical composition and compared it to Q. suber cork under a material’s perspective. The cork of Q.variabilis has 1.1 % ash, 9.6 % extractives, 34.8 % suberin and 19.1 % lignin. The monosaccharide composition with shows a predominance of hemicelluloses: glucose 42.8 % of total neutral sugars, xylose 27.5 %, arabinose 15.4 %, galactose 9.0 %, mannose 4.0 %, rhamnose 1.2 %. The FT-IR spectrum shows the indicative peaks of suberin. The composition is overall similar to that of Q. suber cork. Q. variabilis cork has the typical cellular characteristics of bark cork tissues with a regular and radially aligned structure of cells without intercellular voids. Solid volume fraction was estimated at approximately 16 %. Compared with Q. suber, the Q. variabilis cork cells are smaller, the cell wall undulation and the overall row alignment less homogeneous, the cell surface is irregular and the solid volume proportion higher. The characteristics of Q. variabilis cork support its use as a cellular material for sealing, insulation and energy absorption, but the overall quality is lower than that of Q. suber cork. The negative impact of the higher density and structural lower uniformity at tissue and cell level should be evaluated for processing and product performance.     

Feed restriction followed by realimentation in prepubescent Zebu females

In the present study, the effect of restricting the feed intake for 77 days and subsequent compensatory growth for 50 days of Sindi females were evaluated. Eighteen animals with an initial age of 21 months and a mean weight of 211.7 kg were placed into three groups according to the following alimentary regimens: feed ad libitum, feed restricted to 20 % dry matter, and feed restricted to 40 % dry matter. In the feed-restriction phase, the nutrient intake decreased (P?<?0.001) with an increase in the restriction level. As a consequence, the observed decrease in ingestion and serum concentrations of total protein, albumin and globulin, urea, glucose, calcium, and phosphorus were inversely proportional (P?<?0.001) to the restriction level. Significant differences in the nutrient intake and serum concentration were not observed in the realimentation phase (P?<?0.05). When animals in the control group reached the end of the feed-restriction phase, their weights (P?<?0.05) were similar to those in the 20 % restricted group, and both obtained a final weight that was greater than that of animals in the 40 % restricted group. In the feed-restriction phase, the control group had a similar mean daily weight gain (P?>?0.05) to animals in the 20 % restricted group and (P?<?0.05) 40 % restricted group. However, in the realimentation phase, the 40 % restricted group obtained greater weight gain rates (P?<?0.05), better food conversions, and partial compensatory gains. In particular, none of the restricted groups reached the final weight of the control group. In the feed-restriction phase, ingested nitrogen, nitrogen excreted in urine and feces, nitrogen balance and retained nitrogen decreased (P?<?0.05) with an increase in the restriction level. In the realimentation phase, none of the nitrogen balance variables were influenced by the restriction level (P?<?0.05). Females in the 40 % restricted group presented better food conversion rates and greater weight gains in the realimentation phase. Based on the animals’ compensatory weight gain, a feed-restriction rate of 20 and 40 % can be adopted as a nutritional management practice for prepubescent Sindi females.     

Carbendazim,at concentrations used on pasture for facial eczema control,reduces development of Trichostrongylus colubriformis when sprayed onto infected sheep faeces

Abstract

AIM: To determine whether the fungicide, carbendazim, as applied to pastures for controlling facial eczema (FE), would inhibit development of the free-living stages of the gastrointestinal nematode parasite Trichostrongylus colubriformis.

METHODS: Two studies were conducted, using sheep faeces containing eggs of T. colubriformis. In the first, the faeces were either exposed or not to an application of carbendazim sprayed at the recommended rate for FE control. After spraying, dishes containing the faeces were incubated at 20°C for 14 days, and the resulting third-stage infective larvae (L3) extracted by baermannisation and counted. In addition, naturally infested pasture was also sprayed, and the number of L3 present 7 days later was assessed by cutting herbage samples and extracting larvae by soaking in water and baermannisation. In the second, the faeces were incubated at 20°C for 0, 3 or 7 days before being exposed to no, one or two applications of carbendazim. After further incubation for 14, 11 or 7 days, L3 were similarly extracted by baermannisation and counted.

RESULTS: In the first study, there was a 74% reduction in the number of T. colubriformis larvae recovered from faeces exposed to carbendazim compared with faeces not exposed, but there was no reduction in the number of L3 recovered from herbage. In the second study, faeces incubated for 0 or 3 days prior to exposure to a single application of carbendazim yielded 98% or 89% fewer larvae, respectively, than faeces not exposed. Faeces incubated for 7 days prior to exposure yielded similar numbers of larvae to faeces not exposed.

CONCLUSION: Treatment of pastures with carbendazim for FE control is likely to result in reduced development of the larvae of T. colubriformis, and by inference those of other species, where the application coincides with the presence of freshly deposited faeces containing eggs and developing larvae. However, no effect of treatment on L3 was indicated. The significance of this for on-farm nematode parasite control remains to be determined, as does any potential for strategic applications of carbendazim to pasture aimed at reducing numbers of parasite larvae on pasture. The latter should not be contemplated without due consideration of the implications for the development of anthelmintic resistance.     

Drench-and-shift is a high-risk practice in the absence of refugia

Abstract

AIM: To examine the effect of an anthelmintic treatment to lambs, followed immediately by a shift onto pastures with differing levels of larval contamination, on the development of anthelmintic resistance, in order to support recommendations to farmers regarding drench-and-shift practices for sustainable worm control.

METHODS: Newly weaned Romney lambs (n=72) were dosed with third-stage infective larvae (L3) of two nematode parasite species, Teladorsagia (=Ostertagia) circumcincta and Trichostrongylus colubriformis, comprising benzimidazole-resistant and -susceptible isolates, calculated to yield, after treatment with albendazole, a 95% reduction in faecal nematode egg count (FEC). Once infections became patent (Day 0), lambs were randomised into nine groups of eight animals, treated with albendazole at the manufacturer's recommended dose rate, and moved to individual pastures each previously prepared to have one of three different levels of parasite larval infestation (Treatment 1 = low contamination, Treatment 2 = medium contamination, and Treatment 3 = high contamination), and grazed on those pastures before receiving a second treatment with albendazole at Day 47. Anthelmintic resistance status in each group of lambs was measured using FEC reduction (FECR) and egghatch assays (EHA) after the first anthelmintic treatment, and FECR after the second treatment.

RESULTS: Egg-hatch assays demonstrated significant differences between treatments. The concentration of anthelmintic required to kill 50% of the eggs (LC₅₀) for Treatment 1, comprising the least contaminated pastures, was significantly higher than for Treatments 2 and 3 on Days 33 and 40. Treatment 1 also had a significantly lower FECR at the final anthelmintic treatment, and significantly lower FEC than the other two treatments from Days 26 to 47.

CONCLUSIONS: The results demonstrated that the populations of T. circumcincta and T. colubriformis in lambs treated with anthelmintic had significantly higher levels of albendazole resistance at the end of the grazing period in lambs moved onto pastures with relatively low levels of parasite contamination than those moved onto pastures with relatively higher contamination, confirming drench-and-shift onto ‘clean’ pasture as a high-risk practice for the selection for anthelmintic resistance. While this does not necessarily preclude the use of this practice it does emphasise the importance of taking appropriate remedial action to minimise the risk.     

The impact of highly concentrated Mo and Cu dietary supplements,fed as a bolus,on the efficacy of chelated versus inorganic Cu in cattle on a low-Cu diet

AIM: To compare the efficacy of chelated versus inorganic forms of dietary Cu supplements, fed as a bolus, when challenged by a daily bolus of dietary Mo in cattle on a low-Cu diet.

METHODS: Forty non-lactating, Friesian dairy cows of adequate Cu status were assigned to four groups and fed a basal diet of baled silage containing 5.3 mg Cu and 0.4 mg Mo/kg DM. The experimental design was a factorial of two chemical forms of supplemental Cu and two levels of Mo intake, provided as pelleted grain supplements made from crushed barley/molasses plus Cu and Mo. The supplements contained 140 mg Cu/kg as Cu sulphate pentahydrate (CS), 140 mg Cu/kg as Cu glycinate (CG), CS plus 38 mg Mo/kg as sodium molybdate (CS+Mo), or CG plus 38 mg Mo/kg (CG+Mo). Commencing on Day 0, supplements were fed once daily (offered 1–1.2 kg/cow) and were completely consumed within 5–10 minutes, which constitutes a bolus type of administration. Liver samples were collected by biopsy at Days ?24, 13, 41 or 47, and 69 for Cu determinations.

RESULTS: The diets fed to the Cu+Mo groups were roughly equivalent to 25 mg Cu and 5.7 mg Mo/kg DM. Mean initial concentration of Cu in liver for all groups was 516 (SE 54) μmol Cu/kg fresh tissue. In cows supplemented with CS and CG, the final (Day 69) concentrations increased (p<0.01) to 939 (SE 166) and 853 (SE 163) μmol Cu/kg, respectively. These values were not different (p=0.72). For groups CS+Mo and CG+Mo, the final concentrations of 535 (SE 122) and 453 (SE 102) μmol Cu/kg were not different from initial values or from each other (p>0.25). The rate of accumulation of Cu in liver following bolus Cu and Mo intake was highly variable but was not affected by initial concentration of Cu in liver (p>0.9) or by the form of Cu (p>0.6). Mean rates of accumulation of Cu in liver were 4.0 (SD 3.8) and 0.65 (SD 2.0) μmol Cu/kg fresh tissue/day for the Cu-only treatments and the Cu+Mo treatments, respectively.

CONCLUSIONS: When fed together as a bolus, high Mo intake negated the effect of supplemental Cu but it did not reduce liver Cu stores. There was no difference in the reaction of dietary Mo with chelated Cu (as glycinate) versus inorganic Cu (as sulphate) dietary supplements.     

Anthelmintic resistance and management of nematode parasites on beef cattle-rearing farms in the North Island of New Zealand

AIM: To provide information on current farmers’ opinions and farming practices thought to be related to anthelmintic resistance, and to test for associations between the presence of anthelmintic resistance and management practices on beef cattle- rearing farms in the North Island of New Zealand.

METHODS: A study using an interview-based questionnaire about management of internal parasites was conducted on 62 beef cattle-rearing farms in the North Island of New Zealand, using case-control analyses to test for associations between management practices and the presence or absence of resistance to ivermectin or albendazole. Resistance was inferred from faecal nematode egg count (FEC) reduction (FECR) tests (FECRTs) when there was <90% reduction in FEC 7-10 days after treatment of calves <12 months of age.

RESULTS: Of the 59 farmers who completed the questionnaire, most (n=40) ranked parasites highly, and at about the same level as quality and quantity of feed, as important production-limiting factors for their enterprises. In contrast, anthelmintic resistance was not perceived to be a problem on 13 farms, and its importance was rated low on 24, moderate on 15, and high on only six farms. Despite all farms having planned parasite control programmes, there was heavy reliance on clinical signs of parasitism to determine frequency of treatments. About one in three farmers with beef breeder cows routinely treated their calves at marking, one in five treated mixed-age cows, and almost half treated rising 2-year-old cows before calving. One in four farmers used anthelmintics on calves on 8–12 occasions in their first year of life. Co-grazing with other species was rare, but follow-on grazing within 3 months after older cattle or sheep was common. On most farms, grazing cattle was restricted to part of the farm, a finding with implications for parasite control and persistence of larvae in refugia. Macrocyclic lactone (ML) anthelmintics or their combinations with other action families were currently, and for the past 5 years, used more frequently than benzimidazoles and levamisole, and benzimidazole-levami- sole combinations. The prevalence of resistance to ivermectin was high (82%) and no plausible model of associations could be constructed from the data. The prevalence of resistance to albendazole was 60%, and the risk of resistance increased as the number of rising 1-year-old cattle present mid-winter increased, and decreased as the number of breeding cows >2 years old present mid-winter increased.

CONCLUSION: It is clear that in practice anthelmintic resistance is a secondary consideration to obtaining productivity advantages from the use of anthelmintics in beef cattle. Farmers’ opinions were divided on many issues and the overall impres- sion was of confused and diverse thinking regarding the principles of the use of anthelmintics. The overall outlook regarding anthelmintic resistance in cattle is bleak unless the need for integrated and long-term research activities is acted upon soon.     

Selective and on-demand drenching of lambs: Impact on parasite populations and performance of lambs

AIM: To determine whether drenching regimes for lambs by which a proportion (10%) of the heaviest animals was selectively left untreated, or animals are only drenched ‘on demand’ when faecal nematode egg counts (FEC) exceeded a threshold level, would result in measurable increases in parasite larval challenge in the autumn and/or decreases in the performance of lambs.

METHODS: A replicated study compared three drenching strategies in which mobs of lambs (n=360 in total) received either: a five-drench preventive programme, administered to all animals (Treatment 1); a five-drench preventive programme, but the 10% heaviest animals left untreated each time (Treatment 2); or drench treatments administered only when FEC exceeded 500 eggs per gram of faeces (epg) (Treatment 3). After the five-drench programme, animals in Treatments 1 and 2 were treated according to FEC as for Treatment 3. A triple-combination drench containing ivermectin, oxfendazole and levamisole, administered orally, was used for all treatments. There were nine farmlets, allowing three replicates of each treatment, in a completely randomised design. Parasite infestations on pasture were measured in autumn by pasture plucks, and worm burdens were monitored in tracer lambs, while the performance of lambs was assessed by liveweight gains, fleece weights, and body condition and dag scores.

RESULTS: Increased numbers of Haemonchus contortus and Trichostrongylus colubriformis larvae on pasture were found in the autumn on farmlets treating selectively or on-demand (Treatments 2 and 3). No differences were detected in other parasite species. Mean liveweight gains did not differ between treatments but some differences were detected between drenched and undrenched lambs in Treatment 2. Mean body condition and mean dag scores of lambs in Treatment 3 tended to be lower and higher, respectively, than those of lambs in Treatment 1; Treatment 2 was generally intermediate.

CONCLUSIONS: Drenching strategies for lambs designed to slow the development of anthelmintic resistance, by increasing the pool of susceptible worms available to dilute resistant survivors after treatment, resulted in increased numbers of H. contortus and T. colubriformis but not other species of parasite on pasture. The increased parasite challenge to lambs in the autumn was associated with small production losses, which may be acceptable to farmers wishing to implement such strategies. It is clear that further work is required on the interaction between management practices and the population dynamics of parasites, especially with regard to creating pools of susceptible genotypes to slow the development of drench resistance.     

Treatment Abandonment in Feline Sporotrichosis – Study of 147 Cases

This study describes the epidemiological, clinical and mycological aspects of feline sporotrichosis cases attending the Laboratory of Clinical Research on Dermatozoonosis in Domestic Animals – Evandro Chagas Clinical Research Institute (LAPCLIN‐DERMZOO/IPEC/FIOCRUZ), from 1998 to 2005. It was possible to get in contact with 147 (19.2%) cat owners. One hundred and thirteen (76.9%) cats were male, 117 (79.6%) had no defined race and 87 (59.2%) were sexually intact. The age ranged from 72 to 216 months (median = 108 months). Nineteen cats were reassessed: eleven (57.8%) were male, thirteen (36.8%) were breed and fifteen (47.3%) castrated. Fourteen (52.6%) animals lived at home and did not roamed the streets. Seven (36.8%) had normal clinical findings and negative mycological examination. Twelve (63.1%) cats had skin lesions compatible with sporotrichosis. Thirty‐one (21%, n = 147) cats disappeared after abandoning treatment, 36 (24.5%, n = 147) were alive and 80 (54.4%, n = 147) had died. Causes of death informed by the owners were: sporotrichosis in 35 (43.7%, n = 80), accidental death in 27 (33.7%, n = 80) and other diseases in 18 (22.5%, n = 80). Withdrawal of treatment occurred mainly at the time of clinical improvement and may represent a serious obstacle to the control of sporotrichosis.