Penn State Particle Separator 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.

PSII-26 Feeding Behavior and Feed Conversion in Roughage-Lacking Diets Containing Ionized Amino Acids as Antibiotic Alternative

Abstract To improve animal performance there has been an increase of starch amounts in the ruminant diets; however, feeding high-grain diets can induce metabolic disturbs, needs to include antibiotics in the diet to avoid acidosis and control the growth of lactic acid producing microorganism. In this study was used ionized amino acids to replace monensin and withdraw all forage of diet. Twenty-four Nellore young bulls were allocated into two groups. The first group was fed with high-grain diet containing Brachiaria brizantha hay (15% of DM) and sodium monensim (120 mg/d). The second group was fed with high-grain diet without forage and without antibiotics, containing 82 mg/kg of ionized amino acids (no-forage diet, MJ Nutricao Animal). The feeding lasted 100 d before slaughter, at the end of period l rumen fluid was collected for VFA and lactic acid measurements. The Penn State Particle Separator has been used to monitor feeding sorting, the dry matter intake (DMI) was monitored daily in GrowSafe system and body weight (BW) was measured monthly. A completely randomized design was used. In the forage plus monensin diet the animals sorted larger particle (7.8 to 19 and > 19 mm), the proportion of larger particles decrease after feeding, the proportion of particles from 1.7 to 7.8 mm increased and there was no effect on smaller particles (< 1.7 mm). The animals feeding with no-forage diet avoided the whole cottonseed, the proportion of particles from 1.7 to 7.8 mm decreased and smaller particles (< 1.7 mm) did not change, before or after feeding (Table 2). The feeding behavior was changed; there were visits in the Growsafe feeder, the visits were faster and there was greater consumption per visit, in no-forage diet (Table 1). However, there were greater concentrations of propionic acid (50.9 vs 16.0 mM), smaller acetic:propionic ratio (1.1 vs 3.4), a trend to increased lactic acid (0.3 vs 0.2 mM), and the pH decreased in no-forage diet (6.29 vs 6.68), reducing the DMI (2 vs 2.5% of BW). There was a trend to reduce the BWG (1.7 vs 2.0 kg/d) in no-forage diet. There was no difference in feed conversion (6.43 in forage diet vs 6.08 no forage diet). In conclusion, the faster starch consumption of no-forage diet can induce greater propionic acid concentration, reducing DMI, on the other hand, the no-forage diet representing advantage to become the management of feedlot diets easier, allowing supply concentrate with less frequency, reducing dependence of forage production on farm, with the same feed conversion, without use of antibiotics. We hypothesize that fast passage rate reduces the hind gut starch digestibility, thus, further investigation can include supplies to improve alfa-amylase, to achieve even better feed conversion.

Effects of particle size reduction of meadow hay on feed intake, performance, and apparent total tract nutrient digestibility in dairy cows

ABSTRACT Forage-based diets are encouraged in organic dairy cattle production as this can increase the net human food supply, but their voluminous nature can limit dry matter intake (DMI) and performance. This study investigates the effects of a substantial particle size reduction of hay on dairy cows’ feed intake, performance, and body characteristics, as well as on apparent total tract digestibility (ATTD). Eighteen lactating Holstein cows were allocated to two balanced feeding groups. The control group received long stem hay with a conventional particle size (CON), the experimental group received chopped hay (RED). Both groups were supplemented with concentrates (3.6 kg/d, DM basis). After 14 adaptation days, data were collected for 20 consecutive days. A covariate period of 21 days preceded the experimental feeding period. Particles retained on the 19-, 8- and 4-mm screens and on the pan of the Penn State Particle Separator accounted for 21%, 20%, 20% and 39% of the RED hay. CON hay consisted of 72% large particles, followed by 8%, 7% and 13% retained on the other screens. Average DMI levels of cows in the CON group reached 20.8 kg/d, with a nonsignificant increase (+1.05 kg/d) in the RED group (p = 0.28). Intakes of both NFC (+0.65 kg/d, p = 0.01) and CP (+0.28 kg/d, p = 0.05) were significantly greater in the RED group, resulting in a slightly increased milk yield (+0.8 kg energy corrected milk/d) (p = 0.45), likely because the ATTD decreased significantly when feeding RED hay. No impact was observed on energy balance (103.7 vs 103.9%, p = 0.95), feed conversion efficiency (kg ECM/kg DMI), or N use efficiency. Overall, the results indicate increases in intake of NFC and CP in the RED group when feeding a hay-based (>83%, DM basis) diet, but also a decrease in nutrient digestibility, likely due to increased passage rate, potentially because of the high fraction of hay particles < 4 mm. In conclusion, hay-based rations with a lower proportion of fine particles should be tested to exploit the potential of particle size reduction in terms of improving hay use efficiency.

Physical effectiveness of corn silage fractions stratified with the Penn State Particle Separator for lactating dairy cows

This study evaluated the physical effectiveness of whole-plant corn silage (CS) particles stratified with the Penn State Particle Separator, composed of 19- and 8-mm-diameter sieves and a pan, for lactating dairy cows. Eight Holstein cows (27.6 ± 2.8 kg/d of milk, 611 ± 74 kg body weight; 152 ± 83 d in milk) were assigned to two 4 × 4 Latin squares (22-d periods, 16-d adaptation), where one square was formed with rumen-cannulated cows. Three CS particle fractions were manually isolated using the 8- and 19-mm diameter sieves and re-ensiled in 200-L drums. The 4 experimental diets were (% dry matter): (1) CON (control): 17% forage neutral detergent fiber (NDF) from CS (basal roughage), 31.5% starch, and 31.9% NDF; (2) PSPan: 17% forage NDF from CS + 9% NDF from CS particles <8 mm, 25.9% starch, and 37.9% NDF; (3) PS8: 17% forage NDF from CS + 9% NDF from CS particles 8 to 19 mm, 25.5% starch, and 38.3% NDF; and (4) PS19: 17% forage NDF from CS + 9% NDF from CS particles >19 mm, 24.9% starch, and 38.8% NDF. Cows fed PS8 had greater dry matter intake and energy-corrected milk yield (22.4 and 26.9 kg/d, respectively) than cows fed CON (20.8 and 24.7 kg/d) and PS19 (21.2 and 24.8 kg/d), but no difference was detected between PSPan (21.6 and 25.8 kg/d) and other treatments. Milk fat concentration was greater for PS8 than CON, with intermediate values for PSPan and PS19. Milk fat yield was greater for cows fed PS8 than CON and PS19, and cows fed PSPan secreted more fat than CON cows but were not different from cows fed the other 2 diets. Cows fed CON had a lower meal frequency than cows fed PSPan, shorter meal and rumination times than PS8, and greater meal size and lower rates of rumination and chewing than the other 3 diets. Total chewing per unit of NDF was higher for PS8 than PSPan, although neither treatment differed from CON or PS19. Cows fed PS19 had higher refusal of feed particles >19 mm than cows fed CON and PSPan. The refusal of dietary NDF and undigested NDF in favor of starch were all greater for PS19 than on the other treatments. Cows fed PS19 had a greater proportion of the swallowed bolus and rumen digesta with particles >19 mm than the other 3 diets. Cows fed CON had the lowest ruminal pH and greatest lactate concentration relative to the other 3 diets. Plasma lipopolysaccharide was higher for cows fed CON and PSPan than for cows fed PS8 and PS19, and serum d-lactate tended to be lower on PSPan than for CON and PS8. In summary, the inclusion of CS fractions in a low-forage fiber diet (CON) reduced signs of ruminal acidosis. Compared with CS NDF <8 and >19 mm, CS NDF with 8- to 19-mm length promoted better rumen health and performance of dairy cows. These results highlight the importance of adjusting CS harvest and formulating dairy diets based on the proportion of particles retained between the 8- and 19-mm sieves.

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.

Knowledge transfer from students and rural producers about the importance of particle size in corn silage for dairy cows

This study aimed to guide UFGD students and rural producers about the importance of the ideal particle size in corn silage for dairy cows and its influence on milk production. The work was developed in a rural property in the District of Panambi, in the Municipality of Douradina, Mato Grosso do Sul state. The property is specialized in dairy cattle farming, where the food base of the animals is corn silage. An equipment called Penn State Particle Separator was inserted in the corn silage production process, which allows estimating the quality of the corn chopping process and inferring how the particle size interferes in the quality of the silage. The action allowed those involved to see in practice the importance of the ideal particle size (1 to 2 cm) when evaluating different samples of corn silage with the Penn State Particle Separator and later the animals' consumption and the quality of the animals' leftovers. The exchange of knowledge between the academy and the field, allows the identification of complex issues about the impact of the physical characteristics of food on rumen kinetics, in order to impact the productivity of every rural enterprise. Students and farmers could see in practice the importance of the appropriate particle size for the ensiling process as it is related to forage compaction and how the appropriate particle size can positively influence consumption, produce rumination, salivation and proper peristaltic motion and consequently animal production.

Effectiveness of cottonseed cake fibre included in the diet of Nellore steers finished in confinement

ABSTRACT It was aimed to evaluate the use of cottonseed cake (CSC) as a source of physically effective neutral detergent fibre (peNDF) to replace corn silage (CS) in diet of feedlot-finished cattle. The design used was completely randomised, with 2 treatments (30% CSC and 30% CS) and 12 replications. There was interaction between fibre source and nutrient in the material retained in the Penn State Particle Separator. The highest concentrations (P = 0.0001) of peNDF and the in vitro digestibility of peNDF (DpeNDF) were for CSC. There was a higher (p < 0.05) dry matter intake (DMI) and neutral detergent fibre (NDF) intake (NDFI) by the animals on the CSC diet. The CSC-fed steers showed higher (P = 0.0001) final body weight (BW) and total weight gain. The steers fed CSC showed a longer (P = 0.0001) feeding time, feed efficiency, and lower rumination time (P = 0.0001) and rumination efficiency (P = 0.0001). There were positive correlations between the variables: rumination time × intake, rumination time × NDFI and peNDF × DpeNDF. It was observed that there was a negative correlation between the variables: rumination time × peNDF, rumination time × DpeNDF, NDFI × peNDF, and NDFI × DpeNDF. Cottonseed cake is an alternative source of peNDF for feedlot beef cattle.

Transition cow nutrition and management strategies of dairy herds in the northeastern United States: Part III—Associations of management and dietary factors with analytes, health, milk yield, and reproduction

The objective was to evaluate relationships between putative periparturient management and dietary factors at the pen and herd levels with metabolic- and inflammation-related analytes, health disorders, milk yield, and reproductive performance. Multiparous and primiparous cows from 72 farms in the northeastern United States were enrolled in a prospective cohort study. Farms were visited 3 times during the prepartum and postpartum periods: during the far-off dry, close-up dry, and fresh periods. Pen measurements were taken at each visit for the pens where cows sampled were housed, and particle size was determined for the total mixed ration for the pen. A survey was used to acquire data on herd-level management variables. Blood samples were collected from the same 11 to 24 cows per farm during the close-up and fresh period visits. Whole blood was analyzed for postpartum β-hydroxybutyrate (BHB) concentrations, and plasma was analyzed for prepartum and postpartum nonesterified fatty acids (NEFA) and postpartum haptoglobin (Hp) concentrations. Health event, milk yield, and reproductive records were acquired through the records management software program used on the farm. For the pen-level analysis, primiparous and multiparous cows were analyzed separately. For the pen- and herd-level analysis, a simple linear regression was conducted on all possible explanatory variables. Variables were included in the full multivariable general linear model if P < 0.20, and a manual backward stepwise elimination process ensued until all variables had P < 0.10. Our results indicate that pen- and herd-level management factors are associated with blood biomarkers, health, milk yield, and reproductive performance. For the prepartum period, our results support increasing the proportion of particles on the 19-mm sieve of the Penn State Particle Separator, optimizing bunk space, and not overfeeding metabolizable energy (ME), to decrease the prevalence of elevated postpartum NEFA, BHB, and Hp concentrations, decrease disorder incidence, maximize milk yield, and improve pregnancy risk to first service. For the fresh period, our results generally support optimizing bunk space, avoiding commingling, increasing feeding frequency, avoiding high physically effective undigested neutral detergent fiber (NDF) after 240 h of in vitro fermentation and high total fermentable carbohydrate diets while optimizing the inclusion of forage NDF, and ensuring adequate diet ME and metabolizable protein to reduce the prevalence of elevated postpartum NEFA, BHB, and Hp concentrations, minimize disorder incidence, maximize milk yield, and improve pregnancy risk to first service. At the herd level, our results generally support not vaccinating in the calving pen, minimizing the number of prepartum and postpartum pen moves, and avoiding long stays in the calving pen after parturition to reduce the prevalence of elevated biomarker concentrations, decrease disorder incidence, increase milk yield, and improve reproductive performance.

Transition cow nutrition and management strategies of dairy herds in the northeastern United States: Part I—Herd description and performance characteristics

Our objective was to describe management and herd characteristics of the transition period on freestall dairy herds in the northeastern United States using an on-farm survey and prospective cohort design. Enrolled herds (n = 72) had a median of 900 milking cows (range: 345-2,900) and a rolling herd average of 12,674 kg (standard deviation ± 1,220 kg), and 87.2% (n = 82/94) of fresh pens were milked at least 3×/d. The prevalence of herds with ≥15% of sampled cows with elevated concentrations of nonesterified fatty acids prepartum (≥0.27 mmol/L, 2-14 d before parturition) and postpartum [primiparous: ≥0.60 mmol/L, multiparous: ≥0.70 mmol/L, 3-14 d in milk (DIM)], β-hydroxybutyrate postpartum (≥1.2 mmol/L, 3-14 DIM), and haptoglobin postpartum (≥1 g/L, 0-12 DIM) was 51%, 51%, 51%, and 57%, respectively. In most herds, cows were moved to a calving pen when showing signs of labor (73.6%; n = 53/72) instead of 0 to 3 d before expected calving (26.4%, n = 19/72). Cows remained in the calving or maternity pen for a median (range) time of 2 (0-24) h after parturition before moving to the next pen. Primiparous cows remained in the first pen moved to after parturition for a longer period than multiparous cows [median (range) days: 12 (1.5-25) vs. 6 (1.5-22)]. Approximately 20% of herds had routine vaccinations administered in the maternity or calving pen, first pen after parturition, or both. Almost all herds (n = 69/72) performed fresh cow health checks; however, only 53% (n = 38/72) locked up all fresh cows daily. More herds housed primiparous and multiparous cows in separate pens during the far-off dry (65.3%; n = 47/72) and high-lactation (81.9%; n = 59/72) periods compared with the close-up dry (31.9%; n = 23/72) and fresh periods (27.8%; n = 20/72). At least half of the pens observed during the far-off dry, close-up dry, and fresh periods had a stocking density <100%. Approximately one-third of pens observed during the far-off dry period had feed pushed up ≤4×/d compared with approximately 15 to 20% of pens observed during the close-up dry, fresh, and high-lactation periods. More than half of the total mixed ration samples acquired from the far-off and close-up dry period visits had greater than the recommended proportion of particles in the 19-mm screen of the Penn State Particle Separator. The results of this observational study illustrated the range of management practices used in freestall herds in this region and lay the groundwork for future hypothesis-driven studies using this sampled population.

Effects of Grinding Almond Hulls with a Hammermill on Particle Size and Bulk Density

The objective of this experiment was to evaluate the effects of grinding almond hulls with different screens on subsequent particle size and bulk density. Twenty pounds of almond hulls from the California Central Valley were ground with a laboratory-scale 1.5 HP Bliss Hammermill (Model 6K630B) using a 7/16 in., 3/4 in., 1 in., or no screen. Each screen size treatment was ground at three separate time points to provide three replications per treatment. For each replication, two samples were collected and analyzed for particle size geometric mean and standard deviation and bulk density. Geometric mean particle size was greater (P < 0.01) when no screen was used to grind almond hulls compared with 3/4-in. and 1-in. screens; moreover, particle size was decreased (P < 0.01) when ground with a 7/16 in. screen compared to all other treatments. Particle standard deviation did not differ (P = 0.13) between treatments. Bulk density of almond hulls tended to be greater (P = 0.07) when a 7/16-in. screen was used as compared to no screen, a 3/4-in. screen, and a 1-in. screen. Overall, unground almond hulls had a bulk density of 14.1 lb/ft3. Therefore, grinding almond hulls using a 7/16 in., 3/4 in., 1 in., or no screen led to an increase in their bulk density by 140, 115, 114, and 111%, respectively. Particle size was also evaluated using the Penn State Particle Separator. Grinding almond hulls with no screen tended (P < 0.01) to increase proportions of medium (i.e., 0.31 to 0.75 in.) particles and decrease (P ≤ 0.02) proportions of fine (i.e., < 0.16 in.) particles compared to grinding with a 7/16-in. screen. In conclusion, decreasing hammermill screen size reduced particle size from 2217 µm to 1324 µm but did not impact particle size standard deviation. In addition, grinding almond hulls increased bulk density by 111 to 140%. A live-bottom trailer with a load capacity of 2,835 ft3 could transport approximately 20 tons of unprocessed almond hulls. Conversely, the same trailer could transport 25 to 30 tons of ground almond hulls, thus, reducing transportation costs by 20 to 33% per ton, respectively.

Accuracy and physical characteristics of total mixed rations and feeding sorting behavior in dairy herds of Castro, Paraná

The objective of this study was to assess the accuracy of the content of total mixed rations (TMR) offered to high-producing cows from 20 dairy herds of Castro, Paraná State, Brazil. The average milk yield during the sample collection period was 38.0±6.8 kg/day, with 3.47±0.25% milk fat and 3.05±0.18% milk protein. The particle size distribution of samples of fresh diet and leftovers was evaluated using the Penn State Particle Separator (PSPS) and chemical analysis was also conducted. The TMR [...]

Influence of the addition of water to total mixed rations on the feeding behaviour, feed intake and milk performance of high-yielding dairy cows

The goal of this study was to investigate the influence of the addition of water to total mixed rations (TMR) with a dry matter (DM) content of 42 - 47% and high proportions of ensiled forage on feeding behaviour, DM intake (DMI) and milk performance, as well as changes in TMR temperature. The underlying hypothesis was a reduction in the selective feeding behaviour and a resulting increase in DMI of the cows, which were provided with a moist TMR. During two feeding trials, 48 German Holstein cows per trial were split into 2 groups (Trial I, winter: 85 ± 28 d in milk (DIM); Trial II, summer: 67 ± 34 DIM). Both trials were set up as a crossover design with period lengths of 45 (Trial I) and 35 (Trial II) d. The rations in each trial were made of the same components, had the same energy and nutrient concentrations and had slightly different DM contents. In Trial I, a TMR with 46.4% DM (dry TMR) was mixed with 12.5 kg water per cow per day, to reduce the DM content of the TMR to 37.3% DM (wet TMR). In Trial II, the DM content of 41.8% (dry TMR) was reduced to 33.9% (Wet TMR) after 14 kg of water per cow per day were added. The DMI of the individual animals and their milk yield were measured daily, and the milk composition was determined weekly. To judge the feeding behaviour, samples were taken from each feeding group at five points throughout the day during Trial I, and three during Trial II. The samples were tested for particle size distribution using a Penn State Particle Separator (PSPS). In both trials, the selective feeding behaviour was reduced as a consequence of the addition of water to TMR. In the case of the dry TMR, a change in particle size distribution in the troughs was already discernible 10 h after the feed was provided. In both trials, the addition of water had a positive influence on the DMI. In Trial I, the cows consumed 1.3 kg DM/d more as a consequence of the addition of water (p < 0.001), and in Trial II the difference equated to 0.6 kg DM/d after the addition of water (p < 0.001). The increased energy and nutrient intake of the cows that had been fed with the moistened TMR led to higher daily milk yield (Trial I: +0.6 kg/d; Trial II: +0.5 kg/d) and drinking water intake (p < 0.001). During the first 24 h after mixing the rations in Trial II (summer), no temperature differences were observed between the dry and moistened TMR. During the time period of 24–48 h after feeding, the dry TMR had an average temperature of 36.8 °C and the wet TMR had a temperature of 40.1 °C, which was a significant difference (p < 0.001). Furthermore, in Trial II, the increased energy and nutrient intake was reflected in a higher fat and protein yield and in an increased energy-corrected milk yield by 0.8 kg/d (p = 0.015). These results confirm that by adding water to TMR, selective feeding behaviour can be reduced and DMI increased, both during summer and winter trials. The importance of a uniform, non-selective feed intake in high-performing dairy cows is also evident from the results.

308 Effects of Roughage Source on Growth Performance, Carcass Characteristics, and Rumination Time of Beef Steers Fed Steam-flaked Corn Finishing Diets

Abstract We hypothesized that roughage source would not impact rumination time and growth performance if the different sources provided a similar concentration of dietary neutral detergent fiber (NDF) and physically effective NDF (peNDF). This experiment’s objective was to evaluate rumination time, and growth performance steers consuming finishing diets with differing roughage sources (corn stalks, cotton burrs, or wheat silage). Beef steers (n = 49; BW = 317 + 5.6 kg) were used in a completely randomized design with 3 dietary treatments. Steers consumed a steam-flaked corn-based diet containing corn stalks (CS), cotton burrs (CB), or wheat silage (WS) included at 7% (DM basis). Dietary NDF was similar (P = 0.36) across treatments. Each steer was fitted with a sensory collar to record daily rumination. Weekly ingredient and dietary samples were estimated for physically effective NDF (epeNDF) using the Penn State Particle Separator. Actual physically effective NDF (apeNDF) was calculated based upon rumination time. Neither initial nor final body weight (BW) differed between treatments (P &amp;gt; 0.52); nor did average daily gain (ADG), dry matter intake or carcass adjusted variables of FBW, ADG, empty BW, or empty body fat (P &amp;gt; 0.31). However, gain to feed (G:F) tended to differ (P = 0.06) between treatments. The CS diet had the greatest G:F with no difference (P = 0.75) between CB and WS. Dietary NDF and epeNDF were similar (P &amp;gt; 0.35) among roughage sources; however, CB had the least apeNDF, consistent with lower rumination time (P &amp;lt; 0.01). When energy values were calculated from animal performance, the CS diet had the greatest observed energy values, followed by WS and CB having the least. These results indicate roughage source impacted rumination time, although steers were fed a steam-flaked corn-based finishing diet with similar dietary roughage and NDF inclusions.

233 Effects of Harvest Maturity And/or Kernel Processing on Corn Silage Processing Score and Particle Size of Corn Silage

Abstract A single corn hybrid was used to evaluate harvest maturity (Mat) and/or kernel processing (KP) effects on corn silage processing score (CSPS) and particle size (PS). Treatments were arranged in a 2 × 2 factorial of 1) Mat (early and late) and 2) KP (no or yes). A single corn field was planted on April 27, 2020. There were 12 loads (experimental unit) per simple effect treatment mean. Data were analyzed as a completely randomized design. Early harvest occurred on August 28, 2020 [yield (as is) = 39.1 Mg/hectare; DM = 43.1%; CP, NDF, and starch = 6.5, 46.0, and 32.9%, respectively (DM basis)]. Late harvest occurred on September 9, 2020 [yield = 37.8 Mg/hectare (as is); DM = 49.2%; CP, NDF, and starch = 6.6, 49.8, and 37.5%, respectively (DM basis)]. The same equipment was used for both Mat with KP achieved by narrowing processing rollers. The CSPS was determined as the proportion of starch retained below a 4.75-mm sieve. Grain content (DM basis) of the corn silage was calculated from starch/0.72. Particle size was assessed using the Penn State Particle Separator. A Mat × KP interaction (P = 0.05) was detected for CSPS. Early/no and late/no had decreased (P ≤ 0.05) CSPS compared to early/yes and late/yes had the greatest CSPS (P ≤ 0.05) compared to others. Grain content was 13.9% greater in late compared to early (P = 0.01). A Mat × KP interaction (P = 0.03) was detected for PS. Early/no had the greatest (P ≤ 0.05) PS, early/yes and late/no were intermediate, and late/yes had decreased PS compared to others (P ≤ 0.05). These data indicate that Mat and KP influence CSPS synergistically. Producers should consider KP when corn silage is harvested at a later maturity to enhance CSPS.

251 Effects of Roughage Source on Rumination Time and Ruminal Ph in Steers Fed a Steam-flaked Corn Finishing Diet

Abstract Research is limited on how physically effective fiber from various roughage sources aids in rumination time and ruminal pH of finishing beef cattle. This experiment’s objective was to evaluate rumination time and ruminal pH of beef steers consuming finishing diets with varying roughage sources (corn stalks, cotton burrs, or wheat silage). We hypothesized that roughage type would not impact rumination time and ruminal pH if different sources provide similar dietary neutral detergent fiber (NDF). Ruminally cannulated steers (n = 6; average BW = 644.56 + 13.15 kg) were used in a 3 × 3 replicated Latin square with 3 dietary treatments and 3, 21-d periods (20-d diet adaptation, 1-d sampling). Steers consumed a steam-flaked corn-based finishing diet containing corn stalks (CS), cotton burrs (CB), or wheat silage (WS) included at 7% (DM basis) of the diet. Dietary NDF was similar across treatments. Steers were fitted with a sensory collar to record daily rumination (Allflex Livestock Intelligence). Ruminal pH was measured using a handheld pH probe on d-21 at 0, 3, 6, 12, 24 hr postprandial. The NDF and dry matter intake (DMI) were greatest for steers consuming the WS diet (P &amp;lt; 0.01) while CS and CB diets did not differ (P = 0.81). While dietary NDF and estimated physically effective NDF (peNDF) were similar among roughage sources, CB had the lowest actual peNDF, consistent with lower rumination time (P &amp;lt; 0.01) and lower ruminal pH (P = 0.29). This experiment’s results indicate that roughage source impacted rumination time despite feeding steers a steam-flaked corn-based finishing diet with similar roughage and NDF levels. Using rumination time (min/d) to determine peNDF was a better indicator of rumen function parameters than particle size measured via the Penn State Particle Separator equation.

Rumen morphometry and sorting behavior of fattening male goat fed pelleted and unpelleted TMR with two levels of wheat straw

Abstract The physical form of the diet and level of straw in fattening total mixed rations (TMR) can influence sorting behavior and rumen morphometry. Therefore, the objectives of this experiment were to evaluate two levels of wheat straw (WS) in conventional and pelleted TMR on feed sorting behavior, rumen morphometry, the thickness of stratum corneum (SC), and color of reticulorumen mucosa. Thirty-two Beetle male goats (8 goats/treatment) were assigned to one of the four treatments in a 2 × 2 factorial arrangement: CTMR15 and CTMR 25 (conventional TMR containing 15 and 25 % WS, respectively), the PTMR15 and PTMR25 (pelleted TMR containing 15 and 25 % WS, respectively). In PTMR, the WS was ground to 8 mm and then pelleted. Feed sorting behavior of goats fed conventional TMR was evaluated twice weekly using Penn State Particle Separator (PSPS). At the end of the experiment, goats (n = 8/treatment) were slaughtered and rumen tissues preserved for further rumen morphometric examination. The CTMR25 fed goats consumed more medium ( 8 mm) and short (> 1.18) particles. There was a significant interaction (P 0.05) by the PF or the SL in the diet. The thickness of stratum corneum (SC) (18.55 μm) was highest (P

181 Evaluation of mixer performance in cattle finishing diets with 15 or 30 percent dry matter basis inclusion of corn silage

Abstract Batch fraction (BF), corn silage inclusion level (DIET), and mixing duration (DUR) were evaluated in an experiment using finishing diets based on corn silage and a blend of dry-rolled (DRC) and high-moisture corn (HMC). A 2.35 m3 horizontal mixer was used to manufacture all diets. The experiment was designed as a 5 x 2 x 2 factorial arrangement with nine replications per simple treatment mean. Factors included: 1) BF (n = 5), 2) DIET (n = 2) containing (DM basis) 15% corn silage or 30% corn silage replacing the corn blend, and 3) DUR (n = 2) of 20 or 25 mixer revolutions. Diets contained corn silage, a 1:1 ratio of DRC:HMC, a liquid supplement (5% DM inclusion), and a meal supplement (7% DM inclusion). Data were analyzed as a completely randomized design using the GLIMMIX procedure of SAS 9.4 (SAS Inst., Inc., Cary, NC) using a multinomial approach. The Penn State Particle Separator was used to separate fractions of the total mixed ration (TMR) with special interest on the portion of the TMR retained on the 19 mm sieve. No interactions between BF, DIET, and REV were detected (P ≥ 0.44). There was a 53.5% increase (P = 0.01) in retention on the 19 mm sieve from the first BF (first 20% of the TMR unloaded from the mixer) compared to the last BF (last 20% of the TMR unloaded from the mixer). The LOW diet had 71.3% decrease (P = 0.01) in retention on the 19 mm sieve (2.13 vs. 7.43 ± 0.220%) compared to the HIGH diet. Increasing DUR from 20 to 25 revolutions had no appreciable influence (P = 0.23) on particles greater than 19 mm. These data indicate that BF fed could alter dry matter intake, dietary net energy content, and influence daily gain. Wednesday, July 22, 2020

227 Evaluation of mixer performance in cattle finishing diets of varying physical characteristics

Abstract An experiment was conducted to evaluate batch fraction (BF), physical characteristics (DIET), and mixing duration (DUR) on long particle distribution in finishing diets. Diets were mixed in a 2.35 m3 horizontal mixer. The experiment was designed as a 5×3×2 factorial arrangement with nine replications per simple mean. Factors included 1) BF (n = 5), 2) DIET (n = 3) containing no corn-milling by-product (CON), a dry-corn milling by-product [47.45 ± 1.015% DM (as-is basis); DRY], or a wet-corn milling by-product [43.67 ± 1.786% DM (as-is basis); WET], and 3) mixing duration (n = 2) of 20 or 25 revolutions. Diets contained a 1:1 blend of DRC:HMC, the corn-milling by-products replaced the corn blend (20% total diet DM inclusion), grass hay (6% DM inclusion), liquid supplement (5% DM inclusion), and a meal supplement (7% DM inclusion). Data were analyzed as a CRD using the GLIMMIX procedure (SAS Inst., Inc., Cary, NC) using a multinomial approach. Samples of the total mixed ration (TMR) were subjected to separation via the Penn State Particle Separator. The dependent variable of interest was the portion of the TMR retained on the 19 mm sieve. No interactions were detected (P ≥ 0.49). There was an 87.1% (P = 0.01) increase in retention on the 19 mm sieve for last BF compared to the first BF. Diet influenced (P = 0.04) 19 mm sieve retention, there was 10.2% less TMR retained on the 19 mm sieve for DRY versus WET; CON was intermediate. Mixing duration did not influence (P = 0.73) 19 mm sieve retention. These data indicate that as the mixer unloads there can be nearly double the amount of roughage fed; differing physical characteristics of the diet only moderately influence the true roughage content fed. Differing roughage content delivered depending upon the BF could influence daily intake, feed efficiency and alter observed to expected ratios of dietary net energy.

Effects of feeding frequency and oil supplementation on feeding behavior, ruminal fermentation, digestibility, blood metabolites, and milk performance in late-lactation cows fed a high-forage diet

Many dairy producers are keen to feed low-producing late-lactation cows only once per day (1×) to reduce production costs. This study examined effects of feeding frequency (FF: thrice versus once daily) on behavioral patterns, ruminal fermentation, and milk production performance of cows and supplementation of yellow grease oil (YO) rich in 18:2n-6 as a potential strategy to alleviate the possible negative effects of 1× daily feeding. Twenty-four late-lactation Holstein cows (215 ± 53.8 DIM) housed in tiestalls were assigned to 4 treatments according to a 2 × 2 factorial arrangement with 2 FF [3 times daily (3×) at 0800, 1400, and 2000 h; or 1× at 0800 h] and 2 high-forage total mixed rations (TMR), without (CON) or with 25 g/kg of dry matter of YO (YGO), in a randomized complete block design. Treatments were applied for 21 d. Feeding behavior was recorded every 5 min over a 24-h period on d 19. Fresh TMR and orts were sampled (d 15 to 21) and separated using a 3-screen (19, 8, and 1.18 mm) Penn State Particle Separator for sorting activity. Ruminal fluid samples were collected using oral stomach tubing on d 21. Cows on 1×-CON spent more time eating during the first 6 h after feeding at 0800 h than did cows on 3×-CON or 1×-YGO. Decreasing FF increased meal length and tended to increase meal size for CON cows, but supplementing YO increased meal bouts and reduced meal length and size for cows fed 1×. Cows on 1×-CON had the greatest ruminating time between 2000 and 0800 h compared with other treatments. Total and daytime distribution of lying time did not vary by treatments. Sorting activity was higher for cows fed frequently, and the extent of sorting was increased by oil supplementation. In the morning ruminal fluid samples, pH was not different among treatments, but in the evening samples 1× daily feeding reduced ruminal pH compared with 3×. In the morning and evening samples, ratios of acetate to propionate were the lowest for 1×-CON cows compared with other treatments. Dry matter intake and milk yield were similar among the groups. Milk fat content and yield decreased with 1×-CON treatment, but supplementing YO numerically increased milk fat for cows fed 1×. These results suggest that decreasing FF from 3× to 1× daily increases meal length, particularly after feed delivery, in cows fed high-forage diets; but supplementation of plant oil changes feeding patterns and may improve ruminal pH and milk fat in cows fed once a day.

Accuracy and homogeneity of total mixed rations processed through trailer mixer or self-propelled mixer, and effects on the yields of high-yielding dairy cows

Total mixed ration (TMR) quality depends on feed levels and values, and appropriate diet formulation, but also on diet preparation practice. We examined the accuracy and homogeneity of rations, as affected by the machinery used for TMR preparation, and their effects on dairy cow performance. Multiparous Israeli-Holstein cows (n = 216) were stratified into 2 groups, according to milk yields, days in milk, parity, and body weight; they were fed the same formulated TMR, prepared by either a trailer mixer (TM) or an self-propelled loading mixer (SPLM). To examine the accuracy of diet preparation we have recorded and analyzed 10 times the difference between the programmed and the actual loaded content (as fed matter) of each feed ingredient. For evaluation of the accuracy and homogeneity of the ration contents, the TMRs from 6 spots along the feeding trough were sampled at 10 time-points, and the samples were analyzed for DM, protein, ADF, aNDF and ash contents; the results were compared with the programmed values. On another 7 occasions, samples of the TMRs were taken from 3spots along the feeding trough for evaluation of the particle sizes distribution using the Penn State Particle Separator. The mean difference – in percentage units – between the programmed and actual, loaded concentrate feeds was similar (∼5.7 %) for both TMRs (SEM = 1.5; P = 0.98), but for forage feeds it was +17.6 and - 0.6 % (SEM = 3.7; P = 0.001), for TM and SPLM TMR, respectively. The mean differences of contents (in percentage units; DM basis) between the programmed and prepared diets, were: for protein – 1.1 and 0.9 % (SEM = 0.2, P = 0.25), for ADF – 2.7 and 1.3 % (SEM = 0.2, P < 0.001), and for aNDF – 6.9 and 5.7 % (SEM = 0.2; P < 0.002), in TM and SPLM TMRs, respectively. Except for ash content, the chemical-composition homogeneity was greater in the SPLM TMR than in the TM TMR. The fraction of particles>19 mm was 2.9 percentage units greater (P = 0.04), and that of particles ≤8 mm was 3.3 percentage units less (P = 0.04) in the TM than in the SPLM ration. The milk yield was 1.2 kg/d greater (2.7 %) in cows fed the SPLM than in those fed the TM TMR (P < 0.001), and the milk-fat content was 0.8 g/kg greater in cows fed the TM TMR (P = 0.03). In conclusion, the accuracy and homogeneity of the SPLM-prepared TMR were greater than those of the TM-prepared TMR, which influenced the cows’ performance. This study demonstrates the importance of the preparation machinery for TMR quality, indicating that more attention should be dedicated in practice and research to the methods used for TMR preparation.