Abstract:RESUMO -Objetivou-se avaliar nutricionalmente a grama-estrela ( Cynodon nlemfuensis) cv. Africana utilizada sob pastejo rotacionado por vacas leiteiras. Dez vacas mestiças foram manejadas em 2 ha de grama-estrela e divididas em 11 piquetes/ha. O período de pastejo foi de três dias e os 30 subseqüentes foram destinados à recuperação da pastagem. Durante o período experimental, os animais foram ordenhados duas vezes ao dia e receberam suplementação com 2 kg de concentrado. Amostras representativas do pasto inger… Show more
“…The use of the CNCPS model to evaluate diets is useful to estimate the nutritive value of different forage resources and other tropical foragebased diets (Cabral et al, 2000;Vieira et al, 2000a,b,c). The dietary synchronization is important for microbial growth and, depending on the availability of non-fibrous carbohydrates, the microbial biomass uses degradable nitrogen more efficiently Malafaia et al, 1998;1999;Vieira et al, 2000c;Favoreto et al, 2008;Fernandes et al, 2014). Because of the nutritional imbalances of sugarcane, e.g., high soluble sugars and low protein content, it should be used with caution to prevent excess nutrient losses (Fernandes et al, 2001).…”
-Ten Holstein-Zebu crossbred cows distributed into two simultaneous Latin squares (5 × 5) as a 2 × 2 factorial arrangement formed by chopped sugarcane or elephant grass silage, both with high or low protein degradability supplements and a corn silage as a control treatment, were compared using orthogonal contrasts. The studied variables were the performance, plasma concentrations of urea-N, glucose, and creatinine, urine-N and milk urea-N, and the nychthemeral variation in NH 3 -N in the rumen fluid of dairy cows. Nutrient intake, milk production, and milk composition were affected by the treatments. The total mixed ration containing elephant grass silage combined with rumen undegradable protein (RUP) provided balanced amounts of carbon and nitrogen in the rumen. This effect may explain the 18% increase in milk yield compared with the other treatments. The diurnal pattern of ruminal NH 3 -N was interpreted with a sinusoid model. In general, cows fed elephant grass silage exhibited higher concentrations of blood plasma and milk urea-N than animals fed sugarcane. The cows that consumed elephant grass silage with rumen degradable protein concentrate showed a higher milk urea-N compared with animals that consumed elephant grass silage with the RUP concentrate. The use of diets based on corn silage leads to a better use of nitrogen compounds because these diets resulted in lower levels of urea-N in the plasma, urine, and milk at the same level of milk production compared with diets containing elephant grass silage or chopped sugarcane as roughages. In sugarcane-based diets, even greater nitrogen losses in the urine are observed, despite the presence of readily fermentable carbohydrates in the diet.
“…The use of the CNCPS model to evaluate diets is useful to estimate the nutritive value of different forage resources and other tropical foragebased diets (Cabral et al, 2000;Vieira et al, 2000a,b,c). The dietary synchronization is important for microbial growth and, depending on the availability of non-fibrous carbohydrates, the microbial biomass uses degradable nitrogen more efficiently Malafaia et al, 1998;1999;Vieira et al, 2000c;Favoreto et al, 2008;Fernandes et al, 2014). Because of the nutritional imbalances of sugarcane, e.g., high soluble sugars and low protein content, it should be used with caution to prevent excess nutrient losses (Fernandes et al, 2001).…”
-Ten Holstein-Zebu crossbred cows distributed into two simultaneous Latin squares (5 × 5) as a 2 × 2 factorial arrangement formed by chopped sugarcane or elephant grass silage, both with high or low protein degradability supplements and a corn silage as a control treatment, were compared using orthogonal contrasts. The studied variables were the performance, plasma concentrations of urea-N, glucose, and creatinine, urine-N and milk urea-N, and the nychthemeral variation in NH 3 -N in the rumen fluid of dairy cows. Nutrient intake, milk production, and milk composition were affected by the treatments. The total mixed ration containing elephant grass silage combined with rumen undegradable protein (RUP) provided balanced amounts of carbon and nitrogen in the rumen. This effect may explain the 18% increase in milk yield compared with the other treatments. The diurnal pattern of ruminal NH 3 -N was interpreted with a sinusoid model. In general, cows fed elephant grass silage exhibited higher concentrations of blood plasma and milk urea-N than animals fed sugarcane. The cows that consumed elephant grass silage with rumen degradable protein concentrate showed a higher milk urea-N compared with animals that consumed elephant grass silage with the RUP concentrate. The use of diets based on corn silage leads to a better use of nitrogen compounds because these diets resulted in lower levels of urea-N in the plasma, urine, and milk at the same level of milk production compared with diets containing elephant grass silage or chopped sugarcane as roughages. In sugarcane-based diets, even greater nitrogen losses in the urine are observed, despite the presence of readily fermentable carbohydrates in the diet.
“…Favoreto et al (2008) observed levels of 20.37 g/100 g in star grass (Cynodon nlemfuensis). Vieira et al (2000) highlighted the importance of determining this fraction, as it is considered to be unavailable in the rumen and the intestines.…”
Section: Resultsmentioning
confidence: 92%
“…Fractions A' (simple sugars) and B 1 ' (non-fibrous complex carbohydrates) were estimated by in vitro gravimetric and gas production techniques. A gravimetric profile of degradation of neutral detergent fiber corrected for ash and protein (NDFap) was obtained after incubation of samples (Favoreto et al, 2008).…”
Section: Revista Brasileira De Zootecniamentioning
confidence: 99%
“…Protein fractions were determined as follows: fraction A (non-protein nitrogen) as the difference between total N and N insoluble in trichloroacetic acid; fraction C as the acid detergent insoluble protein (ADICP) that is indigestible in the gastrointestinal tract of the animal; fraction B 2 (protein with a slow degradation rate) as the difference between neutral detergent insoluble protein (NDICP) and ADICP according to Sniffen et al (1992); and fraction B 1 (protein with a faster degradation rate than fraction B 2 ) by the difference, according to the equation 100 − (A + B 2 + C) (Favoreto et al, 2008).…”
Section: Revista Brasileira De Zootecniamentioning
confidence: 99%
“…Recently, mathematical models for diet formulation using non-linear optimization techniques have been suggested by several authors (Souza, 2006;Tedeschi et al, 2008;Jardim et al, 2013). These models allow for simultaneous diet formulation and evaluation to meet animal protein, energy, and fiber requirements, subject to the constraint of maximum fiber intake capacity (Favoreto et al, 2008;Jardim et al, 2013). However, these models need to be repeatedly evaluated and updated to enhance predictive and optimization powers.…”
-A nutritional analysis of Tanzania grass (Megathyrsus maximus Jacquin cv. Tanzânia was conducted. Pasture was managed in a rotational grazing system with a 30-day resting period, three days of paddock occupation and two grazing cycles. Ten Holstein × Zebu crossbred cows were kept within a 2-ha area divided into 11 paddocks ha -1 . Cows were fed 2 kg of corn meal daily and performance was evaluated by weighing the animals every 14 days and by recording milk production twice a day. Nutritional composition of the Tanzania grass was determined from forage (extrusa) samples collected by esophageal fistulae from two animals. The nutritive value of Tanzania grass was estimated according to a modification of the CNCPS evaluation model. Tanzania grass supplemented with 2 kg of corn meal supplied 33.2% more net energy for lactation than required by the animals to produce 13.7 kg of milk day -1 . Nevertheless, the amount of metabolizable protein met the daily protein requirement of the animals. Although the model used in the study requires adjustments, Tanzania grass has the potential to produce milk in a rotational grazing system.
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