Silage Particle Size Research Articles

Effect of the grass silage particle size offered as TMR on the ruminal thiamine concentration in high-yielding dairy cows

Effect of the grass silage particle size offered as TMR on the ruminal thiamine concentration in high-yielding dairy cows

The Effect of Corn Silage Particle Size on Eating Behavior, Chewing Activities, and Rumen Fermentation in Lactating Dairy Cows

The objective of this experiment was to evaluate effects of reducing corn silage particle size on eating behavior, chewing activity, and rumen fermentation in lactating dairy cows. Four cannulated, multiparous cows averaging 110±4 d in milk and weighing 675±70kg were randomly assigned to a 4×4 Latin square. During each of four 14-d periods, animals were offered one of four diets that were chemically similar but varied in corn silage particle size: short (SH), mostly short (MSH), mostly long (MLG), and long (LG), with a geometric mean particle length of 7.4, 7.8, 8.3, and 8.8mm, respectively. Reducing particle size increased dry matter intake (DMI) linearly (28.0, 26.8, 26.8, and 25.7 kg/d for SH, MSH, MLG, and LG respectively). At 8, 16, and 24h postfeeding, the neutral detergent fiber (NDF) concentration of feed remaining in the bunk decreased linearly with reduced particle size. Time spent eating or ruminating was not different across treatments; however, total chewing activity (TC; sum of time spent eating and ruminating) exhibited a quadratic response with highest chewing activities observed for diets with shortest and longest particle size. Eating or ruminating time per kilogram of DMI was not affected by corn silage particle size, but TC per kilogram of DMI decreased linearly with decreasing particle size. In comparison, when expressed as minutes per unit of NDF intake (NDFI), ruminating, and TC were linearly reduced as particle size decreased. Rumen pH was not affected by corn silage particle size even though total concentration of volatile fatty acids increased linearly from 89.1mM/L to 93.6mM/L as diet particle size decreased. A quadratic effect was observed in molar proportion of acetate and propionate with the highest concentration observed in animals consuming diets of intermediate particle size. Results of this experiment suggest that reducing corn silage particle size may increase DMI, positively affect rumen fermentation, and reduce sorting behavior. Because both chewing activity and sorting tendencies increased when proportion of TMR particles>19.0mm increased, results suggest that particle size measurement as estimated by the PSPS is useful in understanding some factors that affect feeding behavior.

Effects of barley silage particle size and concentrate level on rumen kinetic parameters and fermentation patterns in steers

Four Hereford steers (471 ± 31 kg) fitted with ruminal cannulae were used in a 4 × 4 Latin square design to evaluate the effects and possible interactions between silage particle size and concentrate level on digestion and ruminal fermentation parameters. Diets were designed with two forage to concentrate ratios [low forage, 20:80, high forage, 50:50 on a dry matter (DM) basis], combined with two theoretical chop lengths of barley silage; short (SBS) = 4.7 mm and long (LBS) =18.8 mm. Results showed that steers fed diets with SBS consumed more DM than those fed LBS. An interaction (P < 0.05) between particle size and concentrate level was noted for molar proportion of acetate. At the higher concentrate level, feeding SBS diets reduced the molar proportion of acetate but increased the molar proportion of propionate. An interaction (P < 0.05) between particle size and concentrate level was noted for ruminal pH. When compared to LBS, the daily mean rumen pH was lower (P < 0.05) for steers fed SBS with 80% concentrate but not for those fed the 50% concentrate diet. Ruminal ammonia concentration was higher (P < 0.05) for those steers fed the 50% concentrate diets than for those fed the 80% concentrate diets. With high concentrate levels, SBS greatly reduced (P < 0.05) ammonia concentration. Passage rates for particulate matter and the retention time were decreased (P < 0.05) when SBS was fed. Feeding SBS reduced (P < 0.05) total tract digestibility of dry matter, crude protein (CP) and neutral detergent fiber (NDF) (65.5 vs. 68.5%, 66.5 vs. 73.4% and 39.4 vs. 45.9%), respectively. These results suggest that barley silage with a theoretical cut length of 18.8 mm can promote higher rumen pH, ammonia nitrogen, and reduced particulate passage rates. These changes in rumen fermentation parameters should favor optimum rumen function and digestion when high concentrate diets are fed. Key words: Barley silage, particle size, steers, concentrate level, rumen fermentation

The Effect of Corn Silage Particle Size and Cottonseed Hulls on Cows in Early Lactation

The objective of this study was to evaluate the effects of reducing forage particle length (FPL) and the inclusion of cottonseed hulls (CSH) on intake, digestibility, chewing activity, and milk production of cows in early lactation. Sixteen multiparous cows averaging 17±3 d in milk and 677±58kg BW were assigned to one of four 4×4 Latin squares. One square contained ruminally cannulated cows to evaluate effects of treatment on rumen fermentation and function. During each of the 23-d periods, cows were offered one of four total mixed rations that differed in particle length (long or short corn silage) and CSH inclusion rate (0 or 8% DM). Dietary treatments were: long no CSH (LGNH), long with CSH (LGH), short no CSH (SHNH), and short with CSH (SHH). Total physically effective NDF content, measured as percentage of NDF greater than 1.18mm, was similar across diets, but mean particle length decreased with reducing FPL and inclusion of CSH. Dry matter intake was not significantly affected by FPL but was significantly increased with the inclusion of CSH. Decreasing FPL and the inclusion of CSH significantly increased neutral detergent fiber intake. Total chewing activity expressed as minutes per day was unaffected by FPL and the inclusion of CSH. Both eating and ruminating efficiency expressed as minutes per kilogram of neutral detergent fiber intake increased with increasing FPL and decreased with the inclusion of CSH. Milk production did not differ across treatments, but the inclusion of CSH significantly increased percent and yield of milk protein. Reducing FPL tended to reduce percentage milk fat but not yield. Mean ruminal pH was not affected by FPL but was highest on diets containing CSH, even though no treatment effects were observed on total VFA, acetate, or propionate concentration. These results indicate that corn silage FPL is a poor predictor of total chewing time and rumen pH but is useful in understanding factors affecting feeding behavior. In addition, the inclusion of CSH, resulted in increased rumination and mean rumen pH even though effects on VFA concentration were not observed.

Starch and fibre distribution in maize silages in relation to particle size

AbstractIn a first trial the particle size distribution of four maize silages was measured by two different sieving methods, dry and wet sieving. Particle size distribution was quantified by three values, mean particle size, extent of dispersion, and proportion of large particles. Wet sieving separated particles better than dry sieving and was more suitable for measuring maize silage particle size. In a second trial the particle size distribution of 10 maize hybrids grown in the same conditions was measured by wet sieving. Starch proportion in large particles varied widely between maize hybrids, from 39.7 to 82.4%, against a variation from 75.4 to 100% for cell wall proportion in the same class of particles, and these variations might be predicted by dry matter distribution.© 2003 Society of Chemical Industry

Influence of Particle Size on the Effectiveness of the Fiber in Alfalfa Silage

The objective was to determine the influence of alfalfa silage particle length on milk yield, milk composition, and chewing activity. Sixteen multiparous lactating Holsteins were used in each of two separate feeding trials over a 2-yr period providing two repetitions. Each trial was based on 4×4 Latin squares with 21-d periods. All four diets (2-yr average, dry basis) contained a basal level of 10.7% neutral detergent fiber from corn silage and 2.3% neutral detergent fiber from chopped alfalfa-grass hay. One of the diets served as a low forage, low fiber control and contained only the basal forages. The other three diets contained an additional 8.6% neutral detergent fiber from coarser alfalfa silage, finely rechopped alfalfa silage or an equal mixture of the two. An increase in the forage content above the basal amount using alfalfa silage increased 4% fat-corrected milk yield, milk fat yield and concentration, eating time, and total chewing time. Dry matter intake was not influenced by diet. Linear increases in rumination and total chewing times were observed as the mean particle size of the alfalfa silage increased from finer to coarser. There was no linear effect of alfalfa silage particle size on milk yield, 4% fat-corrected milk yield, dry matter intake, or milk composition.

Effects of barley silage of different theoretical cut length on digestion kinetics in ruminants

Two studies were conducted to determine the effects of two theoretical lengths of cut (TLC) (short = 4.7 mm and long = 18.8 mm) on the feeding value of barley silage to steers fed an all-forage diet. In the first study, six steers were used to determine intake of dry matter, total tract digestibility of dry matter (DMD), neutral detergent fiber (NDFD), and acid detergent fiber (ADFD) in a replicated switchback design. In the second study, six steers equipped with rumen cannulas were used to determine the effects of barley silage particle size on ruminal kinetic and fermentation parameters. Feeding short barley silage to steers increased (P < 0.05) dry matter intake (DMI), DMD, NDFD, and ADFD compared with feeding long barley silage. The results of the second study showed that reducing barley silage particle size decreased (P < 0.05) ruminal retention time and increased (P < 0.05) passage rate of particulate matter. Ruminal pH was lower (P < 0.05) at 1000, 1200, 1800, 2000, and 2200 h for steers fed the short barley silage compared with those fed the long barley silage. However, the effects of barley silage particle size on ruminal ammonia nitrogen and volatile fatty acid (VFA) concentrations were minimal. Eating rate was similar in both dietary treatments (average 40.3 g min-1). However, steers fed the long silage produced more (P < 0.05) saliva per kg DMI compared with those fed the short barley silage diets. It was concluded that reducing TLC of barley silage increased feed intake and improved total tract utilization of cell wall components by steers. Results of the metabolism study also showed changes in fermentation parameters, but no adverse physiological changes were noted when cattle were fed all forage diets. Key words: Barley silage, particle size, fermentation patterns

Corn Silage Management I: Effects of Hybrid, Maturity, and Mechanical Processing on Chemical and Physical Characteristics

Two experiments were conducted to evaluate the effects of hybrid, maturity, and mechanical processing of whole plant corn on chemical and physical characteristics, particle size, pack density, and dry matter recovery. In the first experiment, hybrid 3845 whole plant corn was harvested at hard dough, one-third milkline, and two-thirds milkline with a theoretical length-of-cut of 6.4mm. In the second experiment, hybrids 3845 and Quanta were harvested at one-third milkline, two-thirds milkline, and blackline stages of maturity with a theoretical length-of-cut of 12.7mm. At each stage of maturity, corn was harvested with and without mechanical processing by using a John Deere 5830 harvester with an onboard kernel processor. The percentage of intact corn kernels present in unprocessed corn silage explained 62% of variation in total tract starch digestibility. As the amount of intact kernels increased, total tract starch digestibility decreased. Post-ensiled vitreousness of corn kernels within the corn silage explained 31 and 48% of the variation of total tract starch digestibility for processed and unprocessed treatments, respectively. For a given amount of vitreous starch in corn kernels, total tract starch digestibility was lower for cows fed unprocessed corn silage compared with processed corn silage. This suggests that processing corn silage disrupts the dense protein matrix within the corn kernel where starch is embedded, therefore making the starch more available for digestion. Particle size of corn silage and orts that contained corn silage was reduced when it was processed. Wet pack density was greater for processed compared with unprocessed corn silage.

Influence of Particle Size on the Effectiveness of the Fiber in Barley Silage

We used eight multiparous Holstein cows in a 4 × 4 Latin square design to evaluate the effects and possible interactions between silage particle size and concentrate level on chewing activities and productivity of cows fed barley-based total mixed rations (TMR). Diets were designed with two forage-to-concentrate ratios (low forage, 45:55, high forage 55:45), combined with two theoretical chop lengths of barley silage (short = 4.68mm and long = 18.75mm). Diets were formulated to provide similar and above-minimum neutral detergent fiber recommended for cows in early lactation. Increasing silage particle size of the forage did not affect dry matter intake. The 3.5% fat-correct milk and fat yields trended higher for increased particle size. Percent milk protein was higher for short particle size. Increasing the concentrate levels in the diets increased proportions of milk protein and lactose, but not milk fat. Cows fed short silage spent 90min less per day chewing and ruminating than did those on long silage. Total chewing activity per kilogram of forage intake was higher for cows on long silage compared with those on short silage diets. Although a reduction in silage particle size did not depress milk fat, rumination and chewing activity were significantly reduced. These results suggest that particle size of the silage may have dominant control over chewing activity despite adequate neutral detergent fiber intakes.

Influence of particle size on the effectiveness of the fiber in corn silage.

This experiment evaluated the influence of particle size on the effectiveness of fiber in corn silage relative to that in hay crop, which consisted of mostly alfalfa silage. Fifteen multiparous Holstein cows were assigned to five treatments in each of 2 yr. The design was replicated but truncated 5 x 5 Latin squares with three 21-d periods in 1994 and four 21-d periods in 1995. The five diets (2-yr average, dry basis) were a basal, low fiber control with 12% neutral detergent fiber (NDF) from hay crop forage (60% of total diet NDF); a high fiber control with 22% NDF from hay crop forage (82% of total diet NDF); and three diets each containing 12% NDF from hay crop forage and 9% NDF from coarse corn silage, fine corn silage, or an equal mixture of the two. An increase in the forage content above the basal amount with either hay crop or corn silage increased rumination and total chewing time. No detectable differences in rumination, total chewing time, or milk fat concentration were detected among the corn silage diets. In yr 1, yield of milk components and dry matter intake were greater for cows fed the four low alfalfa diets, but there was no effect due to particle size of the corn silage. In yr 2, linear increases in milk, fat, and protein yields were observed as the mean particle size of the corn silage decreased. Reduction of corn silage particle size did not affect chewing behavior.

Effect of Particle Size of Forage and Rumen Cannulation upon Chewing Activity and Laterality in Dairy Cows

Three ruminally cannulated Holstein dairy cows housed in free stalls (with .7% slope) were fed three total mixed rations, differing in silage particle size, in a 3 × 3 Latin square design. Observations on cow behavior were made every 5min during 24h for each of three periods. Additional observations of six cows (three intact, three cannulated) housed under identical conditions yielded information concerning recumbent rumination activity and laterality. Results indicated that decreasing particle size of forage reduced time spent ruminating, whether standing or recumbent, and had no effect upon rumination rate or number of rumination bouts per 24-h period. Eating time was unaffected by treatment. Effect of forage particle size upon baseline rumination activity appeared to be most pronounced from 0800 to 2000h, although maximum rumination activity occurred during nighttime hours. Ruminally cannulated cows demonstrated increased right-side laterality (70%) compared with intact cows (47%), but the cows tend to ruminate while lying on their left side. The percentage of time spent ruminating while recumbent on the left side was similar (55%) for intact and cannulated cows.

Intake, Duodenal Flow, and Ruminal Characteristics of Long or Short Chopped Alfalfa-Timothy Silage with or without Inoculant1,2

Eight crossbred wethers each fitted with reentrant duodenal cannula and rumen fistula were used in a crossover design with a 2 × 2 factorial arrangement in order to measure the effects of inoculation and chop length of silage on intake, rate of flow into the duodenum, and ruminal characteristics. As chop length increased, silage DM decreased. Microbial inoculation had no effect on silage composition but increased its intake. Short chop length of silage decreased the amount of total N reaching the duodenum. The rumen acetate:propionate ratio was decreased by feeding the short vs. chopped silage. Rumen acetate concentration was lower when the sheep were fed short chopped silage compared with long chopped silage. Rumen volume and DM content were higher for sheep fed inoculated silages. The pH and NH3 N of the rumen and rumen dilution rate of liquid and solids were similar for all treatments. Data show that microbial inoculation increased silage intake and that silage particle size modified duodenal flow of N and production of rumen VFA, which might alter performance of animals.

Milk Fat Depression in Dairy Cows: Role of Silage Particle Size

The effect of particle size of alfalfa silage on lactating cow metabolism was investigated with reference to milk fat depression. Eighteen cows in a crossover design were fed total mixed rations containing either fine (2.0mm), medium (2.6mm), or coarse (3.1mm) ground alfalfa silage as 55% of dietary DM. Intake of DM and NDF was not influenced by particle size of the ration. Actual milk production also was unaffected, but milk fat percentage decreased from 3.8% for cows fed the coarse ration to 3.0% for cows fed the fine ration. This decline lowered 4% FCM yield and efficiency of production for cows fed the fine ration compared with cows fed medium or coarse rations. Cows fed the coarse ration had longer rumination and total chewing times. Ruminal pH and acetate:propionate ratio decreased when cows consumed the fine ration. Plasma glucose and serum insulin increased with decreasing particle size of silage. Results indicated that reduced size of silage particles altered chewing behavior, ruminal fermentation, glucose metabolism, and decreased milk fat secretion.

Particle Size Reduction of Alfalfa Silage Did Not Alter Nutritional Quality of High Forage Diets for Dairy Cattle

Twelve multiparous, lactating Holsteins were fed an energy adequate diet (50% wilted alfalfa silage) and two isonitrogenous diets containing 80% of the same silage. The two 80% alfalfa diets were identical in all respects except that for one diet 38% of the alfalfa silage was rechopped after fermentation to reduce the particle length from 5.63 to 3.12mm. Feeding the 80% alfalfa diets decreased milk production due to limitation of digestible energy intake. Under conditions of energy restriction, reduction of particle size of alfalfa silage after fermentation did not result in any changes in feed intake, feed digestibility, or milk production. The results do not preclude the possibility of some changes for intake or digestibility with more extensive reductions in particle length of alfalfa silage. However, because the extent of forage particle size reduction is limited by nutritional and economic constraints, the results of this study indicate that there is no practical advantage to reducing the particle size of fermented alfalfa beyond that required for adequate fermentation.