M. E. Cossu

Nutritional and eating quality of Argentinean beef : A review

This review deals with distinctive aspects of quality of Argentinean beef in terms of tenderness, flavour, colour, juiciness, taste, acceptability, lipid content and composition and its resultant nutraceutical characteristics. Differences are due to beef production systems based on temperate or tropical grasslands aimed at shortening the fattening phase as far as possible, with limited or null use of concentrates. However, the effect of limited supplemental feeding is also discussed as well as the responses arising from the use of beef cattle genotypes, including British, Continental, Dairy, Zebu breeds and their crosses, adapted to the various environments and systems found in the country.

The effect of silo type and dry matter content on the maize silage fermentation process and ensiling loss

To compare the fermentation process and ensiling losses in experimental silos and farm bunker silos (BS) and determine the correlation with the dry matter (DM) content at harvesting, maize forage was chopped and ensiled in four farms. Using similar harvesting and ensiling systems, one BS and 12 experimental silos were prepared in each farm; the latter consisted of three S100 silos (100 1 capacity with effluent discharge valve and no airtight sealing), three S500 pilot-scale silos (500 1 capacity with effluent discharge valve and airtight sealing) and six S002 micro-silos (2 1 capacity with airtight sealing and no effluent discharge valve). DM content of maize forage at harvesting varied from a minimum of 29.0% to a maximum of 38.3%, with important differences both among farms and among plots within the same farm (three plots per farm). Chemical characteristics of maize silage harvested in BS and in experimental silos were similar, but some differences in fermentation quality were observed. Experimental silos showed a more active fermentation, with higher production (P < 0.01) of lactic acid (4.72%, 4.87% and 5.21% vs. 3.45% DM; in S100, S500, S002 silos and BS, respectively), acetic acid (1.43%, 1.30% and 1.40% vs. 1.03% DM) and ethanol (0.81%, 0.63% and 0.55% vs. 0.29% DM) than in BS, probably as a result of a lower degree of compression of the ensiled forage. S100 silos, with no airtight sealing, were characterized by a more heterolactic fermentation, showing a homolactic index (lactic acid to acetic acid + ethanol ratio) significantly lower than the other experimental silos and BS (2.12 vs. 2.62, 2.70 and 2.83; P < 0.01). Ensiling losses, measured on experimental silos, appeared to be higher in S100 silos than in S500 and S002 silos (DM loss was 5.3% vs. 3.3% and 2.6%, respectively; P < 0.05). Fermentation characteristics and ensiling losses were significantly correlated with DM content of maize plant at harvesting. The following regression equations were determined for the estimation of lactic acid concentration and DM loss of silage on the basis of initial DM content (x, %): lactic acid (% DM)=10.384−0.171x±0.968; n=96; r0.725 DM loss (%)=292.24−16.48x+0.235x2±2.90; n=48; r=0.679 S500 and S002 experimental silos appear to be useful devices to study the conservation of ensiled forage because they faithfully reflect the process that normally occurs in farm bunker silos.

Dietary inclusion of tannin extract from red quebracho trees (Schinopsis spp.) in the rabbit meat production

Abstract Two levels (1% and 3%) of condensed tannin extract from red quebracho (QT) were added to a diet of growing rabbits in a 6-wk feeding trial up to 12 wk of age. Health status was unaffected by the QT supplementation. The E. coli count of caecal content denoted a bactericidal activity of the QT. Weight gain and slaughter weigh were significantly higher and conversion index was significantly lower in rabbits fed QT diets, compared to those fed the control diet (P<0.05). Meat traits, as well the meat fatty acid profile weren’t influenced by the QT supplementation. Our results contributed to increase the knowledge on the dietary use of QT in the rabbit. QT extract supplemented at 1% and 3% in fattening rabbits diet had a clear beneficial effect on live performance. Further studies are needed to assess if supplementing diets with QT can be a valuable strategy.

Influencia del área productiva de la región pampeana y del tiempo de maduración sobre la calidad sensorial de carne de novillos

The quality of steer meat of different regions of Argentina has been partially characterized. The aim of the present work was to evaluate the influence of the production area of the Pampeana Region, and the ageing time (4 and 7 days) on sensory steer’s meat quality. Ninety steers were sampled from different areas of the “Pampeana” region, slaughtered in two slaughter plants belonging to the same company, located in the provinces of Santa Fe (called Plant S) and Entre Rios (called Plant E). After 72 h post-slaughters, samples of the Longissimus dorsi muscle (9°-13° rib) were taken. A sensory panel of eight trained assessors performed a quantitative descriptive analysis using a not structured 10 cm linear scale. 16 descriptors were considered: appearance (2), flavor (9) and texture (5). Data were analyzed statistically using the procGLM and Tukey’s test (p < 0.05). Results showed influence of the slaughter plants on the sensory quality, and significant differences were observed (p < 0.01) for the following attributes: global color, intensity of odour, hardness, chews and whereas the descriptors: intensity and typical odor, tastes acid, salty and metallic, hardness, chewiness, number of chews and juiciness. When analyzing the ageing time influence, it could be observed that the attributes related to the smell (intensity and typical odor), taste (sweet, salty and metallic flavor), texture (chewiness number of chews, and fibrousness) were significantly affected in each slaughter plant. In conclusion, the area of origin of the meat of the Pampeana region, influenced the meat tenderness and chewiness, being “more tender” the meat from the plant located in Santa Fe.