Effects of heat stress and diet on milk production and feed and energy intake of Sarda ewes

Ten Sarda dairy ewes (5th-6th month of lactation; 1995 ± 353 g/d of milk yield) were divided into two isoproductive groups and fed two different diets (high and low fiber) from May 20th to June 18th 2003, to evaluate diet effects on milk yield and intake. In addition, the relationships between meteorological conditions, measured during that unusually hot period, and milk yield and quality, dry matter intake, NDF or NDL were determined, to study animal responses to heat stress. Diet did not have any significant effect on the evaluated parameters. Milk yield was reduced by 20% (0.39 kg/d per head) as minimum temperatures changed from 9-12 °C to 18-21 °C. Similar milk yield reduction was observed as mean temperature-humidity index (THI) went from 60-65 to 72- 75. As wind speed increased from 1.5-2.5 m/s to 2.5-4 m/s, milk yield increased by 10%. Milk composition was not affected by heat stress throughout the experiment except for milk somatic cell count, which was increased by high temperatures. Dry matter, fibre and net energy intake varied significantly during the trial, with consistent and marked decreases as heat load increased

Cold markedly influences milk yield of Sardinian dairy sheep farms

The effects of cold stress on milk production have been widely examined in cattle and goats but little studied in dairy sheep. For this reason, the milk production of 10 dairy sheep farms, located throughout the Sardinian island, was analysed in relation to winter and early-spring meteorological conditions. From January 1st to March 31st, in 2003 and 2004, bulk milk production data were collected every 48 hours. From January 15th to April 30th of the same years, bulk milk production was also measured daily in five out of the ten studied farms. During the same periods, meteorological data were collected from stations of the Weather Forecast Service of Sardinia located near the farms. To determine the effects of meteorological conditions on milk yield, analysis of variance using the SAS (SAS Institute Inc., Cary, NC, USA) mixed procedure was performed. The results showed that minimum and mean temperatures, as well as number of hours under a critical threshold temperature (-3 °C, 0 °C and 3 °C), influenced milk yield, with a progressive decrease in milk yield as unfavourable cold conditions increased. In particular, as minimum temperatures decreased from the optimal values of 9-12 °C down to -3 °C, milk yield decreased by 25% (0.30 kg/d per head), with relevant decreases as temperatures went below 0-3 °C. In addition, in the daily dataset decreases up to 30% (0.40 kg/d per head) in milk yield occurred, as mean temperatures went below the optimal values of 15-18 °C. Other factors such as maximum temperature, wind speed, rainfall, relative humidity, Wind Chill Index (WCI) and number of hours under 7 °C and 10 °C did not significantly influence milk yield. The only interaction that significantly influenced milk yield was that between wind speed and number of hours under -3 °C. In fact, in particularly cold days, wind increased animal discomfort, thus negatively influencing milk production. Non significant variations occurred between the two years studied, while production differed significantly among farms, probably due to differences in their managerial techniques. In conclusion, cold stress can markedly decrease milk yield of dairy ewes even in Mediterranean climatic conditions

Effects of heat stress on milk yield in Sardinian dairy sheep farms

The effects of heat stress on milk production of dairy ewes have been very little studied, especially under Mediterranean conditions. For this reason, such effects were studied in ten Sarda dairy sheep farms associated to the Sardinian Breeders Association, located throughout Sardinia. They had whole farm milk yield records registered every 48 hours from April 1st until July 15th, in the years 2003 and 2004. Meteorological data were obtained from data collected by meteorological stations of the Weather Forecast Service of Sardinia located near each farm. To determine the effects of meteorological conditions on milk yield, analysis of variance using the SAS (SAS Institute Inc., Cary, NC, USA) mixed procedure was performed. The results showed that Sarda dairy sheep were highly sensitive to high temperatures, especially when they persisted for long periods. All analysed meteorological factors, except for wind speed, significantly influenced milk yield. Milk yield was more influenced by minimum air temperatures than by any other meteorological parameter. Increases in minimum temperatures from the optimal range of 9-12 °C up to 27-30 °C caused on average a decrease in milk yield of 36% (0.35 kg/d per head). The highest milk yields were observed at maximum air temperatures ranging from 24 to 30 °C and at mean temperatures varying from 15 to 18 °C, with progressive decreases, up to 20% (about 0.22 kg/d per head), at higher temperatures. The effects of duration of temperatures higher than some threshold values on milk yield were also relevant. Optimal air relative humidity for milk production was between 65 and 75%, in accordance with values reported in the literature. Rainfall negatively influenced milk yield, probably because it disturbs grazing, with decreases up to 23% (0.20 kg/d per head) under conditions of 6 mm-cumulative rainfall in two days. Milk production was also influenced by Temperature Humidity Index (THI), with a decrement of 25% (0.23 kg/d per head) as THI increased from 60-65 to 72-75.Wind influenced milk yield only when associated with other meteorological factors; it alleviated the negative effects of heat stress on milk yield at higher speed values. In conclusion, despite of their small body size, which should favour heat exchange and thermoregulation, milk yield of Sarda ewes was markedly reduced by heat stress

The Endemic Vascular Flora of Sardinia: A Dynamic Checklist with an Overview of Biogeography and Conservation Status

The vascular flora of Sardinia has been investigated for more than 250 years, with particular attention to the endemic component due to their phylogeographic and conservation interest. However, continuous changes in the floristic composition through natural processes, anthropogenic drivers or modified taxonomical attributions require constant updating. We checked all available literature, web sources, field, and unpublished data from the authors and acknowledged external experts to compile an updated checklist of vascular plants endemic to Sardinia. Life and chorological forms as well as the conservation status of the updated taxa list were reported. Sardinia hosts 341 taxa (15% of the total native flora) endemic to the Tyrrhenian Islands and other limited continental territories; 195 of these (8% of the total native flora) are exclusive to Sardinia. Asteraceae (50 taxa) and Plumbaginaceae (42 taxa) are the most representative families, while the most frequent life forms are hemicryptophytes (118 taxa) and chamaephytes (106 taxa). The global conservation status, available for 201 taxa, indicates that most endemics are under the ‘Critically Endangered’ (25 taxa), ‘Endangered’ (31 taxa), or ‘Least Concern’ (90 taxa) IUCN categories. This research provides an updated basis for future biosystematics, taxonomic, biogeographical, and ecological studies and in supporting more integrated and efficient policy tools

Notulae to the Italian alien vascular flora: 11

In this contribution, new data concerning the distribution of vascular flora alien to Italy are presented. It includes new records, confirmations, exclusions, and status changes for Italy or for Italian administrative regions. Nomenclatural and distribution updates published elsewhere are provided as Suppl. material 1

Influenza della temperatura e del fotoperiodo sul ciclo di sviluppo vegetativo in grano duro, triticale ed orzo

Dottorato di ricerca in agrometeorologia. 7. ciclo. A.a. 1994-95. Coordinatore P. Deidda. Docente guida M. DeiddaConsiglio Nazionale delle Ricerche - Biblioteca Centrale - P.le Aldo Moro, 7, Rome; Biblioteca Nazionale Centrale - P.za Cavalleggeri, 1, Florence / CNR - Consiglio Nazionale delle RichercheSIGLEITItal

Developmental ideotype in the context of the dual-purpose use of triticale, barley and durum wheat

Phenology strongly affects the performance of dual-purpose (forage plus grain) cereals by defining the rate of leaf and tiller appearance, the duration of the pre-grazing period and anthesis date. Here, the combined effect of genotypic and environmental variation conditions on anthesis date and the pre-grazing period in durum wheat, triticale and barley was analysed to define a developmental ideotype for their dual-purpose use. The extensive variation for the Haun stage reached at the time of apex emergence from the soil surface was associated with variation in the final leaf number, regardless of environment, species and cultivar. The timing of the terminal spikelet stage was the best predictor of apex emergence. The durum wheats tillered poorly, whereas the barleys and the triticales performed comparably in three of the four environments. In general, the higher the final leaf number, the higher the number of leaves and tillers produced by the time of apex emergence, the higher the number of leaves which emerges subsequently. The development of a high number of leaves both before and after apex emergence is advantageous, provided that anthesis is not overly delayed such that flowering and grain fill occur within a period where stressful conditions are likely to occur. Barley developed many leaves and had a low phyllochron, so was identified as the species with the development best suited for dual-purpose cropping. However, the near simultaneous emergence of the first two tiller apices exposes it to a risk of grazing damage

An integrated experimental and theoretical investigation on Cu(hfa)2*TMEDA: structure, bonding and reactivity

The physico-chemical properties of the b-diketonate diamine Cu(II) compound with hfa (1,1,1,5,5,5-hexafluoro-2-4-pentanedionate) and TMEDA (N,N,N',N' tetramethylethylenediamine), Cu(hfa)2*TMEDA, have been thoroughly investigated via an integrated multi-technique experimental\u2013computational approach. In the newly found orthorhombic polymorph, as revealed by low temperature single-crystal X-ray studies, the complex is present as a monomer with a distorted octahedral geometry at the Cu(II) centre. The compound sublimates, without premature side decompositions, at 343 K and 10-3 Torr. The structural, vibrational, electronic and thermal behavior of the neutral Cu(hfa)2*TMEDA complex has been investigated along with its fragmentation pathways, initiated by the release of an anionic hfa ligand with formation of a positive Cu(hfa)*TMEDA+ ion. Joint experimental and theoretical analyses led to the rationalization of the first fragmentation steps in terms of the Cu(II)\u2013ligands bonding properties and Jahn\u2013Teller distortion. The present study suggests applications of Cu(hfa)2*TMEDA as a precursor for copper and copper oxide materials by Chemical Vapor Deposition