Produção e composição do leite em função da alimentação de vacas mestiças Holandês x Zebu confinadas em condições experimentais no Brasil: metanálise / Milk yield and composition a function of feeding of crossbred Holstein x Zebu cows confined under experimental conditions in Brazil: meta-analysis

Objetivou-se avaliar os fatores da composição da dieta que podem interferir no consumo, na digestibilidade, na produção e na composição do leite de vacas mestiças Holandês x Zebu confinadas em condições experimentais no Brasil. A metanálise foi utilizada para o levantamento de trabalhos científicos de domínio público, compreendendo o período de janeiro de 2000 a dezembro de 2015. A base de dados foi constituída por 40 experimentos com 159 tratamentos, envolvendo 735 vacas em lactação. O consumo de nutrientes digestíveis totais (NDT) é comprometido pelo teor de fibra em detergente ácido (FDA) da dieta, relacionando-se com a digestibilidade da matéria seca (MS) e da fibra em detergente neutro (FDN), o que repercute na eficiência alimentar (EA). Observa-se a relação do teor de carboidratos não fibrosos (CNF) da dieta com o teor de lactose e o efeito do teor de MS da dieta e o elevado teor de FDN no consumo em função das características específicas dos tipos de volumosos utilizados. O consumo de NDT da dieta é prejudicado pela digestibilidade da MS e, principalmente, da FDN em função da proporção e das características dos volumosos utilizados na dieta, e esses fatores repercutem na EA, bem como na produção e na composição do leite.(AU)

The aim was to evaluate diet composition factors that may interfere with intake, digestibility, milk yield and composition of crossbred Holstein x Zebus cows confined under Brazilian experimental conditions. The meta-analysis was used for the survey of scientific works of public domain, covering the period from January 2000 to December 2015. The database consisted of 40 experiments with 159 treatments, involving 735 lactating cows. The voluntary intake of total digestible nutrients (TDN) is compromised by the acid detergent fiber (FAD) content of the diet, related to dry matter digestibility (DM) and neutral detergent fiber (NDF), affecting dietary efficiency (DE). The relation of the non-fibrous carbohydrate (NFC) content of the diet with the lactose content and the effect of the DM diet content and the high NDF content on the voluntary intake are specific characteristics of the types of roughage used. Dietary NDT intake is affected by the digestibility of DM and, mainly, NDF, depending on the proportion and characteristics of the nutrients used in the diet, and these factors have an impact on dietary efficiency, as well as on milk composition.(AU)

Produção e composição do leite em função da alimentação de vacas mestiças Holandês x Zebu confinadas em condições experimentais no Brasil: metanálise / Milk yield and composition a function of feeding of crossbred Holstein x Zebu cows confined under experimental conditions in Brazil: meta-analysis

Objetivou-se avaliar os fatores da composição da dieta que podem interferir no consumo, na digestibilidade, na produção e na composição do leite de vacas mestiças Holandês x Zebu confinadas em condições experimentais no Brasil. A metanálise foi utilizada para o levantamento de trabalhos científicos de domínio público, compreendendo o período de janeiro de 2000 a dezembro de 2015. A base de dados foi constituída por 40 experimentos com 159 tratamentos, envolvendo 735 vacas em lactação. O consumo de nutrientes digestíveis totais (NDT) é comprometido pelo teor de fibra em detergente ácido (FDA) da dieta, relacionando-se com a digestibilidade da matéria seca (MS) e da fibra em detergente neutro (FDN), o que repercute na eficiência alimentar (EA). Observa-se a relação do teor de carboidratos não fibrosos (CNF) da dieta com o teor de lactose e o efeito do teor de MS da dieta e o elevado teor de FDN no consumo em função das características específicas dos tipos de volumosos utilizados. O consumo de NDT da dieta é prejudicado pela digestibilidade da MS e, principalmente, da FDN em função da proporção e das características dos volumosos utilizados na dieta, e esses fatores repercutem na EA, bem como na produção e na composição do leite.(AU)

The aim was to evaluate diet composition factors that may interfere with intake, digestibility, milk yield and composition of crossbred Holstein x Zebus cows confined under Brazilian experimental conditions. The meta-analysis was used for the survey of scientific works of public domain, covering the period from January 2000 to December 2015. The database consisted of 40 experiments with 159 treatments, involving 735 lactating cows. The voluntary intake of total digestible nutrients (TDN) is compromised by the acid detergent fiber (FAD) content of the diet, related to dry matter digestibility (DM) and neutral detergent fiber (NDF), affecting dietary efficiency (DE). The relation of the non-fibrous carbohydrate (NFC) content of the diet with the lactose content and the effect of the DM diet content and the high NDF content on the voluntary intake are specific characteristics of the types of roughage used. Dietary NDT intake is affected by the digestibility of DM and, mainly, NDF, depending on the proportion and characteristics of the nutrients used in the diet, and these factors have an impact on dietary efficiency, as well as on milk composition.(AU)

Effect of packaging during storage time on retail display microbial population of beef strip loins from two different production systems.

Two studies were conducted to evaluate the influence of packaging during storage of strip loins (to simulate export shipment) from steers fattened on intensive grazing systems (Uruguay; UR) or on a high-concentrate diet (United States; US) on retail display life microbial growth. Four or 3 different packaging treatments were applied to UR and US strip loin roasts or steaks during 35 d of storage; treatments were applied 7 d following slaughter. After 35 d of storage, the samples were evaluated during simulated retail display for up to 6 d. In Exp. 1, the treatments were vacuum packaging (VP), low-oxygen modified atmosphere packaging (MAP) with N and CO (MAP/CO), low-oxygen MAP with N plus CO and CO, and VP plus an application of peroxyacetic acid (VP/PAA). In Exp. 2, block 1, the treatments were VP, MAP/CO, and VP with ethyl--lauroyl--arginate HCl incorporated into the film as an antimicrobial agent (VP/AM). In Exp. 2, block 2, the treatments were VP, MAP/CO, MAP/CO, and VP/AM. For retail display, VP treatments were sliced and repackaged in PVC overwrap, and MAP treatments were actually PVC overwrap trays that were removed from a master bag with the prescribed gas treatment. Regardless of production system and packaging treatment, mesophilic and psychrotrophic counts of 6.9 to 7.8 and 6.7 to 7.7 log10 CFU/cm, respectively, were obtained at the end of retail display, except for US samples in Exp. 2 (5.5 to 6.3 log CFU/cm). No differences ( > 0.05) were detected for spp. counts among packaging treatments in US steaks at the end of the display time in Exp.1, whereas, for UR steaks, both MAP treatments had lower ( < 0.05) spp. counts than VP treatments. spp. counts were lower ( < 0.05) in the MAP/CO treatment than in the other 3 treatments in US samples on d 6 of retail display for Exp. 2. At the end of display time and for Exp. 1, US steaks under MAP/CO had greater ( < 0.05) lactic acid bacteria (LAB) counts than samples in both VP treatments; no differences ( > 0.05) among packaging were detected for UR steaks. Both MAP and VP/AM treatments in the US samples for Exp. 2 had lower ( < 0.05) LAB counts on d 6 of display than the VP treatment, but no differences ( > 0.05) were found among packaging treatments for the UR samples. To maximize shelf life (storage and display life) of exported fresh beef, it is critical to minimize bacterial populations during processing and storage.

Effect of packaging during storage time on retail display shelf life of longissimus muscle from two different beef production systems.

Two studies were conducted to evaluate the influence of packaging and production system (PS) on retail display life color (L*, a*, and b*), fatty acid profile (% of total fatty acids), lipid oxidation (thiobarbituric acid reactive substances; mg malondialdehyde/kg of muscle), vitamin E content (µg/g of muscle), and odor (trained panelists) during storage of LM. Four (or 3) different packaging treatments were applied to LM from steers fattened on grazing systems (Uruguayan) or on high-concentrate diets (U.S.). From fabrication to application of treatments, Uruguayan LM were vacuum packaged for air shipment and U.S. LM were also vacuum packaged and kept in a cooler until Uruguayan samples arrived. Treatments were applied 7 d after slaughter. In Exp. 1, treatments were vacuum packaging (VP), low-oxygen (O) modified atmosphere packaging (MAP) with nitrogen (N2) and carbon dioxide (MAP/CO), low-O MAP with N2 plus CO and carbon monoxide (MAP/CO), and VP plus an application of peroxyacetic acid (VP/PAA). In Exp. 2 block 1, treatments were VP, MAP/CO, and VP with ethyl-arginate HCl incorporated into the film as an antimicrobial agent (VP/AM). In Exp. 2 block 2, treatments were VP, MAP/CO, MAP/CO, and VP/AM. After 35 d storage, steaks were evaluated during simulated retail display for up to 6 d. In Exp. 1, Uruguayan steaks under MAP/CO had greater ( < 0.05) a* values than VP/PAA and MAP/CO on d 6 of display. For U.S. beef, the MAP/CO had the reddest lean color ( < 0.05) compared with the other 3 packaging treatments on d 6 of display in Exp. 1. Packaging × PS × time interaction was significant ( < 0.05) in Exp. 1. In Exp. 2, MAP/CO in Uruguayan steaks also had the greatest a* values on d 6 of display, but no differences ( > 0.05) were detected among both VP and MAP/CO in U.S. steaks at this time. No significant ( > 0.05) packaging × PS × time interaction was observed in Exp. 2. Only PS (both experiments) and time (Exp. 1) affected ( < 0.05) L* values. In both experiments, U.S. steaks had greater ( < 0.05) L* values than Uruguayan steaks. Vitamin E content in Uruguayan steaks was greater ( < 0.05) than in U.S. steaks. Packaging × PS, PS × time, and packaging × PS × time interactions were not significant ( > 0.05) for any of the fatty acids. Beef from Uruguayan had lower ( < 0.05) SFA and MUFA and greater ( < 0.05) PUFA and n-6 and n-3 fatty acid percentages than U.S. beef. Complexity of fresh meat postmortem chemistry warrants a more comprehensive approach to maximize shelf life.