Degradable Fraction Of Dry Matter Research Articles

Chemical, Physical, and Degradation Characteristics of Ryegrass Cultivars Grown in Autumn and Winter for Dairy Cows.

During winter and early spring, pasture supply is usually lower than the demand in New Zealand dairy farming systems and thus the 'autumn saved pastures' (stockpiling) are introduced to fill the gap. This study aimed to investigate the chemical, physical, and degradation characteristics of ryegrass pastures, the predominant forage in New Zealand, grown in autumn and winter. To serve as 'autumn saved pasture', nine ryegrass cultivars, comprising three types (three perennial, three hybrid, and three Italian), were grown in late autumn (Autumn) and early winter (Winter) and harvested after 7 and 9 weeks of regrowth, respectively. The experiment had two experimental factors: ryegrass type (or cultivar) and harvest season. These experimental factors were in a randomised block design with the forage plot as the experimental unit. The degradation characteristics were assessed in the rumen of fistulated cows using the in situ incubation technique. Perennial ryegrass had a greater neutral detergent fibre (NDF) concentration (468 g/kg dry matter (DM)) than the hybrid (435 g/kg DM) or Italian (414 g/kg DM) ryegrasses. Italian ryegrasses had the greatest soluble fraction of DM (64.2% vs. 46.7% and 40.7%) and the greatest degradation rate of an insoluble but degradable fraction of DM (0.221 vs. 0.189 and 0.145/h) than the hybrid and perennial ryegrasses. Compared with the Winter ryegrass, the Autumn ryegrass had a greater crude protein concentration (246 vs. 208 g/kg DM) and a greater NDF concentration (486 vs. 392 g/kg DM) but a lower calculated soluble carbohydrate concentration (152 vs. 263 g/kg DM). It is concluded that there are notable variations among the cultivars, highlighting distinctions in parameters, such as NDF concentration, soluble fractions, degradation rates, and nutrient content among the perennial, hybrid, and Italian ryegrasses, as well as the seasonal variations observed between autumn and winter growth. These findings will not only facilitate enhanced nutrition for dairy cows as they undergo the transition phase but also have practical implications for future research and dairy cow nutrition.

Chemical Composition and In Situ Degradability of Desmanthus spp. Forage Harvested at Different Maturity Stages

This study evaluated the change in nutritive value and in situ degradability of Desmanthus spp. (desmanthus) cultivars JCU2; D. virgatus, JCU4; D. bicornutus and JCU7; D. leptophyllus harvested at varying maturity stages to test the hypothesis that the nutritive value and in situ degradability of desmanthus differ between cultivars and with maturity stage at harvest. In Experiment 1, desmanthus was harvested at 11, 38, 72 and 103 days of regrowth (maturity), separated into the leaf and stem portion, dried and analysed for dry matter (DM) and chemical composition. In Experiment 2, desmanthus was harvested 78, 122 and 168 days after planting (maturity). Samples were dried, and DM, crude protein (CP) and neutral detergent fibre (NDF) and acid detergent fibre (ADF) degradation were determined using the in situ technique with three fistulated Droughtmaster steers. The results showed an interaction between cultivar and maturity on the leaf to stem mass ratio, leaf CP, stem NDF and the leaf ADF (p ≤ 0.04). The leaf-to-stem mass ratio declined more steeply with maturity in JCU7 compared to JCU2 and JCU4 (p = 0.04), while there was a higher decline in leaf CP of JCU4 than JCU2 and JCU7 (p < 0.01). The total potentially degradable fraction of DM and CP did not differ between cultivars (p ≥ 0.30) but declined with maturity (p ≤ 0.04). However, the effective DM degradability at a high particle outflow rate was higher in JCU4 than in JCU7. Taken together, these results indicate that differences exist between cultivars, and higher livestock production may be achieved by utilising the different cultivars in a blend and at earlier maturity stages. Therefore, the hypothesis that nutritive value and in situ degradability of desmanthus differ between cultivars and with maturity stage at harvest was accepted.

Variability among Animals and Incubation Protocols for Ruminant In Situ Degradation Studies with Tropical Feeds.

Simple SummaryThe knowledge on the nutritive value of feeds is essential to feed animals with adequate diets and to optimize production with minimal environment impact. In situ degradation is an important tool for nutritionists because it is a reliable, cheap, and fast way to assess information on feed digestion in ruminants. However, the lack of standards procedures for in situ trials with cattle in the tropics may compromise the reliability of information obtained from those studies. Thus, we aimed to generate useful information for animal scientists on how to perform that kind of study using adequate and minimal resources yet keeping accuracy to interpret feed characteristics. Our findings indicated an important variation among animals on the estimates of the rumen degradation rate of feeds, and taking into account that variation can allow for a more adequate comparison among feeds. On the other hand, we also found that an in situ trial cannot be performed using fewer than three animals, otherwise the risk of obtained biased and imprecise information increases. Minimum sets of incubation times were defined and evaluated. They can be used to decrease the costs and the labor when tropical feeds are evaluated through in situ trials with cattle.Our objectives were to evaluate the variability among animals regarding to the degradation rate of the potentially degradable fraction of dry matter, crude protein, and neutral detergent fiber, as well as to establish the minimum number of animals and provide a standardized design of sampling times for in situ ruminal degradation assays of tropical feeds with cattle. Seven feeds were evaluated, four concentrates and three forages. The incubations were performed using five rumen-cannulated Nellore heifers (328 ± 9.8 kg of body weight). The complete sets of incubation sampling times encompassed 16 time points for forage samples (0–240 h) and 13 time points for concentrate samples (0–144 h). The profiles were adjusted using both fixed and mixed model approaches. When the variation among animals on the degradation rate was considered using the mixed model approach, the precision of the adjusted degradation profiles was increased. Moreover, the utilization of a low number of animals increases the probability to obtain biased estimates of degradation rate and increased random variances. A minimum of three animals is recommended for in situ trials with cattle. Minimum designs of sampling times regarding number and position of incubation times were proposed, discussed, and recommended to assess the dynamics of tropical feed degradation.

Effect of replacing soybean meal with marula nut meal on rumen dry matter and crude protein degradability.

In situ rumen degradability of dry matter (DM) and crude protein (CP) in ruminant diets composed of graded inclusion levels of marula nut meal (MNM) as a protein source to replace soybean meal were evaluated. The five diets denoted as diet 1 (0.0gkg-1 MNM: control), diet 2 (45.5gkg-1 MNM), diet 3 (91.7gkg-1 MNM), diet 4 (138.4gkg-1 MNM), and diet 5 (185.9gkg-1 MNM) were tested. Three cannulated mid-lactating Holstein cows were used to incubate triplicate subsamples of each diet for 2, 4, 8, 16, 24, and 48h in polyester bags. The soluble fractions of DM and CP increased (P < 0.05) with increasing levels of MNM (138.4-185.9gkg-1 MNM). However, the insoluble but degradable fractions of DM and CP increased (P < 0.05) with decreasing levels of MNM (45.5-0.0gkg-1 and 91.7-0.0gkg-1 MNM, respectively). While the degradation rate of fraction and the effective degradability of DM increased (P < 0.05) with decreasing levels of MNM (91.7-0.0gkg-1), those of CP increased with increasing levels of MNM (138.4-185.9gkg-1 MNM) in the diet. These results suggest that dietary inclusion of MNM up to 91.7gkg-1 in ruminant diets can provide undegradable protein to be absorbed in the small intestines and used for metabolic function, while an inclusion of up to 185.9gkg-1 can be degraded in the rumen for microbial protein synthesis.

Efeitos da inclusão de taninos em suplementos de bovinos de corte em pastejo sobre a degradabilidade in situ da matéria seca

Objetivou-se com o presente estudo avaliar o efeito da inclusão de tanino na suplementação de bovinos a pasto sobre a degradabilidade da matéria seca. Foram utilizados dois bovinos machos Nelore, não castrado, canulados no rúmen, e suplementados com suplemento proteico-energético com 26% de proteína bruta (PB) a 0,5% do peso corporal, contendo na dieta de um dos animais a inclusão de 1g de tanino por kg de matéria seca (MS). Avaliou-se a degradação da MS das amostras de DDG (que significa grãos secos por destilação, na sigla em inglês), farelo de soja e milho. Para todos os alimentos não houve diferença significativa entre os tratamentos. O DDG apresentou fração indigestível (65,6%) maior que a fração potencialmente digestível (20,5%), a fração potencialmente degradável da MS (B0) do farelo de soja foi inferior ao observado na literatura, entretanto a taxa de degradação da fração B0 (0,037) foi semelhante (0,080). O melhor ajuste dos modelos de desaparecimento para MS do milho foi com os tratamentos separados. Porém, não houve diferença significativa entre eles. A taxa de degradação do tratamento com tanino (0,178) não apresenta confiabilidade por incluir o zero dentro do intervalo de confiança. Existe uma diferença significativa somente no tempo de meia vida, sendo possível observar que o tratamento com tanino demora quase que o dobro de tempo (96,35%) para digerir metade da fração potencialmente digestível do tratamento sem tanino.

Effect of heat-treated canola meal and glycerol inclusion on performance and gastrointestinal development of Holstein calves

The objectives of this study were to assess the effect of using heat-treated canola meal (CM) and glycerol inclusion in starter mixtures on starter intake, growth, and gastrointestinal tract development in Holstein bull calves. In the first study, a protocol for the heat treatment of CM was evaluated by comparing commercial CM that was exposed to 0, 100, 110, or 120°C of heat treatment for 10 min. Following heat treatment, in situ crude protein (CP) ruminal degradability and estimated intestinal CP digestibility were assessed. It was observed that the degradable fractions of dry matter and CP in CM decreased linearly with increasing temperature of heat treatment. The estimated intestinal CP digestibility was greatest when CM was heated to 110°C. In the second study, 28 bull calves were used in a randomized complete block design. Calves were fed pelleted starters containing CM or CM that was heat-treated to 110°C for 10 min. Diets also contained 0 or 5% glycerol on a dry matter basis. The study lasted 51 d, ending on the first day of weaning. Starter intake, average daily gain (ADG), ruminal short-chain fatty acid concentrations, morphology of the rumen and small intestine, gene expression (MCT1, GPR41, GPR43, UTB, AQP3, PEPT1, PEPT2, ATB0+, and EAAC1) in the ruminal, jejunal, and ileal epithelium, and brush border enzyme activities in the duodenum, jejunum, and ileum were investigated. Few interactions between heat-treated CM and glycerol inclusion were observed. Feeding heat-treated CM did not affect starter intake. However, feeding heat-treated CM to calves tended to reduce ADG and decreased the weight of ruminal and jejunal tissue. Heat treatment did not affect gene expression or brush border enzyme activities in the small intestine. Glycerol inclusion tended to increase cumulative starter intake and increased cumulative body weight gain. Use of glycerol reduced ruminal pH and increased the concentration of ruminal short-chain fatty acids. Additionally, glycerol inclusion increased abomasal, duodenal, jejunal, and cecal digesta weights and tended to increase the weight of the jejunal tissue. Glycerol supplementation tended to downregulate the expression of MCT1 in the ruminal epithelium, and upregulated the expression of MCT1 in the epithelium of proximal jejunum. In conclusion, heat treatment of CM may negatively affect calf growth and gastrointestinal tract development. Glycerol inclusion may increase starter intake, ADG, ruminal fermentation, and intestinal development in calves when CM is used as a main source of protein in pelleted starter mixture.

Comparative Grain Yield, Straw Yield, Chemical Composition, Carbohydrate and Protein Fractions, In Vitro Digestibility and Rumen Degradability of Four Common Vetch Varieties Grown on the Qinghai-Tibetan Plateau.

Simple SummaryThe common vetch (Vicia sativa L.) is an important legume crop of mixed crop-livestock systems that provides high-quality grains used as food/feed and straw used as ruminant feed. The objective of this study was to determine the variability in grain yield, straw yield, straw chemical composition, carbohydrate and protein fractions, in vitro gas production, and in situ ruminal degradability of four different varieties of common vetch grown on the Qinghai-Tibetan Plateau. The results showed that grain yield, straw yield, and straw nutrient value varied significantly among the four varieties. Overall, the findings indicated that in terms of straw yield and nutritive quality, variety Lanjian No. 1 has the greatest potential as a crop for supplementing ruminant diets in the smallholder mixed crop–livestock systems on the Qinghai-Tibetan Plateau.Four varieties of common vetch, including three improved varieties (Lanjian No. 1, Lanjian No. 2, and Lanjian No. 3) and one local variety (333A), were evaluated for varietal variations in grain yield, straw yield and straw quality attributes on the Qinghai-Tibetan Plateau. Crops were harvested at pod maturity to determine grain yield, straw yield, harvest index, and potential utility index (PUI). Straw quality was determined by measuring chemical composition, carbohydrate and protein fractions, in vitro gas production and in situ ruminal degradability. Results showed a significant effect (p < 0.01) of variety on the grain yield [875.2–1255 kg dry matter (DM)/ha], straw yield (3154–5556 kg DM/ha), harvest index (15.6–28.7%) and PUI (53.3–63.2%). Variety also had a significant effect on chemical composition, carbohydrate and protein fractions (p < 0.05) except non-structural carbohydrates and rapidly degradable sugars. Significant differences (p < 0.05) were observed among the varieties in potential gas production [188–234 mL/g DM], in vitro organic matter (OM) digestibility (43.7–54.2% of OM), and metabolizable energy (6.40–7.92 MJ/kg DM) of straw. Significant differences (p < 0.001) were also observed among the varieties in rapidly degradable DM fraction and effective DM degradability of straw; however, no difference was observed in other DM degradation parameters and neutral detergent fiber degradation parameters. In conclusion, based on straw yield and quality, Lanjian No. 1 has the greatest potential among the tested varieties as a crop for supplementing ruminant diets for smallholder farmers on the Qinghai-Tibetan plateau.

Nutrient evaluation and ruminal degradation of dry matter and protein from amarula (Sclerocarya birrea), macadamia (integrifolia) and baobab (Adansonia digitata L.) oilcakes as dietary supplements for ruminants.

Inadequate availability of feed ingredients significantly contributes to reduced animal production. Nutritional evaluation of feed ingredients for potential use in feed ration is key. Triplicate samples of oil extraction by-products viz.: amarula (Sclerocarya birrea), macadamia (integrifolia) and baobab (Adansonia digitata L.) oilcakes were analysed for proximate, mineral and amino acids content. To determine the in situ rumen degradability of dry matter (DM) and crude protein (CP) from the oilcakes, polyester bags were used to incubate triplicate subsamples of each oilcake in the ventral rumen of each of the three cannulated mid-lactating Holstein cows for 2, 4, 8, 16, 24, or 48h. Amarula oilcake (AOC) had higher (P < 0.05) CP, ether extract and essential amino acid content than macadamia (MOC) and baobab (BOC) oilcakes. Fibre fractions were higher (P < 0.05) in MOC and BOC than in AOC. While calcium (Ca) and potassium (K) concentrations were high (P < 0.05) in MOC and BOC, phosphorus (P) concentration was high (P < 0.05) in AOC. The effective degradability of DM and water-soluble, rapidly degradable fractions of DM and CP were high (P < 0.05) in AOC. Insoluble but degradable fraction of CP was high (P < 0.00) in BOC and effective degradation of CP was high (P < 0.05) in AOC and BOC. The AOC with its high CP, EE and essential AA can be used as both protein and energy source for ruminants. Seemingly, MOC and BOC can be used as supplements for fibre as well as Ca and K in ruminant diets. Hence, these non-conventional oilcakes have the potential to partially replace conventional oilcakes in ruminant diets. Evaluation of growth performance, nitrogen digestion and carcass characteristics in ruminants fed diets containing the AOC, BOC and MOC are recommended.

Impact of Pediococcus pentosaceus and Pichia anomala in combination with chitinase on the preservation of high‐moisture alfalfa hay

AbstractThis study assessed the effects of applying Pediococcus pentosaceus (PED) or Pichia anomala (PIC) in combination with chitinase (CH) on the conservation characteristics and rumen digestibility of large round‐bale high‐moisture alfalfa hay (HMH). Alfalfa was wilted in the field to 23%–27% moisture and baled without (Control) or with PED + CH, PIC + CH and propionic acid (PA). The study was repeated yearly from 2012 to 2014. The PED + CH‐treated HMH had the numerically lowest high degree day (bale internal temperature &gt;30°C) in all 3 years, which was less (p &lt; .05) than Control HMH and PA in 2012. Treatments had no effect on pH, but mixed effects on chemical and microbial compositions across 3 years. The PED + CH treatment had the highest water‐soluble carbohydrate (WSC) content (p &lt; .05) in 2012 and 2014, whereas PA treatment had the lowest (p &lt; .05) WSC in these years. Total bacteria were decreased (p &lt; .001) by PIC + CH and PED + CH in 2012 only. The PED + CH treatment had greater (p &lt; .01) soluble fraction of dry matter (DM) than Control HMH and PA in both 2012 and 2014, but treatments did not affect the potential degradable fraction of DM. The PED + CH and PIC + CH treatments increased (p &lt; .01) in situ neutral detergent fibre digestibility after 6, 24 and 96 hr of ruminal incubation in 2012 but not in 2014. Combinations of P. pentosaceus or P. anomala with chitinase have potential as high‐moisture hay inoculants to reduce microbial spoilage and to increase fibre digestibility.

In situ and in vitro ruminal starch degradation of grains from different rye, triticale and barley genotypes

In recent years, advances in plant breeding were achieved, which potentially led to modified nutritional values of cereal grains. The present study was conducted in order to obtain a broad overview of ruminal digestion kinetics of rye, triticale and barley grains, and to highlight differences between the grain species. In total, 20 genotypes of each grain species were investigated using in situ and in vitro methods. Samples were ground (2 mm), weighed into polyester bags, and incubated in situ 1 to 48 h in three ruminally cannulated lactating dairy cows. The in vitro gas production of ground samples (1 mm) was measured according to the ‘Hohenheim Gas Test’, and cumulative gas production was recorded over different time spans for up to 72 h. There were significant differences (P<0.05) between the species for most parameters used to describe the in situ degradation of starch (ST) and dry matter (DM). The in situ degradation rate (c) and effective degradability (assuming a passage rate of 8%/h; ED8) of ST differed significantly between all grains and was highest for rye (rye: 116.5%/h and 96.2%; triticale: 85.1%/h and 95.0%; barley: 36.2%/h and 90.0% for c and ED8, respectively). With respect to DM degradation, the ranking of the species was similar, and predicted c values exhibited the highest variation within species. The in vitro gas production rate was significantly higher (P<0.05) for rye than for triticale and barley (rye: 12.5%/h; triticale: 11.5%/h; barley: 11.1%/h). A positive relationship between the potential gas production in vitro and the maximal degradable DM fraction in situ was found using all samples (r=0.84; P<0.001) as well as rye (P=0.002) and barley (P<0.001) alone, but not for triticale. Variation in ruminal in situ degradation parameters within the grain species resulted from the high c values, but was not reflected in the ED estimates. Therefore, the usage of mean values for the ED of DM and ST for each species appears reasonable. Estimated metabolisable energy concentrations (ME, MJ/kg DM) and the estimated digestibility of organic matter (dOM, %) were significantly lower (P<0.05) for barley than for rye and triticale. Rye and triticale dOM and ME values were not significantly different (P=0.386 and 0.485).

Effects of corn treated with foliar fungicide on in situ corn silage degradability in Holstein cows

With increasing feed prices and decreasing profit margins livestock producers are constantly searching for ways to increase nutritive value of the feed in order to get more production per unit of feedstuff. The objective of this study was to assess the digestibility of corn silage made of corn plants treated with various foliar fungicide applications. Treatments were: control (CON), corn received no foliar fungicide application; 1X, corn received one application of pyraclostrobin foliar fungicide (PYR; Headline; BASF Corp.) at vegetative stage 5 (V5); 2X, corn received 2 applications of foliar fungicides, PYR at stage V5, and a mixture of pyraclostrobin and metconazole (PYR+MET; Headline AMP; BASF Corp.) at reproductive stage 1 (R1); and 3X, corn received 3 applications of foliar fungicides, PYR at stage V5, PYR+MET at stage R1, and PYR+MET at reproductive stage 3. Corn was harvested at the same time and ensiled for 7 months. Dried unground corn silage was put into 288 (3 per time points/treatment/cow) 10×20cm bags and incubated for 8 different time points (0, 2, 4, 8, 12, 48, 72, and 96h). A sample of unground dried corn silage was also placed into 20×40cm bag and incubated for 48h. Digestibility of corn silages was estimated using in situ procedure with 3 rumen-cannulated lactating multiparous Holstein cows. The degradable fraction of dry matter (DM) tended to be greater (P=0.08) for corn silages treated with fungicide when compared with CON. There was no treatment effect (P>0.05) on neutral detergent fiber (aNDF), acid detergent fiber (ADF), starch, and crude protein (CP). However, the soluble fraction of DM, aNDF, and ADF decreased (P<0.05) as fungicide applications increased. Effective degradability (ED) was greater (P<0.05) in CON than corn silages treated with fungicide mainly due to decreased ED in 3X compared with 1X and 2X. In situ digestibility for bigger and smaller bags was different. Degradability of DM, aNDF, and ADF was higher (P<0.05), while starch and CP degradability was lower (P<0.01) in the larger bags. Fungicide application to corn for silage lead to higher DM degradable fraction which seems to be the result of increased sugar and starch along with decreased aNDF and ADF.

Effects of silage crop and dietary crude protein levels on digestibility, ruminal fermentation, nitrogen use efficiency, and performance of finishing beef cattle

Two trials were conducted to evaluate the effects of silage crop and levels of dietary crude protein (CP) in Nellore beef cattle. The experimental diets consisted of Stylosanthes (StS) or corn silage (CS) with two levels of dietary CP, 110 and 130g CP/kg diet on a dry matter (DM) basis. The forage to concentrate ratio was 50:50 on a DM basis. In Experiment 1, the four bulls that were used had an average initial body weight (BW) of 450±37.9kg, and were surgically cannulated in the rumen and abomasum. The bulls were assigned to a 4×4 Latin square with a 2×2 factorial design of treatments, and four 16-d periods. During this experiment, we collected ruminal fluid, abomasal digesta, feces, urine, and blood. In addition, the kinetic parameters of DM, CP, and neutral detergent fiber (NDF) degradation were estimated. In Experiment 2, 40 bulls with an average initial BW of 374±16.5kg were distributed into a 2×2 factorial in a randomized design with ten replicates. The trial lasted for 99 d and was divided into a 15-d period for adaptation and an 84-d period for data collection. The intake and digestibility of nutrients as well as animal performance were evaluated in Experiment 2. The potentially degradable fractions of DM, CP, and NDF of StS were lower than CS (P<0.004). The diets containing StS showed lower ruminal digestibility of organic matter (OM) and lower total tract digestibility of OM, CP, and NDF than diets containing CS (P<0.050). The StS-based diets showed higher values for ruminal pH in comparison with CS-based diets (P=0.010). The ruminal NH3–N concentration was higher for the level of 130g CP/kg diet in comparison with the 110g CP/kg diet (P<0.001). The dietary CP level affected urea nitrogen in blood (P<0.001) and urine (P=0.017), which were higher in the diets containing StS and CS at the level of 130g CP/kg diet. The diets containing StS showed a higher intake of DM, OM, CP, NDF, and indigestible neutral detergent fiber (iNDF) than diets containing CS (P<0.008). However, the amount of digested nutrients (kg/d) was similar between treatments (P>0.050). The silage crop and dietary CP levels had no effect on productive performance (P>0.050), but the StS-based diet tended to decrease feed efficiency (P=0.085). Thus, StS, as well as the level of 110g CP/kg diet, can be used to feed finishing beef cattle.

Degradabilidade ruminal in situ de silagens de capim-elefante aditivadas com farelo de milho e inoculante da microbiota autóctone

Objetivou-se avaliar a degradabilidade ruminal in situda matéria seca, proteína bruta e fibra em detergente neutro de silagens de capim-elefante aditivadas com farelo de milho e inoculante da microbiota autóctone. Para as silagens foi utilizado esquema fatorial 4x2 (quatro níveis de farelo de milho - 0, 5, 10 e 20 dag/kgx com e sem inoculante) e cinco repetições, em delineamento inteiramente casualizado. No ensaio de degradabilidade, o delineamento experimental utilizado foi o de blocos ao acaso, com parcelas subdivididas, no qual os três animais representaram os blocos; as silagens representam os sete tempos de incubação dos alimentos no rúmen (0, 6, 12, 24, 48, 96 e 144 horas), as subparcelas. Houve acréscimo da fração solúvel nas silagens com adição do farelo de milho, sendo que no tratamento com 20dag/kg proporcionou o maior resultado, com 31,49 e 29,02%, para os tratamentos sem e com inoculante, respectivamente. A fração insolúvel potencialmente degradável, da matéria seca, foi maior nas silagens com 20dag/kg de farelo de milho. Na fibra em detergente neutro, os maiores valores fração insolúvel potencialmente degradável foram observados nas silagens sem farelo de milho, 56,52 e 57,19%, respectivamente, nas silagens de capim sem e com inoculante da microbiota autóctone. A adição de farelo de milho em silagens de capim-elefante melhora a degradabilidade da matéria seca das silagens e diminui a da fibra em detergente neutro.

Relationship between chemical composition and in situ rumen degradation characteristics of grass silages in dairy cows

The DVE/OEB2010 system in the Netherlands uses a large database of in situ rumen incubations with grass silage and grass hay samples to derive prediction formulas to estimate the rumen degradation characteristics of a number of feed value parameters. These in situ rumen incubations were not performed for this specific purpose and the data were generated at different research institutes over more than 40 years, using different grass management and fertilization practices and using different protocols. The objectives of this study were to 1) generate a new database on the rumen degradability of dry matter (DM), organic matter (OM), crude protein (CP) and neutral detergent fibre (NDF) of grass silages, 2) compare this new database with the old database used in the DVE/OEB2010 system, and 3) derive regression equations using the new database to investigate the relationships between chemical composition and in situ ruminal degradation characteristics of DM, OM, CP and NDF of the grass silages. Sixty nine grass silages, with a broad range in chemical composition and quality parameters, were selected and incubated using the nylon bag technique in the rumen of three lactating Holstein Friesian cows for 2, 4, 8, 16, 32, 72 and 336h. There was a large range in the rumen degradable fractions of DM, OM, CP and NDF of the grass silages at each rumen incubation period. The data on the rumen degradation characteristics of DM, OM, CP and NDF in the present study were determined using the same standard incubation protocol, the same cows, and the same chemical analysis procedures for all the grass silage samples. Regression analysis, using the new database, showed relationships between the washable (W) fraction, rumen undegradable (U) fraction, potentially rumen degradable (D) fraction and effective rumen degradation (ED) of DM, OM, CP and NDF, respectively, and the chemical composition of the grass silages.

Relationship between chemical composition and in situ rumen degradation characteristics of maize silages in dairy cows

Several in situ studies have been conducted on maize silages to determine the effect of individual factors such as maturity stage, chop length and ensiling of maize crop on the rumen degradation but the information on the relationship between chemical composition and in situ rumen degradation characteristics remains scarce. The objectives of this study were to determine and describe relationships between the chemical composition and the rumen degradation characteristics of dry matter (DM), organic matter (OM), CP, starch and aNDFom (NDF assayed with a heat stable amylase and expressed exclusive of residual ash) of maize silages. In all, 75 maize silage samples were selected, with a broad range in chemical composition and quality parameters. The samples were incubated in the rumen for 2, 4, 8, 16, 32, 72 and 336 h, using the nylon bag technique. Large range was found in the rumen degradable fractions of DM, OM, CP, starch and aNDFom because of the broad range in chemical composition and quality parameters. The new database with in situ rumen degradation characteristics of DM, OM, CP, starch and aNDFom of the maize silages was obtained under uniform experimental conditions; same cows, same incubation protocol and same chemical analysis procedures. Regression equations were developed with significant predictors (P<0.05) describing moderate and weak relationships between the chemical composition and the washout fraction, rumen undegradable fraction, potentially rumen degradable fraction, fractional degradation rate and effective rumen degradable fraction of DM, OM, CP, starch and aNDFom.

Chemical composition, intake by sheep, and in situ disappearance in cannulated cows of bermudagrass hayed at two moisture concentrations and treated with a non-viable Lactobacillus-lactic acid preservative

Bermudagrass [ Cynodon dactylon (L.) Pers.] is commonly used for grazing and haying in the southern USA, but hay curing can be challenging due to frequent rainfall events during spring and early summer. An existing stand of ‘Greenfield’ bermudagrass was divided into 12 plots using a randomized complete block design with a 2×2 factorial treatment arrangement to evaluate the influence of a non-viable Lactobacillus-lactic acid preservative and moisture concentration at baling on chemical composition, intake by sheep, and in situ disappearance in cattle. At time of mowing, half of the plots in each block were either spray-treated (T) or not treated (U) with 81 mL/t forage dry matter (DM) of the preservative solution. Hay was then baled at target moisture concentrations of either 174 g/kg DM (L) or 267 g/kg DM (H). Maximum temperature and heating degree days were greater (P<0.05) from H compared with L during the 42-d storage period. An interaction between spray and moisture treatments tended (P<0.10) to affect recovery of DM; recoveries for LT (0.992) differed (P<0.10) from HT (0.913), but LU and HU were intermediate between the spray-treated hays, and did not differ from either (P>0.10). Post-storage nutritive value was largely influenced by moisture treatments only. Intake and digestibility, and in situ DM disappearance of these same hays were determined using 16 wether lambs (43 ± 3.7 kg initial BW), or six ruminally cannulated cows (617 ± 3.5 kg initial BW), respectively. Dry matter intake by sheep was not affected by either treatment factor (P>0.05), but DM digestibility and digestible DM intake were greater (P<0.05) from U compared with T. The in situ immediately soluble DM portion was greater from (P<0.05) L compared with H, but the reverse was true for the potentially degradable DM fraction. The lag time tended (P<0.10) to be greater from H compared with L. Treating bermudagrass with a non-viable Lactobacillus acidophilus-lactic acid spray product at time of baling may not offset the negative effects on forage quality and digestibility of baling bermudagrass hay at excessive moisture concentrations.

Cinética da degradação ruminal de dietas contendo farelo de casca de pequi

A casca de pequi é um resíduo do processamento do fruto, encontrado em grande volume nas regiões do cerrado brasileiro, que pode constituir uma alternativa para a alimentação de ruminantes. Avaliou-se a cinética da degradação ruminal da matéria seca (MS), proteína bruta (PB) e fibra em detergente neutro (FDN) do farelo da casca de pequi (FCP) e de dietas contendo diferentes níveis do resíduo em substituição ao capim-elefante (CE). Foram utilizados quatro caprinos, machos, portando cânulas ruminais, dispostos em um delineamento experimental de blocos ao acaso com parcela subdividida. Avaliaram-se os parâmetros de degradabilidade do FCP, capim-elefante e de dietas contendo 0, 10, 20 e 30% de FCP em substituição ao CE. Os alimentos foram incubados no rúmen nos tempos de 4, 8, 12, 24, 48, 72 e 96 horas. Os resultados indicaram degradação potencial da MS, PB e FDN do resíduo superiores a 90, 80 e 80%, respectivamente. A adição do FCP em substituição ao CE resultou em maior degradabilidade da matéria seca e fibra em detergente neutro, reflexo da maior fração solúvel e potencialmente degradável da MS do FCP. Para a fração protéica, a adição de FCP correlacionou-se negativamente com a fração solúvel, degradação potencial e efetiva, e positivamente com a fração insolúvel potencialmente degradável. A substituição do capim-elefante por FCP permite melhor aproveitamento da dieta, elevando o aporte de nutrientes ao animal.

Influence of palm fatty acid distillate on rumen degradability and protozoa population in buffaloes

Oil and fat as energy sources at low cost are relevant in ruminant nutrition. The aim of this study was to evaluate the effects of palm fatty acid distillate (PFAD) on the degradability and ciliate protozoa population in buffalo. Four rumen fistulated buffaloes were fed a basal diet in a Latin square (4×4) design trial. Treatments were designed with four of different levels of PFAD added directly into the rumen: 0; 200; 420 and 500 g/animal/d. High levels of PFAD (420 and 500 g/d) promoted higher degradation of the soluble fraction and lower in potentially degradable fraction of dry matter (DM) and neutral detergent fibre (NDF) with lower values of potential and effective degradability in two evaluated grasses, bermudagrass and brachiariagrass. Significant decreases in the total number of protozoa/mL of rumen content, Entodinium and ciliates belonging to subfamily Diplodiniinae were observed at higher level of PFDA addition in the rumen. Also, Epidinium and Holotrich ciliates disappeared from the rumen. Significant correlations were observed of the ciliate concentration and composition as a function of dietary lipids content. Entodinium composition increased from 68.0% to 99.6% and Diplodiniinae reduced from 30.4% to 0.4% with increasing PFAD level indicating higher fat toxicity effect on the Diplodiniinae ciliates than Entodinium species and direct action of the larger ciliates on the fibre degradation.

Cinética ruminal de espécies forrageiras nativas da caatinga

This study aimed at evaluating the kinetics of in situ ruminal degradation of the dry matter (DM), crude protein (CP) and neutral detergent fiber (NDF) of five local forage species from the semi-arid region of Paraiba (Brazil): “Orelha de Onca” (Macroptilium Martii Benth), “Amor de Vaqueiro” (Desmodium canum), “Feijao Bravo” (Capparis Flexuosa), “Manicoba” (Manihot Epruinosa) and “Imburana de Cambao” (Camniphora leptophloes). Four two-year-old male sheep, castrated, belonging to the breed Santa Ines, with an average weight of 40 kg, previously rumen-fistulated, were distributed in an entirely randomized statistical design, with subdivided portion. The animals were housed in individual stalls and fed ad libitum with diets containing hays of the studied forages and a mineral supplementation. The foods were ground, put into nylon bags and incubated during 0, 6, 12, 24, 48 and 96 hours. Chemical-bromatological analyses of the forages were carried out to determine in situ ruminal degradation. The solubility of DM was larger for “Feijao Bravo” hay. For the potentially degradable fraction of DM, "Manicoba" hay presented the highest average value. Compared to the other forages, "Manicoba" and “Feijao Bravo” hays showed the lowest percentage of the undegradable fraction (P <0,01), but the highest PD and ED (2-5%/h) of DM (P <0,01). “Feijao Bravo” hay presented the highest rates of PD and ED (2-5%/h) of CP. Among the forages examined, "Manicoba" and “Feijao Bravo” hays presented the best potential for feeding. The degradability in the DM, CP and NDF indicated the best potential of use for “Feijao Bravo” and "Manicoba", since the nutritional quality and efficiency of utilization in the rumen was higher for these forages.

Cinética ruminal de espécies forrageiras nativas da caatinga

This study aimed at evaluating the kinetics of in situ ruminal degradation of the dry matter (DM), crude protein (CP) and neutral detergent fiber (NDF) of five local forage species from the semi-arid region of Paraiba (Brazil): “Orelha de Onca” (Macroptilium Martii Benth), “Amor de Vaqueiro” (Desmodium canum), “Feijao Bravo” (Capparis Flexuosa), “Manicoba” (Manihot Epruinosa) and “Imburana de Cambao” (Camniphora leptophloes). Four two-year-old male sheep, castrated, belonging to the breed Santa Ines, with an average weight of 40 kg, previously rumen-fistulated, were distributed in an entirely randomized statistical design, with subdivided portion. The animals were housed in individual stalls and fed ad libitum with diets containing hays of the studied forages and a mineral supplementation. The foods were ground, put into nylon bags and incubated during 0, 6, 12, 24, 48 and 96 hours. Chemical-bromatological analyses of the forages were carried out to determine in situ ruminal degradation. The solubility of DM was larger for “Feijao Bravo” hay. For the potentially degradable fraction of DM, Manicoba hay presented the highest average value. Compared to the other forages, Manicoba and “Feijao Bravo” hays showed the lowest percentage of the undegradable fraction (P <0,01), but the highest PD and ED (2-5%/h) of DM (P <0,01). “Feijao Bravo” hay presented the highest rates of PD and ED (2-5%/h) of CP. Among the forages examined, Manicoba and “Feijao Bravo” hays presented the best potential for feeding. The degradability in the DM, CP and NDF indicated the best potential of use for “Feijao Bravo” and Manicoba, since the nutritional quality and efficiency of utilization in the rumen was higher for these forages.