Impatti, adattamento e vulnerabilita Le cause e le responsabilita dei cambiamenti climatici sono state trattate sul numero di ottobre della rivista Cda. Approfondiamo l’argomento presentando il documento: “Cambiamenti climatici 2007: impatti, adattamento e vulnerabilita” votato ad aprile 2007 dal secondo gruppo di lavoro del Comitato Intergovernativo sui Cambiamenti Climatici (Intergovernmental Panel on Climate Change). Si tratta del secondo di tre documenti che compongono il quarto rapporto sui cambiamenti climatici.

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Climate Change 2007: Impacts, Adaptation and Vulnerability.

Nutrient requirements of dairy cattle , Nutrient requirements of dairy cattle , مرکز فناوری اطلاعات و اطلاع رسانی کشاورزی

Nutrient requirements of dairy cattle

Nutrient requirements of beef cattle

http://www.remugants.cat/2/upload/llet_racionament_model_cornell_animal_feed_science_and_technology_2004.pdf

The Cornell Net Carbohydrate and Protein System model for evaluating herd nutrition and nutrient excretion

One of the most intriguing protein materials found in nature is bone, a material composed of assemblies of tropocollagen molecules and tiny hydroxyapatite mineral crystals that form an extremely tough, yet lightweight, adaptive and multifunctional material. Bone has evolved to provide structural support to organisms, and therefore its mechanical properties are of great physiological relevance. In this article, we review the structure and properties of bone, focusing on mechanical deformation and fracture behavior from the perspective of the multidimensional hierarchical nature of its structure. In fact, bone derives its resistance to fracture with a multitude of deformation and toughening mechanisms at many size scales ranging from the nanoscale structure of its protein molecules to the macroscopic physiological scale.

On the Mechanistic Origins of Toughness in Bone

This review gives an overview of several experiments conducted in vivo on the effects of plants rich in essential oils (EO) or of EO extracts on dry matter intake, milk production and composition. Based on in vivo studies on the effects of EO or whole plants rich in EO in lactating ruminants, it was possible to conclude that: i) milk yield was often positively affected after the first part of the lactation, in long-term studies, at high dosages of EO, and in sheep and goats rather than in dairy cows; and ii) milk composition was marginally affected, except for milk fatty acid composition, for which all studies on lactating goats and ewes, but none of those on cattle. In general, it appears that small ruminants are more responsive to the action of EO.

Efeitos dos óleos essenciais sobre o consumo de matéria seca, produção e composição do leite de ruminantes: uma revisão

63. Evaluation of prediction models of voluntary dry matter intake of Sarda ewes in the transition stage: early lactation

72. Using system thinking to gain insight into social, economic, and environmental aspects of sustainability for food production

A study was undertaken to assess the impact of the timing of grazing on rumen and plasma metabolites and some metabolic hormones in lactating dairy sheep allocated to an Italian ryegrass (Lolium multiflorum Lam) pasture in spring for 4 h/d. Twenty-four mid lactation Sarda ewes stratified for milk yield, body weight, and body condition score, were divided into four homogeneous groups randomly allocated to the treatments (2 replicate groups per treatment). Treatments were morning (AM, from 08:00 to 12:00) and afternoon pasture allocation (PM, from 15:30 to 19:30). Samples of rumen liquor (day 39) and blood plasma (days 17 and 34 of the experimental period) were collected before and after the grazing sessions. Moreover, on days 11 and 35, grazing time was assessed by direct observation and herbage intake measured by the double weighing procedure. Grazing time was longer in PM than AM ewes (P < 0.001) but herbage intake was undifferentiated between groups. The intake of water-soluble carbohydrates at pasture was higher in PM than AM ewes (P < 0.05). The post-grazing propionic and butyric acid concentration, as measured on day 39, were higher in PM than AM ewes (P < 0.05). The basal level of glucose on day 34 and insulin (on both sampling days) were higher in PM than AM (P < 0.05). The opposite trend was detected for non-esterified fatty acids (P < 0.05, day 34) and urea (both days). Pasture allocation in the afternoon rather than in the morning decreased plasma concentration of ghrelin (P < 0.001) and cortisol (P < 0.001), with a smoothed trend on day 34 in the latter variable. To conclude, postponing the pasture allocation to afternoon increased the intake of WSC, favoring a glucogenic pattern of rumen fermentation and a rise of glucose and insulin levels in blood, although these effects were not consistent across the whole experimental period. Moreover, the afternoon grazing decreased the level of cortisol and ghrelin, suggesting a higher satiation-relaxing effect.

Does the timing of pasture allocation affect rumen and plasma metabolites and ghrelin, insulin and cortisol profile in dairy ewes?

Knowledge of nutritional requirements is decisive for a successful nutrition system, since animals fed properly convert more efficiently the nutrients ingested in products. Current feeding systems for goats still comprise information extrapolated from sheep and/or cattle. However, the data obtained with these species should not be used for goats, because of differences between these species, such as dietary habits, physical activity, milk and carcass composition, different adaptation mechanisms, among others (NRC, 2007). Therefore, the objective of this study was to determine net energy and protein requirements for growth of goat kids, using meta-analysis as a statistical tool.

Antonello Cannas

Papers

Efeitos dos óleos essenciais sobre o consumo de matéria seca, produção e composição do leite de ruminantes: uma revisão

63. Evaluation of prediction models of voluntary dry matter intake of Sarda ewes in the transition stage: early lactation

72. Using system thinking to gain insight into social, economic, and environmental aspects of sustainability for food production

Does the timing of pasture allocation affect rumen and plasma metabolites and ghrelin, insulin and cortisol profile in dairy ewes?

Net energy and protein requirements for growth of goats kids