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Tall fescue pastures have an increasing potential to be used worldwide. The purpose of this study was to test the ability and flexibility of the model Dairy Mod to represent herbage mass accumulation ( HMA) of tall fescue pastures from Argentina under several environmental conditions, including different seasons, fertilizer nitrogen levels and irrigation. Species-specific responses were obtained by customizing particular parameters (i.e. number of living leaves per tiller, leaf appearance interval, optimum plant N concentration and the response of leaf gross photosynthesis to temperature). Additionally, a simulation experiment to compare the model assumption that optimum N concentration stays constant through HMA with the application of a reference critical N dilution curve verified for temperate forage grasses (N% = 4·8 HMA−0·32) was conducted. Application of Dairy Mod simulated with reasonable accuracy the HMA of tall fescue pastures under a wide range of climatic and management conditions; however, the model tended to underestimate HMA where pastures grew under high N availability. The use of a reference critical N curve substantially improved this bias, indicating that a further analysis on the N issue of the model is necessary. Results from this study provide support for further evaluations of the model under other scenarios and conditions. An upgrade of the model to improve simulation of N nutrition is suggested to enhance its performance to predict growth dynamics at high N availabilities as well as its value to address the effectiveness of N-management practices. [ABSTRACT FROM AUTHOR]

This study investigated the effects of levels of supplementation with maize grain and herbage allowance (HA) on grass herbage and maize intake, animal performance and grazing behaviour in two replicated grazing experiments with Angus beef cattle in Argentina. In Experiment 1, the response to increasing HA (2·5, 5·0 and 7·5 kg DM herbage 100 kg−1 live weight (LW) d−1 with and without 0·5 kg DM maize grain 100 kg−1 LW d−1) was investigated. In Experiment 2, the responses to level of maize grain offered (0, 0·5 and 1·0 kg DM maize grain 100 kg−1 LW d−1) at an HA of 2·5 kg DM herbage 100 kg−1 LW d−1 and an HA of 5·0 kg 100 kg−1 LW d−1 without maize grain were assessed. In Experiment 2, soyabean meal was added to control the crude protein concentration in the diet. Two methods were used for intake estimations: pre- and post-feeding herbage mass difference, and the use of the n-alkane and 13C technique. The latter predicted most accurately the metabolizable energy requirements calculated from live weights and liveweight gain of beef cattle attained in each treatment in both experiments. Increasing HA significantly increased herbage intake and liveweight gain ( P < 0·01), and general quadratic relationships between these variables could be fitted across experiments despite differences in animal and pasture characteristics. Increasing the amount of maize grain offered significantly reduced herbage intake and grazing time, but increased liveweight gain and digestibility of the diet. Substitution rate increased with increasing HA in Experiment 1 but was not affected by level of maize supplementation in Experiment 2. These relationships will aid the development of grazing management models for Argentinean conditions. [ABSTRACT FROM AUTHOR]

Introduction: Early-onset dementia (EOD) is defined as dementia with onset before the age of 65 years. EOD is increasingly recognised as an important clinical and social problem with devastating consequences for patients and caregivers., Objective: Determine the annual crude incidence rate and the specific incidence rates by sex and age in patients with EOD, and the standardised rate using the last national census of the population of Argentina (NCPA), from 2010., Materials and Methods: Hospital Privado de Comunidad, Mar del Plata, Argentina, attends a closed population and is the sole healthcare provider for 17 614 people. Using the database pertaining to the Geriatric Care department, we identified all patients diagnosed with EOD between 1 January, 2005 and 31 December, 2011. EOD was defined as dementia diagnosed in patients younger than 65., Results: The study period yielded 14 patients diagnosed with EOD out of a total of 287 patients evaluated for memory concerns. The crude annual incidence of EOD was 11 per 100 000/year (CI 95%: 6.25-19.1): 17 per 100 000 (CI 95%: 7.2-33.1) in men and 8 per 100 000 (CI 95%: 3.4-17.2) in women. We observed a statistically significant increase when comparing incidence rates between patients aged 21 to <55 years and ≥ 55 to <65 years (3 vs 22 per 100 000, P=.0014). The rate adjusted by NCPA census data was 5.8 cases of EOD habitants/year., Conclusion: This study, conducted in a closed population, yielded an EOD incidence rate of 11 per 100 000 inhabitants/year. To the best of our knowledge, this is the first prospective epidemiological study in Argentina and in Latin America., (Copyright © 2013 Sociedad Española de Neurología. Published by Elsevier Espana. All rights reserved.)