Evaluation of the effect of eprinomectin in young dairy heifers sub-clinically infected with gastrointestinal nematodes on grazing behaviour and diet selection

Inappetence is commonly associated with parasitism and has been observed in both housed and pastured ruminants. In seeking a functional explanation for these observations, it has been hypothesised that parasitized animals may feed more selectively in order to proportionally increase the protein content of their diet and thus partially compensate for their reduced feed intake. Support for this theory is found principally in studies in housed animals under carefully controlled experimental conditions. Grazing animals face a far more heterogeneous environment and a multiplicity of potentially confounding factors that could influence diet selection. Controlled grazing of adjacent monocultures of grass and clover can mitigate some of these variables and was used in the current study to examine the dietary preference of dairy heifers with sub-clinical parasitic gastroenteritis when compared to those receiving regular anthelmintic treatments. Grazing behaviour and herbage intake rates were determined through the use of jaw-movement recorders, direct observation and short-term liveweight change. Consistent with previous observations and despite evidence that nematode burdens were low in the untreated control heifers, a reduction in daily grazing time of 56 min (P = 0.054) was observed in the control animals. There was, however, no evidence that the control heifers showed greater preference for clover compared with ryegrass: partial preference for clover was 73.0% in the untreated controls and 75.5% in the treated heifers. Furthermore control heifers were observed grazing the clover swards significantly (P = 0.032) less frequently than the treated heifers. This study provides additional evidence in grazing cattle for parasite-induced inappetence, manifest as a reduction in grazing time and in subtle changes in ingestive behaviour. The observed partial preference for clover in both treated and control cattle was not significantly affected by the level of parasitism.     

Site fidelity,survival and conservation options for the threatened flapper skate (Dipturus cf. intermedia)

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Lily of the valley poisoning in an Angora goat

Extract

Madam: — We recently treated a goat poisoned by the lily of the valley tree. On Thursday the 30th of December, an adult Angora buck was presented with the following symptoms: projectile vomiting, ataxia, depression, excessive salivation, toxic mucous membranes, weak ruminal movements and a subnormal temperature. The vomiting was spectacular and included numerous leaves of one species of plant.     

Insect natural enemies of <Emphasis Type="Italic">Ips typographus</Emphasis> (L.) (Coleoptera,Scolytinae) in managed and unmanaged stands of mixed lowland forest in Poland

We tested the effects of forest management type (managed vs. unmanaged) on the abundances of Ips typographus (L.) (Col., Curculionidae, Scolytinae) and related parasitoids and predators reared from spruce bolts exposed in Białowieża, Poland. Habitat availability for these species differed between forest types mainly as a result of regular sanitary fellings occurring in managed forests. Populations of the common polyphagous insect predators Paromalus paralellepipedus (Herbst) and Plegaderus vulneratus (Panz.) (Col., Histeridae) or parasitoids Rhopalicus tutela (Walk.), Dinotiscus eupterus (Walk.) and Roptrocerus xylophagorum Ratz. (Hym., Pteromalidae) related to I. typographus did not differ between managed and unmanaged forests. Only Thanasimus spp. (Col., Cleridae) was significantly more abundant in managed forest, possibly because it was favored by the more open, sunny stands. However, the experiment was performed in stands where spruce is only a minor component and during the non-epidemic phase of the bark beetle population, so further experiments may be necessary to determine if the effects of sanitary fellings are greater in different forest types and at different stages of the population cycle.     

Genetic variation in Candidatus Phytoplasma australiense

This study examined whether genes that are less conserved than the 16S rRNA gene can distinguish Candidatus Phytoplasma australiense strains that are identical based on their 16S rRNA genes, with a view to providing insight into their origins and distribution, and any patterns of association with particular plant hosts. Sequence analysis of the tuf gene and rp operon showed that Ca . P. australiense strains could be differentiated into four subgroups, named 16SrXII-B ( tuf -Australia I; rp -A), 16SrXII-B ( tuf -New Zealand I; rp -B), 16SrXII-B ( tuf -New Zealand II) and 16SrXII-B ( rp -C). Strawberry lethal yellows 1, strawberry green petal, Australian grapevine yellows, pumpkin yellow leaf curl and cottonbush witches' broom phytoplasmas were designated members of the 16SrXII-B ( tuf -Australia I; rp -A) subgroup. The strawberry lethal yellows 2 and cottonbush reduced yellow leaves phytoplasmas were assigned to the 16SrXII ( tuf -New Zealand II; rp -B) subgroup. No relationship was observed between these phytoplasma subgroups and collection date, location or host plant. However, the study revealed evolutionary divergence in the 16SrXII group.     

Detection and identification of a phytoplasma from lucerne with Australian lucerne yellows disease

Foliar and root symptoms are described for Australian lucerne yellows (ALuY), a disease common in Australian lucerne seed crops. A phytoplasma was detected in plants exhibiting symptoms, but not in symptomless lucerne plants. Oligonucleotide primers specific to the phytoplasma 16S-23S rRNA intergenic spacer region (SR) were used in polymerase chain reaction (PCR) assays on DNA extracted from lucerne plants with and without symptoms. Identical restriction fragment length polymorphism (RFLP) enzyme profiles were obtained for PCR products amplified from 10 yellows-affected lucerne samples. RFLP profiles obtained for four restriction enzymes were different from those of the tomato big bud (TBB) phytoplasma. ALuY phytoplasma PCR products were sequenced to determine phylogeny and were found to fall within the faba bean phyllody phytoplasma group, or phytoplasma group 16srII. Transmission electron microscopy revealed phytoplasmas in the phloem of yellows-affected plant samples, but not in symptomless plant samples. Fungal, bacterial and viral agents in the aetiology of Australian lucerne yellows were ruled out.     

Induction of peroxidase as a disease resistance response in resistant (<Emphasis Type="Italic">Hibiscus trionum</Emphasis>) and susceptible (<Emphasis Type="Italic">Althea armeniaca</Emphasis>) species in the family malvaceae

The pathogen-induced biosynthesis of peroxidase (PO) in resistant and susceptible wild species of Malvaceae was studied. Specifically,Hibiscus trionum was found to be resistant to the wilt pathogenVerticillium dahliae, andAlthea armeniaca was susceptible. After inoculation withV. dahliae, PO activity increased more rapidly in the resistant plant: increased activity inH. trionum was noted within 1 h after inoculation, remained high for 5 h, and decreased after 18 h. After 5 days, the levels did not differ from the control. In the susceptibleA. armeniaca, PO activity did not differ statistically from the control even after 18 h, but was significantly higher after 5 days. Electrophoretic analysis of inoculated tissue extracts showed the occurrence of two new isoforms inh. trionum after inoculation; new isoforms did not occur inA. armeniaca. A chitin affinity chromatography column showed the presence of a chitin-binding peroxidase isozyme in healthyH. trionum that increased dramatically after inoculation. Two chitin-binding peroxidase isozymes were observed in healthyA. armeniaca: one (R _f 0.26) did not increase and the other (R _f 0.89) evinced only a small increase after inoculation.     

Effect of a trainer cow on health, behavior, and performance of newly weaned beef calves

Experiments were conducted to investigate the effects of the presence of a trainer cow on behavior, performance, health, and feeding patterns of newly weaned beef calves. In Exp. 1,252 weaned calves (270+/-18 kg) were allocated to 22 pens (11 to 15 calves per pen). A trainer cow was randomly assigned to each of 11 pens. Calves were weighed prior to feeding on d 0, 3, 7, 14, 21, and 28. Rectal temperatures were taken on each of these days (except d 28) and blood samples were collected on d 0, 3, and 7 and subsequently analyzed for serum haptoglobin and leukotoxin antibody titers. Instantaneous scan observations of calf behavior were made at 10-min intervals between 0730 and 1730 on d 1, 2, 4, 5, and 6. A similar protocol was used in Exp. 2, in which 297 calves (258+/-17 kg) were allocated to 24 pens. Blood analyses included haptoglobin, white blood cell counts (WBC), and neutrophil:lymphocyte (NL) ratios. In Exp. 3, the above protocol was followed and patterns of feed bunk attendance of individual calves were also monitored using radio frequency identification by passive transponder ear tags. Trainer cows did not influence (P > .10) calf rectal temperatures, requirements for antibiotic therapy, WBC, NL ratios, or leukotoxin antibody titers. Pooled across treatments, NL ratios were lower (P < .01) on d 0 (.31) than on d 3 (.36) or d 7 (.39). Although differences in weight gain were detected in some periods within the three experiments, there were no differences (P > .10) overall (d 0 to 28). Trainer cows did not affect (P > .05) frequency or duration of bunk visits by the calves. Averaged across treatments, frequency and duration of bunk visits increased (P < .001) from 9.6 visits/d and 56.7 min/d between d 0 and 3 to 12.3 visits/d and 108.9 min/d between d 15 and 21. The number of calves observed eating during scan sampling observations also increased from 16.4% on d 1 to 25% on d 4 (P < .10) and 29% on d 5 and 6 (P < .05). More (P < .05) calves were observed lying on d 1 (41.7%) and d 2 (45.3%) than on d 4 (37.5%), d 5 (34.8%), or d 6 (36.2%). With a trainer cow present, fewer (36.7% vs 41.5%; P < .001) calves were observed lying and more (11.7% vs 10.2%; P = .08) were observed walking than when no cow was present. Trainer cows did not improve calf health, time spent at the feed bunk, or performance of newly weaned calves.