Forty-eight lowland lambs were used in a completely randomized design (23-d period) with a factorial arrangement of treatments: 2 breeds (Highlander vs. Texel) × 3 sexes (female vs. intact male vs. wether) × 2 diets (fresh grass vs. fresh grass plus 0.5 kg/d pelleted concentrate). Animals ( = 48) were approximately 5 mo old and 36 ± 5.0 kg BW at the commencement of the study with 4 lambs for each breed-sex-diet combination. Fresh grass was harvested daily from the first regrowth of perennial ryegrass sward and offered ad libitum with a similar growth stage throughout the experiment. The animals were individually housed in pens and fed experimental diets for 19 d before being transferred to individual calorimeter chambers for a further 4 d with feed intake, fecal and urine outputs, and methane (CH) emissions measured. Lambs offered 0.5 kg/d concentrate had greater DM and energy (i.e., GE, DE and ME) intake, BW, and CH production (g/d) and greater N intake, fecal and manure N outputs, and fecal N per N intake than those given only fresh grass ( < 0.05). However, diets had no effect on CH emission rates (i.e., CH/DMI [ = 0.408] and CH energy/GE intake [ = 0.821]). Texels produced more CH/DMI (g/kg) than Highlanders ( = 0.044), and sex had no effect on CH/DMI (g/kg; = 0.101). Neither breed nor sex had an effect on N utilization efficiency ( > 0.05). The results reflected that high-quality forages may play a role similar to concentrate in mitigation of enteric CH emissions. The effects of sex and breed on rumen function require further investigation to understand relationships with CH emissions and N excretion in sheep.
1. Farmland ponds are a highly threatened freshwater habitat which has undergone dramatic losses during the last 200 years due to land drainage schemes and agricultural intensification. Agri-environment schemes (AES) incentivize farmers to adopt farming methods to benefit biodiversity, yet there are a paucity of data evaluating the success of artificially created AES ponds as analogues of natural ponds in an attempt to recreate lost environments. 2. We examined variation in environmental parameters and aquatic and terrestrial invertebrate communities between 38 natural ponds and 91 artificial ponds that were created in southwest Ireland (n = 129). 3. Artificial ponds in agricultural grassland did not replicate natural ponds in adjacent semi-natural habitats differing significantly in size, pH, conductivity, productivity (indicated by submerged and emergent plant cover including algae) and surrounding vegetation structure that is, sward height. These differences significantly influenced aquatic and terrestrial invertebrate community structure with a suite of indicator taxa in both natural and artificial ponds. 4. The conservation value of artificial ponds in agricultural grasslands should not be underestimated as they had 43% higher aquatic species richness and 33% higher aquatic species abundance than natural ponds in adjacent semi-natural habitats. 5. Synthesis and applications. We demonstrate that artificial agri-environment scheme ponds created in agricultural grasslands, whilst not direct analogues of natural ponds in adjacent semi-natural habitats, do fulfil a role in preserving high local biodiversity albeit representing a different community of species. Creation of ponds in farmland as well as in adjacent natural habitats could provide a wider range of environmental conditions and richer associated macroinvertebrate communities, increasing landscape connectivity and further enhancing regional biodiversity. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
Recent developments suggest the use of other gases such as carbon dioxide (CO2) to estimate methane (CH4) emissions from livestock, yet little information is available on the relationship between these two gases for a wide range of animals. A large respiration calorimeter dataset with dairy cattle (n = 987 from 30 experiments) was used to investigate relationships between CH4 and CO2 production and oxygen (O2) consumption and to assess whether the predictive power of these relationships could be improved by taking into account some dietary variables, including forage proportion, fibre and metabolisable energy concentrations. The animals were of various physiological states (young n = 60, dry cows n = 116 and lactating cows n = 811) and breeds (Holstein-Friesian cows n = 876, Jersey × Holstein-Friesian n = 47, Norwegian n = 50 and Norwegian × Holstein-Friesian n = 14). The animals were offered forage as a sole diet or a mixture of forage and concentrate (forage proportion ranging from 10 to 100%, dry matter basis). Data were analysed using a series of mixed models. There was a strong positive linear relationship between CH4 and CO2, and observations within an experiment were very predictable (adjusted R2 = 0.93). There was no effect of breed on the relationship between CH4 and CO2. Using O2 instead of CO2 to predict CH4 production also provided a very good fit to the observed empirical data, but the relationship was weaker (adjusted R2 = 0.86). The inclusion of dietary variables to the observed CO2 emissions, in particular forage proportion and fibre concentration, provided a marginal improvement to the prediction of CH4. The observed variability in the CH4:CO2 ratio could only marginally be explained by animal physiological state (lactating vs. dry cows and young cattle) and dietary variables, and thus most likely reflected individual animal differences. The CH4:CO2 ratio can therefore be particularly useful to identify low CH4 producing cows. These findings indicate that CO2 production data can be used to accurately predict CH4 emissions to generate large scale data for management and genetic evaluations for the dairy industry.
Molecular methods can play a crucial role in species management and conservation. Despite the usefulness of genetic approaches, they are often not explicitly included as part of species recovery plans and conservation practises. The Natterjack toad (Epidalea calamita) is regionally Red-Listed as Endangered in Ireland. The species is declining and is now present at just seven sites within a highly restricted range. This study used 13 highly polymorphic microsatellite markers to analyse the population genetic diversity and structure. Genetic diversity was high with expected heterozygosity between 0.55 and 0.61 and allelic richness between 4.77 and 5.92. Effective population sizes were small (Ne < 100 individuals), but not abnormal for pond breeding amphibians. However, there was no evidence of historical or contemporary genetic bottlenecks or high levels of inbreeding. We identified a positive relationship between Ne and breeding pond surface area, suggesting that environmental factors are a key determinant of population size. Significant genetic structuring was detected throughout the species’ range, and we identified four genetic entities that should be considered in the species’ conservation strategies. Management should focus on preventing further population declines and future loss of genetic diversity overall and within genetic entities while maintaining adequate local effective population size through site-specific protection, human-mediated translocations and head-start programs. The apparent high levels of genetic variation give hope for the conservation of Ireland’s rarest amphibian if appropriately protected and managed.
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