Indigestible Neutral Detergent Fiber Research Articles

PSIX-2 Feeding 3-nitrooxypropanol reduces methane emissions by feedlot cattle

Abstract Our objective was to evaluate the effects of feeding 3-nitrooxypropanol (3NOP; Bovaer®, DSM Nutritional Products) at two doses on methane emissions and performance by feedlot cattle. The experiment was designed as a completely randomized block, in which 138 Nellore bulls (iBW, 360 ± 37.3 kg) were placed in collective pens (9 pens per treatment) and fed a high-concentrate diet (R:C, 11:89) according with the following three treatments: 1) 0ppm 3NOP /day; 2) 100ppm 3NOP/day, or 3) 150ppm 3NOP/day. For performance and DMI assessments the pen was the experimental unit. For methane emission evaluations, CH4 and DMI were assessed individually in 12 pens (2 bulls/pen, 8 bulls (experimental units)/treatment). Methane emission was measured for 6 consecutive days using the sulfur hexafluoride (SF6) tracer technique in two times over the experimental period (d15d -d21) and (105d to 111d), whereby the gross energy (GE) variables were calculated using equations. The individual DMI was measured using the two markers technique (Chromium oxide and indigestible NDF). The data were analyzed using the Mixed procedure of SAS and means comparison were carried out by Tukey’s test. Regardless of the level, dietary supplementation with 3NOP decreased (P < 0.001) methane emissions by 49.7% as expressed as g/d (146.0 vs. ~74 g/d−1); by 38.6% when expressed as g/kg ADG (91 vs ~56 g/kg ADG), and by 40.7% when expressed as g/kg DMI (13.5 vs. ~8 g/kg DMI). Likewise, dietary supplementation with 3NOP decreased (P < 0.001) the GE loss as a percentage of the GE intake by 42.4% (4.74 vs ~2.73%). However, feeding 3NOP had no effect on animalsˈ DM intake (~2.43 %BW; P = 0.23), ADG (~1.52 kg/d; P = 0.11) and HCW (~284 kg, P = 0.26). We conclude that Bovaer® can be used to effectively reduce methane emission by feedlot cattle without adverse effects on performance.

204 Effects of sorghum silage kernel processing on intake and apparent total tract digestibility of beef heifers

Abstract This study evaluated the effect of different kernel processors in terms of nutrient digestibility of whole-plant sorghum silage. Grain sorghum (hybrid ADV1250IG, Advanta Seeds, Irving, TX) was harvested at the hard-dough stage with a Class Jaguar 960 and 930 harvesters, switching the kernel processor to generate the forage material for the three treatments: conventionally processed (CONV), unprocessed (UN), and shredlage processed (SHRED). The material was bagged in three 2.7 m bags and allowed to ferment for 1 mo. Twenty-four black Angus heifers (13 ± 1 mo, 267 ± 10.9 kg of BW) were randomly assigned to treatments (8 heifers/treatment) and allocated to individual pens (36 m2) with access to feed and water. Diets were ad libitum sorghum silage from each respective treatment, plus soybean meal top-dressed at 0.5% of BW. After a 15-d adaptation period, feed and feces were collected for 5 d. Feed was offered once daily, and orts were collected the following day. Fecal samples were collected twice daily and apparent total tract digestibility was determined using indigestible NDF as a marker. Data were analyzed as a completely randomized design using heifer as the experimental unit, and initial BW as a covariate. Dry matter (DM) intake as a percentage of BW (P = 0.09) and NDF digestibility (P = 0.06) tended to differ among treatments, where CONV tended to be lesser than UN (P = 0.08), whereas SHRED was intermediate. Digestibility of DM was affected by treatment (P = 0.05), where UN (71.3%) tended (P = 0.06) to be greater than CONV (67.9%), while SHRED (70.8%) did not differ from any of the treatments (P ≥ 0.12). In conclusion, kernel processing affects nutrient digestibility of sorghum silage. Differences in ruminal kinetics and fermentation parameters, resulting from contrasting particle sizes, grain processing and sorting, may help explain these findings.

PSVII-11 Fecal parameters as indicators of starch digestibility and feedlot performance of water buffaloes

Abstract This study evaluated fecal parameters indicative of starch digestibility of water buffaloes (Bubalus bubalis) of three genetic groups (GG: Jafarabadi, Mediterranean, and Murrah). Seventy-eight non-castrated males [n = 26 of each GG; 200 kg of initial body weight (BW); 210 days of age] were used. Animals were finished in feedlot, receiving a diet rich in starch [38.76% in dry matter (DM) basis]. Samples of feces, diet offered, and orts were collected for digestibility test during 3 consecutive days. Diet samples were incubated in situ in the rumen of cannulated buffaloes. The remaining material was submitted to analysis to quantify the indigestible neutral detergent fiber levels. Fecal starch (FS) determination was performed by near infrared reflectance spectroscopy. Final BW (BW, kg), metabolic BW (BW0.75, kg0.75), average daily gain (ADG, kg/day), DM intake (DMI, in kg/day, and %BW) were recorded. Data were analyzed using MIXED and CORR procedure in SAS, with significance considered if P ≤ 0.05. Starch digestibility and FS concentration are not influenced by GG (P ≥ 0.23), unlike fecal DM and fecal pH (P ≤ 0.04; Table 1). Although weak, negative correlations were detected between FS and BW (r = -0.247; P = 0.05) and BW0.75 (r = -0.261; P =0.03), as well as between fecal DM and BW (r = -0.245; P = 0.05), ADG (r = -0.341; P < 0.01), DMI, kg/day (r = -0.374; P < 0.01), and DMI, %BW (r = -0.335; P < 0.01) variables. The results demonstrate that there are differences among GG of water buffaloes regarding fecal parameters. Furthermore, the high FS content and the low fecal pH may indicate the low capacity of water buffaloes to digest starch. Thus, the research results provide evidence that water buffaloes are not able to use high-grain diets, and fecal parameters proved to be potential tools to evaluate the feedlot performance of these animals.

124 Polyclonal Antibody Preparations from Avian Origin Increased Fiber Digestibility of Beef Cattle Receiving a Backgrounding Diet

Abstract This study investigated the effects of feeding an avian-derived polyclonal antibody preparation (PAP; CAMAS, Inc.) against Streptococcus bovis, Fusobacterium necrophorum, and lipopolysaccharides (40, 35, and 25% of the preparation, respectively) on plasmatic haptoglobin and glucose concentrations (Exp. 1), and apparent total tract digestibility (Exp. 2) of beef cattle consuming a backgrounding diet. In Exp. 1, Angus crossbreed heifers and steers (n = 90; 373 ± 62 kg BW) were randomly assigned to receive a common ad libitum diet (76% TDN, 15.9% CP, DM basis) with the addition of 1 (PAP1), 3 (PAP3), or 0 g (CON) of PAP daily. Plasmatic concentrations of glucose and haptoglobin were measured on d 0, 14, 28, 42, and 56. In Exp. 2, 25 Angus crossbreed steers (390 ± 65 kg BW) were used in a completely randomized design. Steers were housed in 3 pens to receive the same diet and treatments from Exp. 1. Feed intake was measured using GrowSafe feed bunks, and indigestible neutral detergent fiber was used as the internal marker. In Exp. 1, a day effect was detected for plasmatic haptoglobin and glucose concentrations (P ≤ 0.04). In Exp. 2, no difference in DMI was observed (P = 0.88). Dry matter, organic matter, and acid detergent fiber digestibility in the total tract were reduced (P ≤ 0.05), whereas CP digestibility tended to decrease (P ≤ 0.07) in steers receiving PAP3 vs. CON and PAP1. Apparent total tract starch digestibility was increased (P ≤ 0.02) for PAP1 vs. PAP3. Neutral detergent fiber digestibility was greater (P < 0.01) for PAP1 vs. CON and PAP3. Feeding 1 g/d of a PAP against Streptococcus bovis, Fusobacterium necrophorum, and lipopolysaccharides increased fiber digestibility in backgrounding diets; however, further research is needed to understand the impaired responses on nutrient digestibility when greater doses are provided.

52 Effects of an energy or protein supplement on forage dry matter intake for steers grazing summer native range

Abstract The objective of this study was to determine the effects of supplementation level and type on forage intake of steers grazing a high-quality native range. This study was conducted in late May through the end of June. On d 0, steers (n=16, initial BW = 193.7 kg ± 14.3 kg) were randomly assigned to one of 5 dietary treatments, fed once daily in individual stalls for 28 d. Treatments were control (no supplement, n=4), or supplemented with either cottonseed meal or dry rolled corn, each at either 0.45 kg or 1.81 kg as-fed/d (n=3 for each combination). Beginning on d 7, steers were orally administered titanium dioxide boluses (10 g/steer) once daily for 21 d. Fecal samples were collected from the rectum once daily for 14 d, analyzed for Ti concentration via a handheld X-ray fluorescence analyzer, and total fecal output was estimated. Diet digestibility was estimated after a 288-h in situ incubation of forage and fecal samples to determine indigestible NDF. Some steers had orts, therefore actual mean supplement intake was used in analysis. Results were analyzed with regression, with animal as the experimental unit. Mean estimated forage DMI of unsupplemented animals was 1.6% BW. Contrary to expectation, corn supplemented steers exhibited greater forage DMI as a percentage of BW than cottonseed meal supplemented steers (P = 0.01; 1.5 vs. 1.1, respectively).

Effects of different physical forms of starter on digestibility, growth, health, selected rumen parameters and blood metabolites in Holstein calves

This study was designed to determine whether physical forms of starter feed could influence digestion, growth, rumen fermentation parameters, and blood metabolites in Holstein dairy calves. Sixty-three female calves (averaging 41 kg body weight (BW)) were randomly assigned to 1 of the following 3 starter diets differing in physical form or formulation: texturized starter (TS; n = 21), pelleted starter with the same formula as TS (PSA; n = 21), and a commercial pelleted starter (PSB; n = 21) with a different formulation. Twelve male calves were selected and randomly assigned to each treatment group to determine feed digestibility using indigestible neutral detergent fiber (iNDF) and acid insoluble ash (AIA) as the internal markers. The dry matter intake (DMI) of calves in three treatments was not different within the first 6 wk (P = 0.19), and there were also similar gain-to-feed ratios (P = 0.91) and Average daily gain (ADG) (P = 0.26). During wk 7, starter DMI of the calves in TS and PSA groups was greater than PSB animals (P < 0.01). The ADG of TS and PSA-fed groups were greater than the animals fed with PSB during wk 7. Offering TS resulted in tendentionally greater starter DMI and ADG than PSA during the following 2 wk after weaning (P = 0.08, P = 0.09). During the 9-wk study, calves receiving PSB had lower ADG than the other two treatments (P = 0.04), but there were no differences in gain-to-feed ratio (P = 0.86). Serum biochemical parameters were not different among the 3 treatments. Calves began exhibiting ruminating behavior for TS about 2 d numerically earlier than that for PSA and PSB (P = 0.54). Butyrate in the rumen of PSB-fed animals was greater than in PSA and TS calves (P < 0.01) on day 63. Also, PSB-fed calves had a greater ruminal acetate: propionate ratio than calves receiving PSA and TS (P < 0.01) on day 49. The TS starter had the lowest digestibility of CP, DM, and ADF (P < 0.01) by both digestibility methods. Overall, the pelleted starter with soybeans and distillers dried grains had lower DMI and ADG than the other pelleted starter and texturized starter which had the same formulation.

How does herbage mass effect voluntary dry matter intake and in vivo organic matter digestibility in sheep and the in vitro gas production of perennial ryegrass?

It is essential to have accurate data relating sward herbage mass (HM) to voluntary dry matter intake (VDMI) and in vivo organic matter digestibility (OMDIV) across the year. This will ensure that the production performance of animals grazing differing HM swards can be accurately predicted using in vitro and in situ methods. The objectives of this experiment were to (i) determine the OMDIV and VDMI of sheep offered perennial ryegrass differing in HM throughout the growing season and (ii) evaluate in vitro gas production (IVGP) and in situ indigestible neutral detergent fibre (iNDFIS) as methods of predicting OMDIV. A 3 × 3 Latin square design was used to investigate three HM treatments. The target HM (measured > 4 cm) of perennial ryegrass for the three HM treatments was 1200 kg dry matter (DM)/ha (Low), 2500 kg DM/ha (Medium) and 4000 kg DM/ha (High). The experiment was a Latin square design repeated in three time stages (TS) in 2013 (TS1, TS2 and TS3). A 3 × 2 incomplete Latin square design was used in early spring 2014 (TS4). In TS4 the HM were lower than in the previous TS at 1000 kg DM/ha (Low), 1800 kg DM/ha (Medium) and 2500 kg DM/ha (High). Each experimental period within each TS consisted of a 6 day adaptation phase and 6 day measurement phase; with 12 Texel wether sheep used. Sheep were fed ad libitum to ensure a 10% refusal rate. The interaction between TS and HM treatment had the greatest effect on chemical composition, VDMI and OMDIV. Low HM swards had the greatest VDMI and OMDIV. For each 1000 kg DM/ha increase in HM, OMDIV was reduced by 2.3% on average. This varied from 0.9% in TS4 to 2.7% in TS3. There was no difference between HM treatments in the rate of digestion of digestible NDF using the IVGP technique. In situ indigestible NDF concentration and OMD derived from IVGP (OMDGP) were highly correlated with OMDIV (r2 = 0.901 and 0.895 respectively) and moderately correlated with digestible organic matter intake (DOMI) (r2 = 0.633 and 0.652 respectively). It can be concluded that the interaction between HM and TS will greatly affect OMDIV and VDMI. Secondly OMDIV can be predicted by both iNDFIS and OMDGP with acceptable accuracy to allow for their use in future feed evaluations.

Digestibility of diets with passion fruit by-product estimated through external and internal markers in dairy heifers

This study examined the influence of the external markers chromium oxide (CO), titanium dioxide (TD), isolated, purified and enriched lignin (LIPE®) and isolated, purified, enriched lignin in nanoparticles (NANOLIPE®) as well as the internal markers indigestible dry matter (iDM), indigestible neutral detergent fiber (iNDF) and indigestible acid detergent fiber (iADF) in diets with inclusion of passion fruit by-product for dairy heifers on the estimation of fecal output and nutrient digestibility. Sixteen Holstein × Zebu crossbred heifers at an average live weight of 363 ± 28 kg were randomly distributed in a completely randomized design where they received diets in which Tifton 85 (Cynodon sp.) hay was replaced with passion fruit by-product (0, 12, 24 and 36%, as-fed basis). The CO, LIPE®, NANOLIPE® and iNDF markers did not differ from the total collection method (p &gt; 0.05) in the estimation of fecal output and nutrient digestibility. The TD and iDM markers overestimated, while iADF underestimated fecal output. Under the presented conditions, we recommend using the CO, LIPE®, NANOLIPE® and iNDF markers to estimate fecal output and nutrient digestibility in diets with inclusion of passion fruit by-product for dairy heifers.

Evaluation of source of corn silage and trace minerals on rumen characteristics and passage rate of Holstein cows

The effects of source of corn silage and trace mineral on rumen fermentation, turnover, and particle passage rates were evaluated with 8 ruminally cannulated Holstein cows averaging 83 (standard error = 5) days in milk in a replicated 4 × 4 Latin square design with a 2 × 2 factorial arrangement of treatments and 28-d periods. The diets consisted (dry basis) of 55% conventional (CON) or brown midrib-3 (BM3) corn silage, 2% chopped wheat straw, and 43% grain mix with either sulfate (STM) or hydroxy (HTM) source of Cu, Zn, and Mn trace minerals. The targeted supplemental amount of Cu, Zn, and Mn was 194, 1,657, and 687 mg/d, respectively. The dietary treatments were (1) CON-STM, (2) CON-HTM, (3) BM3-STM, and (4) BM3-HTM. Dietary nutrient composition of BM3 diets averaged 32.1% amylase neutral detergent fiber on an organic matter basis (aNDFom) and 6.9% undigested neutral detergent fiber at 240 h of in vitro fermentation (uNDF240om; % of dry matter), and CON diets averaged 36.2% aNDFom and 8.6% uNDF240om (% of dry matter). Data were summarized by period and analyzed as a replicated Latin square design with fixed model effects for corn silage, trace mineral, corn silage and trace mineral interaction, period within replicated square, and replicated square using the MIXED procedure of SAS (version 9.4, SAS Institute Inc., Cary, NC). Cow within replicate was a random effect. Daily mean, standard deviation, minimum, and maximum for rumen pH were unaffected by corn silage or trace mineral source. Cows fed the CON diets had greater rumen acetate percentage than cows fed the BM3 diets (65.7 vs. 64.7 molar %). In contrast, cows fed the BM3 diets had greater rumen propionate percentage than cows fed the CON diets (21.4 vs. 20.4 molar %). Total volatile fatty acid concentration was lower for cows fed STM versus HTM in BM3 diets, but not for the cows fed the CON diets. Cows fed the BM3 diets had faster turnover rate and shorter turnover time for uNDF240om than cows fed the CON diets (3.12 vs. 2.86%/h and 33.3 vs. 36.5 h, respectively). Cows fed the BM3 diets had a faster passage rate of small and medium corn silage neutral detergent fiber particles than cows fed the CON diets (5.73 vs. 5.37%/h and 4.74 vs. 4.31%/h, respectively). We observed a corn silage by source of trace mineral interaction on organic matter and uNDF240om rumen pool size and organic matter turnover. Overall, source of corn silage had a pronounced influence on rumen dynamics presumably related to greater in vitro neutral detergent fiber digestibility and lower uNDF240om content of BM3 corn silage that allowed for faster turnover of indigestible neutral detergent fiber and greater passage rate of corn silage particles. In contrast, the source of trace mineral had much less significant effects on rumen fermentation, turnover, and particle passage rates. Corn silage-based diets intended to enhance rumen fiber fermentation, turnover, and passage are more affected by source and digestibility of neutral detergent fiber than source of dietary trace minerals.

Effects of bismuth subsalicylate and encapsulated calcium ammonium nitrate on ruminal fermentation of beef cattle.

A replicated 5 × 5 Latin square design with a 2 × 2 + 1 factorial arrangement of treatments was used to determine the effects of bismuth subsalicylate (BSS) and encapsulated calcium ammonium nitrate (eCAN) on ruminal fermentation of beef cattle consuming bahiagrass hay (Paspalum notatum) and sugarcane molasses. Ten ruminally cannulated steers (n = 8; 461 ± 148 kg of body weight [BW]; average BW ± SD) and heifers (n = 2; 337 ± 74 kg of BW) were randomly assigned to one of five treatments as follows: 1) 2.7 g/kg of BW of molasses (NCTRL), 2) NCTRL + 182 mg/kg of BW of urea (U), 3) U + 58.4 mg/kg of BW of BSS (UB), 4) NCTRL + 538 mg/kg of BW of eCAN (NIT), and 5) NIT + 58.4 mg/kg of BW of BSS (NITB). With the exception of NCTRL, all treatments were isonitrogenous. Beginning on day 14 of each period, ruminal fluid was collected and rectal temperature was recorded 4× per day for 3 d to determine ruminal changes every 2 h from 0 to 22 h post-feeding. Ruminal gas cap samples were collected at 0, 3, 6, 9, and 12 h on day 0 of each period followed by 0 h on days 1, 2, 3, and 14. Microbial N flow was determined using Cr-Ethylenediaminetetraacetic acid, YbCl3, and indigestible neutral detergent fiber for liquid, small particle, and large particle phases, respectively. Data were analyzed using the MIXED procedure of SAS. Orthogonal contrasts were used to evaluate the effects of nonprotein nitrogen (NPN) inclusion, NPN source, BSS, and NPN source × BSS. There was no treatment effect (P > 0.05) on concentrations of H2S on day 0, 1, 2, or 14; however, on day 3, concentrations of H2S were reduced (P = 0.018) when NPN was provided. No effect of treatment (P = 0.864) occurred for ruminal pH. There was an effect of NPN source on total concentrations of VFA (P = 0.011), where a 6% reduction occurred when eCAN was provided. There were effects of NPN (P = 0.001) and NPN source (P = 0.009) on the concentration of NH3-N, where cattle consuming NPN had a greater concentration than those not consuming NPN, and eCAN reduced the concentration compared with urea. Total concentrations of VFA and NH3-N were not affected (P > 0.05) by BSS. There was an effect of BSS (P = 0.009) on rectal temperature, where cattle not consuming BSS had greater temperatures than those receiving BSS. No differences for NPN, NPN source, nor BSS (P > 0.05) were observed for microbial N flow. In conclusion, eCAN does not appear to deliver equivalent ruminal fermentation parameters compared with urea, and BSS has limited effects on fermentation.

Apparent total tract digestibility, ruminal fermentation, and blood metabolites in beef steers fed green-chopped cool-season forages.

An experiment was conducted during the winter of two consecutive years to evaluate the effects of feeding green-chopped cool-season forages on digestibility, ruminal fermentation, and blood parameters in beef steers. Nine ruminally cannulated Angus crossbred steers (year 1: 359 ± 79 kg; year 2: 481 ± 105 kg) received ad libitum green-chopped forages from pastures planted with one of the following mixtures: 1) OAT = Horizon 201 oats (Avena sativa L.)/Prine annual ryegrass (Lolium multiflorum Lam.) at 95 and 17 kg/ha, respectively; 2) RYE = FL401 cereal rye (Secale cereale L.)/Prine annual ryegrass (Lolium multiflorum Lam.) at 78 and 17 kg/ha, respectively; or 3) TRIT = Trical 342 triticale (X Triticosecale spp.)/Prine annual ryegrass (Lolium multiflorum Lam.) at 95 and 17 kg/ha, respectively. Intake was measured using the GrowSafe system and orts were discarded prior to subsequent feeding. After a 14-d adaptation, feed and fecal samples were collected twice daily for 4 d to determine apparent total tract nutrient digestibility using indigestible neutral detergent fiber (NDF) as an internal marker. On day 19, blood and ruminal fluid samples were collected every 3 h during a 24-h period to analyze plasma urea nitrogen (PUN) and glucose, ruminal pH, and concentration of ruminal ammonia nitrogen (NH3-N) and volatile fatty acids (VFA). Data were analyzed as a generalized randomized block design with repeated measures using the PROC MIX of SAS. No effect of treatment (P > 0.05) was observed for intake of dry matter, organic matter (OM), crude protein, NDF, or acid detergent fiber. Apparent total tract digestibility of nutrients was greater (P < 0.05) for OAT and TRIT when compared with RYE, with OM digestibility being 82.7%, 79.6%, and 69.5%, respectively. An effect of time (P < 0.01) was observed for ruminal pH. Plasma concentration of glucose was greater (P < 0.01) in steers consuming OAT, whereas steers fed RYE had greater (P < 0.05) concentrations of ruminal NH3-N and PUN, and the least concentration of total ruminal VFA (P < 0.05), despite having the greatest (P > 0.05) molar proportion of acetate, branched-chain VFA, and acetate:propionate. Increased nutrient digestibility and favorable ruminal fermentation and blood metabolites of OAT and TRIT are potentially conducive to enhanced growth performance when compared with RYE.

The effect of stage of regrowth on the physical composition and nutritive value of the various vertical strata of kikuyu (&lt;i&gt;Cenchrus clandestinus&lt;/i&gt;) pastures

A plot study was conducted at the Gatton Research Dairy, Queensland, Australia, to quantify the effects of 5 regrowth periods (9, 11, 14, 16 and 18 days) and 4 vertical strata on the composition and nutritive value of kikuyu (Cenchrus clandestinus) pastures using a block factorial design with 4 replicates. Pasture samples were analyzed for crude protein (CP), ethanol-soluble carbohydrates (ESC), acid detergent fiber (ADF), neutral detergent fiber (aNDFom), in vitro indigestible neutral detergent fibre (iNDF240) and minerals. Metabolizable energy (ME) was then calculated from the concentrations of other nutrients. Regardless of the stage of regrowth, stems were located mainly in the bottom 1 or 2 strata, while leaves were present mainly in the top 2 or 3 strata. CP, ESC and ME declined, but aNDFom, ADF and iNDF240 increased with stage of regrowth and from top to bottom of the swards (P&lt;0.05). While herbage quality variables were affected by both factors, vertical stratum had a much larger impact on quality than stage of regrowth. These results indicate that grazing management of kikuyu pastures should be based not only on stage of regrowth but also on level of defoliation, as both have strong impacts on the nutritive value of the consumed forage.

Digestive Potential of Soybean Agro-Industry Byproducts.

Simple SummaryThis manuscript addresses the use of nutritional alternatives: that the addition of soybean hull levels affect protein and carbohydrate fractionation, with significant changes in rumen degradability; that most of the analyzed variables were affected linearly, so levels of additive inclusion resulted in the satisfactory growth of rumen microorganisms and synchronism between the protein and carbohydrate digestion rates; and that these had an important effect on the end products of fermentation and on animal production. This is significant because animals fed diets showing these characteristics can better express their animal performance. The results obtained in this study indicate that the addition of intermediate levels of soybean hulls close to 20–30% ensures better characteristics in the silage of Brachiaria decumbens.This study aimed to determine the protein and carbohydrate fractions as well as the in situ rumen degradability of Brachiaria decumbens silage (BDS) supplemented with soybean hulls. Five soybean hull inclusion levels were used: 0, 10, 20, 30, and 40% of the fresh matter of B. decumbens grass, distributed into a completely randomized design with five replications. The inclusion of soybean hulls caused a linear decrease (p < 0.001) in carbohydrate fractions A + B1 and a linear increase (p < 0.001) in carbohydrate fraction C. The percentage of non-protein nitrogen fraction increased linearly (p < 0.001), but the nitrogen fractions B1 + B2 and B3 presented a negative quadratic effect (p < 0.01) with soybean hull level and fraction C presented a linear decrease (p < 0.001). The dry matter (DM) degradability of soluble fraction (A) and the undigestible DM decreased linearly (p < 0.01) with the soybean hull level. The potentially degradable water-insoluble portion (DM fraction B) and degradability rate (c) of the DM fraction B increased linearly (p < 0.001) with soybean hull level. The crude protein (CP) fraction A presented a linear increase (p < 0.001) with soybean hull inclusion; however, soybean hull levels caused a linear decrease (p < 0.001) in the CP level of fraction B. The degradable insoluble fraction of NDF (D) of the silage increased linearly (p < 0.001) and the indigestible NDF fraction of the silage was linearly decreased with the soybean hull level (p < 0.001). The inclusion of intermediate levels (20–30%) of soybean hulls provided better protein and carbohydrate fractions and better quality of BDS.

Machine learning estimators for the quantity and quality of grass swards used for silage production using drone-based imaging spectrometry and photogrammetry

Drones offer entirely new prospects for precision agriculture. This study investigates the utilisation of drone remote sensing for managing and monitoring silage grass swards. In northern countries, grass swards are fertilised and harvested three times per season when aiming to maximise the yield. Information about the grass quantity and quality is necessary to optimise these operations. Our objectives were to investigate and develop machine-learning techniques for estimating these parameters using drone photogrammetry and spectral imaging. Trial sites were established in southern Finland for the primary growth and regrowth of grass in the summer of 2017. Remote-sensing datasets were captured four times during the primary growth season and three times during the regrowth period. Reference measurements included fresh and dry biomass and several quality parameters, such as the digestibility of organic matter in dry matter (the D-value), neutral detergent fibre (NDF), indigestible neutral detergent fibre (iNDF), water-soluble carbohydrates (WSC), the nitrogen concentration (Ncont) in dry matter (DM) and nitrogen uptake (NU). Machine-learning estimators based on random forest (RF) and multiple linear regression (MLR) methods were trained using the reference measurements and tested using independent test datasets. The best results for the biomass estimation, nitrogen amount and digestibility were obtained when using hyperspectral and 3D data, followed by the combination of multispectral and 3D data. During the training process, the best normalised root-mean-square errors (RMSE%) were 14.66% for the dry biomass and 12% for fresh biomass; the best RMSE% values for NU, the D-value and NDF were 13.6%, 1.98% and 3% respectively. For the primary growth, the accuracies of all quality parameters were better than 20% with the independent test datasets; for the regrowth, the estimation accuracies of the D-value, iNDF, NDF, Ncont and NU were better than 20%. The results showed that drone remote sensing was an excellent tool for the efficient and accurate management of silage production.

In vitro ruminal fermentation parameters and methane production of Marandu palisadegrass (Urochloa brizantha) in a silvopastoral system associated with levels of protein supplementation

AbstractThe addition of protein supplementation in a silvopastoral system can contribute to improved forage intake and digestibility. Our objective was to evaluate in vitro ruminal parameters, digestibility and gas production of Marandu palisadegrass [Urochloa brizantha (Hochst. ex A. Rich.) R. D. Webster] in a silvopastoral system and compare this to parameters obtained from diets with protein supplementation. Forage was sampled during the growing season (November to April) in 2016/17 and 2017/18. In vitro incubation treatments consisted of four levels of protein supplement (20% of crude protein; CP) in the diet (0.1, 0.2, 0.3 and 0.4 g/kg of body weight). The neutral detergent fibre, acid detergent fibre and indigestible neutral detergent fibre concentrations were highest in the first year. In the second year, CP concentration was 21% greater than in the first year. There was a linear increase for digestion rate, a quadratic effect for lag time and a linear decrease for average digestion time as supplementation levels were increased. The least lag time and digestion time occurred in the second year. There was no supplementation effect on ruminal pH, acetate and butyrate concentrations. Second‐year in vitro dry matter digestibility (IVDMD) was greater than in the first year. Increases in supplementation levels linearly enhanced IVDMD and reduced methane (CH4) production. The inclusion of a protein supplement contributed to reduced CH4 and increased volatile fatty acids production; therefore, we recommended the supplement inclusion of &gt;0.28 g/kg of BW for animals grazing in well‐managed palisadegrass pastures.

Short communication: Diet digestibility measured from fecal samples and associations with phenotypic and genetic merit for milk yield and composition

Selection for improved feed utilization is of high interest globally but is limited by the high cost of obtaining feed intake for individual cows and relies on indirect measures of feed efficiency. Supplementing selection with mechanistic measures of feed use could make selection for feed utilization more direct and effective. The objectives of this study were to evaluate fecal sampling as a method of determining digestive efficiency of individual cows and to evaluate associations of digestive efficiency with genetic and phenotypic merit for milk yield and composition. Fecal samples were obtained manually from the rectum of 90 Holstein cows in the morning, afternoon, and evening on a single date and composited across the day. The fecal samples were dried, ground, and stored. Diet and fecal neutral detergent fiber (NDF) were determined using the filter bag method, and indigestible NDF was determined in situ with a 12-d rumen incubation. Fecal NDF (60.1%) and indigestible NDF (41.9%) were higher than that from feed samples (14.2 and 35.9%, respectively). Total-tract digestibility was calculated using the marker ratio method. Total-tract dry matter (DM) digestibility averaged 66.0 ± 2.4% and total-tract NDF digestibility averaged 42.8 ± 3.0%. Higher milk fat percent and genetic merit for milk fat percent were associated with greater NDF and DM digestibility. Milk yield was negatively associated with NDF and DM digestibility. Fecal sampling is a feasible method to directly measure digestive efficiency, and substantial variation was observed among cows. Given significant between-cow variation and associations with milk fat percent and genetic merit for milk fat percent, potential selection for total-tract NDF digestibility estimated via fecal sampling warrants further exploration.

Cashew processing product as alternative energy feedstuff for grazing beef cattle under tropical conditions

The aim of this study was to examine the effect of replacing corn with dried cashew processing product (CPP) in dietary supplements on the intake, digestibility and nitrogen (N) metabolism of grazing beef cattle. Five Nellore bulls with an average initial weight of 359 ± 34.8 kg were used in a 5 × 5 Latin square design. The animals were kept in five 0.32-ha paddocks of marandu grass (Urochloa brizantha cv. Marandu). Five isonitrogenous protein-energy supplements (310 g crude protein [CP]/kg of supplement) were formulated with CPP replacing corn at different levels (0, 0.25, 0.50, 0.75 or 1.00 g/g). The diets were supplied daily in the amount of 1.0 kg/animal. The replacement of corn with CPP caused a linear decrease in the intakes of supplement DM, total DM, CP and digestible organic matter, but did not influence forage DM intake. On the other hand, the substitution resulted in a linear increase in the intakes of indigestible neutral detergent fiber and total tannins. The replacement of corn with CPP caused a linear decrease in the digestibility coefficients of total DM, organic matter, CP and neutral detergent fiber and in the dietary concentration of OM. A linear decrease was also noted for N retention, microbial N synthesis, rumen ammonia N and blood urea N, while no changes were detected in fecal or urinary N excretion or microbial efficiency. Replacing corn with cashew processing product reduces intake, apparent diet digestibility, microbial nitrogen synthesis and nitrogen retention in grazing cattle.

Body weight and sex effects on digesta mean retention time in growing Saanen goats.

Despite the important role of digesta mean retention time (MRT) on digestive efficiency of ruminants, it is poorly investigated in total gastrointestinal tract (GIT) of growing ruminants, especially in goats. The objective of this study was to evaluate the effect of body weight (BW) and sex on GIT MRT of particles and solutes in growing Saanen goats. A dataset from two studies, comprising 103 individual records of castrated males (n = 36), females (n = 34), and intact males (n = 33) Saanen goats slaughtered at 15, 22, 30, 37, and 45 kg BW, was used. Goats were fed basically with total mixed ration composed by dehydrated corn plant (Zea mays) milled to pass a 10-mm screen, cracked corn grain, and soybean (Glycine max) meal. Variables evaluated were BW, feed intake, feed intake level, composition of ingested diet, wet weight of GIT tissues, wet digesta pool size, digesta composition (dry matter and neutral detergent fiber [NDF]), indigestible NDF:NDF ratio of ingested diet and GIT digesta, MRT of particles (MRTiNDF) and solutes (MRTCr), and reticulorumen selectivity factors (large particles/solutes). Reticulorumen, omasum, abomasum, small intestine, cecum, and colon–rectum segments were evaluated. The dataset was analyzed as mixed models considering sex, BW, and sex × BW interaction as fixed effects, and study and residual error as random effects. Sex did not affect MRTiNDF in any GIT segments. Females and intact males presented similar reticulorumen MRTCr (5.6 h; P = 0.92) and they presented lower reticulorumen MRTCr than castrated males (7.0; P ≤ 0.04). Total GIT MRTCr was similar between castrated males and females (15.7 h; P = 0.11) and between females and intact males (14.2 h; P = 0.76). Body weight (BW) did not affect MRTiNDF in reticulorumen and colon–rectum and total GIT MRTCr (P ≥ 0.11). Reticulorumen and omasum MRTCr increased as BW increased (P < 0.01), and abomasum MRTCr decreased as BW increased (P = 0.02). Feed intake, and wet tissues and wet pool size of all GIT segments increased as BW increased, except abomasum wet pool size (P ≤ 0.01). The mechanism related to sex effect on MRT has to be elucidated. Reticulorumen MRTiNDF and total GIT MRTCr were modulated by intake and capacity of reticulorumen and GIT, respectively. On the other hand, reticulorumen MRTCr seemed to be regulated by reticulo-omasal orifice opening and saliva secretion.

Effects of finishing diet sorting and digestibility on performance and feed efficiency in beef steers

The aim of this study was to test the hypotheses that differences in residual feed intake (RFI) of beef steers are related to diet sorting, diet nutrient composition, energy intake and apparent digestibility. To phenotype steers for RFI, 69 weaned Angus × Hereford steers were fed individually for 56 days. A finishing diet was fed twice daily on an ad libitum basis to maintain approximately 0.5 to 1.0 kg refusals. Diet offered and refused was measured daily, and DM intakes (DMI) were calculated by difference. Body weights were recorded at 14-day intervals following an 18-h solid feed withdrawal. The residual feed intake was determined as the residual of the regression of DMI versus mid-test metabolic BW (BW0.75) and average daily gain (ADG). Particle size distributions of diet and refusals were determined using the Penn State Particle Separator to quantify diet sorting. Sampling of diet, refusals and feces were repeated in four sampling periods which occurred during weeks 2, 4, 6 and 8 of the study. Particle size distributions of refusals and diet were analyzed in weeks 2, 4 and 6, and sampling for chemical analysis of refusals and feces occurred in all four periods. Indigestible neutral detergent fiber (288 h in situ) was used as an internal marker of apparent digestibility. We conclude that preference for the intakes of particles > 19 mm and 4 to 8 mm were negatively correlated to RFI and ADG, respectively. Although steers did sort to consume a different diet composition than offered, diet sorting did not impact intake energy, digestible energy or DM digestibility.

Grass silage pulp as a dietary component for high-yielding dairy cows

Green biorefineries provide novel opportunities to use the green biomass efficiently and utilize the ecosystem services provided by grasslands more widely. The effects of the inclusion of fractionated grass silage solid fraction (pulp) on feed intake, rumen fermentation, diet digestion and milk production in dairy cows were investigated. Pulp was separated from grass silage using a screw press simulating a green biorefinery. Partial removal of liquid from forage increased DM concentration from 220 to 432 g/kg and NDF from 589 to 709 g/kg DM while CP decreased from 144 to 107 g/kg DM. A feeding trial using an incomplete changeover design with 24 Nordic Red cows and two 3-week periods was conducted. The pulp replaced grass silage in the diet at 0 (P0), 25 (P25) and 50 (P50) percentage of total forage, which was fed ad libitum with 13 kg of concentrate for all treatments. The forage DM intake was highest on P25 (14.1 kg/day) while P0 and P50 did not differ from each other (13.2 and 13.0 kg/day, respectively). There were no differences between the treatments in rumen pH or ammonia N, but the proportion of acetate increased with increasing pulp inclusion. The digestibility was measured using acid insoluble ash and indigestible NDF (iNDF) as internal markers. Neither of the markers detected differences in NDF digestibility, but according to iNDF, apparent total tract organic matter digestibility decreased with increasing pulp inclusion. The cows maintained milk production at P25, but it showed some decline at P50 (energy-corrected milk at P0 and P25 was 39.8 kg/day while for P50, it was 38.5 kg/day, P = 0.056) and the milk protein yield significantly declined with higher pulp inclusion. Simultaneously, the nitrogen use efficiency in milk production increased. It seems that the fibrous grass-based fraction from a biorefinery process has potential to be used as a feed for ruminants.