Tract Organic Matter Digestibility Research Articles

Precise evaluation of the nutritional value of yeast culture and its effect on pigs fed low-protein diets

The purpose of the present study was to assess the nutritional value of yeast culture (YC) and to explore the effect of YC on growth performance and health of piglets fed low-protein (LP) diets. In Exp.1, 12 growing barrows were allocated into control diet and YC diet treatments to determine the available energy of YC. Results showed that the digestible energy and metabolizable energy of YC are 12.12 and 11.66 MJ/kg dry matter (DM), respectively. In Exp.2, 12 growing barrows were surgically equipped with a T-cannula near the distal ileum and were assigned to 2 dietary treatments (nitrogen-free diet and YC diet), and the amino acid digestibility of YC was determined. In Exp.3, a total of 96 weaned piglets were randomly divided into 4 treatments, including LP basal diet (Basal), Basal+0.5% YC (0.5%YC), Basal+1.0% YC (1%YC), and Basal+1.5% YC (1.5%YC). The results were as follows: YC supplementation linearly improved the weight gain and feed intake ratio (P < 0.001), linearly increased the activity of glutathione peroxidase on d 14 (P = 0.032) and linearly decreased the concentration of malondialdehyde on d 14 (P = 0.008) and d 32 (P = 0.004) in serum, and linearly decreased the concentration of total short-chain fatty acid on d 14 in feces (P = 0.045). Compared with other treatments, 1.5%YC group showed a greater abundance of various probiotics, such as Prevotellaceae, Prevotella and Turicibacter. In Exp.4, twelve growing barrows with an ileal T-cannula were randomly assigned to Control and 1.5%YC treatments to clarify the impact of YC supplementation on nitrogen balance and nutrient digestibility. Results showed that YC had no significant effect on nitrogen efficiency and nutrient digestibility, except for trend of reducing the total tract digestibility of organic matter (P = 0.067). In conclusion, the present study assessed the digestible and metabolizable energy values (12.12 and 11.66 MJ/kg DM, respectively) and standardized ileal digestibility of amino acid (from 43.93% to 82.65%) of YC in pig feed and demonstrated that moderate supplementation of YC (1.5% of diet) can effectively improve feed conversion efficiency, enhance antioxidant capacity, and promote a balanced gut microbiota in piglets.

PSVI-5 Extruded blend of Nannochloropsis oculata microalgae and flaxseed and its effects on ruminal fermentation and nutrient digestion

Abstract Omega-3 fatty acids are essential nutrients for mammals, and are required for cellular growth and synthesis of numerous cellular signaling molecules. NBO3 Technologies, LLC (Manhattan, KS) has developed an omega-3 supplement consisting of an extruded blend of flaxseed and Nannochloropsis oculata microalgae (GreatOplus; GOP). Our objective was to evaluate effects of GOP on dry matter intake (DMI), water intake (WI), ruminal metabolism, and apparent total tract nutrient disappearance in cannulated Holstein steers (n = 11; initial body weight 586.4 ± 49.7 kg). Treatments consisted of backgrounding diets (40% roughage, 60% concentrate) containing 0% (CON) or 10% GOP (dry basis). Feed and water intake were recorded using an Insentec Roughage and Water monitoring system (Hokofarm Group; Emmeloord, The Netherlands). Steers were utilized in a cross-over design with two 19-d periods. Each period consisted of a 15-d adaptation phase and a 4-d collection phase. Ruminal contents, duodenal digesta, and feces were collected at 8-h intervals for 4 d starting at 1000 h on d 16. The sampling schedule was advanced by 2 h with each subsequent sampling day, thus generating a 24-h profile at 2-h intervals post-feeding over the 4-d sampling phase. Titanium dioxide (15 g) was dispensed directly into the rumen of each steer 15 min before feeding and to estimate apparent ruminal flow and fecal excretion of nutrients. There was a Treatment X Day interaction for DMI (P &amp;lt; 0.001); DMI was greater for steers fed GOP some of the days during the adaptation phase compared with steers fed the control diet, but intakes were similar during the collection phase. Ruminal fluid pH, ruminal ammonia concentration, and WI were not affected by treatment (P &amp;gt; 0.10). As expected, ruminal outflows of total fatty acids (195.6 vs 338.1 g/d for CON and GOP, respectively) and α-linolenic acid (ALA; 1.6 vs 6.3 g/d, respectively) were greater for steers fed GOP compared with steers fed CON (P &amp;lt; 0.05); however, ruminal disappearance (i.e., biohydrogenation) of ALA was extensive, with only 8% and 4.7% of ALA intake exiting the rumen for CON and GOP, respectively. Apparent total tract digestion of organic matter was not impacted by diet (P &amp;gt; 0.20; 78.1 and 76.8% for CON and GOP, respectively). Supplementing an extruded blend of flaxseed and microalgae can effectively increase the amount of α-linolenic acid available for absorption in the small intestine, but overall recovery of dietary α-linolenic acid is relatively low due to extensive biohydrogenation by microbes within the rumen.

PSXII-24 Examining Relationships Between Residual Feed Intake Classification, Enteric Emissions, and Apparent Total Tract Digestibility in Late Gestation Beef Heifers

Abstract Improving feed efficiency on forage-based systems can be an important tool for beef producers to reduce their environmental footprint. The objective of this project is to assess the relationship between traditional residual feed intake (RFI) efficiency classification, enteric gas emissions, and apparent total tract nutrient digestibility in late gestation beef heifers. Pregnant Angus crossbred heifers in late gestation (n = 72, BW = 576 ± 45.8 kg) were blocked by expected calving date and randomly assigned to pen groups. Heifers had ad libitum access to a common haylage-based diet formulated to meet nutritional requirements for the last eight weeks of gestation. Individual feed intake and behavior data were recorded daily using Insentec feeding stations (Insentec B.V., Marknesse, The Netherlands). Groups of heifers were rotated through pens with access to GreenFeed trailers (C-Lock Inc., Rapid City, SD, USA) to measure enteric gas emissions of methane (CH4), carbon dioxide (CO2), and oxygen (O2). To determine individual apparent total tract digestibility, fecal samples were collected from each heifer every 9 h over three days, mixed, dried at 65 °C for 96 h, and analyzed for nutrient values (A&amp;L Canada Laboratories, London, ON, Canada). Nutrient digestibility was determined for each heifer using acid-insoluble ash (AIA) and undigestible neutral detergent fiber (uNDF) as internal markers. Heifer RFI was determined using predicted DM intake as a regression of midpoint BW and ADG, and heifers were classified by RFI quartile group. Data were analyzed using PROC GLIMMIX in SAS, with efficiency quartile group as the fixed effect and pen as a random effect, comparisons between quartile groups were assessed with a Tukey test. Heifers classified as efficient (lowest RFI) had decreased DMI (8.2 vs 10.7 ± 0.21 kg/d, P &amp;lt; 0.01), less bunk visits (43 vs 64 ± 5 visits/day, P &amp;lt; 0.01) and greater time per visit (4.8 vs 3.0 ± 0.53 min/visit, P = 0.05). Efficient heifers also had reduced CH4 (219 vs 245 ± 6.2 g/d, P = 0.03) and CO2 (7,517 vs 8,074 ± 165.9 g/d, P = 0.01) emissions compared with inefficient (greatest RFI) heifers. However, apparent total tract digestibility of organic matter, crude protein, NDF, ADF, starch, and sugar using AIA (P &amp;gt; 0.08) or uNDF (P &amp;gt; 0.06) as internal markers were not correlated with heifer efficiency. These data indicate that more efficient heifers in late gestation consume less feed and have reduced enteric emissions, despite no differences in apparent total tract digestibility.

PSVI-3 Effects of Different Concentrate Inclusion Levels in Diets Containing Agri002E Sorghum Silage on Intake and Digestibility in Growing Nellore Bulls

Abstract The sorghum hybrid, AGRI002E, sorghum was developed for high dry matter (DM) production per area. However, there are no reports in the literature evaluating the use of this silage with different inclusion levels of concentration on the ingestive and digestive variables of beef cattle. Therefore, this study aimed to access the effects of different concentrate levels in diets containing AGRI002E sorghum silage (SS) on feed intake, ruminal and apparent total tract digestibilities of organic matter (OM), neutral detergent fiber corrected for contaminant ash and protein (apNDF), and starch. Nellore rumen-cannulated bulls (n = 5; BW = 242 ± 5 kg) were used in a 5×5 Latin square design. The experimental treatments consisted of five concentrate levels (0, 200, 400, 600, and 800 g of concentrate/kg of diet DM) in SS-based diets. The concentrates used in the experimental diets were based on corn, soybean meal, sulfated urea, virginiamycin, and mineral supplement. The diets were formulated to provide approximately 120 g of crude protein per kg dietary DM. In the 0% concentrate diet, the protein level was adjusted with sulfated urea. All diets contained the same amount of virginiamycin and mineral supplement. Each experimental period lasted 24 d, with 17 d adaptation, 4 d of total feces collection, and 3 d collection to obtain omasal flow using a double marker technique (indigestible NDF and Co-EDTA). Data were analyzed using MIXED-SAS. Starch and OM intake linearly increased (P &amp;lt; 0.001) with increasing concentrate inclusion. Intake of apNDF decreased linearly (P = 0.018) and tended to be quadratically influenced (P = 0.022) with increasing concentrate inclusion (Table 1). Ruminal digestibility of OM increased linearly (P &amp;lt; 0.001) with increasing concentrate inclusion. Starch ruminal digestibility decreased linearly (P = 0.003) and tended to be influenced quadratically (P = 0.0015) with increasing concentrate inclusion. Ruminal digestibility of apNDF tended to decrease linearly (P = 0.057) with increasing concentrate inclusion. Total apparent digestibility of OM increased linearly (P &amp;lt; 0.001) and apNDF and starch total apparent digestibility decreased linearly (P ≤ 0.002) with increasing concentrate inclusion. Increasing inclusion of concentrate in AGRI002E sorghum silage-based diets increased OM and starch intake, and ruminal and total apparent OM digestibility and decreased apNDF intake and ruminal and apNDF and starch total apparent digestibility.

Effect of canola oil supplementation level on total tract digestion, ruminal fermentation, and methane emissions of cows grazing Urochloa sp. supplemented with a fixed amount of concentrate

Four rumen-cannulated cows (Bos taurus × Bos indicus, 657 ± 92 kg body weight, BW) in a rotational grazing (Urochloa sp.) system were assigned to different canola oil (CO) inclusion levels, 0.0, 0.40, 0.80, and 1.2 g/kg according to shrunk body weight (SBW, BW adjusted for gastrointestinal filling) in a 4 × 4 Latin Square design to evaluate CO on the CH4 emissions and dietary energy intake. CH4 emissions were estimated using an infrared analyzer methodology (Sniffer method). Grass intake and fecal production were estimated using Cr2O3 as an external marker. CO supplementation increased (linear effect, P ≤ 0.05) total dry matter and gross energy intake with a linear increase (P = 0.09) in neutral detergent fiber (NDF) intake. While digestible energy (Mcal/kg) linearly increased with increasing CO supplementation level (linear effect, P < 0.05), total tract digestion of organic matter, NDF, and CP was comparable (P > 0.05) between levels. Maximal CO supplementation (1.2 g/kg SBW) significantly decreased total ruminal protozoa population, acetate:propionate ratio, and enteric methane production (g/kg DMI) by 9, 5.3, and 17.5%, respectively. This study showed that, for cows grazing tropical forages, CO can be supplemented up to 1.2 g/kg SBW (5.8% of the total diet) without negatively affecting intake and nutrient digestion while reducing ruminal fermentation efficiency and enteric methane emission (≤ 17.5%).

Influence of level of dried distillers grains plus solubles substitution for steam-flaked corn on characteristics of growth performance, and dietary energetics of calf-fed Holstein steers during the initial 16-week growing phase: metabolizable protein versus metabolizable amino acids.

This study evaluates the partial replacement of steam-flaked corn (SFC) with increasing dried distillers grains plus solubles (DDGS) levels in growing-finishing diets for calf-fed Holstein steers. Two experiments were conducted. In trial 1, 100 Holstein calves (136 ± 7 kg) were used to evaluate the effect of DDGS as a metabolizable protein source on cattle growth performance, and dietary energetics of calf-fed Holstein steers during the initial 111 d growing phase. Four dietary levels of DDGS were evaluated (10, 15, 20, and 25%, dry matter basis), replacing SFC (flake density, 0.31 kg/L). In trial 2, four Holstein steers (368 ± 20 kg) with cannulas in the rumen and proximal duodenum were used to evaluate treatment effects on characteristics of ruminal and total tract digestion of organic matter (OM), neutral detergent fiber, nitrogen (N), and indispensable amino acid supply to the small intestine. The increasing level of DDGS did not affect (P ≥ 0.13) average daily gain, gain efficiency, and estimated dietary net energy values. Replacement of SFC with increasing levels of DDGS decreased (linear; P = 0.01) ruminal OM digestion. There was no treatment effect on the flow of microbial nitrogen to the small intestine (P = 0.34) and ruminal microbial efficiency (P = 0.79). However, increasing levels of DDGS in the diet increased (linear; P ≤ 0.04) flow of methionine, histidine, phenylalanine, threonine, leucine, isoleucine, and valine but did not affect (P = 0.74) intestinal supply of lysine. Increasing DDGS in the diet increased (linear, P < 0.01) flow of N to the small intestine but decreased (linear; P < 0.01) ruminal N efficiency. Replacing SFC with DDGS increased intake and amino acid leaving the abomasum. Still, this effect was not sufficient to increase the growth performance of calf-fed Holstein during the first 111 d on feed.

Exogenous enzymes, meal size, and meal frequency: effect on ileal and total tract digestibility of carbohydrates, and energy and fiber degradation in growing pigs fed a wheat-barley grain-based high-fiber diet.

When conducting a digestibility trial, pigs are usually fed only twice a day with a restricted feed intake which is not representative of the feeding conditions in a commercial farm. This study aimed to determine the effects of meal size and frequency, and exogenous enzymes (xylanase and phytase) on the digestibility of a high-fiber diet using porcine in vivo and in vitro approaches. Pigs (n = 6) were fitted with a T cannula, and each received all treatments using a 6 × 6 Latin square experimental design. The diets were supplemented (Enz) or not with a combination of xylanase and phytase and distributed into three feeding programs: one received two meals per day that met three times the maintenance energy requirement (2M), one received the same quantity of feed in eight meals (8M), and another received an amount that met five times the maintenance energy requirements in eight meals (8M+). For in vitro experiment, the degradability of fiber with or without xylanase supplementation only was determined. Enzyme supplementation increased apparent ileal digestibility (AID) of dry matter, starch, and degradation of insoluble non-starch polysaccharides (I-NSP) in all in vivo treatments (P < 0.05). The 2M compared with 8M increased the AID of starch and total tract digestibility of organic matter and I-NSP (P < 0.05). Enzyme supplementation decreased the content of insoluble arabinoxylan (P < 0.05) and increased arabinoxylan oligosaccharides (P < 0.05) in the in vivo ileal digesta and in vitro incubation. The results of this study confirm degradation by xylanase of the fiber fraction at the ileal level, which resulted in less fermentation of fiber in the large intestine. However, number and size of meals had little influence on feed digestibility. The consequences of shifting fiber fermentation more towards the upper part of the gastrointestinal tract need further investigation. The in vitro model provided a confirmation of the action of xylanase on the degradation of non-starch polysaccharides.

Interaction of replacing corn silage with soyhulls as a roughage source with or without 3% added wheat straw in the diet: impacts on intake, digestibility, and ruminal fermentation in steers fed high-concentrate diets.

Six ruminally cannulated steers [475.0 ± 49.6 kg initial body weight (BW)] were used in a 6 × 3 incomplete Latin square design (six treatments and three periods), to evaluate the impacts replacing of corn silage with pelleted soyhulls as roughage in high-concentrate finishing diets containing 30% modified distillers grains with solubles. Treatments were based on increasing dietary inclusion of soyhulls and consisted of: (1) Control (0), roughage supplied by dietary inclusion of 20% corn silage [dry matter (DM) basis]; (2) 50% replacement of corn silage with soyhulls (50); (3) 100% replacement of corn silage with soyhulls (100), and the same three treatments repeated with 3% added wheat straw (DM basis) replacing corn in the diet (0S, 50S, and 100S, respectively). Absolute dry matter intake (DMI; kg/d basis) tended to decrease both linearly and quadratically (P ≤ 0.09) and proportional DMI (% of BW) decreased linearly (P = 0.04) with increasing soyhull inclusion but was not affected by the addition of straw in the diet (P = 0.68). Total tract digestibility of organic matter and crude protein were not affected by soyhull inclusion or added straw (P ≥ 0.32). Ruminal pH did not differ (P = 0.65) with increasing soyhull inclusion but increased with the addition of straw (P < 0.01; 5.9 vs. 6.1 for no straw and straw, respectively). Molar proportions of acetate and butyrate decreased while propionate increased with increased soyhull inclusion (P ≤ 0.03; linearly and quadratically, respectively). Ruminal fluid kinetics were unaffected by either rate of replacement of corn silage with soyhulls or wheat straw inclusion (P ≥ 0.13). Decreases in DMI observed in this study would likely decrease finishing cattle performance and underscores the need for additional research before recommending this practice to cattle feeders.

Nutritive value for ruminants of different fresh and ensiled sorghum (Sorghum bicolor (L.) Moench) varieties harvested at varying maturity stages

ABSTRACT The occurrence of the Western corn rootworm and increasing frequency of summer droughts have reduced forage maize yields and quality in Central Europe in recent years. Therefore, sorghum (Sorghum bicolor (L.) Moench) has been increasingly used as alternative forage in ruminant feeding, although information on the nutritive value of whole crop sorghum silage (WCSS) under Central European climate conditions is scarce. This research project aimed to study differences between sorghum varieties and harvest dates regarding dry matter (DM) yield, chemical composition of fresh panicle, fresh stover, fresh whole plant and WCSS as well as whole tract digestibility and energy content of WCSS. For this purpose, six sorghum varieties, classified by their predominant use (biomass, silage, grain), were cultivated and harvested at three maturity stages (late milk stage, dough stage, full maturity). Furthermore, WCSS quality was compared with feed value of fresh and ensiled forage maize. Dry matter yield was higher (p < 0.05) in biomass sorghum (24.9 t/ha) compared to other sorghum varieties (12.4 to 16.7 t/ha). However, panicle proportion was lowest in biomass sorghum (10.5%), highest in grain sorghum (59.1%) and intermediate in silage sorghum. Fibre content declined and starch content increased with rising panicle proportion in fresh panicle, fresh whole plant and WCSS. Therefore, whole tract organic matter digestibility (66.8%) and metabolisable energy (ME) content (9.49 MJ/kg DM) were highest in grain sorghum silage. Especially low ME content was found in the biomass sorghum silage (7.43 MJ/kg DM). Dry matter yield of sorghum increased between late milk and dough stage of maturity, while it remained constant afterwards. Furthermore, ME content of WCSS rose tendentially (0.05 < p < 0.10) between late milk and dough stage of maturity and dropped again between dough stage and full maturity. Highest nutritive value of WCSS is achieved if grain sorghum varieties are used and both nutritive value and DM yield are optimised if harvest is carried out at dough stage of maturity. However, compared to forage maize, grain sorghum varieties have disadvantages both in DM yield and in nutritive value under common Central European climate conditions.

Evaluation of graded levels of Bacillus coagulans GBI-30, 6086 on apparent nutrient digestibility, stool quality, and intestinal health indicators in healthy adult dogs

Bacillus coagulans GBI-30, 6086 is a commercially available spore-forming non-toxigenic microorganism approved for use in dog foods with high resiliency to stresses associated with commercial manufacturing. The objectives of this research were to examine the effect of B. coagulans on stool quality, nutrient digestibility, and intestinal health markers in healthy adult dogs. Extruded diets containing graded levels of B. coagulans applied either to the base ration before extrusion or to the exterior of the kibble as a topical coating after extrusion were randomly assigned to 10 individually housed adult beagle dogs (7 castrated males and 3 spayed females) of similar age (5.75 ± 0.23 yr) and body weight (12.3 ± 1.5 kg). The study was designed as a 5 × 5 replicated Latin square with 16-d adaptation followed by 5-d total fecal collection for each period. Five dietary treatments were formulated to deliver a dose of 0-, 6-, 7-, 8-, and 9-log10 colony-forming units (CFU) per dog per day for the control (CON), extruded B. coagulans (PEX), and low, moderate, and high B. coagulans coating levels (PCL, PCM, and PCH), respectively. Food-grade TiO2 was added to all diets at a level of 0.4% to serve as an indigestible dietary marker for digestibility calculations. Data were analyzed using a mixed model through SAS (version 9.4, SAS Institute, Inc., Cary, NC) with treatment as a fixed effect and room (i.e., replicate), period, and dog(room) as random effects. Apparent total tract digestibility of organic matter, crude protein, crude fat, and gross energy calculated by the marker method were numerically greatest for dogs fed the 9-log10 dose treatment with increases (P < 0.05) observed in gross energy and organic matter digestibility compared with the negative control. No significant differences were observed in food intake, stool quality, fecal pH, fecal ammonia, fecal short-chain fatty acids, or branched-chain fatty acids for the extruded B. coagulans treatment (PEX) or the coated B. coagulans treatments (PCL, PCM, and PCH) compared with CON. These results suggest that B. coagulans has a favorable impact on nutrient digestibility and no apparent adverse effects when added to extruded diets at a daily intake level of up to 9-log10 CFU in healthy adult dogs.

Dichanthium hay combined with green cassava foliage or pelleted cassava foliage as fed for Black Belly rams

Intake, digestion and nitrogen retention were measured in fifteen 1-year-old Black Belly rams that had an average weight of 35.3 (± 1.59)kg and that consumed mixed diets. Diets consisted of old Dichanthium spp. hay distributed ad libitum, combined with 500g (dry matter basis) of green or pelleted cassava foliage. Alfalfa pellets were used as a control for foliage supplement. The experiment was run in a 3 × 3 Latin square design. Total dry matter intake was lower (P < 0.05) with the green foliage cassava diet compared with the alfalfa pellet diet. Differences were not significant (P < 0.12) with the green cassava foliage diet compared with the cassava foliage pellet diet. Total tract digestion of organic matter, crude protein and cell wall components in cassava green foliage and cassava foliage pellet diets were significantly lower than in the alfalfa diet. Crude protein total tract digestion was similar for cassava green foliage and cassava foliage pellet diets, while fibre digestion was lower with cassava green foliage diets. Retained nitrogen was significantly higher with the alfalfa diet compared with cassava diets-between which there were no differences. Urinary nitrogen excretion was similar between all diets. In conclusion, pelleting does not decrease the feed value of cassava foliage, but this value is nevertheless lower than the feed value of alfalfa.

Effects of energy sources and inclusion levels of concentrate in sugarcane-silage-based diets of finishing Nellore young bulls: Nutrient digestibility, rumen metabolism and ecosystem

AbstractIntake in sugar-rich diets can be limited either via rumen fill or excessive rumen fermentation and source of non-fibre carbohydrate (NFC) in the diet can affect both factors. The aim of the current study was to quantify the effect of partially replacing ground maize (GM) with steam-rolled maize (SRM) or pelleted citrus pulp (PCP) at two concentrate levels in sugarcane-based diets on digestibility, rumen ecosystem and metabolism of Nellore steers. Six rumen-cannulated steers were assigned to a 6 × 6 Latin square, replicated in time, in a 2 × 3 factorial arrangement of treatments with two levels of concentrate (600 or 800 g concentrate/kg dry matter [DM]) and three NFC sources. Each steer within a period was considered an experimental unit. Feeding more concentrate increased total tract digestibility of organic matter and decreased fibre intake and passage rate. It also reduced rumen populations ofFibrobacter succinogenesandStreptococcus bovisand increasedRuminococcus flavefaciens. Substituting PCP for GM increased rumen pH, acetic acid and organic matter digestibility. Feeding PCP also reducedR. flavefaciensandR. amylophilusrumen populations. Substituting SRM for GM increased starch digestibility and rumen propionic acid, but decreased rumen ammonia concentration. Feeding SRM increased rumen populations ofMegasphaera elsdeniiwith the high-concentrate diet but reducedRuminococcus albuspopulations at both concentrate levels. In conclusion, partial replacement of GM by PCP decreased intake in sugar-rich diets, while increasing total tract neutral detergent fibre digestibility. Replacement of GM with SRM increases rumen fermentation and total tract digestibility of starch.

Effects of ruminal degradability of ensiled whole crop maize varieties on feed intake and milk production of dairy cows

The feed value of whole crop maize silage (WCMS) depends on nutrient composition, ruminal degradability and whole tract digestibility. However, as the ruminal degradation rate is involved in physical regulation of feed intake, ruminal degradability of WCMS may also affect feed intake and milk production of dairy cows. Thus, the aim of this study was to examine relationships between nutrient composition, ruminal degradability, and whole tract digestibility of WCMS and feed intake and milk production of dairy cows. Nine varieties were tested in 3 consecutive years. Nutrient composition analyses included proximate analysis and determination of cell wall constituents. Whole tract digestibility was determined in vivo using wethers and ruminal degradability was examined in situ using four rumen-fistulated steers. Feed intake and milk production were measured using nine cows per variety. Cows were fed a ration consisting of 75.0% WCMS, 8.5% hay and 16.5% soya bean meal (dry matter basis) ad libitum. Variety did not influence nutrient composition, except for the concentration of ADF (ADFom), ADL and utilisable CP (uCP). In contrast, variety had a significant effect (P < 0.05) on ruminal degradability of NDF (aNDFom) and on whole tract digestibility of organic matter (OM) and non-fibre carbohydrates. Dry matter intake (DMI) of WCMS tended to be affected by variety (0.05<P < 0.10) whereas no effect on energy-corrected milk production (ECM) was observed. The year of harvest had an influence on net energy for lactation and uCP concentration, ruminal degradability and whole tract digestibility of nutrients, as well as on DMI and ECM of dairy cows. Whole tract aNDFom digestibility of WCMS was positively correlated with aNDFom concentration (R2 = 0.48) and whole tract OM digestibility (R2 = 0.58). Furthermore, ruminal OM degradability was positively correlated with DMI (R2 = 0.57) and ECM (R2 = 0.49) of dairy cows. The results indicate that ruminal degradability and whole tract digestibility have a greater impact on the feed value of WCMS than nutrient composition and should be focused on to optimise feed intake and milk production of dairy cows. Thus, maize breeders should include ruminal degradability and whole tract digestibility parameters in variety testing programs to increase the informative value of variety descriptions for farmers.

Effect of diet synchrony on rumen fermentation, production performance, immunity status and endocrine in Chinese Holstein cows

In order to maximise utilisation of nutrients for ruminants, researchers directed the supply of nitrogen and organic matter synchronously to the rumen. In the current research, two experiments were conducted, one using the in situ nylon bag technique and the other using in vivo study. In Experiment 1, dynamic degradation rates of organic matter (OM) and nitrogen of each feedstuff were determined using the in situ nylon bag technique. Accordingly, three diets were formulated with the same chemical components, but differing in synchrony index (0.74, 0.85 and 0.97). Experiment 2 was subsequently carried out in vivo to evaluate the influence of diet synchrony on rumen fermentation, productive performance, immunity status and endocrine in Chinese Holstein cows. Rumen degradability of OM and neutral detergent fibre (NDF) and total tract digestibility of OM were linearly increased with the increase of synchrony index, respectively (P &amp;lt; 0.05). Total volatile fatty acids concentration of rumen fluid was increased linearly with the increase of synchrony index (P &amp;lt; 0.05). Meanwhile, rumen ammonia nitrogen concentration and blood urea nitrogen concentration were decreased in cows with the increase of synchrony index, (P &amp;lt; 0.05). Microbial crude protein production, the efficiency of microbial protein synthesis, and milk protein percentage, were linearly increased with the increase of synchrony index (P &amp;lt; 0.05). Serum concentrations of prostaglandin E2 and immunoreactive fibronectin-γ were linearly decreased with the increase of diet synchrony index (P &amp;lt; 0.05). The aforementioned results implicate that an increase of diet synchrony index could improve diet’s nitrogen utilisation, apparent digestibility of OM, and NDF. Additionally, it could promote rumen fermentation capacity, productive performance and immunity status in dairy cows.

Plant oil supplements reduce methane emissions and improve milk fatty acid composition in dairy cows fed grass silage-based diets without affecting milk yield

Four lipid supplements varying in chain length or degree of unsaturation were examined for their effects on milk yield and composition, ruminal CH4 emissions, rumen fermentation, nutrient utilization, and microbial ecology in lactating dairy cows. Five Nordic Red cows fitted with rumen cannulas were used in a 5 × 5 Latin square with five 28-d periods. Treatments comprised total mixed rations based on grass silage with a forage-to-concentrate ratio of 60:40 supplemented with no lipid (CO) or 50 g/kg of diet dry matter (DM) of myristic acid (MA), rapeseed oil (RO), safflower oil (SO), or linseed oil (LO). Feeding MA resulted in the lowest DM intake, and feeding RO reduced DM intake compared with CO. Feeding MA reduced the yields of milk, milk constituents, and energy-corrected milk. Plant oils did not influence yields of milk and milk constituents, but reduced milk protein content compared with CO. Treatments had no effect on rumen fermentation characteristics, other than an increase in ammonia-N concentration due to feeding MA, RO, and SO compared with CO. Lipid supplements reduced daily ruminal CH4 emission; however, the response was to some extent a result of lower feed intake. Lipids modified microbial community structure without affecting total counts of bacteria, archaea, and ciliate protozoa. Dietary treatments had no effect on the apparent total tract digestibility of organic matter, fiber, and gross energy. Treatments did not affect either energy secreted in milk as a proportion of energy intake or efficiency of dietary N utilization. All lipids lowered de novo fatty acid synthesis in the mammary gland. Plant oils increased proportions of milk fat 18:0, cis 18:1, trans and monounsaturated fatty acids, and decreased saturated fatty acids compared with CO and MA. Both SO and LO increased the proportion of total polyunsaturated fatty acids, total conjugated linolenic acid, and cis-9,trans-11 conjugated linoleic acid. Feeding MA clearly increased the Δ9 desaturation of fatty acids. Our results provide compelling evidence that plant oils supplemented to a grass silage-based diet reduce ruminal CH4 emission and milk saturated fatty acids, and increase the proportion of unsaturated fatty acids and total conjugated linoleic acid while not interfering with digestibility, rumen fermentation, rumen microbial quantities, or milk production.

Effects of quebracho tannin extract (Schinopsis balansae Engl.) and activated charcoal on nitrogen balance, rumen microbial protein synthesis and faecal composition of growing Boer goats

ABSTRACTUnder irrigated arid conditions, organic fertiliser rich in slowly decomposable nitrogen (N) and carbon (C) is needed for soil fertility maintenance. Feeding ruminants with condensed tannins will lower ruminal protein degradation, reduce urinary N excretion and might increase the faecal fraction of slowly decomposable N. Supplementation with activated charcoal (AC) might enrich manure with slowly degrading C. Therefore, we investigated the effects of feeding quebracho tannin extract (QTE) and AC on the N balance of goats, the efficiency of microbial protein synthesis in the rumen (EMPS) and the composition of faeces. The feeding trial comprised three periods; in each period, 12 male Boer goats (28 ± 3.9 kg live weight) were assigned to six treatments: a Control diet (per kg diet 500 g grass hay and 500 g concentrate) and to further five treatments the Control diet was supplemented with QTE (20 g and 40 g/kg; diets QTE2 and QTE4, respectively), with AC (15 g and 30 g/kg, diets AC1.5 and AC3.0, respectively) and a mixture of QTE (20 g/kg) plus AC (15 g/kg) (diet QTEAC). In addition to the N balance, EMPS was calculated from daily excretions of purine derivatives, and the composition of faecal N was determined. There was no effect of QTE and AC supplementation on the intake of organic matter (OM), N and fibre, but apparent total tract digestibility of OM was reduced (p = 0.035). Feeding QTE induced a shift in N excretion from urine to faeces (p ≤ 0.001) without altering N retention. Total N excretion tended to decrease with QTE treatments (p = 0.053), but EMPS was not different between treatments. Faecal C excretion was higher in QTE and AC treatments (p = 0.001) compared with the Control, while the composition of faecal N differed only in concentration of undigested dietary N (p = 0.001). The results demonstrate that QTE can be included into diets of goats up to 40 g/kg, without affecting N utilisation, but simultaneously increasing the excretion of slowly decomposable N and C fractions. Feeding AC up to 30 g/kg of the diet increases slowly degradable faecal C concentration, without negative effects on N metabolism of goats.

Effects of two yeast based direct fed microbials on performance of high producing dairy cows

Our aim was to determine effects of two S. cerevisiae yeast based direct fed microbial (DFM) feed additives on the productive response of high producing early lactation dairy cows. The study consisted of three high producing Holstein cow pens (±315 cows/pen) in a 3×3 Latin square design experiment with 3 periods of 28 d each. The 3 treatments were: (1) Basal total mixed ration (Control), (2) Control supplemented with ‘XPC’ yeast culture at 14g/cow/d and, (3) Control supplemented with ‘Yeasture (YST)’ DFM at 10g/cow/d. Milk (P=0.01), milk true protein (P=0.01), lactose (P=0.01) and energy (P=0.02) outputs were higher for YST cows, and there was a tendency for milk fat (P=0.07) to increase compared to Control cows. In contrast, milk and component yields were not impacted by feeding XPC. Total net energy (NE) output was higher for both DFM treatments vs. Control (YST (P<0.01) and XPC (P=0.01)), but neither treatment impacted the NE level of the diets. Total tract apparent digestibility of organic matter (OM) and crude protein (CP) tended to be lower (P=0.08 and 0.05) than Control for the XPC treatment, while total tract apparent digestibility of OM and CP for YST cows was lower (P=0.02 and<0.01 respectively) than Control. Total tract apparent digestibility of ash-free neutral detergent fibre (aNDFom) and starch were not affected by treatment, and there was no effect of either DFM treatment on microbial CP (MCP) flow from the rumen. Total plasma essential amino acid (EAA) concentrations tended to be higher (P=0.07) with YST, which was mainly driven by increases in threonine (P=0.03), tryptophan (P=0.02), valine (P=0.08) and histidine (P=0.06). Although total plasma non-essential amino acids (NEAA) did not differ with YST feeding, there was an increase in concentrations of glycine (P=0.04), asparagine (P=0.03), tyrosine (P=0.05), serine (P=0.07), proline (P=0.06) and taurine (P=0.07). In contrast, XPC had no impact on plasma concentrations of any AA. Overall, MCP flow and whole tract aNDFom data suggest no substantive impact of either yeast additive on rumen fermentation, but whole tract digestibility of OM and plasma AA concentrations suggest a post-ruminal effect of YST wherein gut health improved thereby leading to increased efficiency of nutrient absorption.

Effects of feeding dry glycerol on milk production, nutrients digestibility and blood components in primiparous Holstein dairy cows during the early postpartum period

The aim of this study was to evaluate the glucogenic property of glycerol supplementation in the dairy cow’s diet. Sixty primiparous cows (control, n=30, and glycerol supplemented, n=30) were used to measure milk yield and components, blood hormone and metabolite profiles, and body condition score. Feed intake and apparent total-tract digestibility were also measured using 10 primiparous cows (control, n=5, and glycerol supplemented, n=5). Dry glycerol was top dressed at 250 g/day/cow from parturition to 21 days postpartum. Average feed intake, milk yield and components were not affected by glycerol supplementation. Apparent total–tract digestibility of organic matter and neutral detergent fibre were not influenced by dry glycerol supplementation, but lipid digestibility was greater (p=0.01) in cows fed glycerol. The serum concentration of glucose and insulin tended to be higher in dry glycerol-supplemented cows (p=0.1; p=0.06, respectively). While, serum concentrations of nonesterified fatty acids and β-hydroxybutyrate were not affected. Supplemented cows had lower body condition loss during weeks 1 to 5 after calving (p=0.09). The glucogenic effect of glycerol did not affect milk yield during the first 3 weeks of lactation. However, daily milk yield during the 13 weeks recording period was higher in the glycerol-supplemented cows (28.5 vs. 30.3 kg, p&lt;0.001). Percentages of cows cycling at the planned breeding date was greater (p=0.01) for cows fed dry glycerol. The results demonstrated that feeding dry glycerol as a glucogenic supply could be useful in saving body reserves and improving energy balance of primiparous Holstein dairy cows during the early postpartum period.

Comparative feeding value of steam-flaked triticale as a replacement for steam-flaked corn in finishing diets for feedlot cattle

ABSTRACTForty-eight crossbred steers (296 ± 5 kg) were used in a 155-day trial to compare the feeding value of steam-flaked triticale (SFT) with steam-flaked corn (SFC). Dietary treatments were: (1) basal finishing diet (BD), (2) 40% BD plus 60% SFT, and (3) 40% BD plus 60% SFC. Substitution of BD with SFT or SFC increased gain efficiency (P < .01), tended to increase average daily gain (ADG) (P = .07) and decrease dry matter intake (P = .11). The derived net energy for maintenance (NEm) and net energy for gain (NEg) values of SFT averaged 2.28 and 1.59 Mcal/kg, respectively. Four steers (442 ± 28 kg) were used in a 4 × 4 Latin square experiment to determine the effects of replacement of SFC with SFT on digestion. Treatments consisted of a SFC basal diet where SFT replaced 0, 32, 64, and 96% of SFC. Increasing level of SFT decreased total tract digestion of organic matter (OM) (linear component, P = .03), acid detergent fiber (ADF) (linear component, P < .01), and digestible energy (DE) (linear component, P < .01). The replacement DE value for SFT averaged 3.88 Mcal/kg, corresponding to NEm and NEg values of 2.18 and 1.50 Mcal/kg, respectively. It is concluded that the replacement net energy (NE) value of SFT is 92–96% that of SFC.

Digestibility, ruminal fermentation, ingesta kinetics and nitrogen utilisation in dairy cows fed diets based on silage of a brown midrib or a standard maize hybrid

The aim of the present experiment was to investigate an experimental brown midrib (Bm) maize hybrid in comparison with a control (Con) non-Bm maize hybrid on ruminal and total tract digestibility, ruminal fermentation, ruminal ingesta kinetics, nitrogen (N) utilisation and microbial efficiency. A total of six ruminally and duodenally cannulated German Holstein cows were used. Animals were fed diets of either 11.5 kg dry matter (DM) of a Con or a Bm maize silage plus 4.1 kg DM of concentrate. Ruminal and total tract digestibility of organic matter, neutral detergent fibre and acid detergent fibre did not differ between hybrids. Short-chain fatty acid concentrations and pH in the rumen were not affected, but ruminal mean retention time was lower for Diet Bm (Con: 45.4 ± 2.39 h; Bm: 40.6 ± 2.39 h; least squares means ± standard error). Cows fed Diet Bm had greater efficiency of N utilisation (Con: 30.1 ± 1.37%; Bm: 33.1 ± 1.37%) and increased flow of microbial crude protein at the duodenum (MCPF) (Con: 7.0 ± 0.37 g/MJ metabolisable energy (ME); Bm: 8.1 ± 0.37 g/MJ ME). Thus, MCPF and utilisable crude protein at the duodenum (uCP) were greater for Diet Bm (MCPF – Con: 1117 ± 52.1 g/d; Bm: 1306 ± 52.1 g/d; uCP – Con: 1594 ± 57.9 g/d; Bm: 1807 ± 57.9 g/d) and ruminal N balance was lower for Diet Bm (Con: 98.7 ± 8.92 g/d; Bm: 65.6 ± 8.92 g/d). The present results show that the Bm maize hybrid might be advantageous for dairy cow nutrition with regard to N utilisation and MCPF. However, further research is necessary to draw more precise conclusions on the potential of Bm maize hybrids in general.