Estimation of endogenous contribution and urinary excretion of purine derivatives from the total digestible nutrient intake in Nellore heifers

The objectives of this experiment were to estimate the endogenous excretion of purine derivatives (PD), the intake and digestibility of nutrients, the urinary excretion of PD from the intake of total digestible nutrients (TDN) and digestible organic matter (DOM) in Nellore heifers. Eight heifers, 267±17 kg body weight (BW), were assigned to two 4 × 4 latin squares. The planned treatments were four dry matter intake (DMI) levels: 10, 14, 18 and 22 g/kg BW. The diet contained 70% corn silage and 30% concentrate. The endogenous losses were obtained by regression between excretion of PD (mmol/BW0.75) and DMI (g/BW0.75). When PD excretion (mmol/d) was related to the intake of DOM and TDN (kg/d), the following equations were obtained: ŶPD= 32.98 + 21.94*DOM and ŶPD= 32.47 + 20.40*TDN, respectively. The excretion of PD (mmol/d) was a function of DMI (kg/d): ŶPD = 0.605 + 0.014 x (r2 = 0.46), and 0.60 mmol/BW0.75 was the endogenous fraction of PD. The endogenous losses of PD and nitrogen compounds obtained when the animals were fasted for 5 d, with free access to water, were 0.332 mmol/BW0.75 and 0.384 gN/BW0.75, respectively. The net protein requirement for maintenance was estimated at 2.4 g/BW0.75. Creatinine excretion is not affected by feed restriction

Use of infused 15N15N-urea by via jugular vein in Nellore cattle

Objetivou-se avaliar o efeito de classe sexual e de níveis dietéticos de proteína bruta sobre o consumo e a digestibilidade total dos constituintes das dietas, o balanço de compostos nitrogenados, as quantidades de ureia filtrada e reabsorvida nos rins e excretada na urina em bovinos Nelore. Avaliou-se, também, a produção de proteína microbiana e a reciclagem qualitativa da ureia. Foram utilizados oito animais da raça Nelore, sendo quatro novilhos inteiros e quatro novilhas, com peso corporal (PC) médio inicial de 333,5±24,4 e 292±12,9 kg, respectivamente, fistulados no rúmen, distribuídos em dois Quadrados Latino (QL) 4 x 4. As dietas, contendo 50% de silagem de milho e 50% de concentrado na base da matéria seca (MS), foram fornecidas duas vezes ao dia, ad libitum e foram constituídas de quatro níveis de proteína bruta (PB): 9,0; 11,0; 13,0 e 15,0 % na base da MS, correspondendo a 65,91; 68,32; 70,00 e 71,35% de PDR. Cada período experimental teve duração de 14 dias, com sete dias de adaptação e sete dias para procedimentos e coletas de amostras de alimentos, sobras, sangue, digesta e fluido ruminais, urina e fezes. Para avaliar a reciclagem de ureia, utilizou-se infusão intravenosa de 15N15N-ureia, na dose diária de 220 mg de 15N-ureia, por 72 horas. As variáveis dependentes foram avaliadas de acordo com o delineamento em QL 4 x 4 e a comparação entre níveis dietéticos de PB foi realizada através da decomposição ortogonal da soma dos quadrados associada às fontes de efeito linear, quadrática e cúbica. Essas análises foram conduzidas utilizando o procedimento MIXED do SAS, assumindo-se variâncias homogêneas entre as dietas. Não houve efeito de interação (P > 0,05) entre as classes sexuais e níveis dietéticos de PB para qualquer das variáveis avaliadas neste estudo. A classe sexual e os níveis dietéticos de PB não afetaram (P > 0,05) os consumos de MS, matéria orgânica (MO), MO digerida (MOD), extrato etéreo (EE) e carboidratos não fibrosos (CNF), em kg/dia, nem os consumos de MS e da fibra insolúvel em detergente neutro corrigida para cinzas e proteína (FDNcp), em função do PC. Não houve efeito de classe sexual (P > 0,05), mas houve efeito linear de níveis dietéticos de PB (P 0,05), mas foram afetadas linearmente pelos níveis dietéticos de PB (P 0,05) para resultar em diferenças no N retido expresso em função do N ingerido sendo em média 26,05 % do N ingerido. Não houve efeito de classe sexual (P > 0,05) ou de níveis dietéticos de PB (P > 0,05) sobre a excreção urinária de creatinina cuja média foi de 23,2 mg/kg PC nem sobre a taxa de filtração glomerular com média de 1,84 mL/min/kg PC. Não houve efeito da classe sexual (P > 0,05), contudo, houve efeito linear crescente de níveis dietéticos de PB (P 0,05) pelas classes sexuais ou pelos níveis dietéticos de PB. Em relação à eficiência microbiana houve efeito de classe sexual (P 0,05) quando expressa em função do consumo de NDT. Ajustando-se a produção de PBmic (g/dia) em função dos consumos de PB (kg/dia) e de NDT (kg/dia) obteve-se a seguinte equação: PBmic = 179,98 + 37,6030 x NDT + 0,2577 x PB. A excreção fecal de N pode ser estimada por: N fecal = -46,807 + 3,0662 x NDT (kg/dia) + 0,1579 x Ning (g/dia) + 0,1697 x PC (kg). A excreção urinária de N (g/dia) pode ser predita pela equação: N urinário = -1,8803 – 7,6528 x NDT + 0,5401 x Ning. A regressão Ŷ = 36,51 + 0,405X foi ajustada considerando-se a produção de Nmic (Ŷ, g/dia) e a ingestão de N (X, g/dia). Não houve efeito de classe sexual (P > 0,05) sobre a concentração de NH3 ruminal, os teores de 15N-NH3 ruminal e os teores e excreção diária de 15N fecal. Houve efeito linear crescente de níveis dietéticos de PB (P 0,05) sobre a excreção diária de 15 N fecal sendo em média 17,75 mg/dia. As regressões Ŷ = 23,6183e0,0104X e Ŷ = 0,2416e-0,0145X foram ajustadas a partir da concentração ruminal de amônia (Ŷ, mg/dL) e os teores de 15 N-NH3 (Ŷ, %) em função da ingestão de N (X, g/dia), respectivamente. Os teores de 15 N fecal (Ŷ, %) foram avaliados em função da ingestão de N (X, g/dia), obtendo-se a seguinte regressão: Ŷ = 0,08878 – 0,00034X. Não houve interação tripla (P > 0,05) entre as classes sexuais, os níveis dietéticos de PB e as fases de bactérias, BAL e BAP sobre os teores de N-total microbiano nem sobre os teores de 15 N nas bactérias ruminais, nem diferença (P > 0,05) entre as fases BAL e BAP para as variáveis quantificadas. As interações duplas entre as variáveis independentes não foram significativas (P > 0,05), assim como os efeitos individuais (P > 0,05), com exceção dos níveis dietéticos de PB sobre os teores de N-total e de 15 N nas bactérias ruminais. Houve efeito cúbico (P 0,05) sobre os percentuais de 15 N infundido no plasma que foi recuperado nas fezes ou nas bactérias. Também não houve efeito de níveis dietéticos de PB (P > 0,05) sobre os percentuais de 15 N infundido no plasma que foi recuperado nas fezes, sendo em média 8,06%. Entretanto, houve efeito linear decrescente dos níveis dietéticos de PB (P 0.05) between animal categories and levels of CP dietary to any variables evaluated in this study. There was no effect (P > 0.05) from animal categories or levels of CP dietary on intake of DM, organic matter (OM), digested OM (dOM), ether extract (EE) and non-fibrous carbohydrates (NFC), in kg/day, neither on DMI and neutral detergent fiber corrected for ash and nitrogenous compounds (NDFap) in BW function. There was no effect (P > 0.05) from animal categories, but there was increased linear effect (P 0.05) on intake, urinary excretion of total-N, urea and N-urea, N retained, relationship NU:TN and plasmatic concentration of N-urea (PUN) from animal categories, but those variables increased linearly (P 0.05) to change N retained related to N intake that was 26.05 % g of N retained/g of N intake. There was no effect from animal categories (P > 0.05) neither from dietary CP (P > 0.05) on creatinine urinary excretion whose average was 23.2 mg/kg BW and on glomerular filtration rate with 1.84 mL/min/kg PC as average. There was no effect (P > 0.05) from categories animal, however the quantities of urea filtered, reabsorved and fraccional excretion increased linearly as dietary CP increased. Considering the urea urinary excretion (Ŷ) in function of N intake (X), in g/day, the equation Ŷ = 0.5606X was obtained. Regarding to PUN (Ŷ, mg/dL) and N intake (X, g/dia), the equation Ŷ = 0.1234X was obtained, while the equation Ŷ = 3.9293X was obtained regarding to urea urinary excretion (Ŷ, g/dia) and PUN (X, mg/dL). The relationship between urea fractional excretion (Ŷ) and N intake (X, g/day) was described on equation: Ŷ = 0.3684(1-e-0.0105X). There was increased linear effect (P 0.05) from animal categories neither from dietary CP. Regard to microbial efficiency, there was linear effect (P 0.05) when it was expressed in TDN intake function. CPmic (g/day) was adjusted using CP and TDN intake (kg/day) according to the follow equation: CPmic = 179.98 + 37.6030 x TDN + 0.2577 x CP. While fecal N excretion was estimated by: N-fecal = -46.807 + 3.0662 x TDN (kg/day) + 0.1579 x Nintake (g/day) + 0.1697 x BW (kg). N urinary excretion can be predicted from equation: N urinary = -1.8803 – 7.6528 x TDN + 0.5401 x Nintake. The equation Ŷ = 36.51 + 0.405X was adjusted regarding to Nmic production (Ŷ, g/day) and N intake (X, g/day). There was no effect (P > 0.05) from animal categories on ruminal NH3 concentration, the proportion of ruminal 15N-NH3 and the proportion and daily excretion of fecal 15N. The ruminal NH3 concentration, the proportion of 15 N-NH3 ruminal and the proportion of fecal 15 N increased linearly (P 0.05) from dietary CP on 15 N fecal daily excretion whose average was 17.75 mg/day. The equations Ŷ = 23.6183e0.0104X and Ŷ = 0.2416e-0.0145X were adjusted from ruminal NH3 concentration (Ŷ, mg/dL) and 15N-NH3 proportion (Ŷ, %) as function of N intake (X, g/day), respectively. The proportion of fecal 15 N (Ŷ, %) was evaluated as a function of N intake (X, g/day), according to the follow equation: Ŷ = 0.08878 – 0.00034X. There was no triple interaction (P > 0.05) among animal categories, levels of dietary CP and bacterial phasis liquid-associated bacteria (LAB) and particule-associated bacteria (PAB), on the proportion of microbial total-N neither on the proportion of 15N in the ruminal bacteria. There was also no difference (P > 0.05) between LAB and PAB phases to the variables measured. Double interaction between the independent variables was not significant (P > 0.05), as well as individual effects (P > 0.05), except from dietary CP level on the proportion os total-N and 15N in the ruminal bacteria. There was cubic effect (P 0.05) from animal categories on the proportion of 15 N infused in the plasma recovered in feces or in bacteria. There was also no effect (P > 0.05) from dietary CP on the proportion of 15N infused in the plasma and recovered in feces, average of 8.06%. However, there was decreased linear effect (P < 0.05) from dietary CP on the proportion recovered in bacterias. From this it can be conclude that the microbial protein production is not affected by animal categories, but increases linearly as CP and TDN intake increase. LAB and PAB have the same proportion of total-N and recovery of N-urea infused. Ruminal 15 N-NH3 concentration and bacterial 15N increase as dietary CP decreases. There is higher recovery of N-urea infused in the microbial protein production in diets with low CP level.Coordenação de Aperfeiçoamento de Pessoal de Nível Superio

Endogenous fraction and urinary recovery of purine derivatives in Nellore and Holstein heifers

Objetivou-se quantificar a contribuição endógena para a excreção urinária de derivados de purinas (DP) e estabelecer a proporção de purinas no abomaso recuperadas na urina, bem como pesquisar possíveis diferenças entre as raças Nelore e Holandesa através da infusão abomasal de RNA (Torula yeast) como fonte de purinas. Utilizaram-se oito novilhas fistuladas no rúmen e no abomaso, sendo quatro Nelore (Ne) e quatro Holandesas (Hol), com pesos corporais (PC) de 270±7,76 e 225±7,16 kg, respectivamente, alimentadas com dieta a base de silagem de milho e concentrado na proporção de 60:40. Os animais foram distribuídos nos tratamentos segundo o delineamento em dois quadrados latinos (QL) 4 x 4, balanceados para efeito residual, sendo um QL para cada grupo genético. Os tratamentos experimentais foram constituídos de infusões no abomaso de RNA nas doses de 0; 33; 66 e 100 mmol/dia. Após sete dias de ajustamento ao nível de ingestão da dieta a 13 g MS/kg do PC, cada período experimental com duração de 14 dias decorreu da seguinte maneira: 1° ao 5° dia, adaptação; 6° ao 9° dia, coleta de digesta de abomaso e de fezes; 9º ao 13º, infusões de RNA no abomaso; 10º ao 13º dia, coleta total de urina e de fezes; 14º dia, coleta de digesta de rúmen para isolamento de bactérias. Do 1° ao 9° dia de cada período experimental, cada animal recebeu 15 g de óxido crômico (Cr2O3), como indicador externo, em única dose, sendo administrado via fístula ruminal sempre às 10h00, para se obter o fluxo de MS no abomaso. Para a coleta total de urina foram utilizadas sondas do tipo Folley n° 22, duas vias, com balão de 30 mL. O fluxo de bases purinas em cada período no abomaso foi obtido somando-se o valor de cada animal antes da infusão com a respectiva quantidade infundida, enquanto o fluxo de MS abomasal foi obtido pela relação entre a quantidade do indicador externo oferecido e a sua concentração nas amostras de digesta. A quantidade de compostos nitrogenados microbianos no abomaso foi calculada através do fluxo de N-RNA presente no abomaso dividido pela relação N-RNA:N-total nas bactérias isoladas do rúmen. As perdas endógenas e a recuperação de bases purinas como derivados de purinas foram estimadas por regressão entre a excreção diária dos derivados de purinas na urina (Y) e as bases purinas no abomaso (X), expressas em mmol/kg0,75, representadas, respectivamente, pelo intercepto e pelo coeficiente da regressão. As análises foram conduzidas utilizando-se o PROC MIXED do SAS pressupondo-se variâncias homogêneas entre tratamentos, sendo os graus de liberdade estimados pelo método de Kenward-Roger. Os procedimentos estatísticos foram conduzidos considerando-se 0,05 como nível crítico de probabilidade para o erro tipo I. Os consumos médios de MS, matéria orgânica (MO), proteína bruta (PB), extrato etéreo (EE), fibra em detergente neutro corrigida para cinzas e proteína (FDNcp), carboidratos não fibrosos (CNF) e de nutrientes digestíveis totais (NDT), expressos em kg/dia e, os de MS e FDNcp expressos em g MS/kg PC foram 3,40; 3,26; 0,36; 0,08; 1,14; 1,70; 2,53 kg/dia; 13,72 e 4,63 g MS/kg PC, respectivamente. Os consumos não diferiram (P>0,05) para as quatro doses de infusão de RNA no abomaso e entre os grupos genéticos, quando expressos em relação ao PC. As digestibilidades aparentes totais de MS, MO, EE, FDNcp e CNF e os teores NDT não foram influenciados (P>0,05) pelas doses de infusão e pelos grupos genéticos, sendo em média de 728,5; 744,9; 847,1; 601,0; 859,4 e 743,6 g/kg MS , respectivamente. As digestibilidades ruminais médias para MS, MO, PB, EE, FDNcp e CNF foram de 624,0; 664,5; 211,1; 134,4; 903,0 e 629,6 g/kg MS, respectivamente, e não diferiram (P>0,05) entre as doses de infusão e os grupos genéticos. Relacionando a excreção de derivados de purinas na urina (&#374;) e as quantidades de bases purinas no abomaso (X), foram obtidas as seguintes regressões: &#374;= 0,389 + 0,926 X, onde 0,389 representa a fração endógena dos derivados de purinas na urina e 0,926, a recuperação das bases purinas para novilhas Nelore; &#374;= 0,439 + 0,911 X, sendo a fração endógena igual a 0,439 mmol/kg0,75 e a recuperação de bases purinas igual a 0,911 para novilhas Holandesas; &#374; = 0,405±0,148 + 0,923±0,077 × X; sXY = 0,219, onde 0,405 mmol/kg0,75 representa a fração endógena e 0,92 representa as bases purinas recuperadas para os dois grupos genéticos em conjunto. Após ajuste dos modelos de regressão, observou-se que a equação conjunta pode ser utilizada tanto para novilhas Nelore quanto para Holandesas. A excreção urinária média de creatinina foi de 27,23 mg/kg PC, não sendo afetada (P>0,05) pela infusão abomasal de RNA e pelos grupos genéticos. Conclui-se que não há diferenças entre novilhas Nelore e Holandesas para a fração endógena de DP, para a recuperação urinária de purinas e para a excreção de creatinina que são, em média, 0,405 mmol/kg0,75, 0,92 e 27,23 mg/kg PC, respectivamente.This work aimed to quantify the endogenous purine derivatives in urine and establish the proportion of purines raised in abomasum that were recovered in urine of Nellore and Holsteins heifers, using abomasal infusion of RNA (Torula yeast) as source of purine. Eight heifers fistulated in rumen and abomasum were used, being four Nelore (Ne) and four Holsteins (Hol), with body weight (BW) of 270±7,76 and 225±7,16 kg, respectively, fed corn silage and concentrate (60:40). The feed intake was adjusted in 13 g/ kg BW. The heifers were allocated in two 4x4 Latin square design (LS), and each LS was composed by a genetic group and balanced for residual effect. The treatments consisted of increasing abomasum infusions (0, 33, 66, and 100 mmol/d). The experimental periods were constituted of 5 days to adaptation and 9 for sample collection. The sampling of the abomasal digesta and feces collection was made in days 6th to 9th, RNA infusion in days 9th to 13th, the total urine and feces collection in day 10th to 13th and sampling of rumen digesta for bacterial isolation in day 14 th. From 1st to 9th day of each experimental period each animal received 15 g of chromic oxide (Cr2O3), as external marker, in a single dose, via ruminal cannula at 10h00, to obtain the DM flow in abomasum. A 2-way Foley catheter with a 30-mL balloon was used during the total urine collection. The purine bases flow in abomasum was obtained with the sum of the value of each animal before infusion with the respective amount infused. The abomasal flow of DM was obtained from the ratio between the amounts of the Cr2O3 administered and its concentration in the abomasal digesta sample. The amount of microbial nitrogen in the abomasum was calculated using the abomasal N-RNA flow divided by the N-RNA:totalN ratio in the isolated bacteria at the rumen. The endogenous losses and the purine bases recovery as urinary PD were estimated by a linear regression between the daily urinary PD excretion (Y) and the purine bases in the abomasum (X), expressed in mmol/kg0,75, respectively represented by the intercept and by the regression coefficient, respectively. The statistical analyses were performed using PROC MIXED (SAS) assuming homogeneous variances among treatments by Kenward-Roger. The statistical procedures were conducted considering 0,05 as critical level of probability from the type I error. The means of nutrient intake were 3,40 kg/d of DM; 3,26 kg/d of organic matter (OM); 0,36 kg/d of crude protein (CP); 0,08 kg/d of ether extract (EE); 1,14 kg/d of neutral detergent fiber corrected ash and protein (apNDF); 1,70 kg/d of nonfiber carbohydrates (NFC) and 2,53 kg/d of total digestible nutrients (TDN); 13,72 and 4,63 g DM/kg BW of DM and apNDF, respectively. Abomasal infusion of RNA and the genetic groups did not affect the feed intake, when expressed in g/kg of BW and the total apparent digestibility of DM, OM, EE, CP apNDF and NFC (P>0,05) with means of 728,5; 744,9; 847,1; 601,0; 859,4 and 743,6 g/kg DM, respectively. The ruminal digestibility means of DM, OM, CP, EE, NDFap and NFC were 624,0; 664,5; 211,1; 134,4; 903,0 and 629,6 g/kg DM, respectively, and not differ (P>0,05) between the levels of infusion and the genetic groups. In relation to the daily urinary PD excretion (Y) and the purine bases in the abomasum (X), the follow equations were obtained: &#374;= 0,389 + 0,926 X, when 0,389 mmol/kg0,75 represented the endogenous PD excretion and 0,926 was the urinary recovery of the purine bases in Nellore heifers; &#374;= 0,439 + 0,911 X, when 0,439 mmol/kg 0,75 represented the endogenous PD excretion and 0,911 was the urinary recovery of the purine bases in Holsteins heifers; &#374; = 0,405±0,148 + 0,923±0,077 × X; sXY = 0,219, when 0,405mmol/kg0,75 represented the endogenous PD excretion and 0,923 was the urinary recovery of the purine bases in both genetic groups. After adjustment of regression models, we observed that the latter equation can be used both for Nellore and for Holstein heifers. The urinary excretion of creatinine was 27,23 mg/kg BW and was not affected (P>0,05) by abomasal infusion of RNA and by genetic groups. In conclusion, there is no difference between Nellore and Holstein heifers for endogenous fraction of PD, for urinary recovery of purine bases and for the urinary excretion of creatinine. The mean values were 0,405, mmol/kg0,75 0,92 and 27,23 mg/kg BW, respectively

Relationship of carbohydrates and lignin molecular structure spectral profiles to nutrient profile in newly developed oats cultivars and barley grain

The objectives of this study were to quantify the chemical profile and the magnitude of differences in the oat and barley grain varieties developed by Crop Development Centre (CDC) in terms of Cornell Net Carbohydrate Protein System (CNCPS) carbohydrate sub-fractions: CA4 (sugars), CB1 (starch), CB2 (soluble fibre), CB3 (available neutral detergent fibre – NDF), and CC (unavailable carbohydrate); to estimate the energy values; to detect the lignin and carbohydrate (CHO) molecular structure profiles in CDC Nasser and CDC Seabiscuit oat and CDC Meredith barley grains by using Fourier transform infrared attenuated total reflectance (FTIR-ATR); to develop a model to predict nutrient supply based on CHO molecular profile. Results showed that NDF, ADF and CHO were greater (P 0.05) for oat and barley grains as well as non-structural CHO. However, cellulosic compounds peak area and height were greater (P < 0.05) in oat than barley grains. Multiple regressions were determined to predict nutrient supply by using lignin and CHO molecular profiles. It was concluded that although there were some differences between oat and barley grains, CDC Nasser and CDC Meredith presented similarities related to chemical and molecular profiles, indicating that CDC Meredith barley could be replaced for CDC Nasser as ruminant feed. The FTIR was able to identify functional groups related to CHO molecular spectral in oat and barley grains and FTIR-ATR results could be used to predict nutrient supply in ruminant livestock systems

Performance of primary health care according to PCATool instrument: a systematic review

This study aims to analyze studies that evaluated the performance of Primary Health Care (PHC) services by using the Primary Care Assessment Tool (PCATool) under a worldwide user perspective. This is a systematic review that implemented the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) model, from the following databases: Lilacs, Medline, SciELO, PubMed and the Coordination for the Improvement of Higher Education Personnel (CAPES) Journals Website, using descriptors Primary Care Assessment Tool and PCATool. Considering inclusion and exclusion criteria, we analyzed 22 research papers published from 2007 to 2015. The best-evaluated attributes were cultural competence, first contact use and longitudinality. On the other hand, the worst evaluated were first contact accessibility, family orientation, community orientation and comprehensiveness. Most of the health services evaluated were from Brazil, applied to “traditional” primary care clinic (UBS) and the Health Family Strategy (FHS). Services evaluated should strengthen structure and process components to achieve a better performance in PHC

Evaluation of Barley Silage with Varying Ruminal In Vitro Fiber Digestibility on Lactation Performance and Chewing Activity of Lactating Dairy Cows in Comparison with Corn Silage

There is limited knowledge on the effect of barley silage with different ruminal in vitro NDF digestibility (ivNDFD) on dairy cow performance and chewing activity. The objective of this study was to assess the effects of barley silage varieties selected for varying rates of ivNDFD on lactation performance and chewing activity of high-yield dairy cows in comparison with a new corn silage hybrid. A 4Ă 4 Latin square design was applied in this study with four mid-lactating multiparous Holstein cows. The cows were fed diets containing 49% barley-based concentrate and 51% forage (DM basis). The results show that cows fed corn silage produced more milk (PThe accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

Comparing sheep and cattle to quantify internal markers in tropical feeds using in situ ruminal incubation

The main focus of this work was to verify the hypothesis that there are differences between cattle and sheep to obtain internal markers in tropical forages using in situ ruminal incubation. A presupposition that the indigestible fraction is exclusively inherent to feed was considered, and its ruminal incubation in different animal species should not change the estimate of this fraction; but should change the minimum time required to obtain this value, or the critical-time (Tc). The Tc to obtain indigestible fractions were compared between species for neutral detergent fiber (INDF) and acid detergent fiber (IADF) in feeds and feces. A total of 16 samples were divided into two groups of forages; one group of concentrates and another one of feces. These samples were placed inside bags and incubated in the rumens of 4 sheep and 4 cattle, at following time-points: 0, 12, 24, 48, 96, 144, 192, 240, 288, and 336 h, using two 4 × 4 Latin squares. There was no effect on the species with regard to the degradation rate (kd) of both the aNDF and ADF in alfalfa hay (P = 0.36; P = 0.14). All other forages, which were tropical types, were affected by animal specie (P < 0.05). Cattle was associated with lesser Tc when compared to sheep, both for INDF and IADF. All concentrate feeds were affected by the species (P < 0.05), with sheep providing greater Tc for both undegradable fractions. Feces from cattle and sheep fed with low concentrate required higher Tc when incubated in sheep (P < 0.05), while feces from cattle and sheep fed with low concentrate required the same Tc to obtain IADF in cattle or sheep (P = 0.19; P = 0.11). Sheep is not a practical recommendation to obtain internal markers based on in situ trials, due to the high incubation time length to obtain the non-degraded fraction of feeds and feces. Internal markers IDNF and IADF from sheep trials can be obtained from 216 h of in situ incubation in cattle

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