Physiology and behavior of dogs during air transport

Twenty-four beagles were used to measure physiological and behavioral reactions to air transport. Each of 3 groups of 4 sedated (with 0.5 mg/kg body weight of acepromazine maleate) and 4 non-sedated (control) dogs was flown on a separate flight between Montreal, Quebec, and Toronto, Ontario, after being transported by road from Quebec City to Montreal. Saliva and blood samples were taken before ground and air transport and after air transport. The heart rate was monitored during the whole experiment except during ground transport, and behavior was monitored by video during air transport. Sedation did not affect any of the variables measured. The mean plasma cortisol concentration was significantly higher (P < 0.05) after ground transport than at baseline (225.3 vs 134.5 nmol/L); the mean salivary cortisol concentration was significantly higher (P < 0.05) after both ground and air transport than at baseline (16.2 and 14.8, respectively, vs 12.6 nmol/L). The mean neutrophil count was significantly higher (P < 0.05) after both ground and air transport than at baseline (80.6 and 81.4, respectively, vs 69.5 per 100 white blood cells), whereas the mean lymphocyte count was significantly lower (P < 0.05) (13.2 and 13.7, respectively, vs 22.4 per 100 white blood cells). Loading and unloading procedures caused the largest increase in heart rate. On average, the dogs spent more than 50% of the time lying down, and they remained inactive for approximately 75% of the time, except during take-off. These results suggest that transportation is stressful for dogs and that sedation with acepromazine, at the dosage and timing used, does not affect the physiological and behavioral stress responses of dogs to air transport.     

Treatment of Unobserved Oestrus in a Dairy Cattle Herd with Low Oestrous Detection Rate up to 60 days Post-partum

The efficiency of treatments for unobserved oestrus and their effect on the reproductive performance of a dairy cattle herd with low oestrous detection rate till 60 days post‐partum (dpp), attributed to the declivous and slippery concrete floor were investigated. The herdsman requested advice in order to improve the mean days open of the herd, but no investments were allowed because a new unit was about to be built. Due to the low oestrus detection rate of the herd, the breeding policy was to inseminate at the first detected post‐partum oestrus. Cows were examined at 20–30 dpp to assess uterine involution, ovarian activity and prevalence of reproductive disorders and, at 60 dpp if no previous oestrus was detected. Each examination included palpation per rectum, ultrasound scanning and collection of a blood sample for plasma progesterone (P4) measurement. Cows with unobserved oestrus till 60 dpp were allocated either to a treatment group (n=139) or to a control group (n=139). Three treatments were used: (a) injection of PGF_2α (PG) upon detection of a corpus luteum (CL; n = 30), cows not observed in oestrus being re‐injected 11–12 days later. AI was at oestrus; (b) PRID (n=35) or Crestar (n=74) devices kept in situ for 12 and 9 days, respectively, were associated to an injection of PG and of equine chorionic gonadotrophin (eCG) at device removal. Cows were double‐fixed time‐inseminated at 48 and 72 h after device removal. All treated cows were examined at 48–72 h after treatment to confirm oestrus. The percentage of cows detected in oestrus up to 60 dpp remained unchanged through the trial (35 and 47% for years before intervention: 1994–95; 51 and 48% for years of intervention: 1996–97). In contrast, the oestrous detection rate was high both in treated (93%) and control (100%) cows. This possibly resulted from an improvement in the oestrous detection efficiency of the herd's personnel and from examination of cows at 48–72 h after treatment. Treated and control cows had identical conception rate (CR; 36 and 37%, respectively) and reproductive performance. However, the mean days open of the herd in 1996 was significantly improved in comparison with previous years (mean ± SEM: 134 ± 6, 126 ± 5, 110 ± 4 and 114 ± 5 days, for years 1994, 1995, 1996 and 1997, respectively, p < 0.05, ANOVA ). Conception rate to AI up to 40 dpp was significantly reduced, compared with the period between 60 and 100 dpp but, mean days open were significantly improved in cows inseminated up to 60 dpp, compared with thereafter (p < 0.05).     

US economic assistance to two Micronesian nations: Aid impact,dependency and migration

Abstract: The USA provides economic assistance to the Federated States of Micronesia and the Republic of the Marshall Islands under the Compacts of Free Association. Both economies demonstrate three of the four MIRAB components: migration, aid and bureaucracy. Only the remittance structure has not developed. Significant US assistance supported large government sectors in both nations. Reductions in US assistance of over a 17‐year period led many island citizens to migrate to the USA. However, to date, remittances have not been substantial. In addition to structural challenges, both nations face institutional constraints including poor governance and lack of accountability over assistance. To improve future growth through more effective use of US assistance, these institutional constraints must be overcome. Future US assistance to both nations will fall over the next 20 years, putting pressure on the island governments and will likely contract their economies. The need for remittance streams is likely to increase. New Compact assistance structures strive to improve aid accountability.     

Patterns of fish invasions in the Great Plains of North America

A basic step toward controlling invasive species outbreaks is to predict which assemblages or habitats are most susceptible to invasion and effects of invading species on native communities. However, because predictive models may not work across a wide range of conditions it is important to examine processes associated with fish invasions across different regions. In this study, we use data from 949 sites in Oklahoma and Kansas to examine spatial patterns of species invasions in the Great Plains region of the US. Of these sites, 16 were intensively sampled between 1977 and 1994 and used to evaluate temporal patterns of species introductions. We found a trend of increasing introduced species richness without a decline in native species richness over 18 years. However, total abundance and community structure of native assemblages has changed at several of these sites during this time period. Because some of these changes occurred at sites with few or no introduced species, factors other than interactions with introduced fishes may have been responsible for this pattern. A stepwise multiple regression model that included human population size, native species richness, mean annual precipitation and drainage area explained 43% of the variation in the number of non-native species across all sites. Most introduced species in this region have native ranges within the Mississippi River basin and therefore are presumably adapted to regional environmental conditions. Great Plains streams have, to some extent, resisted invasion by introduced species; however, our analysis shows that proximity to dense human populations and importance to humans has largely structured species introductions and can partly explain spatial patterns of species invasions in this region.     

Effects of Lumbricus terrestris, Allolobophora chlorotica and Eisenia fetida on microbial community dynamics in oil-contaminated soil

Oil spills are one of the most common types of soil pollution. Bioremediation has become an attractive alternative to physicochemical methods of remediation, where feasible. Earthworms have been shown to stimulate the degradation of petroleum hydrocarbons in soil, and it was hypothesized that the role of earthworms in remediation lies in the enhancement of an oil degrading microbial community. The aim of this study was to characterize microbial activity and community dynamics in oil-contaminated soil incubated with or without earthworms. Three earthworm species (Eisenia fetida, Allolobophora chlorotica and Lumbricus terrestris) were incubated in crude oil polluted soil (ca. 10,000 mg/kg total petroleum hydrocarbons (TPH)) and a reference soil for 28 d. Control treatments with manual mixing and/or cattle dung amendment were also included. In the oil-contaminated soil, respiration and concentration of microbial biomass was significantly enhanced by earthworm amendment, and TPH concentrations decreased significantly. These effects were less evident in treatments with A. chlorotica, possibly due to a difference in behavior, since individuals of this endogeic species were found in a state of inactivity (aestivation). Microbial community dynamics were described by phospholipid fatty acid (PLFA) analyses. After 28 d, similar shifts in the soil PLFA composition were observed in the oil-contaminated soil irrespective of worm species. Fungal:bacterial ratios were increased in the presence of worms, but also by addition of dung as a food source, indicating a non-specific effect of metabolizable substrates. In contrast, the fatty acids 17:1ω8 (=Δ9-heptadecenoic acid) and 20:4ω6c (arachidonic acid) were specifically stimulated by the presence of earthworms in the oil-contaminated soil. The results showed that earthworms can contribute positively to bioremediation of oil-contaminated soil, but that the effect may be species-dependent.     

Performance of broiler chickens fed least-cost diets formulated to model predicted amino acid requirements

Two 3-week battery brooder experiments were conducted with male broiler chicks to investigate the use of a model equation to predict amino acid requirements. In the first experiment, chicks were fed four diet treatments based on published recommendations (Guelph, (Summers & Leeson, 1976) NRC, 1977; Maryland, (Thomas et al. 1978); AEC, 1978), two diet treatments based on model-calculated recommendations (Hurwitz et al., 1978) and one commercial chick starter. A second experiment comparing one diet treatment each for a published (NRC), model-calculated and commercial recommendation was necessiated due to updating the model. In Experiment 1, significant differences (p < 0.05) were noted in feed efficiency at 15 days in favour of birds on the commercial treatment relative to those receiving days in favour of birds on the commercial treatment relative to those receiving treatments based on published recommendations. Over the trial period, the commercial treatment and a model-based treatment supported a significantly (p < 0.05) better feed efficiency than did the other published recommendations. The model-based diet treatment of Experiment 2 resulted in significantly (p < 0.01) superior bird weights at 7 and 14 days and feed efficiency at 7 days (p < 0.01) and 14 days (p < 0.05) relative to both NRC (1977) and the commercial diet treatment. These results indicate the potential of using model-calculated amino acid recommendations for 0- to 3-week old broiler chickens.     

Dynamics of number fluctuations: motile microorganisms

The time dependence of the intensity of light scattered from motile Escherichia coli bacteria is studied in population densities so low that the intensity autocorrelation function reflects fluctuations in the total number of particles in the scattering region. Measured correlation functions are analyzed by using a random walk model of bacterial motion.