Supplementation of Dairy Cows under Alfalfa Grazing Conditions with Ground Corn

Two trials were carried out during the Autumn of 1991 and 1992 to investigate the effects of corn supplementation on lactational performance of dairy cows under alfalfa grazing. Forty two multiparous Holstein cows with 30-60 days in milk were used in a randomized continuous design with covariance analysis. The treatments were 0.0, 3.5 and 7.0 kg.day-1 of corn grain supplementation (T1, T2 and T3 respectively) in 1991 and 0.0, 3.0, 6.0 and 9.0 kg.day-1 (T1, T2, T3 and T4 respectively) in 1992. Six cows per treatment were used divided in 3 cows per grazing paddock. Dry matter (DM) intake (DMI) was estimated weekly for each group of cows. The pasture allowance was between 22-26 kg DM.cow-1.day-1. Pasture and grain DMI were 16.6 and 0.0, 13.5 and 3.2, 13.3 and 6.1 kg.cow-1.day-1 (T1, T2 and T3 respectively) in 1991; 16.8 and 0.0, 15.7 and 2.1, 14.0 and 4.1, 12.2 and 6.3 kg.cow-1.day-1 (T1, T2, T3 and T4 respectively) in 1992. The substitution rate was 0.66 kgDM pasture per kgDM corn. There was a lineal effect of supplementation on milk production the responses were 0.936 (1991) and 1.173 (1992) kg milk kgDM-1 corn. However, non significant effects (P \u3e0.05) on fat content (32.8 and 31.9 g. kg-1 milk) and protein contents (30.7 and 30.7 g. kg-1 milk) in milk during both years (1991 and 1992 respectively) were observed

High Moisture Sorghum Grain Silage: Effects of Tannin Content and Urea Treatment on the Performance of Dairy Cows

Grain sorghum silage tannin content effect was evaluated on milk production and chemical composition of Argentinean Holstein bred cows, and it are described dry matter (DM) and crude protein (CP) in situ digestion parameters and effective degradability. The base diet was constituted by alfalfa pasture, maize silage, and a protein – mineral supplement, differing in three treatments based on high moisture grain silage characteristic: LTS= Low tannin grain sorghum, HTS= High tannin grain sorghum, and HTSu= High tannin sorghum plus the addition of urea. Grain sorghum silage tannin content affects milk production, without significant alteration of chemical composition. Beside the effect of urea addition on grain sorghum tannin content, improvement in animal response was only moderate

The DNA of coral reef biodiversity: predicting and protecting genetic diversity of reef assemblages

Conservation of ecological communities requires deepening our understanding of genetic diversity patterns and drivers at community-wide scales. Here, we use seascape genetic analysis of a diversity metric, allelic richness (AR), for 47 reef species sampled across 13 Hawaiian Islands to empirically demonstrate that large reefs high in coral cover harbour the greatest genetic diversity on average. We found that a species’s life history (e.g. depth range and herbivory) mediates response of genetic diversity to seascape drivers in logical ways. Furthermore, a metric of combined multi-species AR showed strong coupling to species richness and habitat area, quality and stability that few species showed individually. We hypothesize that macro-ecological forces and species interactions, by mediating species turnover and occupancy (and thus a site’s mean effective population size), influence the aggregate genetic diversity of a site, potentially allowing it to behave as an apparent emergent trait that is shaped by the dominant seascape drivers. The results highlight inherent feedbacks between ecology and genetics, raise concern that genetic resilience of entire reef communities is compromised by factors that reduce coral cover or available habitat, including thermal stress, and provide a foundation for new strategies for monitoring and preserving biodiversity of entire reef ecosystems

Common garden experiments in the genomic era : new perspectives and opportunities

PdV was supported by a doctoral studentship from the French Ministère de la Recherche et de l’Enseignement Supérieur. OEG was supported by the Marine Alliance for Science and Technology for Scotland (MASTS)The study of local adaptation is rendered difficult by many evolutionary confounding phenomena (e.g. genetic drift and demographic history). When complex traits are involved in local adaptation, phenomena such as phenotypic plasticity further hamper evolutionary biologists to study the complex relationships between phenotype, genotype and environment. In this perspective paper, we suggest that the common garden experiment, specifically designed to deal with phenotypic plasticity has a clear role to play in the study of local adaptation, even (if not specifically) in the genomic era. After a quick review of some high-throughput genotyping protocols relevant in the context of a common garden, we explore how to improve common garden analyses with dense marker panel data and recent statistical methods. We then show how combining approaches from population genomics and genome-wide association studies with the settings of a common garden can yield to a very efficient, thorough and integrative study of local adaptation. Especially, evidence from genomic (e.g. genome scan) and phenotypic origins constitute independent insights into the possibility of local adaptation scenarios, and genome-wide association studies in the context of a common garden experiment allow to decipher the genetic bases of adaptive traits.PostprintPeer reviewe

Unifying approaches to Functional Marine Connectivity for improved marine resource management: the European SEA-UNICORN COST Action

Truly sustainable development in a human-altered, fragmented marine environment subject to unprecedented climate change, demands informed planning strategies in order to be successful. Beyond a simple understanding of the distribution of marine species, data describing how variations in spatio-temporal dynamics impact ecosystem functioning and the evolution of species are required. Marine Functional Connectivity (MFC) characterizes the flows of matter, genes and energy produced by organism movements and migrations across the seascape. As such, MFC determines the ecological and evolutionary interdependency of populations, and ultimately the fate of species and ecosystems. Gathering effective MFC knowledge can therefore improve predictions of the impacts of environmental change and help to refine management and conservation strategies for the seas and oceans. Gathering these data are challenging however, as access to, and survey of marine ecosystems still presents significant challenge. Over 50 European institutions currently investigate aspects of MFC using complementary methods across multiple research fields, to understand the ecology and evolution of marine species. The aim of SEA-UNICORN, a COST Action supported by COST (European Cooperation in Science and Technology), is to bring together this research effort, unite the multiple approaches to MFC, and to integrate these under a common conceptual and analytical framework. The consortium brings together a diverse group of scientists to collate existing MFC data, to identify knowledge gaps, to enhance complementarity among disciplines, and to devise common approaches to MFC. SEA-UNICORN will promote co-working between connectivity practitioners and ecosystem modelers to facilitate the incorporation of MFC data into the predictive models used to identify marine conservation priorities. Ultimately, SEA-UNICORN will forge strong forward-working links between scientists, policy-makers and stakeholders to facilitate the integration of MFC knowledge into decision support tools for marine management and environmental policies

Genetic diversity and connectivity of southern right whales (Eubalaena australis) found in the Brazil and Chile-Peru wintering grounds and the South Georgia (Islas Georgias del Sur) feeding ground

As species recover from exploitation, continued assessments of connectivity and population structure are warranted to provide information for conservation and management. This is particularly true in species with high dispersal capacity, such as migratory whales, where patterns of connectivity could change rapidly. Here we build on a previous long-term, large-scale collaboration on southern right whales (Eubalaena australis) to combine new (nnew) and published (npub) mitochondrial (mtDNA) and microsatellite genetic data from all major wintering grounds and, uniquely, the South Georgia (Islas Georgias del Sur: SG) feeding grounds. Specifically, we include data from Argentina (npub mtDNA/microsatellite=208/46), Brazil (nnew mtDNA/microsatellite=50/50), South Africa (nnew mtDNA/microsatellite=66/77, npub mtDNA/microsatellite=350/47), Chile-Peru (nnew mtDNA/microsatellite=1/1), the Indo-Pacific (npub mtDNA/microsatellite=769/126), and SG (npub mtDNA/microsatellite=8/0, nnew mtDNA/microsatellite=3/11) to investigate the position of previously unstudied habitats in the migratory network: Brazil, SG and Chile-Peru. These new genetic data show connectivity between Brazil and Argentina, exemplified by weak genetic differentiation and the movement of one genetically identified individual between the South American grounds. The single sample from Chile-Peru had a mtDNA haplotype previously only observed in the Indo-Pacific and had a nuclear genotype that appeared admixed between the Indo-Pacific and South Atlantic, based on genetic clustering and assignment algorithms. The SG samples were clearly South Atlantic, and were more similar to the South American than the South African wintering grounds. This study highlights how international collaborations are critical to provide context for emerging or recovering regions, like the SG feeding ground, as well as those that remain critically endangered, such as Chile-Peru

Ecological commonalities among pelagic fishes: comparison of freshwater ciscoes and marine herring and sprat

Systematic comparisons of the ecology between functionally similar fish species from freshwater and marine aquatic systems are surprisingly rare. Here, we discuss commonalities and differences in evolutionary history, population genetics, reproduction and life history, ecological interactions, behavioural ecology and physiological ecology of temperate and Arctic freshwater coregonids (vendace and ciscoes, Coregonus spp.) and marine clupeids (herring, Clupea harengus, and sprat, Sprattus sprattus). We further elucidate potential effects of climate warming on these groups of fish based on the ecological features of coregonids and clupeids documented in the previous parts of the review. These freshwater and marine fishes share a surprisingly high number of similarities. Both groups are relatively short-lived, pelagic planktivorous fishes. The genetic differentiation of local populations is weak and seems to be in part correlated to an astonishing variability of spawning times. The discrete thermal window of each species influences habitat use, diel vertical migrations and supposedly also life history variations. Complex life cycles and preference for cool or cold water make all species vulnerable to the effects of global warming. It is suggested that future research on the functional interdependence between spawning time, life history characteristics, thermal windows and genetic differentiation may profit from a systematic comparison of the patterns found in either coregonids or clupeids

Population Genomics of Parallel Adaptation in Threespine Stickleback using Sequenced RAD Tags

Next-generation sequencing technology provides novel opportunities for gathering genome-scale sequence data in natural populations, laying the empirical foundation for the evolving field of population genomics. Here we conducted a genome scan of nucleotide diversity and differentiation in natural populations of threespine stickleback (Gasterosteus aculeatus). We used Illumina-sequenced RAD tags to identify and type over 45,000 single nucleotide polymorphisms (SNPs) in each of 100 individuals from two oceanic and three freshwater populations. Overall estimates of genetic diversity and differentiation among populations confirm the biogeographic hypothesis that large panmictic oceanic populations have repeatedly given rise to phenotypically divergent freshwater populations. Genomic regions exhibiting signatures of both balancing and divergent selection were remarkably consistent across multiple, independently derived populations, indicating that replicate parallel phenotypic evolution in stickleback may be occurring through extensive, parallel genetic evolution at a genome-wide scale. Some of these genomic regions co-localize with previously identified QTL for stickleback phenotypic variation identified using laboratory mapping crosses. In addition, we have identified several novel regions showing parallel differentiation across independent populations. Annotation of these regions revealed numerous genes that are candidates for stickleback phenotypic evolution and will form the basis of future genetic analyses in this and other organisms. This study represents the first high-density SNP–based genome scan of genetic diversity and differentiation for populations of threespine stickleback in the wild. These data illustrate the complementary nature of laboratory crosses and population genomic scans by confirming the adaptive significance of previously identified genomic regions, elucidating the particular evolutionary and demographic history of such regions in natural populations, and identifying new genomic regions and candidate genes of evolutionary significance