Seasonal influences on livestock keeping in a sedentary crop–livestock system

Although seasonality is recognised as an important part of agricultural-based livelihoods, limited literature is available on the subject area, and it is often only alluded to in discussion of other aspects of rural livelihoods. A 2-year longitudinal study to examine the influences of seasonal changes on livestock keeping in a smallholder crop–livestock production system was carried out in Busia District, western Kenya. The study aimed to obtain a picture of yearly variations in household activities and resources, as a means of understanding decisions made by households regarding animal health management, and household times of vulnerability in terms of losing animals. Data collection coincided with the three main seasons in the study area. Information on (inter alia) seasonal livelihood activities, animal health care expenses, numbers of disease episodes and livestock movements into and out of households was collected using questionnaires and participatory rural appraisal methodologies. Farmers suggested clear and consistent seasonal changes and events, but data analyses did not show the patterns expected in relation to livestock keeping. Important observations were made in relation to livestock disease episodes and the use of veterinary services; livestock disease episodes were higher during the long rains than in the dry season, but more money was spent during the dry season when numbers of disease episodes were low, and more households also used professional veterinary services during this season (χ ² = 81.47, P < 0.001). In both study years, a higher proportion of households treated animals themselves during the rainy seasons (z = −2.4, P = 0.02; z = −5.03, P < 0.001).     

Modeling the relationship between food animal health and human foodborne illness

To achieve further reductions in foodborne illness levels in humans, effective pre-harvest interventions are needed. The health status of food animals that are destined to enter the human food supply chain may be an important, although often overlooked, factor in predicting the risk of human foodborne infections. The health status of food animals can potentially influence foodborne pathogen levels in three ways. First, diseased animals may shed higher levels of foodborne pathogens. Second, animals that require further handling in the processing plant to remove affected parts may lead to increased microbial contamination and cross-contamination. Finally, certain animal illnesses may lead to a higher probability of mistakes in the processing plant, such as gastrointestinal ruptures, which would lead to increased microbial contamination and cross-contamination. Consequently, interventions that reduce the incidence of food animal illnesses might also help reduce bacterial contamination on meat, thereby reducing human illness. Some of these interventions, however, might also present a risk to human health. For example, the use of antibiotics in food animals can reduce rates of animal illness but can also select for antibiotic-resistant bacteria which can threaten human treatment options. In this study, we present a mathematical model to evaluate human health risks from foodborne pathogens associated with changes in animal illness. The model is designed so that potential human health risks and benefits from interventions such as the continued use of antibiotics in animal agriculture can be evaluated simultaneously. We applied the model to a hypothetical example of Campylobacter from chicken. In general, the model suggests that very minor perturbations in microbial loads on meat products could have relatively large impacts on human health, and consequently, small improvements in food animal health might result in significant reductions in human illness.     

Twenty-five essential research questions to inform the protection and restoration of freshwater biodiversity

1. Freshwater biodiversity is declining at an unprecedented rate. Freshwater conservationists and environmental managers have enough evidence to demonstrate that action must not be delayed but have insufficient evidence to identify those actions that will be most effective in reversing the current trend.
2. Here, the focus is on identifying essential research topics that, if addressed, will contribute directly to restoring freshwater biodiversity through supporting ‘bending the curve’ actions (i.e. those actions leading to the recovery of freshwater biodiversity, not simply deceleration of the current downward trend).
3. The global freshwater research and management community was asked to identify unanswered research questions that could address knowledge gaps and barriers associated with ‘bending the curve’ actions. The resulting list was refined into six themes and 25 questions.
4. Although context-dependent and potentially limited in global reach, six overarching themes were identified: (i) learning from successes and failures; (ii) improving current practices; (iii) balancing resource needs; (iv) rethinking built environments; (v) reforming policy and investments; and (vi) enabling transformative change.
5. Bold, efficient, science-based actions are necessary to reverse biodiversity loss. We believe that conservation actions will be most effective when supported by sound evidence, and that research and action must complement one another. These questions are intended to guide global freshwater researchers and conservation practitioners, identify key projects and signal research needs to funders and governments. Our questions can act as springboards for multidisciplinary and multisectoral collaborations that will improve the management and restoration of freshwater biodiversity.

     

Effects of piperonyl butoxide on Bemisia tabaci Genn. (Homoptera: Aleyrodidae): mortality, development, parasitism and predation in Israeli cotton fields

In field trials in Israel, piperonyl butoxide (PB) alone, at concentrations of 2000 and 5000 ppm exerted good control over nymphal Bemisia tabaci populations on cotton. Weekly doses of these concentrations exerted greater control than a recommended oil and were as effective as the standard single application of buprofezin. Cypermethrin caused marked resurgence within the plots, probably as a consequence of its detrimental effects on natural enemies. Neither PB, buprofezin nor the oil reduced the incidence of natural enemies. Treatment with 2000 or 5000 ppm PB resulted in a shift in age structure toward a greater proportion of young instars than in other treatments. There was some evidence that these effects facilitated a greater level of parasitism in PB-treated plots.     

Complementary effect of zoo compost with mineral nitrogen fertilisation increases wheat yield and nutrition in a low-nutrient soil

Excess nitrogen(N) fertiliser use in agriculture is associated with water pollution and greenhouse gas emissions.While practices and programs to reduce N fertiliser application continue to be developed,inefficient fertiliser use persists.Practices that reduce mineral N fertiliser application are needed in a sustainable agricultural ecosystem to control leaching and gaseous losses for environmental management.This study evaluated whether fully or partially replacing mineral N fertiliser with zoo compost(Perth Zoo) could be a good mitigation strategy to reduce mineral N fertiliser application without affecting wheat yield and nutrition.To achieve this,a glasshouse experiment was conducted to assess the complementary effect of zoo compost and mineral N fertiliser on wheat yield and nutrition in a sandy soil of southwestern Australia.Additionally,a chlorophyll meter was used to determine whether there was a correlation between chlorophyll content and soil mineral N content,grain N uptake,and grain protein content at the tillering(42 d after sowing(DAS)) and heading(63 DAS) growth stages.The standard practice for N application for this soil type in this area,100 kg ha^-1,was used with a soil bulk density of 1.3 g cm^-3 to calculate the amount of mineral N(urea,46% N) and Perth Zoo compost(ZC)(0.69% N) for each treatment.Treatments comprised a control(no nutrients added,T1),mineral N only(100 kg N ha^-1,T2),ZC only(100 kg N ha^-1,T7),and combinations of mineral N and ZC at different rates(mineral N at 100 kg N ha^-1+ ZC at 25 kg N ha^-1(T3),mineral N at 75 kg N ha^-1+ ZC at 25 kg N ha^-1(T4),mineral N at 75 kg N ha^-1+ ZC at 50 kg N ha^-1(T5),and mineral N at 50 kg N ha^-1+ ZC at 50 kg N ha^-1(T6)).The T6 treatment significantly increased grain yield(by 26%) relative to the T2 treatment.However,the T7 treatment did not affect grain yield when compared to the T2 treatment.All treatments with mineral N and ZC in combination significantly improved the 1 000-grain weight compared to the T2 treatment.Chlorophyll content was better correlated with soil mineral N content(r = 0.61),grain N uptake(r = 0.62),and grain protein content(r = 0.80) at heading(63 DAS) than at tillering(42 DAS).While ZC alone could not serve as an alternative to mineral N fertiliser,its complementary use could reduce the mineral N fertiliser requirement by up to 50% for wheat without compromising grain yield,which needs to be verified in the field.Chlorophyll content could be used to predict soil mineral N at the heading stage,and further studies are warranted to verify its accuracy in the field.Overall,the application of ZC as part of integrated nutrient management improved crop yield with reduced N fertiliser application.     

Review of infectious agent occurrence in wild salmonids in British Columbia,Canada

Wild Pacific salmonids (WPS) are economically and culturally important to the Pacific North region. Most recently, some populations of WPS have been in decline. Of hypothesized factors contributing to the decline, infectious agents have been postulated to increase the risk of mortality in Pacific salmon. We present a literature review of both published journal and unpublished data to describe the distribution of infectious agents reported in wild Pacific salmonid populations in British Columbia (BC), Canada. We targeted 10 infectious agents, considered to potentially cause severe economic losses in Atlantic salmon or be of conservation concern for wild salmon in BC. The findings indicated a low frequency of infectious hematopoietic necrosis virus, piscine orthoreovirus, viral haemorrhagic septicaemia virus, Aeromonas salmonicida, Renibacterium salmoninarum, Piscirickettsia salmonis and other Rickettsia-like organisms, Yersinia ruckeri, Tenacibaculum maritimum and Moritella viscosa. No positive results were reported for infestations with Paramoeba perurans in peer-reviewed papers and the DFO Fish Pathology Program database. This review synthesizes existing information, as well as gaps therein, that can support the design and implementation of a long-term surveillance programme of infectious agents in wild salmonids in BC.     

Effect of Grain Morphology on Degree of Milling and Iron Loss in Rice

Grain morphological characteristics were thought to play a significant role in genotypic variation in Fe concentration in white rice. Comparing 17 rice cultivars representing six major grain morphological categories, the present study systematically investigated the relationship between grain morphology, the degree of milling (DOM), and the loss of Fe during the polishing process. The relative importance of key morphological parameters in this relationship was also investigated. The grain morphological characteristics of different rice cultivars significantly affected the degree of Fe loss during polishing to produce white rice. This variation in Fe loss from polishing among the six categories of rice cultivars is mainly due to their difference in DOM (r = 0.73**) and this loss in Fe was the primary factor determining the level of Fe concentration in the white rice. Among the morphological parameters investigated, grain length and length-to-width ratios played the most significant role in determining the DOM, which suggests that these two grain attributes may serve as the initial screening parameters when selecting cultivars for high Fe white rice production. Degree of Fe loss was lowest in short-bold grain shape category compared with the other grain shapes.     

Can timing of spawning explain the increase in egg size with female size in salmonid fish?

A common observation is that egg size increases with maternal size within populations. Several hypotheses have been proposed to explain this phenomenon. Most recently, it was suggested that the optimal egg size depends on female size due to correlations between (i) breeding time and egg size selection and (ii) female size and breeding time, and as such, the positive egg size–maternal size relationship represents an adaptive strategy. Here, we test the second of these two premises in two salmonid species, Atlantic salmon (Salmo salar) and coho salmon (Oncorhynchus kisutch) for which we have detailed breeding and egg size data. The body size of spawning females decreased throughout the season in coho salmon, but not in Atlantic salmon. Furthermore, we did not find a direct correlation between egg size and breeding time, which would also be expected if this premise was correct. Accordingly, breeding date does not appear to be as important as other factors in shaping among female differences in egg size.     

Seroprevalence and risk factors for bovine brucellosis in domestic yaks (<Emphasis Type="Italic">Bos grunniens</Emphasis>) in Tibet,China

A cross-sectional study was conducted in three counties (Damxung, Maizhokunggar and Yadong) in Tibet in April and May 2015. A total of 1,523 yaks owned by 181 herders were randomly selected and blood sampled. Sera were tested using the rose bengal test (RBT) and a competitive immune-enzymatic assay (C-ELISA) and the test results interpreted in parallel. The individual yak prevalence was 2.8% (95% CI 2.0–3.7) with a herd prevalence of 18.2% (95% CI 12.9–24.6). At the individual level, two predictor variables, age and production system, were significantly associated with seropositivity by a binary logistic regression analysis. The odds of Brucella infection were significantly higher in older Yaks (3–5 years old, OR = 4.51; 95% CI 1.53–19.29; ≥6 years old, OR = 3.89; 95% CI 1.23–17.21) compared to those of younger yaks (≤2 years old). The odds of seropositivity for yaks managed under an agro-pastoral production system were 2.9 (95% CI 1.48–5.86) times higher compared to those managed under a pastoral production system. At the herd level, an association between the infection with Brucella and a history of abortions in the herd was observed (OR = 4.98, 95% CI 1.48–16.62). Surprisingly, vaccination was not associated with a lower level of infection (p = 0.49 and p = 0.99 for individual and herd level data, respectively). The results of the survey indicate that bovine brucellosis is endemic among the yak population in the plateau region of China, and the risk factors identified in the study should be considered in the epidemiology of the disease and when developing control programs for the disease.