Journal: The Journal of Agricultural Science

Abbreviation

J. agric. sci.

Publisher

Cambridge University Press

Journal Volumes

ISSN

0021-8596
1469-5146

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Publications 1 - 9 of 9
  • Identifying factors limiting legume biomass production in a heterogeneous on-farm environment
    Item type: Journal Article
    Douxchamps, S.; Frossard, E.; Uehlinger, N.; et al. (2012)
    The Journal of Agricultural Science
  • Physical activity, forced by steep pastures, affects muscle characteristics and meat quality of suckling beef calves
    Item type: Journal Article
    Gangnat, Isabelle D.M.; Leiber, Florian; Dufey, Pierre-Alain; et al. (2017)
    The Journal of Agricultural Science
    On steep slopes, grazing is associated with elevated physical activity. This is assumed to influence muscle metabolism, carcass and meat quality in beef cattle. However, there is a lack of experiments which allow distinguishing between physical activity and other factors of influence. In the present experiment, a setup was applied which excluded other factors as best as possible. Two groups of 12 Angus-sired suckling calves were each kept on high altitude pastures with either steep (whole area with about 40% inclination; S-calves) or with flat areas (0% inclination; F-calves). The two areas offered forage of similar nutritional quality. The calves, initially 18 ± 2·5 weeks old, were kept with their dams on the pastures for 11 weeks in a rotational grazing system. The calves were equipped with pedometers and rumination sensors to record physical activity and feeding behaviour, respectively. Slaughter took place on two dates immediately after the grazing period and carcass quality was assessed. Muscle fibre types were classified according to their contractile metabolism and post mortem (p.m.) protein degradation was quantified. The meat, aged for 21 days, was subjected to various physicochemical analyses and sensory evaluation. S-calves walked more steps and spent more time lying down than F-calves, whereas feeding behaviour was not affected by pasture inclination. The daily gains of S-calves were 10% lower compared with those of F-calves. Carcass characteristics were not influenced by pasture inclination. S-calves had a larger proportion of fast-twitch type IIX/B muscle fibres than F-calves. The opposite was observed for intermediate type IIA muscle fibres, whereas the proportion of slow-twitch type I muscle fibres was unaffected. Occasional differences were observed between S- and F-calves regarding indicators of p.m. proteolysis. In S-calves, compared with F-calves, meat from the longissimus thoracis muscle was juicier and showed a tendency to be of lighter colour, whereas meat from the biceps femoris muscle had a smaller shear force (24·5 v. 27·5 N in F-calves). In conclusion, 11 weeks’ exposure to environments forcing calves to exhibit different physical activities in a hypoxic environment was sufficient to cause adaptations in muscle metabolism and several, though small, differences in meat quality.
  • Effects of season, altitude and daylength on floral initiation of two contrasting genotypes of Trifolium repens L.
    Item type: Journal Article
    Von Sury, F.; Nösberger, J. (1986)
    The Journal of Agricultural Science
  • Growth performance and metabolic changes in lambs and steers after mild nutritional restriction
    Item type: Journal Article
    Thomson, E. F.; Bickel, H.; Schürch, A. (1982)
    The Journal of Agricultural Science
  • Planting materials for warm tropic potato production: production and field performance of nursery-produced tubers
    Item type: Journal Article
    Benz, J. S.; Keller, E. R.; Midmore, D. J. (1996)
    The Journal of Agricultural Science
  • In vitro screening of temperate climate forages from a variety of woody plants for their potential to mitigate ruminal methane and ammonia formation
    Item type: Journal Article
    Terranova, Melissa; Kreuzer, Michael; Braun, Ueli; et al. (2018)
    The Journal of Agricultural Science
    Feeding phenol-containing plants to ruminants has the potential to mitigate both methane and ammonia formation. In the present study, mostly woody plants, such as the leaves of trees and shrubs, were tested for their influence on in vitro fermentation. The plants selected grow naturally under temperate climatic conditions, are usually available in bulk and do not directly compete with human food production. The detailed screening included whole plants or parts of different plant species reporting their effects on methane and/or ammonia formation. The plant materials were added at 167 mg/g of total dry matter (DM) to a common total mixed ration and incubated for 24 h with the Hohenheim gas test method. The results from in vitro fermentation were also used to determine the net energy of lactation and utilizable crude protein in the complete diets. Thirteen out of 18 test materials did not impair the organic matter (OM) digestibility of the diet. Ammonia concentrations decreased up to 35% when adding any of the test materials. Methane formation per unit of feed DM and per unit of digestible OM was lowered by 13 of the 18 test materials from 12 to 28% and 5 to 20%, respectively. In conclusion, a number of plant materials tested have the potential to mitigate ruminal ammonia and methane formation without adversely affecting digestibility. The leaves of Betula pendula, Corylus avellana, Ribes nigrum, Vitis vinifera and the aerial part of Geum urbanum were particularly promising in this respect.
  • Nitrogen use efficiency, reticulo-ruminal pH and behaviour of lactating cows grazing either in a full-time system or in a part-time system with indoor feeding of fresh herbage and concentrate
    Item type: Journal Article
    Akert, Franziska S.; Kreuzer, Michael; Hofstetter, Pius; et al. (2020)
    The Journal of Agricultural Science
    Increasing herd size and fragmented or non-uniform land challenge pasture-based milk production systems. Therefore, part-time grazing combined with indoor feeding of fresh herbage (‘cut-and-carry’) allows to maintain the advantages of fresh-herbage-based diets. However, consequences for environmental nitrogen losses, animal behaviour and ruminal metabolism are decisive for its implementation. Animal performance, nitrogen use efficiency (NUE), reticulo-ruminal pH and feeding/locomotive behaviour were compared in six cows subjected either to full-time grazing (system F) or to part-time grazing system with indoor feeding of fresh herbage and concentrate (system P). Biweekly samplings were performed on six lactating cows per treatment in spring, summer and autumn. Nitrogen (N) balance was calculated from estimated N intake and N output via faeces, urine and milk. Reticulo-ruminal pH was recorded using a wireless data recorder. Eating and locomotive behaviour were measured with noseband sensors and pedometers. In spring, but not later, herbage intake per unit of body weight was higher for system F compared to system P cows. Eating time was shorter by 15% in P compared to F cows. Across systems, NUE declined from spring to summer/autumn from about 300 to 200 g milk protein N/kg N intake. Reticulo-ruminal pH was more variable under part-time grazing conditions, with a pronounced decrease subsequent to offering the herbage indoors. The part-time grazing system resulted in similar or higher NUE than full-time grazing. Additional studies with larger numbers of experimental units are required to be able to develop comprehensive recommendations for the improvement of the two grazing systems.
  • Phenology and plant functional type dominance drive CO2 exchange in seminatural grasslands in the Pyrenees
    Item type: Journal Article
    Ibañez, Maria; Altimir, Nuria; Ribas, Angela; et al. (2020)
    The Journal of Agricultural Science
    Understanding the mechanisms underlying net ecosystem CO2 exchange (NEE) in mountain grasslands is important to quantify their relevance in the global carbon budget. However, complex interactions between environmental variables and vegetation on NEE remain unclear; and there is a lack of empirical data, especially from the high elevations and the Mediterranean region. A chamber-based survey of CO2 exchange measurements was carried out in two climatically contrasted grasslands (montane v. subalpine) of the Pyrenees; assessing the relative contribution of phenology and environmental variables on CO2 exchange at the seasonal scale, and the influence of plant functional type dominance (grasses, forbs and legumes) on the NEE light response. Results show that phenology plays a crucial role as a CO2 exchange driver, suggesting a differential behaviour of the vegetation community depending on the environment. The subalpine grassland had a more delayed phenology compared to the montane, being more temperature than water constrained. However, temperature increased net CO2 uptake at a higher rate in the subalpine than in the montane grassland. During the peak biomass, productivity (+74%) and net CO2 uptake (NEE +48%) were higher in the subalpine grassland than in the montane grassland. The delayed phenology at the subalpine grassland reduced vegetation's sensitivity to summer dryness, and CO2 exchange fluxes were less constrained by low soil water content. The NEE light response suggested that legume dominated plots had higher net CO2 uptake per unit of biomass than grasses. Detailed information on phenology and vegetation composition is essential to understand elevation and climatic differences in CO2 exchange.
  • Does closing knowledge gaps close yield gaps? On-farm conservation agriculture trials and adoption dynamics in three smallholder farming areas in Zimbabwe
    Item type: Journal Article
    Cheesman, Stephanie; Andersson, Jens A.; Frossard, Emmanuel (2017)
    The Journal of Agricultural Science
    On-farm demonstration-trials are a common strategy to introduce new technologies to farmers, while simultaneously evaluating these technologies’ performance under farmer conditions. The current study focuses on conservation agriculture (CA) technology adoption dynamics among a small group of farmers who can be considered increasingly knowledgeable, as they have hosted CA demonstration-trials for at least 7 years. Management and performance of farmers’ fields were compared with the CA demonstration-trials implemented on the same farm, focusing on yield gaps (YGs) between the two and the uptake of CA or some of its principles. Comparisons were made between demonstration-trials and farmers’ fields in three distinct land classification areas: Madziwa Communal Area (est. 1910s), Chavakadzi (est. 1980s) and Hereford (est. 2000s) Resettlement Areas. It was found that closing knowledge gaps on CA did not close YGs and that CA adoption was partial. In the Communal Area, CA principles have barely been taken up, but farmer yields were often as good as on the demonstration-trials. In the Resettlement Areas, farmers did take up reduced tillage (CA principle 1) and practised rotations (CA principle 3), but not residue retention (CA principle 2). Rather than partial CA adoption, lower fertilization rates explained the recorded YGs in the Resettlement Areas. In the three areas, farmers’ interest in CA-based increasing of yields was limited, as circumstances drove them to embark on extensification rather than a land use intensification pathway.
Publications 1 - 9 of 9