Energy and protein requirements during the growing phase of indigenous goats

Objetivou-se com o presente estudo, investigar as exigências de proteína e energia para mantença e ganho de caprinos sem padrão racial definido. Para tal, foram utilizados dados individuais de caprinos de 2 estudos. Os caprinos foram desmamados com 79 ± 4,4 dias de idade. Ingestão de leite e dieta sólida foi tomada diariamente. Utilizou-se 32 cabritos de 4,90 ± 0,302 kg de peso corporal (PC) inicial. Nesse momento, 10 cabritos foram abatidos para estimativa de composição corporal inicial. Os cabritos remanescentes foram distribuídos aleatoriamente em dois níveis de ingestão: ad libitum ou com ingestão de 20% acima do nível de mantença. A produção de calor (C) foi calculada pela diferença da energia metabolizável (IEM) ingerida e energia retida. A energia líquida para manteça (ELm) foi estimada pelo parâmetro β00 da relação entre C e IEM [C = β0 × exp (β1 × IEM)]. A exigência de energia metabolizável para mantença (EMm) foi calculada quando C = IEM. A eficiência de utilização de energia para mantença (km) foi calculada por ELm/EMm. Utilizou-se o intercepto da regressão linear da proteína retida pela proteína bruta (PB) ingerida para estimativa da proteína líquida exigida para mantença (PLm). A exigência líquida de proteína e energia para ganho (ELg e PLg, respectivamente) foram obtidas utilizando-se 26 cabritos alimentados à vontade e abatidos aos 5,40 ± 0,484 kg PC (n = 10), 15,8 ± 0,655 kg PC (n = 10) e 26,3 ± 1,27 kg PC (n = 6). A ELg e PLg foram estimadas pela derivada parcial da equação alométrica (i.e., gerada para estimar o conteúdo de energia e proteína no corpo vazio). A simulação de Monte Carlo foi empregada para simular a variação das estimativas da EMm, ELg e PLg. Os resultados do presente estudo indicam que a energia líquida necessária para mantença é 310,1 ± 36,7 kJ kg-0.75 PC vazio, e que a EMm)é igual a 499,1 ± 52,1 kJ kg-0.75 PC vazio, com km) de 0,62. Este estudo indicou que 1,246 g PB kg-0.75 PCVé exigido por cabritos sem padrão racial definido entre 5 a 25 kg PC para atender a PLm). Adicionalmente, cabritos sem padrão racial definido entre 5 a 25 kg PC requerem entre 186,6 ± 2,97 a 214,3 ± 12,9 g de proteína, e 5,39 ± 1,49 a 9,74 ± 2,57 MJ de energia para ganhar um quilo de PC vazio. O presente estudo pode contribuir para futuros ajustes nas atuais recomendações de energia e proteína para cabritos sem padrão racial definido pelos sistemas de alimentação

Energy and protein requirements during the growing phase of indigenous goats

The objective of this study was to investigate both energy and protein requirements for the maintenance and growth of indigenous goats, based on data from two separate studies. Goats were weaned at 79 ± 4.4 days of age, with milk and solid diet intake recorded daily. To determine energy maintenance requirements, 32 kids of 4.90 ± 0.302 kg initial body weight (BW) were used. Ten kids were slaughtered at 5.40 ± 0.484 kg BW to estimate initial body composition, with the remaining kids randomly assigned to one of two DM intake levels: ad libitum and restricted-fed (1.2-times maintenance level). Heat production (HP) was calculated as the difference between ingested metabolizable energy (MEI) and retained energy. Net energy requirement for maintenance (NEm) was estimated as the ?0 parameter of the relationship between HP and MEI [HP = ?0 × exp (?1 × MEI)]. Metabolizable energy required for maintenance (MEm) was calculated iteratively, as HP = MEI. Efficiency of energy utilization for maintenance (km) was calculated as NEm/MEm. The intercept of the linear regression of retained CP on CP intake was used to calculate net protein requirements for maintenance (NPm). Net energy and protein requirement for gain (NEg and NPg, respectively) were obtained using 26 kids fed ad libitum and randomly slaughtered at 5.40 ± 0.484 kg BW (n = 10), 15.8 ± 0.655 kg BW (n = 10), and 26.3 ± 1.27 kg BW (n = 6). The first derivative of the allometric equation (used to calculate energy and protein contents in empty body weight (EBW)) with respect to EBW yielded estimates of NEg and NPg. A Monte Carlo-based method was employed to simulate variation in MEm, NEg, and NPg. This study indicated that the net energy required for maintenance is 310.1 ± 36.7 kJ kg-0.75 EBW, with MEm estimated at 499.1 ± 52.1 kJ kg-0.75 EBW and km equal to 0.62. This study indicated that 1.246 g CP kg-0.75 EBW is required by indigenous kids weighing from 5 to 25 kg BW to meet their NPm. In addition, indigenous goats require between 186.6 ± 2.97 and 214.3 ± 12.9 g CP, and between 5.39 ± 1.49 and 9.74 ± 2.57 MJ to gain one kilogram of EBW. This study may contribute to future adjustments in feeding system energy and protein recommendations for indigenous kids

Selectivity and feeding behavior of Saanen goats subjected to three nutritional levels

This study was conducted to investigate the effect of selective feeding habits on the quality of the ingested diet and the effect of feed restriction on the selectivity and behavior of goats in feedlots. Differences were found only in the amount of feed given to the animals, with a difference in the amount of feed rejected as a function of the nutritional level. Higher levels of orts were measured for those animals that received the ad libitum diet. For the composition of orts, differences were measured only in the ether extract fraction. Animals fed the ad libitum diet increased their intake of ether extract and energy, crude fiber, neutral detergent fiber, and acid detergent fiber. Thus, they had a preference for consuming the fibrous and energetic portions of the diet to the detriment of the mineral matter. The granulometry influenced the leftovers for the male and female treatments only in the diet that contained the 2.00- and 0.063-mm sized particles, with larger leftovers for the females. There were statistical differences as a function of feeding level for time spent in rumination, with stereotypical behavior, and in time spent standing up or lying down. As a function of sex, the differences were the same variables, including the time spent with agonistic behavior. Animals that received the ad libitum diet had a greater gain and final weight, whereas the animals that received the 60% restricted diet had the lowest performance, as did the females. Feed restriction changed the natural feeding behavior of goats, with smaller feed particles preferred. The feed restriction and sex also influenced the time spent on nonproductive activities, and the animals became more restless, with females having a higher social behavior than males

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)