Characteristics of robust animals for grass-based production systems

A characterisation of dairy, beef and sheep breeds and/or strains best suited to profitable/sustainable production within the context of European [semi] intensive pasture-based systems is presented. To deliver optimal performance, pasture must be managed effectively, but pasture-based systems are less energy intensive, are climate sensitive and induce challenges and constraints not normally posed to animals in intensive feeding environments. This emphasises the importance of animal traits associated with robustness and adaptive abilities. A survey of French dairy farmers concluded that a robust cow is an “invisible” cow with a long lifetime. The traits common to both indoor and grazing systems include: efficient converters of feed to human edible products, functionality, being healthy, reproductively fit and exhibiting longevity. Unique to successful grazing is the capability to achieve large intakes of forage to meet productive potential, an ability to adapt to fluctuating feed supply and, in seasonal systems, the ability to conceive and give birth at the appropriate time each year, usually within 365 d. The breed or strain of choice may differ based on local management constraints and objectives; however, general principles apply, and ideally should be guided by a suitable selection index combining all of the economically important traits appropriate to the local conditions and systems.

Genotype–environment interaction in layer chickens in the growing stage: comparison of three genotypes at two different feeding levels with or without red mite (<i>Dermanyssus gallinae</i>) infestation

This study investigated how early growth was affected in various chicken genotypes, which were fed ad libitum or restricted and with or without poultry red mite (PRM) infestation. Atak-S (AS), New Hampshire Red (NHR), and Light Sussex (LS) genotypes were used in the study. In total, 120 chicks were used from each genotype. Four groups were formed: feed-restricted (FR) and infested with parasite (P+), FR only, fed ad libitum and P+ , and fed ad libitum only. Feed restriction was applied as 20 % of the feed consumption of the group fed ad libitum the day before for each genotype. The study was conducted between 2 to 12 weeks of age. Weekly live weights and feed consumption were recorded, and the feed conversion ratio was calculated. Traps were placed in cages to count parasites. Regarding the live weight, NHR tolerated the PRM infestation in the ad libitum feed conditions better than other genotypes. While the infested NHR and AS birds had lower live weights than the non-infested ones under FR conditions, there was no difference between infested and non-infested birds of NHR and AS genotypes when they fed ad libitum. The feed consumption of infested AS and NHR birds was higher than that of non-infested counterparts when fed ad libitum. By contrast, the LS chicks consumed less food in the infested environment. In conclusion, the genotypes responded differently to PRM infestation in different feeding environments.

Feeding of Barbus cyclolepis Heckel, 1837 (Teleostei: Cyprinidae) and its relationship with benthic macroinvertebrate fauna in the Istranca Stream (İstanbul, Turkey)

The aims of the study are to determine what the organisms Barbus cyclolepis consume as food in its feeding environments and to compare prey consumption with prey abundance in the environment. The study was conducted in the Istranca Stream located in Istanbul (Turkey) during the spring and summer of 2012. A total of 142 B. cyclolepis specimens were captured and it is determined that 94 of them had full digestive tracts. Diet analyses of B. cyclolepis showed that its food spectrum consisted of 11 different food types, and the species was found to feed on insects, mainly Diptera (IRI%= 92.26%). The most abundant macroinvertebrate organisms in the environment were Diptera and Gastropoda. The electivity index of B. cyclolepis was positive for Diptera in the spring (E= 0.49), but the value was below the expected value of 0.6 for high selectivity. The electivity values for other macroinvertebrate groups, consumed in low proportions, were negative. In summer, the fish fed on Diptera, Plecoptera, and Trichoptera, but a high electivity index value was found only for Trichoptera (E= 0.87). Results showed that B. cyclolepis mainly consumed Diptera as food and did not consume Gastropoda, although it is the second most abundant macroinvertebrate group in the environment. A relationship was determined between the proportion of food groups consumed in the digestive tracts of fish and the ratios of macroinvertebrates in the environment, and as a result, it was specified that the fish was selective on Diptera.

Shift in bacterial taxa precedes morphological plasticity in a larval echinoid

Morphological plasticity is an adaptive response to heterogenous environments when a fitness advantage is conferred. Larval sea urchins, for example, increase individual fitness in dilute feeding environments by elongating their feeding structure. Morphological plasticity for larval sea urchins is also coupled with significant shifts in the associated bacterial community, but whether this response occurs before, during, or following the expression of plasticity is unclear. Using the sea urchinLytechinus variegatus, we define the temporal pattern of the associated bacterial community throughout the expression of morphological plasticity. From prefeeding through plasticity, we observed thatL. variegatuslarvae exhibit a four-stage successional pattern and the relatedness of the larval-associated bacterial community directly reflects morphological plasticity and does so prior to expression of the environmental-specific morphology. Based on the structure of the larval-associated bacterial communities, the expression of morphological plasticity correlates short-arm larvae deviating from the microbial trajectory of pre-plastic siblings. Taken together, these data suggest that a holobiont may exhibit shifts in the associated bacterial community corresponding with the environmental variation in absence or anticipation of morphological plasticity.

A microbial perspective on the life-history evolution of marine invertebrate larvae: if, where, and when to feed

The feeding environment for planktotrophic larvae has a major impact on development and progression towards competency for metamorphosis. High phytoplankton environments that promote growth often have a greater microbial load and incidence of pathogenic microbes, while areas with lower food availability have a lower number of potential pathogens. Trade-offs between metabolic processes associated with growth and immune functionality have been described throughout the animal kingdom and may influence the life-history evolution of marine invertebrate planktotrophic larvae in these environments. Namely, to avoid potential incidences of microbial-mediated mortality and/or dysbiosis, larvae should regulate time spent between these two feeding environments. We describe here transcriptomic and microbiome data that supports this trade-off in larvae, where larvae in a well-fed environment upregulate genes associated with metabolism and may regularly enter a state of dysbiosis, resulting in mortality. To address the hypothesis that the environmental microbiota is a selective force on if, where, and when planktotrophic larvae should feed, we present a strategy for determining the specific interactions of larvae and microbes at a scale representative of their larger pelagic environment.

Altered trait variability in response to size-selective mortality

Changes in trait variability owing to size-selective harvesting have received little attention in comparison with changes in mean trait values, perhaps because of the expectation that phenotypic variability should generally be eroded by directional selection typical for fishing and hunting. We show, however, that directional selection, in particular for large body size, leads to increased body-size variation in experimentally harvested zebrafish ( Danio rerio ) populations exposed to two alternative feeding environments: ad libitum and temporarily restricted food availability. Trait variation may influence population adaptivity, stability and resilience. Therefore, rather than exerting selection pressures that favour small individuals, our results stress the importance of protecting large ones, as they can harbour a great amount of variation within a population, to manage fish stocks sustainably.

Herbivore diets and the anthropogenic environment of early farming in southern Scandinavia

Farming practice in the first period of the southern Scandinavian Neolithic (Early Neolithic I, Funnel Beaker Culture, 3950–3500 cal. BC) is not well understood. Despite the presence of the first farmers and their domesticated plants and animals, little evidence of profound changes to the landscape such as widespread deforestation has emerged from this crucial early period. Bone collagen dietary stable isotope ratios of wild herbivores from southern Scandinavia are here analysed in order to determine the expected range of dietary variation across the landscape. Coupled with previously published isotope data, differences in dietary variation between wild and domestic species indicate strong human influence on the choice and creation of feeding environments for cattle. In context with palynological and zooarchaeological data, we demonstrate that a human-built agricultural environment was present from the outset of farming in the region, and such a pattern is consistent with the process by which expansion agriculture moves into previously unfarmed regions.

A scalable method for automatically measuring pharyngeal pumping in C. elegans

We describe a scalable automated method for measuring the pharyngeal pumping of Caenorhabditis elegans in controlled environments. Our approach enables unbiased measurements for prolonged periods, a high throughput, and measurements in controlled yet dynamically changing feeding environments. The automated analysis compares well with scoring pumping by visual inspection, a common practice in the field. In addition, we observed overall low rates of pharyngeal pumping and long correlation times when food availability was oscillated.

Continuous bite monitoring: a method to assess the foraging dynamics of herbivores in natural grazing conditions

Accurate estimates of bite mass and variations in the short-term intake rate of grazing herbivores has been historically considered as a fundamental methodological difficulty, a difficulty that increases with the complexity of the feeding environment. Improving these methodologies will help understand foraging behaviours in natural grazing conditions, where habitat structure and interactions among different forages influence feeding decisions and patterns. During the past 30 years, we have been developing the ‘continuous bite-monitoring’ method, an observational method that allows continuous assessment of foraging behaviours, including bite mass, instantaneous intake rate and food selection, in simple to complex feeding environments. The centrepiece of the method is a ‘bite-coding grid’ where bites are categorised by structural attributes of the forage to reflect differences in bite masses. Over the years, we have been using this method with goats, sheep, llamas and cattle across a range of different habitats. After reviewing the development of the method, we detail its planning and execution in the field. We illustrate the method with a study from southern Brazilian native Pampa grassland, showing how changes in the forages consumed by heifers strongly affect short-term intake rate during meals. Finally, we emphasise the importance of studying animals grazing in their natural environments to first identify the relevant processes that can later be tested in controlled experiments.