Dietary Particle Size Research Articles

Particle Size Distribution and Feed Sorting of Hay-Based and Silage-Based Total Mixed Ration of Calabrian Dairy Herds

Dietary particle size is one of the most relevant factors influencing rumen function and the selection of the most palatable components of the total mixed ration (TMR) by cows. The aim of this study was to evaluate the particle size distribution (PSD), homogeneity, sorting level, physically effective NDF (peNDF) content of TMRs, and production performances in Calabrian commercial dairy herds in southern Italy. The research was conducted in 13 farms, including 8 with hay-based TMR and 5 with silage-based TMR. All herds delivered fresh feed once a day. At each farm, the TMRs were examined with the Penn State Particle Separator (PSPS) to determine PSD, homogeneity, and feed sorting at two time points (i.e., at fresh feed delivery = T0 and 24 h after feed delivery = Tf). None of the diets that were evaluated met the recommended PSD, showing an excess of long fraction, very short fraction, or both. The homogeneity was good except for three diets, but particle selection raised some concerns in 85% of the farms due to the preferential consumption of the very short fraction by the cows, with rejection of the long fractions. All the diets analyzed met the Penn State University recommended neutral detergent fiber (NDF) values (>28%) except for one farm’s diet. In three of the TMRs observed, however, the content of peNDF > 8 mm was less than 15%. NDF and peNDF > 8 mm values of TMRs showed statistically significant correlations with milk fat content. Therefore, it is important to evaluate the chemical and physical properties of TMR to provide a consistent diet and prevent feed sorting.

303 Interactive Effects of Pelleting and Particle Size Reduction of Corn on Ileal Digestibility of Starch and Amino Acids in Corn-Soybean Meal Diets Fed to Pigs

Abstract The objective was to determine the interactive effects of particle size reduction and pelleting on the apparent ileal digestibility (AID) of starch and the standardized ileal digestibility (SID) of amino acids (AA) in corn-soybean meal diets fed to pigs. Six corn-soybean meal based diets were arranged in a 3 × 2 factorial with 3 particle sizes of corn (i.e., 700, 500, or 300 μm) and 2 diet forms (i.e., meal or pelleted). An N-free diet was also used and there were, therefore, a total of 7 diets. Pigs were allowed ad libitum access to feed and water. Pigs (n = 7; initial body weight = 59.30 kg; SD = 2.77) that were equipped with a T-cannula in the distal ileum were allotted to the 7 diets using a 7 × 7 Latin square design with 7 periods. Ileal digesta were collected for 2 days after 5 days of adaptation. The statistical model included diet as fixed effect and pig and period as random effects. Contrast coefficients were used to determine effects of diet form, linear effects of particle size, and the interaction. Results indicated that the AID of starch was linearly increased (P = 0.001) with reduced particle size of corn and pelleted diets had greater (P = 0.029) AID of starch than meal diets (Table 1). The SID of Leu, Lys, Met, Phe, Thr, and Val linearly increased with reducing particle size, but the increase was greater in pelleted diets than in meal diets (interaction, P < 0.05). The SID of Arg, His, Ile, and Val also linearly increased (P < 0.05) as the particle size of corn was reduced, and the SID of all indispensable AA except Trp was greater (P < 0.05) in pelleted diets than in meal diets. In conclusion, reducing the particle size of corn from 700 to 300 μm increased the AID of starch and the SID of AA, but the AID of starch and the SID of most indispensable AA was greater in pelleted diets than in meal diets. If there were interactions, the effects of reducing particle size were greater when corn particle size was reduced from 500 to 300 μm in meal diets and from 700 to 500 μm in pelleted diets.

Perspective and Commentary: Chewing behavior of dairy cows: Practical perspectives on forage fiber and the management environment

Our objective is to provide practical perspec- tives on how forage-fiber characteristics interact with feed- bunk management to affect the balance between eating time and ruminating and resting activity. We offer recom- mendations for forage and dietary particle size to imple- ment these concepts on farm. Peer-reviewed scientific literature, research abstracts, and some proceedings and popular press were used to support our perspectives on this topic. Peer-reviewed scientific literature, research abstracts, and some proceedings and popular press were used to support our perspectives on this topic. Chewing comprises eating and ruminating, which are complementary behaviors. Fiber plays a major role in stimulating chewing; source of fiber, dietary fiber content, degradability, fragility, and particle size influence its effect. The major role of forage particle size in many feeding situations is on eating rather than ruminating, since cows often chew feed to a relatively common particle size endpoint before swallowing, and the rumen is popu- lated with a particle distribution that is more uniform than the diet. The time spent eating should fall typically between 3 and 5 h/d and needs to be in balance with recumbent rumination. Cows that accomplish more rumi- nating in stalls and lying down consume more dry matter and produce milk with greater fat and protein content. Diets that allow the cow to meet her time budget require- ments contain >50% particles (as fed) on the 8-mm sieve of the Penn State Particle Separator and <5% on the 19- mm sieve to control sorting and eating time. The length of cut for forages should be adjusted based on maturity and fiber degradability, fragility or susceptibility to breakdown, and moisture content for crops such as corn silage. As for- ages become more mature, lower in degradability, and less fragile, they should be chopped shorter to ensure optimal eating and ruminating responses. Similarly, immature or more fragile forages should be chopped longer. We propose recommendations for theoretical length of cut and ration particle size distribution that incorporate these concepts.

Feed particle size and amylase supplementation in diets for nursery piglets: Digestibility and growth performance

The objective of this study was to evaluate the effect of diet particle size, amylase supplementation, and their possible interaction on nutrient digestibility and performance of nursery pigs. A total of 352 whole male piglets (28-d-old) were distributed in a completely randomized block design with a 2 × 2 factorial scheme: 2 feed particle sizes; with or without inclusion of 80 kg-novo units (KNU) of amylase/kg. Initial weight was the blocking factor. The diets were pelleted, based on corn and soybean meal, and divided into pre-starter (28 to 42 d) and starter (43 to 63 d). The tested particle sizes were 339/588 µm and 696/920 µm for pre-starter and starter phases, respectively, and were obtained through grinding of the corn. Diets were fed ad libitum. Average daily feed intake (ADFI), average daily weight gain (ADWG), and feed conversion ratio (FCR) were evaluated. Apparent digestibility of dry matter (DM), crude protein (CP), and ether extract (EE), as well as digestible energy (DE) were additionally evaluated in the starter phase. No interaction between factors was observed throughout the experiment. In the pre-starter phase, piglets fed finer diets (339 µm) had lower FCR (P < 0.05), although ADFI and ADWG were not affected. In the starter phase, the use of a coarser diet (920 µm) led to greater ADFI and ADWG (P < 0.05), but with no effect on FCR, similarly to what was observed in the total period (28 to 63 days). Reducing the particle size increased EE digestibility (P < 0.05) but had no influence on DM and CP digestibility nor DE. Amylase supplementation increased ADFI and ADWG and reduced FCR in the pre-starter phase and total period (P < 0.05), and led to greater digestibility of DM, CP, and EE, as well as DE (P < 0.05). As a conclusion, fine grinding of diets can be applied to reduce FCR and increase fat digestibility in younger nursery pigs (up to 42-d-old), but coarser diets should be used at an older age (post-42-d) to prevent losses in ADFI and ADWG. Supplementation of 80 KNU/kg of exogenous amylase is recommended through the nursery phase (28 to 63 d) to improve growth performance, nutrient digestibility, and DE, regardless of diet particle size.

Effect of straw particle size in high grain complete pelleted diet on growth performance, rumen pH, feeding behavior, nutrient digestibility, blood and carcass indices of fattening male goats

The study aimed to elucidate the effects of straw particle size of complete pelleted diet (CPD) on feed intake, growth performance, rumen pH, feeding behavior, selected blood metabolites, nutrient digestibility, and carcass attributes of fattening male goats. Sixteen male Beetal goats, averaging 27.0 ± 2.84 kg body weight (BW) were randomly assigned to one of the following dietary treatments (n = 8 male goats /treatment); 1) S4 (CPD having oat straw ground at 4 mm); 2) S8 (CPD having oat straw ground at 8 mm). The diets were iso-nitrogenous and iso-caloric with forage to concentrate ratio of 15:85, and were designed to achieve low NDF contents of 20% by adding 63% corn grains. The experiment lasted for 16 weeks; 2 weeks of receiving and diet adaptability period, 13 weeks of data collection, and last one week for nutrient digestibility. Animals were housed individually and fed the corresponding diet and water ad libitum. Feeding behavior was recorded on day 30, 60, and 90 of the study. Blood samples were collected weekly, whereas, rumen samples were collected on a bi-weekly basis. Total tract nutrient digestibility was performed at the end of the experiment. All goats were slaughtered to determine changes in the carcass attributes. Results revealed that DMI and ADG were higher (P < 0.0001) in the S8 group compared with the S4 group. The feed-to-gain ratio (F: G), however, was lower (P = 0.047) in the S8 group compared with that of the S4 group. Ruminal pH was higher (P < 0.0001) in S8 than S4 only at the beginning of the trial, with no later differences (P > 0.05). There was a significant treatment × week interaction (P < 0.05) for rumen pH during weeks 2 and 4 which remained below 6.0 in the S4 compared with the S8. The odds for diarrhea were 5 times lower in the S8 compared to the S4 male goats. Animals fed on CPD with the straw ground at 8 mm had higher (P ≤ 0.05) rumination time, DMI intake, NDF intake, and drinking time than those fed on CPD with the straw ground at 4 mm. Furthermore, the dressing percentage and marbling score was higher (P ≤ 0.05) in the S8 compared with the S4. The findings of this study suggested that the use of oat straw ground at 8 mm in a complete pelleted diet improved growth performance and carcass yield by improving the feeding behavior and stabilizing the rumen environment.

Roughage level and supplemental fat for newly received finishing calves: effects on growth performance, health, and physiological responses.

This experiment evaluated the effects of roughage levels and supplemental fat on intake, growth performance, health, and physiological responses of newly received finishing cattle during 58-d receiving period. A total of 72 crossbred steers (initial body weight [BW] = 200 ± 13 kg) were used in a randomized complete block design with a 2 × 2 factorial arrangement of treatments, consisting of two roughage levels (wheat hay at 30% [R30] or 60% [R60]; dry matter [DM] basis) and two levels of supplemental fat (yellow grease at 0% [-FAT; no additional fat] or 3.5% [+FAT]; DM basis). Upon arrival, calves were individually weighed, blocked by off-truck shrunk BW, and assigned to 24 soil-surfaced pens (three calves per pen). Shrunk BW was also collected on day 58 for the calculation of average daily gain (ADG). Throughout the study, calves were assessed for bovine respiratory disease (BRD). Effects of roughage level × supplemental fat interaction were only observed for diet particle size distribution and estimated physically effective neutral detergent fiber (peNDF) of diets (P ≤ 0.10). Adding fat to R60 diets tended to increase the percentage of particles retained in the 8-mm screen (P = 0.06) and the estimated peNDF (P = 0.10), but did not affect R30 diets. Dietary roughage level did not affect DM intake (DMI; P = 0.85). Calves-fed R30 tended to have greater ADG and final BW than calves-fed R60 (P ≤ 0.08). Gain efficiency (gain:feed ratio; G:F) was greater for calves-fed R30 than calves-fed R60 (P = 0.01). Dietary roughage level did not affect morbidity and mortality (P ≥ 0.11). Supplemental fat did not affect DMI (P = 0.6) but tended (P = 0.09) to increase ADG compared to -FAT diets. The G:F was greater for calves-fed +FAT than -FAT (P = 0.03). The +FAT diet tended (P = 0.10) to increase the number of retreatments against BRD compared to -FAT, although the total number of antimicrobial treatments required to treat sick calves (P = 0.78) and the mortality rate (P = 0.99) were not affected by supplemental fat. Feeding +FAT diet tended (P ≤ 0.09) to increase plasma concentration of cortisol and immunoglobulin-G compared to -FAT. In summary, feeding 30% roughage diets or adding 3.5% yellow grease (DM basis) as supplemental fat increased G:F during the feedlot receiving period.

Effect of Particle Size of Starter Diet on Broiler Chicken Performance

Background: This study was conducted to determine the effect of particles size of starter diet on growth performance of broiler chickens. Methods: A total of 384 Arbor Acres broiler chicks were usedin a completely randomized design with three treatments and four replicates of 32 birds each.Birds were fed diets with 3 particles sizes of starter diet (T1: 1.0 mm; T2: 0.8 mm; T3: 0.7 mm) during the first week of life. At 7 d, the same starter diet was offered in a crumbled form until 10 d of age. Then, common grower and finisher diets were provided in a pelleted form. Body weight (BW), feed intake (FI), feed conversion ratio (FCR) and mortality rate were evaluated at 7, 14 and 42 days of age. Result: The results showed thatchicks receiving diet with intermediate particles size (0.8 mm) had the higher BW at 7 and 14 d. The FCR was also improved (-6.25%; P less than 0.01) with the same diet at 7 days of age. No feed particle size effect for FIand mortality was observed throughout the 42 d trial. In conclusion, birds fed intermediate particles size (0.8 mm) diet showed better FCR and BW at starter phase. However, no significant effect was observed at slaughter age.

Chewing activities, sorting behaviour and ruminal fermentation of lactating dairy cows fed diets with similar proportions of undigested neutral detergent fibre with wheat straw substituted for alfalfa hay, corn silage or both

Feeding behaviour and ruminal fermentation of dairy cows were evaluated when fed diets formulated to supply a similar proportion of undigested neutral detergent fibre (uNDF) after 30-h incubation (uNDF30), while wheat straw (WS) replaced for corn silage (CS), alfalfa hay (AH) or both. In a randomised block design, 32 multiparous Holstein cows (days in milk = 78 ± 11 d, milk production = 56 ± 6 kg/d) were used. AH and CS were the only forage sources in control diet (CSAH). WS was substituted for alfalfa hay (WSCS), CS (WSAH) or both (WSCSAH) on uNDF30 basis. Dry matter consumption from 6 to 24 h after feed delivery was lower in WSAH than in WSCS or CSAH. No difference existed in total time spent for eating (250 min/d), rumination (460 min/d) and chewing (710 min/d). Total concentration of volatile fatty acids (VFAs) in the rumen was not different between treatments but propionate proportion was lower for cows fed WSAH than CSAH diet (19.0 vs. 24.1 mM/100 mM). Ammonia nitrogen concentration in the rumen fluid was greater for WSAH than WSCS or CSAH. With combining uNDF288 and peNDF, peuNDF288 was calculated and its intake had the highest correlation with chewing time (r = −0.60), sorting index of particles retained on 8-mm sieve (r = 0.42) and rumen pH (r = 0.52). Forage replacement on uNDF30 basis resulted in a relatively similar response on feeding behaviours and ruminal fermentation and enabled to replace high-quality forages with low-quality forages in the dairy cow rations. Highlights Wheat straw (WS) was substituted for alfalfa hay (AH), corn silage (CS) or both on an uNDF30 basis. Treatments had small differences in chewing patterns and ruminal fermentation. Combination of uNDF288 and diet particle size improved correlation coefficient with chewing, long particle intake and rumen pH.

P83. Dietary particle size and gelling affect digesta transit through the stomach of pigs

P83. Dietary particle size and gelling affect digesta transit through the stomach of pigs

Short communication: The relationship between dietary particle size and undegraded neutral detergent fibre in lactating dairy cows: A prospective cohort observational study

Physically effective NDF (peNDF) and undegraded aNDF at 240 h (uNDF.240) are important parameters for characterizing NDF in fibre evaluation and are associated with dietary physical form and fibre digestibility characteristics. A new concept that combines peNDF and uNDF.240, physically effective uNDF.240 (peuNDF.240 = pef × uNDF.240), was recently established. The peuNDF.240 value allows determination of dry matter intake (DMI), and the productive response of cows even in the absence of variation in DMI or when cows are fed rations with low uNDF.240 and high peNDF or rations with high uNDF.240 and more finely chopped fibre. The aim of this study was to improve our understanding of the relationships between dietary uNDF.240 content to other fibre fractions, average cow DMI, gross feed efficiency, and milk yield at the farm level. Furthermore, the relation between peuNDF.240 and the productive response of cows was also investigated at the farm level. In the Po’ Valley, which is a representative area for dairy production in Italy, a cohort of 22 Holstein dairy farms was monitored over two years (2019–2020). Information regarding average cow DMI, milk yield, and ration composition was obtained through interviews with farmers, and feed samples were collected and chemically analysed. Farms were classified according to their dietary uNDF.240 (% of DM) content: low (uL) ≤ 8.29 or high (uH) > 8.29. Farms with low dietary uNDF.240 used less alfalfa forage as a fibre source compared with farms with high dietary uNDF.240 (6.27 vs. 15.5 % of DM) and showed higher average milk yield (35.9 vs. 33.6 kg/cow/day, respectively) and similar DMI (23.9 vs. 24.3 kg/cow/day, respectively). Dietary peuNDF.240 was negatively related to milk yield (milk yield = 47.4 – 1.87 peuNDF.240, R2 = 0.62, adjusted R2 = 0.60, residual standard error (RSE) = 1.87, P = 0.001) and gross feed efficiency (gross feed efficiency = 1.96 – 0.08 peuNDF.240, R2 = 0.65, adjusted R2 = 0.64, RSE = 0.07, P = 0.001). The results of this study have practical significance for farmers, as they suggest that the inclusion of low digestible forages in the ration (i.e., late-harvested alfalfa characterized by high uNDF.240) may require more fine shredding to reduce the overall value of peuNDF.240 and increase cow production.

Growth performance, real-time gizzard pH and calcium solubility in the gut of broiler chickens is dependent on the interaction between dietary calcium concentration and limestone particle size

ABSTRACT 1.The purpose of this study was to determine the effect of limestone particle size and dietary Ca concentration on performance, real-time gizzard pH, and Ca and P solubility in the gastrointestinal tract of 21d broiler chickens. 2. A total of 576, one-day-old Ross 308 male broilers were randomly allocated among 4 treatments, with 8 replicate pens, and 18 birds per pen. Treatments were arranged as a 2 × 2 factorial consisting of two particle sizes of limestone (coarse, CL, 1200 µm; fine, FL, 44 µm) and two Ca concentrations (9.6 or 6.0 g/kg). On d 19 and 20, four birds per treatment were administered Heidelberg pH capsules and readings monitored for 3 h. 3. Reducing Ca concentration from 9.6 to 6.0 g/kg had no effect on d 21 weight gain or FCR of birds fed CL; however, feeding FL at 9.6 g/kg Ca increased weight gain by 10% and reduced FCR by 5% compared to FL at 6.0 g/kg Ca (P < 0.001). 4. Average gizzard pH readings ranged from pH 0.67 to 3.01 across all treatments. Birds fed CL at 6.0 g/kg Ca had lower average gizzard pH compared to birds fed 9.6 g/kg Ca, while birds fed FL at 6.0 g/kg Ca had higher gizzard pH than birds fed CL at both Ca concentrations, but was comparable to birds fed FL at 9.6 g/kg Ca (P < 0.001). 5. For birds fed CL at 6.0 g/kg Ca, soluble Ca in the gizzard was approximately 40% lower (P < 0.05) than all other treatments, and reduced by 44% (P < 0.05) in the small intestine compared with birds fed FL at 6.0 g/kg Ca. 6. These findings demonstrated that the effect of Ca concentration on gizzard pH, Ca solubility and broiler performance was dependent on limestone particle size and suggested that solubility per se had little relevance to performance.

Performance, carcass traits and meat quality of lambs fed with different roughage: concentrate ratios associated with variable physically effective neutral detergent fibre content

AbstractThis study evaluated the effect of roughage:concentrate (R:C) ratio associated with a variable particle size of physically effective neutral detergent fibre (peNDF8) in the forage (Tifton-85 hay) on the performance, carcass traits and meat quality of lambs. Seventy-two 4-month-old, non-castrated Santa Ines male lambs (23.5 ± 2.32 kg BW) were distributed in a completely randomized design, in a 2 × 2 factorial arrangement [two peNDF8 hay particle sizes (13 and 6 mm) and two R:C ratios (700:300 and 500:500 g/kg DM total)]. DMI, DM, NFC and TDN digestibility's, N-intake and N-faecal excretion were affected by the R:C ratio (P &lt; 0.05). However, the N-retained was not affected by the studied variables (P &gt; 0.05). It was observed an interaction (P &lt; 0.05) between the peNDF8 and R:C ratios for final BW, average daily gain (ADG), colour parameters and pH 24 h. The lower roughage ratio provided greater (P &lt; 0.05) concentrations of C14:1, C16:1–cis9, C18:1–cis9, ΣMUFA, Σn–6:Σn–3 and hypocholesterolemic/hypercholesterolemic index, enzymatic activity Δ9desaturase-C16 and -C18. Lambs fed a lower roughage diet had improved performance and feed efficiency, however, presented reduced polyunsaturated fatty acids (PUFA) concentrations in the meat, especially Σn–3 family. Higher roughage diet and larger peNDF8 particle size improved the concentrations of PUFA while decreased Σn–6:Σn–3 ratio in meat. Larger peNDF8 particle size associated with higher roughage proportion, have reduced animal performance however, it increased protein concentration, a* and C* colour parameter without affecting fatty acids profile of Longissimus lumborum muscle.

Effects of feed form and particle size on growth performance, nutrient digestibility, carcass characteristics, and gastric health in growing-finishing pigs

ObjectiveThis study was conducted to evaluate the effects of feed processing and particle size on growth performance, nutrient digestibility, carcass characteristics, and gastric health in growing-finishing pigs.MethodsA total of 360 growing pigs (22.64±0.014 kg initial body weight [BW]) were allocated to 1 of 6 treatments with 6 replicates by BW and sex, and 10 pigs were housed in one pen in a randomized complete block design. The BW and feed intake were recorded to calculate growth performance. For the digestibility trial, a total of 24 barrows with an initial BW of 33.65±0.372 kg were split into 6 treatments with a completely randomized design. Dietary treatments were designed by a 2×3 factorial arrangement of treatments based on two main factors, particle size (600, 750, 900 μm) and feed form (mash and pellet) of diet. Experimental diets were formulated to contain the requirements of the NRC (2012).ResultsThe BW and average daily gain were not changed by dietary treatments, and the feed intake of finishing pigs (wks 6 to 12) was increased when the pigs were fed a mash diet (p<0.05). For the overall period, the feed efficiency of pigs was improved with the pellet diet (p<0.01) and reduced particle size (p<0.05). The pellet diet had effects on increasing crude fat digestibility (p<0.01) relative to a mash diet, but there was no considerable change in dry matter and crude protein digestibilities by dietary treatments. In the evaluation of gastric health, a trend for an increased incidence of keratinization in the esophageal region was observed as particle size decreased (p = 0.07).ConclusionFeed efficiency could be improved by pellet diet and reduced particle size. Nutrient digestibility, carcass characteristics, and gastric health were not affected by feed form, and particle size ranged from 600 to 900 μm.

Replacing alfalfa hay with dry corn gluten feed alters eating behavior, nutrient digestibility, and performance of lactating dairy cows

The objective of this trial was to determine the amount of alfalfa hay (AH) in low forage diets that could be replaced with dried corn gluten feed (DCGF) without negatively altering eating behaviour, ruminal fermentation, nutrient digestibility, and performance of lactating dairy cows. Eight multiparous Holstein cows were used in a replicated 4 × 4 Latin square design experiment. Treatments included (dry matter [DM] basis): 18.81% AH without DCGF (0DCGF,); 12.53% AH and 6.26% DCGF (6DCGF); 6.26% AH and 12.53% DCGF (12DCGF); and 0% AH and 18.81% DCGF (18 DCGF). Diet particle size and physically effective neutral detergent fibre declined linearly (p < .001) as DCGF replaced AH resulting in a linear decrease (p < .001) in time (min/d) spent eating, ruminating, and chewing. As DCGF replaced AH, ruminal pH decreased linearly (p = .003) and total VFA concentrations increased linearly (p = .02) tending to be highest (p = .062) for 12DCGF. Ruminal acetate and butyrate, and plasma β-hydroxybutyrate concentrations declined linearly (p = .001) whereas ruminal propionate concentration increased linearly (p = .001) as DCGF increased. Dry matter intake (DMI; p = .001) and nutrient digestibility increased linearly (p < .05) and tended to be greatest (p < .10) for 12DCGF. Milk yield (MY; p = .016) and protein yield (p = .001) increased linearly, but milk fat yield declined as DCGF replaced 6 and 12% of AH and decreased more when DCGF replaced all AH resulting in a quadratic response (p = .041). Results of this trial suggest that replacing 12% of the AH with DCGF increases MY because of higher DMI and nutrient digestibility, but replacing all of the AH with DCGF reduces milk fat yield and dairy efficiency. Highlights DCGF can replace AH to improve nutrient digestibility and milk yield. Improvements in nutrient digestibility when DCGF replaces AH potentially reduce total waste production of dairy cows. Completely replacing AH with DCGF in low forage diets reduces milk fat yield due to change in ruminal fermentation.

Dietary composition and particle size effects on swine manure characteristics and gas emissions.

Nutrients excreted from animals affect the nutritive value of manure as a soil amendment as well as the composition of gases emitted from manure storage facilities. There is a dearth of information, however, on how diet type in combination with dietary particle size affects nutrients deposited into manure storage facilities and how this affects manure composition and gas emissions. To fill this knowledge gap, an animal feeding trial was performed to evaluate potential interactive effects between feed particle size and diet composition on manure characteristics and manure-derived gaseous emissions. Forty-eight finishing pigs housed in individual metabolism crates that allowed for daily collection of urine and feces were fed diets differing in fiber content and particle size. Urine and feces were collected and stored in 446-L stainless steel containers for 49 d. There were no interactive effects between diet composition and feed particle size on any manure or gas emission parameter measured. In general, diets higher in fiber content increased manure nitrogen (N), carbon (C), and total volatile fatty acid (VFA) concentrations and increased manure VFA emissions but decreased manure ammonia emissions. Decreasing the particle size of the diet lowered manure N, C, VFAs, phenolics, and indole concentrations and decreased manure emissions of total VFAs. Neither diet composition nor particle size affected manure greenhouse gas emissions.

Effect of diet-induced negative energy balance on the feeding behavior of dairy cows

The objective of this study was to determine how feeding behavior of dairy cows is altered in response to diet-induced negative energy balance, and if this response varies depending on dietary particle size distribution. Multiparous Holstein cows (n = 30; days in milk = 59 ± 5; parity = 2.8 ± 0.19), producing 44.6 ± 1.2 kg/d of milk, were fed (on a dry matter basis) a lactating diet [net energy of lactation (NEL) = 1.66 Mcal/kg; 68% forage, including 1.8% wheat straw] during a 2-wk baseline period. To induce negative energy balance, cows were then exposed for 3 wk to 1 of 2 diets formulated for a 20% reduction in energy available for milk (NEL = 1.58 Mcal/kg; 73% forage, including 17.2% wheat straw). These diets were identical, only varying in straw chop length: (1) long straw diet (LS): straw chopped with a 10.2-cm screen, or (2) short straw diet (SS): straw chopped with a 2.54-cm screen. Cows consumed 25.6 ± 0.26 kg/d during the baseline period. Dry matter intake decreased on the experimental diets; dry matter intake was greater for the SS diet as compared with the LS diet (23.1 vs. 22.5 kg/d; standard error = 0.47). During the baseline period, cow serum nonesterified fatty acids (NEFA) and blood β-hydroxybutyrate averaged 0.27 ± 0.02 and 0.71 ± 0.05 mmol/L, respectively. During the experimental period, NEFA and β-hydroxybutyrate averaged 0.34 and 1.04 mmol/L, respectively, with a peak of NEFA (0.63 ± 0.06 mmol/L) occurring 4 d after dietary change. During baseline, cows produced 42.3 ± 0.33 kg/d of milk; milk yield was decreased for both SS cows and LS cows during the experimental period (SS = 39.0, LS = 37.8 kg/d; standard error = 0.67). On the experimental diets, cows spent more time eating (266.8 vs. 221.8 min/d), had longer meal lengths (46.9 vs. 37.5 min/meal), and consumed fewer meals (7.1 vs. 7.7 meals/d) compared with the baseline period. Within the experimental period, LS cows spent more time eating per day than SS cows (LS = 281.3, SS = 252.2 min/d). During the baseline period cows sorted against long particles (>19 mm), did not sort medium particles (8 to 19 mm), and sorted for short (4 to 8 mm) and fine (<4 mm) particles. Cows did not change sorting of long particles on the SS diet, but increased sorting against these on the LS diet. On the SS diet cows did not change their sorting of short and fine particles. On the LS diet cows increased sorting for short and fine particles. In the baseline period, no association was detected between feed sorting and serum NEFA concentration. During the experimental period, greater NEFA concentration was associated with greater sorting in favor of short particles for both the LS and SS diets. Furthermore, greater NEFA concentration was associated with greater sorting against the longest particles for both the LS and SS diets. No associations of blood and meal variables were detected during the experimental period. Overall, cows altered their feed sorting behavior in response to experiencing a diet-induced period of negative energy balance and the severity of negative energy balance was associated with the extent of that change in feed sorting.

Effect of Corn Particle Size on the Particle Size of Intestinal Digesta or Feces and Nutrient Digestibility of Corn-Soybean Meal Diets for Growing Pigs.

Simple SummaryDietary particle size can affect the digestible or metabolizable energy values of diet for pig. So, the mean particle size (MPS) of corn-soybean meal diet was recommended to less than 600 µm to improve growth performance and efficiency of dietary nutrients utilization by growing pigs. However, little information is available on whether further reduction of MPS influences the digestion process and increases digestibility of nutrients. This study evaluated the effects of reducing particle size of corn from 682 to 365 µm on the particle size of intestinal digesta or feces and nutrient digestibility of corn-soybean meal diets for growing pigs. The results showed that the MPS of duodenal digesta, ileal digesta and feces was reduced with the reduction of corn particle size. But, the MPS of corn did not affect the activities of amylase, trypsin and chymotrypsin in the duodenal fluid and the apparent total tract digestibility (ATTD) of dry matter, gross energy, crude protein, ether extract, neutral (NDF) and acid detergent fiber (ADF). These results suggest that the MPS less than 511 µm for corn-soybean meal diet does not improve the utilization of nutrients, thus it’s not necessary to further reduce particle size of corn with MPS of 682 µm.This study was conducted to evaluate the effect of corn particle size on the particle size of intestinal digesta or feces and nutrient digestibility of corn–soybean meal diets. Twenty-four growing barrows (initial BW: 21.9 ± 1.62 kg) were randomly divided into 4 groups of 6 pigs. A T-cannula was surgically placed in the anterior duodenum (about 50 cm from pylorus) of pigs in Groups 1 and 2 or in the distal ileum of pigs in Groups 3 and 4. Corn used to formulate diets had mean particle size (MPS) of 365 µm (Corn 1) or 682 µm (Corn 2), resulting in diets with MPS of 390 µm (Diet 1) or 511 μm (Diet 2). Diet 1 or 2 were randomly assigned within pig Groups 1 or 2 and 3 or 4. The digestive enzyme activities of duodenal fluid, particle size of intestinal digesta and feces, as well as nutrient digestibility, were determined for each pig as the experiment unit. The MPS of duodenal digesta (181 vs. 287 µm, p < 0.01), ileal digesta (253 vs. 331 µm, p < 0.01), and feces (195 vs. 293 µm, p < 0.01) was significantly reduced for pigs fed Diet 1 vs. Diet 2, respectively. Compared with Diet 2, Diet 1 significantly reduced the proportion of particles above 0.5 mm, but significantly increased the proportion of particles between 0.072 and 0.5 mm (p < 0.01) in digesta and feces (p < 0.01). Diet 1 significantly increased solubles percentage (<0.072 mm) in duodenal digesta (p < 0.05) but did not affect solubles percentage in ileal digesta and feces. The MPS of diet did not affect the activities of amylase, trypsin, and chymotrypsin in the duodenal fluid and the apparent total tract digestibility (ATTD) of dry matter, gross energy, crude protein, ether extract, neutral detergent fiber (NDF) and acid detergent fiber (ADF) in pigs offered Diet 1 compared to Diet 2. The in vitro digestible energy (IVDE) (3706 vs. 3641 kcal/kg; p = 0.03) was greater for Corn 1 vs. Corn 2. However, no significant difference was observed in IVDE (3574 vs. 3561 kcal/kg; p = 0.47) for Diet 1 vs. Diet 2. In conclusion, the particle size of digesta and feces was dependent on the dietary particle size. However, the digestive enzyme activities of duodenal fluid and ATTD of energy and nutrients were not affected by reducing dietary MPS from 511 to 390 µm.

Effects of dietary particle size and fiber source on nutrient digestibility and short chain fatty acid production in cannulated growing pigs

The objective of this study was to evaluate the effects of different feed particle sizes and fiber sources on nutrient digestibility and short chain fatty acids (SCFA) concentration in different intestinal segments of pigs. Eighteen barrows with T-cannula in the distal ileum were randomly allotted to a 3 × 2 factorial arrangement with 3 different high-fiber diets including corn bran (CB), sugar beet pulp (SBP) and soybean hulls (SH), and 2 different feed particle sizes. The experiment contained 2 periods, and each period lasted for 15 days, including 10 days for diets adaptation, 3 days for fecal collection, and 2 days for ileal digesta collection. The results indicated that coarse diets decreased (P < 0.05) the apparent ileal digestibility (AID) of gross energy (GE), dry matter (DM), organic matter (OM), total dietary fiber (TDF) and insoluble dietary fiber (IDF), but tended to increase (P < 0.10) the hindgut disappearance of GE. Feed particle sizes did not affect the apparent total tract digestibility (ATTD) of dietary nutrients except for ether extract (EE), the AID of amino acid (AA) and SCFA concentrations in ileal digesta, but fiber sources had significant effects on (P < 0.05) the AID, ATTD and hindgut disappearance of most nutrients in diets and the fecal SCFA concentrations. Moreover, there were interactive effects (P < 0.05) between particle sizes and fiber sources on the hindgut disappearance of fiber fractions. Coarse CB diets increased (P < 0.05) the hindgut disappearance of TDF, soluble dietary fiber (SDF), IDF, neutral detergent fiber (aNDF), acid detergent fiber (ADF) and cellulose, but the different particle size of SBP and SH did not affect the hindgut disappearance of TDF, ADF and cellulose. In conclusion, particle size mainly affected the ileal digestibility of nutrients and fiber fractions in pigs, but had few effects on their whole gastrointestinal digestibility, and these influences varied among different dietary fiber sources.

The effects of coarse and wet feeding on performance parameters, gastrointestinal tract and tibia traits, and digesta phytase activity in egg-type pullets, either fed a low or moderate phosphorus diet

In a 2 × 2 × 2 factorial design, the effects of dietary non-phytate phosphorus (NPP) levels, 0.17% (low) and 0.33% (moderate), diet moisture (dry and wet), and diet particle size (coarse and fine), were studied on egg production, characteristics of gastrointestinal tract (GIT) and tibia, digesta pH, and phytase activity in layer pullets (16 to 28 wk of age). The low NPP diet increased average daily water intake (ADWI) to ADFI ratio (4.2%) from 16 to 17 wk, but decreased this ratio (2.8%) from 23 to 27 wk. It decreased ADFI (1.5%) and egg mass production (3.8%) from 19 to 22 wk. It decreased egg weight (0.29g) and ADWI (2.1%) from 23 to 27 wk. At 22 wk, the GIT relative empty organ weights were (g/kg BW) higher for proventriculus + gizzard (0.96), duodeneum (0.94), and jejunum + ileum (1.95) with the low vs. moderate NPP diet. The low NPP diet decreased digesta phytase activity in crop and proventriculus+gizzard at 28 wk. The wet diet increased ADFI, ADWI, and ADWI/ADFI ratio from 16 to 27 wk, egg mass production (3.0%) from 19 to 22 wk, and egg weight (0.45g) from 23 to 27 wk. The wet diet also increased digesta phytase activity in proventriculus+gizzard. The coarse diet decreased ADFI from 19 to 22 wk (1.7%) and 23 to 27 wk (1.2%). The coarse diet caused reduced egg mass production (2.6%) from 23 to 27 wk. Egg shell breaking strength was increased on the coarse diet (0.9 Newton). The coarse diet increased ADWI/ADFI ratio from 16 to 27 wk, and increased relative gizzard weight by 1.95 and 0.81g/kg BW at 22 and 28 wk, respectively. The coarse diet increased jejunal/ileal pH with 0.16 units at 28 wk. None of the tested parameters affected tibia characteristics. It was concluded that a low NPP diet did not clearly affect the studied parameters. The wet diet increased ADFI, ADWI, and egg production. The coarse diet increased ADWI, egg shell breaking strength, relative gizzard weight, and reduced ADFI and egg production.

Effect of chemical and physical properties of Dried Distillers Grains with solubles (DDGS) on Tribolium castaneum (Herbst) development

Dried Distillers Grains with Solubles (DDGS) has been used as a grain-based supplement in animal feed. The focus of this study was to investigate the effects of chemical and physical characteristics that may affect DDGS susceptibility to Tribolium castaneum (Herbst) infestation. Multiple regression-based models were built to determine if the diet’s chemical and physical characteristics affect T. castaneum development. Based on the regression models, diet particle size was the most influential factor in larval development. Larval weight increased more rapidly on T. castaneum normal laboratory diet, 90% flour/10% brewer’s yeast (F/Y), followed by ground DDGS, compared to raw DDGS with different particle sizes. To determine the effect of diet particle size on larval development, experiments were conducted to increase particle size by pelletizing F/Y using a rotary drum granulation apparatus. T. castaneum larval stage lasted significantly longer on F/Y granules with a particle size of 1.4 mm or larger. Although the chemical properties of DDGS (protein, fat, fiber and ash content) were not significant predictors of T. castaneum larval development, larval developmental time and weight gain on ground DDGS was significantly slower than on F/Y, highlighting the potential importance of nutritional factors not accounted for in our analysis. Our results conclude that storing DDGS as raw ingredient and in the granule or pellet form with large particle size may help limit T. castaneum infestations. Although granulation or pelletization may not be economically feasible for small manufacturing plants, larger producers may benefit from the reduced risk of insect contamination associated with secondary feeders such as T. castaneum.