Metabolizable Protein: 1. Predicting Equations to Estimate Microbial Crude Protein Synthesis in Small Ruminants

Microbial crude protein (MCP) produced in rumen could be estimated by a variety of protocols of experimental sampling and analysis. However, a model to estimate this value is necessary when protein requirements are calculated for small ruminants. This model could be useful to calculate rumen degradable protein (RDP) requirements from metabolizable protein (MP). Then, our objective was to investigate if there is a difference in MCP efficiency between sheep and goats, and to fit equations to predict ruminal MCP production from dietary energy intake. The database consisted of 19 studies with goats (n = 176) and sheep (n = 316), and the variables MCP synthesis (g/day), total digestible nutrients (TDN), and organic matter (OM) intakes (g/day), and OM digestibility (g/kg DM) were registered for both species. The database was used for two different purposes, where 70% of the values were sorted to fit equations, and 30% for validation. A meta-analytical procedure was carried out using the MIXED procedure of SAS, specie was considered as the fixed dummy effect, and the intercept and slope nested in the study were considered random effects. No effect of specie was observed for the estimation of MCP from TDN, digestible Organic Matter (dOM), or metabolizable energy (ME) intakes (P > 0.05), considering an equation with or without an intercept. Therefore, single models including both species at the same fitting were validated. The following equations MCP (g/day) = 12.7311 + 59.2956 × TDN intake (AIC = 3,004.6); MCP (g/day) = 15.7764 + 62.2612 × dOM intake (AIC = 2,755.1); and MCP (g/day) = 12.7311 + 15.3000 × ME intake (AIC = 3,007.3) presented lower values for the mean square error of prediction (MSEP) and its decomposition, and similar values for the concordance correlation coefficient (CCC) and for the residual mean square error (RMSE) when compared with equations fitted without an intercept. The intercept and slope pooled test was significant for equations without an intercept (P < 0.05), indicating that observed and predicted data differed. In contrast, predicted and observed data for complete equations were similar (P > 0.05)

Chemical composition and fermentation characteristic in cassava (“Manihot” sp.) silages with different proportion of grape wine residue Composição química e características fermentativas de silagens de maniçoba ("Manihot" sp.) com percentuais de co-produto de vitivinícolas desidratado

The effects of inclusion of grapewines residue (GR) levels (0, 8, 16 and 24%) on the chemical composition and fermentation characteristics of cassava silages were studied. PVC silos tubes were used and opened after 60 days of fermentation for chemical analyses. The design used was the completely randomized with 8 repetitions. Data were submitted to variance and regression analysis. GR inclusion in the cassava silages increased dry matter, mineral matter, ether extract and lignin. However, GR did not influence levels of neutral and acid detergent fibers, and it promoted reduction of insoluble nitrogen in neutral detergent and total carbohydrates. Dry matter in vitro digestibility increased with the inclusion of GR in the cassava silages, ranging from 44.89 to 46.05%. Silages presented good fermentative characteristics, in function of the low levels of ammonia nitrogen in percentage of total nitrogen and pH values.Foi estudado o efeito da inclusão de co-produto de vitivinícolas (CPV) em proporções (0, 8, 16 e 24%) sobre a composição química e características fermentativas de silagens de maniçoba (Manihot ssp.). Foram utilizados, para ensilagem, silos de tubo de PVC, abertos após 60 dias de fermentação. O delineamento utilizado foi o inteiramente casualizado com 8 repetições. Constatou-se que a inclusão de CPV promoveu aumento no conteúdo de matéria seca, matéria mineral, extrato etéreo e lignina, sem influenciar os teores das fibras em detergente neutro e ácido. Promoveu redução nos teores de nitrogênio insolúvel em detergente ácido e de carboidratos totais, além de promover aumentos na digestibilidade in vitro da matéria seca com maiores valores na inclusão de CPV intermediária. As silagens em estudo apresentaram características fermentativas adequadas, em função dos níveis de nitrogênio amoniacal e de pH

Creatinine as a metabolic marker to estimate urinary volume in growing goats

The objectives of this study were to: (1) quantify the relationship between fasting body weight (FBW, kg) and urinary creatinine excretion (UCE, mg/d) in Boer goats; (2) evaluate the urinary volume estimates obtained from creatinine concentrations in the spot samples collected at different time points; (3) compare them with the 24-h observed urine volume. Thirty growing Boer goats (18 ± 2.2 kg initial BW) were distributed in a complete randomized design. Each collection period fell on 2 consecutive days and collector funnels were used. Spot samples were collected at 0, 4, and 8 h after morning feedings. These procedures were repeated in three runs 25 days apart to obtain different FBWs. All the samples were analyzed to quantify creatinine concentrations. The relationship between UCE and FBW was established by the following equations: UCE = 17.39 x FBW, r^2 = 0.96, P 0.05). Thus both linear and allometric relationships can be used to predict UCE. The spot samples obtained at 4 h after feeding could be used to estimate urinary volume (P < 0.05) instead of at 0 or 8 h. We conclude that UCE can be a metabolic marker to the estimate urinary volume of goats when calculated according to FBW with linear or allometric mathematical relationships