André Soares de Oliveira

Meta-análise do impacto da fibra em detergente neutro sobre o consumo, a digestibilidade e o desempenho de vacas leiteiras em lactação

ABSTRACT - It was evaluated the effects of the chemical characteristics and in vivo NDF digestibility (IVNDFD) onintake, digestibility and performance of dairy cows in fedlot by using a meta-analysis procedure from 285 observations of sixexperiments. It was used data of animals fed diets based on corn silage (n = 213) or sugarcane (n = 72). Despite the lower NDFcontent of sugarcane (45.27% of DM) compared to corn silage (54.48%), it was noted lower intakes of dry matter (DMI) andNDF, which responded with a lower milk yield. It was observed a greater reduction in DMI (kg/day) with the increase of NDFf(NDF forage, % DM) in sugarcane diets (332.4 g of DM for each 1% of NDFf) in relation to corn silage (96 g of DM for each1% of NDFf). The greatest effect of ruminal repletion of sugar cane NDF is caused by the indigestible fraction, majoritary,despite the highest degradation rate of NDF potentially degradable fraction in relation to corn silage. Milk production notcorrected (MP) and MP corrected to 4% fat (MPC) and the content of milk protein decreased linearly with the increase ofNDFf content, regardless of the forage source. However, MP and MPC were not affected by NDFnf (non-forage NDF) level.Intakes of DM, NDF, TDN and milk fat content decreased linearly with increase in the lignin:NDF ratio, with greater amplitudein sugarcane based diets in relation to silage corn. Dry matter intake, MP and MPC reduced linearly and at the same magnitudeamong forage sources, with the increase in NDFD of the diet. The effect of NDF and lignin on intake, digestibility and animalperformance depend upon the source used.Key Words: corn silage, ruminal retention, sugarcane

Urea in sugarcane-based diets for dairy cows

We evaluated the effect of adding four levels (0, 4, 8 and 12 g/kg, as fed) of a mixture (9:1) of urea and ammonium sulfate (UAs) to sugarcane on feed intake and digestibility, productive performance and metabolism of nitrogen compounds of dairy cows. Twelve multiparous Holstein cows (12.6±0.5 kg/d of milk, 225±90 days in milk) were distributed in three 4 × 4 Latin squares, receiving diets with the same amount of nitrogen (125 g crude protein/kg of dry matter). Concentrate feed was supplied at a ratio of 1 kg for each 3 kg of milk produced. The sugarcane presented 21.9 oBrix. The level of UAs did not affect intake, total digestibility of diet components, milk production or milk components. Increasing UAs level linearly increased concentration of plasma urea nitrogen (PUN), urinary excretion of nitrogen and contribution of non-urea nitrogen in the urinary excretion and linearly reduced milk production/urinary excretion of nitrogen ratio. In spite of the linear increase of PUN with increased urea, the maximum value observed (14.31 mg/dL) was below the threshold value of 20 mg/dL, above which reproductive function may be compromised. In diets with sugarcane for dairy cows with production below 15 kg/day, the UAs level may be raised from 0 to 12 g/kg natural matter without impairing performance.

Prediction of intake in growing dairy heifers under tropical conditions.

A meta-analysis was conducted to develop models of the prediction of dry matter intake (DMI) in growing dairy heifers [postweaning to 390 kg of body weight (BW)] under tropical conditions. The adequacy of the models was assessed in a comparison with the 4 US models currently used to predict DMI [Quigley; National Research Council; and 2 Hoffman models]. The data set was created using 95 treatment means from 28 studies published in journals. The data set (studies) was randomly divided into 2 data subsets for the statistical analyses. The first data subset was used to develop the prediction equations for DMI (17 studies; 58 treatment means), and the second data subset was used to assess the adequacy of the predictive models (11 studies; 37 treatment means). The models were developed using nonlinear and linear mixed analyses. Breed (Bos taurus vs. Bos taurus × Bos indicus), BW (240.2±62.2 kg), and average daily gain (ADG, 0.83±0.28 kg/d) were the independent variables. No significant effects of the breed or the interactions between the breed and metabolic BW (BW(0.75)) or breed and ADG were detected. Thus, nonlinear [DMI=0.1175 × BW(0.75) - 3.4984 × e((-2.4690 × ADG))] and linear models [DMI=8.7147 - 0.2402 × BW(0.75) + 0.0027 × (BW(0.75))(2) + 3.6050 × ADG - 1.4168 × ADG(2)] were proposed for both breeds. The nonlinear model explained 81% of the variation in the DMI, over-predicted the DMI by 0.21 kg/d and predicted the DMI with a higher accuracy and precision than the linear model [root mean square error of prediction (RMSEP)=8.82 vs. 10.71% of the observed DMI, respectively]. The Quigley model explained only 54% of the variation in the DMI and was the fourth most accurate and precise model (RMSEP=11.21% of the observed DMI). The National Research Council model explained 69% of the variation in the DMI but under-predicted the DMI by 0.53 kg/d, with an RMSEP of 12.72% of the observed DMI and presence of systematic constant bias. The Hoffman exponential model I (BW as the input) adequately predicted the DMI with an accuracy that was similar to the proposed nonlinear model. The equation of the Hoffman exponential model I explained 75% of the variation in the DMI and over-predicted the DMI by 0.07 kg/d, which was the second most accurate and precise equation (RMSEP=9.35% of the observed DMI). However, the Hoffman exponential model II (BW and diet NDF as the inputs) did not adequately predict the DMI, because it explained only 54% of the variation in the DMI, under-predicted the DMI by 0.72 kg/d, and had a high RMSEP (17.96% of the observed DMI). The use of nonlinear models increase the accuracy and the precision of the prediction of DMI compared with the linear models. Only the models proposed in the present study, the Hoffman exponential model I (BW as the input), and the Quigley model were adequate for the prediction of the DMI of growing dairy heifers under tropical conditions.

Short communication: Prediction of intake in dairy cows under tropical conditions

A meta-analysis was conducted to develop a model for predicting dry matter intake (DMI) in dairy cows under the tropical conditions of Brazil and to assess its adequacy compared with 5 currently available DMI prediction models: Agricultural and Food Research Council (AFRC); National Research Council (NRC); Cornell Net Carbohydrate and Protein System (CNCPS; version 6); and 2 other Brazilian models. The data set was created using 457 observations (n=1,655 cows) from 100 studies, and it was randomly divided into 2 subsets for statistical analysis. The first subset was used to develop a DMI prediction equation (60 studies; 309 treatment means) and the second subset was used to assess the adequacy of DMI predictive models (40 studies; 148 treatment means). The DMI prediction model proposed in the current study was developed using a nonlinear mixed model analysis after reparameterizing the NRC equation but including study as a random effect in the model. Body weight (mean = 540 ± 57.6 kg), 4% fat-corrected milk (mean = 21.3 ± 7.7 kg/d), and days in milk (mean = 110 ± 62 d) were used as independent variables in the model. The adequacy of the DMI prediction models was evaluated based on coefficient of determination, mean square prediction error (MSPE), root MSPE (RMSPE), and concordance correlation coefficient (CCC). The observed DMI obtained from the data set used to evaluate the prediction models averaged 17.6 ± 3.2 kg/d. The following model was proposed: DMI (kg/d) = [0.4762 (± 0.0358) × 4% fat-corrected milk + 0.07219 (± 0.00605) × body weight(0.75)] × (1 - e(-0.03202 (± 0.00615) × [days in milk + 24.9576 (± 5.909)])). This model explained 93.0% of the variation in DMI, predicting it with the lowest mean bias (0.11 kg/d) and RMSPE (4.9% of the observed DMI) and the highest precision [correlation coefficient estimate (ρ) = 0.97] and accuracy [bias correction factor (Cb)=0.99]. The NRC model prediction equation explained 92.0% of the variation in DMI and had the second lowest mean bias (0.42 kg/d) and RMSPE (5.8% of the observed DMI), as well as the second highest precision (ρ = 0.94) and accuracy (Cb = 0.98). The CNCPS and AFRC DMI prediction models explained 93.0 and 85.0% of the variation in DMI but underpredicted DMI by 1.8 and 1.4 kg/d, respectively. These 2 models (CNCPS and AFRC) resulted, respectively, in RMSPE of 11.3 and 10.7% of the observed DMI, with moderate to high precision (ρ = 0.81 and 0.82) and accuracy (Cb = 0.84 and 0.89). The remaining 2 models resulted in the poorest results, underpredicting DMI by 2.3 and 1.9 kg/d, with RMSPE of 22.8 and 14.9% of the observed DMI and moderate to low precision (ρ = 0.49 and 0.76) and accuracy (Cb = 0.81 and 0.86). The new model derived from the current meta-analytical approach provided the best accuracy and precision for predicting DMI in lactating dairy cows under Brazilian conditions.

Desempenho de cordeiros confinados, alimentados com dietas à base de torta de girassol

O objetivo deste trabalho foi avaliar os efeitos da inclusao da torta de girassol na dieta de cordeiros em confinamento sobre o desempenho produtivo dos animais. Utilizaram-se 40 cordeiros sem raca definida, nao castrados, com peso medio inicial de 20,17±2,66 kg, alimentados com 0, 7, 14, 21 e 28% de torta de girassol na dieta (base seca). O experimento foi conduzido em delineamento de blocos ao acaso. A inclusao de torta de girassol na dieta nao alterou o consumo medio de materia seca (883,58 g por dia), a conversao alimentar (4,40) e o consumo medio de agua (2,59 L por dia). O aumento dos niveis de torta de girassol diminuiu linearmente o peso final, o ganho de peso total, o ganho de peso diario e a area de olho de lombo. O nivel de inclusao de ate 28% nao afeta o consumo medio de materia seca e de agua, mas reduz o desempenho e a area de olho de lombo. Para obter o menor custo com a dieta, o nivel de inclusao da torta de girassol pode atingir ate 28% da materia seca, quando o seu preco representar ate 40% do preco da mistura entre milho e farelo de soja.

Capacity of ensilage of Jatropha curcas L. cake to degrade forbol esters

The objective of this study was to evaluate the capacity of the ensilage of Jatropha curcas L. expeller cake to reduce the phorbol esters and its effect on fermentative losses, by adding soluble carbohydrates or microbial inoculants. The design was completely randomized with four replications in a 3 × 2 factorial arrangement, with three sources of soluble carbohydrates (SC, control, 50 g sucrose/kg or 50 g crude glycerin/kg as fed) and two doses of microbial inoculants (MI, 0 or 5 × 105 ufc Lactobacillus plantarum + 3.33 × 105 ufc Propionibacterium per g as fed). Twenty-four mini-silos (982 cm3) of polyvinyl chloride were created and opened after 60 days of fermentation at room temperature. The pre-hydrated Jatropha curcas L. cake (282 g of water/kg) contained 0.424 mg of phorbol esters/g of dry matter. Ensiling reduced the phorbol esters in 47.4%, on average, regardless of the SC or MI. There was no interaction effect between SC and MI on effluent, gases or total dry matter losses. However, both losses were increased when SC were added, and it was higher with glycerin that than sucrose. The addition of MI reduced all fermentation losses. The process of ensiling, although partially to reduce the phorbol esters of pre-hydrated Jatropha curcas L. cake, is not indicated as a biodestoxification procedure.

Esterco de gado leiteiro associado à adubação mineral e sua influência na fertilidade de um latossolo sob plantio direto

Dairy cattle in South Brazil is raised mainly in a system based on partial or total confinement of the animals, generating a significant amount of residues. The residues have been used as the only nutrient source or associated to mineral sources in grain or silage production. Their effect on soil characteristics has however been little explored. This study was conducted to evaluate the influence of fertilization rates with liquid dairy cattle manure associated with mineral fertilizer on P, K, C, and electrical conductivity (EC) levels of a Brown Oxisol, under no-tillage and winter and summer crop rotation (sorghum/black-oat/corn/ryegrass/corn/ ryegrass) for silage production, in the layers 0-5, 5-10, 10-30, 30-50 and 50-80 cm. The treatments were distributed in three randomized blocks, each divided in 12 plots, in a 3 x 4 factorial arrangement, with three mineral fertilizer levels (0, 50 and 100 % of the dose recommended for the crops) and four organic fertilizer levels (0, 30, 60, and 90 m3 ha-1 year-1). Mineral fertilizer resulted in higher values of available P (Mehlich-1 and resin) to a depth of 10 cm, due to the fertilizer application in depth by the planter, whereas the highest values under manure surface application were restricted to the 0-5 cm layer. Potassium depletion was observed along the soil profile due to high extraction by silage, and a linear ratio with available K level could be applied in the case of liquid manure at all depths. The lack of effect by the mineral fertilizer on K is probably due to the low rate of K application. A direct relationship was observed between manure rates and organic C concentration in the 0-5 cm layer, unlike in the case of mineral fertilizer. Low EC values were obtained suggesting high nutrient exportation by silage production. Results indicate that there was no significant P migration in the Oxisol profile, even after six years of dairy cattle manure application at high rates, and that K applied via manure and mineral fertilizer is insufficient to maintain the levels of this nutrient in systems where K extraction by silage is high. In these situations, increased levels of organic C are restricted to the soil surface layer in no-tillage and directly related to the manure rate.

Short communication: Development and evaluation of predictive models of body weight for crossbred Holstein-Zebu dairy heifers

Equations to predict body weight (BW) of crossbred Holstein-Zebu dairy heifers were developed and compared with current models (Heinrichs et al. for Holsteins, United States; Reis et al. for crossbred Holstein-Zebu, Brazil). The data set was constructed from 150 measurements of BW (320 ± 107 kg) and biometric measurements such as heart girth (HG, 161 ± 19.5 cm), withers height (WH, 126 ± 11.0 cm), and hip height (HH, 132 ± 11.3 cm) of heifers from 5 commercial dairy producers in the southern Amazon region in Brazil. The data were evaluated using mixed nonlinear models with herd as a random effect. Three nonlinear equations were fitted: BW (kg)=0.00058·HG (cm)(2.6135); BW (kg)=0.000618·HG (cm)(2.7362); and BW (kg)=0.000196·HH (2.8793). An independent database was constructed to evaluate the models from 38 treatment means of 4 feeding trials: BW 258 ± 54.3 kg, HG 142.5 ± 11.8 cm, WH 113.2 ± 6.0 cm, and HH 118.7 ± 9.1 cm (mean ± SD). The evaluations were based on the relationship between observed and predicted values of BW by linear regression, root mean square prediction error (RMSPE), and concordance correlation coefficient analysis. Only the proposed model using HG accurately predicted observed BW, with bias (observed - predicted) of 4.83 kg and RMSPE of 5.41% of observed BW (87.7% of random error). The models using WH and HH failed to accurately predict observed BW, with a bias of -3.06 and 72.02 kg, and RMSPE of 9.40% of observed BW (75.2% of random error and 23.1% of systematic error) and 30.81% of observed BW (81.2% of mean bias). Additionally, the models of Heinrichs and Reis used for comparison did not predict BW accurately, with a bias of 19.32 and 29.37 kg and RMSPE of 9.08% of observed BW (68.4% of mean bias and 31.4% of random error) and 12.58% of observed BW (81.9% of mean bias). The largest concordance correlation coefficient of the proposed HG-nonlinear model (0.930), compared with the models of Heinrichs and Reis of 0.845 and 0.708, confirmed the greater accuracy and precision of the new equation to predict BW in crossbred Holstein-Zebu dairy heifers.

Effect of adding clay with or without a Saccharomyces cerevisiae fermentation product on the health and performance of lactating dairy cows challenged with dietary aflatoxin B1

The study was conducted to examine the effect of supplementing bentonite clay with or without a Saccharomyces cerevisiae fermentation product (SCFP; 19 g of NutriTek + 16 g of MetaShield, both from Diamond V, Cedar Rapids, IA) on the performance and health of dairy cows challenged with aflatoxin B1 (AFB1). Twenty-four lactating Holstein cows (64 ± 11 d in milk) were stratified by parity and milk production and randomly assigned to 1 of 4 treatment sequences. The experiment had a balanced 4 × 4 Latin square design with 6 replicate squares, four 33-d periods, and a 5-d washout interval between periods. Cows were fed a total mixed ration containing 36.1% corn silage, 8.3% alfalfa hay, and 55.6% concentrate (dry matter basis). Treatments were (1) control (no additives), (2) toxin (T; 1,725 µg of AFB1/head per day), (3) T + clay (CL; 200 g/head per day; top-dressed), and (4) CL+SCFP (CL+SCFP; 35 g/head per day; top-dressed). Cows were adapted to diets from d 1 to 25 (predosing period) and then orally dosed with AFB1 from d 26 to 30 (dosing period), and AFB1 was withdrawn from d 31 to 33 (withdrawal period). Milk samples were collected twice daily from d 21 to 33, and plasma was sampled on d 25 and 30 before the morning feeding. Transfer of ingested AFB1 into milk aflatoxin M1 (AFM1) was greater in T than in CL or CL+SCFP (1.65 vs. 1.01 and 0.94%, respectively) from d 26 to 30. The CL and CL+SCFP treatments reduced milk AFM1 concentration compared with T (0.45 and 0.40 vs. 0.75 µg/kg, respectively), and, unlike T, both CL and CL+SCFP lowered AFM1 concentrations below the US Food and Drug Administration action level (0.5 µg/kg). Milk yield tended to be greater during the dosing period in cows fed CL+SCFP compared with T (39.7 vs. 37.7 kg/d). Compared with that for T, plasma glutamic oxaloacetic transaminase concentration, indicative of aflatoxicosis and liver damage, was reduced by CL (85.9 vs. 95.2 U/L) and numerically reduced by CL+SCFP (87.9 vs. 95.2 U/L). Dietary CL and CL+SCFP reduced transfer of dietary AFB1 to milk and milk AFM1 concentration. Only CL prevented the increase in glutamic oxaloacetic transaminase concentration, and only CL+SCFP prevented the decrease in milk yield caused by AFB1 ingestion.

Replacing ground corn with incremental amounts of liquid molasses does not change milk enterolactone but decreases production in dairy cows fed flaxseed meal

We investigated the effects of replacing ground corn (GRC) with incremental amounts of liquid molasses (LM) on milk enterolactone concentration, antioxidant enzymes activity in plasma, production, milk fatty acid (FA) profile, and nutrient utilization in Jersey cows fed flaxseed meal and low-starch diets. Sixteen multiparous organically certified Jersey cows averaging (mean ± standard deviation) 101 ± 45 d in milk, 462 ± 38 kg of body weight, and 19.8 ± 3.90 kg/d of milk in the beginning of the study were randomly assigned to treatment sequences in a replicated 4 × 4 Latin square design, with 14 d for diet adaptation and 7 d for data and sample collection. Diets were fed as total mixed rations consisting (dry matter basis) of 52% grass-legume baleage, 8% grass hay, 8.5% soyhulls, 2.5% roasted soybean, 15% flaxseed meal, and 2% minerals-vitamins premix. The GRC-to-LM dietary ratios (dry matter basis) were 12:0, 8:4, 4:8, and 0:12. Orthogonal polynomials were used to test linear, quadratic, and cubic effects using the MIXED procedure of SAS (SAS Institute Inc., Cary, NC). The milk concentration of enterolactone tended to respond cubically, thus suggesting that replacing GRC with LM did not affect this lignan in milk. The plasma activities of the antioxidant enzymes glutathione peroxidase and catalase did not differ, but superoxide dismutase activity tended to respond cubically with feeding increasing amounts of LM. Dry matter intake and yields of milk and milk fat, true protein, and lactose decreased linearly with substituting GRC for LM. Whereas the concentrations of milk fat and milk true protein did not differ across treatments, milk lactose content decreased linearly. Feeding incremental levels of LM reduced linearly the milk concentration of urea N and the amount of N excreted in urine, and tended to decrease linearly the concentration of plasma urea N. Apparent total-tract digestibilities of dry matter, organic matter, and neutral and acid detergent fiber did not differ across treatments, whereas digestibility of crude protein decreased linearly. Digestibility of starch responded linearly and quadratically, but the actual differences between treatments were too small to be biologically significant. Milk FA profile was substantially changed most notably by linear increases in cis-9,trans-11 18:2, cis-9,cis-12,cis-15 18:3, Σ odd-chain FA, and the trans-11-to-trans-10 ratio, and linear decreases in cis-9 18:1 and cis-9,cis-12 18:2 when replacing GRC by incremental amounts of LM.