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PubMed2000

Interactions between forage and wet corn gluten feed as sources of fiber in diets for lactating dairy cows.

Twelve early lactation Holstein cows (4 fistulated) were used in replicated 4x4 Latin squares with 4-wk periods to determine the effective neutral detergent fiber (NDF) content of wet corn gluten feed and to measure the effect of forage particle size on ruminal mat consistency and passage rate of wet corn gluten feed. Diets were 1) 23.3% NDF (17.4 percentage units of NDF from alfalfa silage), 2) diet 1 plus 11.1 additional percentage units of NDF from alfalfa silage, 3) diet 1 plus 10.7 percentage units of NDF from wet corn gluten feed, and 4) 8.6 percentage units of NDF from alfalfa silage plus 8.9 percentage units of NDF from coarsely chopped alfalfa hay and 10.7 percentage units of NDF from wet corn gluten feed. The calculated effective NDF factor for wet corn gluten feed, using change in milk fat concentration per unit change in NDF, was 0.74 compared with an assumed 1.0 for alfalfa silage. Rumination activity was measured to calculate a physically effective NDF factor for wet corn gluten feed, which was only 0.11 compared with 1.0 for alfalfa silage. Physically effective NDF also was determined for wet corn gluten feed by wet sieving; 22% of the particles were retained on the 3.35-mm screen or greater. Ruminal mat consistency increased and passage rate of wet corn gluten feed decreased with added hay. The inclusion of chopped alfalfa hay to a diet containing wet corn gluten feed increased ruminal mat consistency, rumination activity, and slowed passage rate, resulting in greater ruminal digestion of NDF from wet corn gluten feed. Depending on the response variable, the effectiveness of NDF from wet corn gluten feed varied from 0.11 to 0.74.

Animal Feed↗
PubMed2004

Effect of alfalfa forage preservation method and particle length on performance of dairy cows fed corn silage-based diets and tallow.

A study was conducted to evaluate the effect of including alfalfa preserved either as silage or long-stem or chopped hay on DMI and milk fat production of dairy cows fed corn silage-based diets with supplemental tallow (T). Fifteen Holstein cows that averaged 117 DIM were used in a replicated 5 x 5 Latin square design with 21-d periods. Treatments (DM basis) were: 1) 50% corn silage:50% concentrate without T (CS); 2) 50% corn silage:50% concentrate with 2% T (CST); 3) 25% corn silage:25% short-cut alfalfa hay:50% concentrate with 2% T (SAHT); 4) 25% corn silage:25% long-cut alfalfa hay:50% concentrate with 2% T (LAHT); and 5) 25% corn silage:25% alfalfa silage:50% concentrate with 2% T (AST). Cows were allowed ad libitum consumption of a TMR fed 4 times daily. Diets averaged 16.4% CP and 30.3% NDF. Including 2% T in diets with corn silage as the sole forage source decreased DMI and milk fat percentage and yield. Replacing part of corn silage with alfalfa in diets with 2% T increased milk fat percentage and yield. The milk fat of cows fed CST was higher in trans-10 C18:1 than that of cows fed diets with alfalfa. No effect of alfalfa preservation method or hay particle length was observed on DMI and milk production. The milk fat percentage and yield were lower, and the proportion of trans-10 C18:1 in milk fat was higher for cows fed LAHT than for cows fed SAHT. Alfalfa preservation method had no effect on milk fat yield. Ruminal pH was higher for cows fed alfalfa in the diets, and it was higher for cows fed LAHT than SAHT. Feeding alfalfa silage or chopped hay appears to be more beneficial than long hay in sustaining milk fat production when 2% T is fed with diets high in corn silage. These results support the role of trans fatty acids in milk fat depression.

Animals↗
PubMed2004

Effects of fiber content and particle size of forage on the flow of microbial amino acids from continuous culture fermenters.

Eight dual-flow continuous culture fermenters (1320 mL) were used in two 10-d consecutive periods to study the effects of fiber content and particle size on rumen fermentation, nutrient flow, and the profile and flow of amino acids (AA) from microbial origin. Treatments were arranged in a 2 x 2 factorial; the main factors were fiber content (high fiber [HF] = 67% alfalfa hay, 33% concentrate; low fiber [LF] = 39% alfalfa hay, 61% concentrate) and forage stem particle size (ground not to pass a 3-mm sieve = large size [LS]; ground to pass a 1-mm sieve = small size [SS]). On the last day of the experiment, liquid- (LAB) and solid- (SAB) associated bacteria were isolated from each fermenter for chemical analysis. Microbial N and AA flows were estimated using LAB or SAB composition data. Total volatile fatty acid concentration was higher for LF (122 mM) than for HF (102 mM). The proportion of acetate was higher for HF (63.5%) than for LF (58.2%). When SS was fed instead of LS, there was a reduction in the acetate proportion (63.4% vs 58.3%, respectively) and in the acetate to propionate ratio (3.13 vs. 2.41, respectively). Bacterial N flow was higher, and dietary N flow was lower, in SS compared with LS when LAB were used for calculations. Efficiency of microbial protein synthesis (EMPS) was affected by particle size, when LAB were used for calculations, and by fiber content, when SAB were used for calculations. The AA profile of LAB differed from SAB in 4 of 16 AA. The fiber content and particle size had small effects on microbial AA profile. However, the bacterial AA flow was higher in 13 of 16 AA, when SAB instead of LAB were used for calculations. Estimates of bacterial N flow, EMPS, AA profile, and flows of microbial origin were dependent on the type of microbial population used for calculations. The representativeness of the microbial samples is essential for the accurate prediction of the AA flow from microbial origin.

Amino Acids↗
PubMed2006

Effects of dairy cow diet forage proportion on duodenal nutrient supply and urinary purine derivative excretion.

Four mature Holstein-Friesian dairy cows were used in a 4 x 4 Latin square change-over design experiment made up of four 4-wk periods to investigate the relationship between microbial protein flow to the duodenum and excretion of purine derivatives (PD) in the urine. Four dietary treatments based on ad libitum access to ryegrass silage were offered, with a standard dairy concentrate included at different forage:concentrate (F:C) ratios, calculated on a dry matter basis: 80:20, 65:35, 50:50, and 35:65. Feed intakes increased as the proportion of concentrate in the diet increased, despite a concurrent decrease in silage intake. Increased feed intake led to increased nutrient flow to the duodenum. Milk yields increased as the diet F:C ratio decreased, with cows offered the 35:65 diet yielding nearly 8 kg/d more milk than cows offered the 80:20 diet; the concentrations of milk fat decreased and milk protein increased with a decreasing F:C ratio. Purine derivative excretion in the urine increased with an increasing proportion of concentrate in the diet, and there was a strong linear relationship between total PD excretion (allantoin and uric acid) and microbial N flow to the duodenum: microbial N (g/d) = 19.9 + 0.689 x total PD (mmol/d); R = 0.887. This strengthens the case for using PD excretion as a noninvasive marker of microbial protein flow from the rumen in dairy cows.

Animal Feed↗
PubMed1975

Ensiled diet containing processed municipal garbage and sorghum forage for heifers.

Diets of similar proximate analysis formulated with a base of sorghum forage and primarily supplemented with equivalent dry matter of 18.4% of aerobically digested municipal garbage (garbage diet) or 17.5% of cottonseed hulls (control diet) were ensiled for 52 days and then individually and group fed to 16 dairy heifers for 56 and 35 days. Apparent digestibility of dry matter, crude protein, ether extract, crude fiber, and nitrogen-free extract in garbage and control diets averaged 54.2 and 47.4, 50.0 and 41.3, 62.0 and 65.1, 53.1 and 42.3, and 61.8 and 54.5% as determined by chromium oxide technique. Potential advantages from digestibility of the garbage diet appeared to be nullified by a 12% depression of dry matter intake and a consequent deterioration of feed efficiency. Dry matter intakes of garbage and control diets during the 56-day comparison were 1.98 and 2.25% of body weight and daily gains of .42 and .57 kg required 13.9 and 11.8 kg dry matter per kilogram of gain. Over the 91 days of combined comparison feeding, the .62 kg of average daily gain from control diet was 32% above the .47 kg from the garbage diet.

Animal Feed↗
PubMed1975

Effect of forage-to-concentrate ratio in complete feeds and feed intake on digestion of starch by dairy cows.

In digestion trials, 16 Holstein cows were fed complete mixed feeds of (a) 75:25, (b) 60:40, (c) 45:55, and (d) 30:70 ratios of forage to concentrate on a dry basis. At an intake of feed for maintenance, digestibility of starch ranged from 96.2 to 96.8%. During the lactation phase when intakes of feed were 2.5 to 3.2 times maintenance, digestibility of starch ranged from 84.7 to 88.1%. Starch in feces represented 2.9, 3.7, 5.5, and 5.9% of the intake of dry matter during the lactation phase, and .6, 1.0, 1.3, and 1.6% of intake at maintenance for the respective rations. At high intakes of concentrate, substantial amounts of dietary starch escaped degradation in the rumen and small intestine and were lost in the feces.

Animal Feed↗
PubMed1980

The effect of starch on forage fiber digestion kinetics in vitro.

Purified corn and wheat starch were added to alfalfa, Coastal bermudagrass, fescue, and orchardgrass hays at 0, 40, 60, and 80% of the total as-fed substrate, and fiber digestion kinetics were determined in vitro. Kinetics were estimated by the model R = Doe-k(t-L) + U where R is residue remaining at time t, Do is digestible fraction, k is digestion rate constant, L is discrete lag time, and U is indigestible fraction. Parameters of the model were estimated by logarithmic transformation and a direct nonlinear least squares procedure. Corn and wheat starch did not differ in their effect upon lag time of fiber digestion, digestion rate, or potential extent of digestion. Alfalfa had a shorter lag time of fiber digestion (.86 h) than Coastal bermudagrass (3.05 h), but not than orchardgrass or fescue (1.66 and 2.42 h). Orchardgrass differed in fiber digestion rate (.0542h-1) from Coastal bermudagrass (.0698h-1) but not from alfalfa or fescue (.0670 and .0658h-1). The potential extent of fiber digestion was similar for fescue (75.8%) and orchardgrass (76.0%). The potential extent of fibre digestion for alfalfa (50.9%) differed from Coastal bermudagrass (64.3%), and both of these forages differed from fescue or orchardgrass. Addition of starch resulted in a linear increase in lag time of fiber digestion, but digestion rate was not affected. Potential extent of digestion was decreased when starch was added.

Animal Feed↗
PubMed1983

Effects of varying particle size of forage on digestion and chewing behavior of dairy heifers.

Eighteen Holstein heifers were fed long and chopped coarse and fine alfalfa hay ad libitum to evaluate effects of physical form on digestion and chemical composition of feed and fecal particles and to examine the applicability of a sinusoidal model to chewing behavior. Recordings of jaw movement were divided into 1-h segments for analysis. Least square mean size of fecal particles from coarse and finely chopped diets were 290 and 297 micrometers as compared to 227 micrometers on long hay. Intakes of dry matter were greater an digestibilities lower for chopped as compared to long hay. Crude protein content of separated feed and fecal particles increased as particle size decreased. Neural and acid detergent fiber concentrations decreased in feed and feces with decreasing particle size. Lignin content of feed particles decreased as particle size decreased, whereas for fecal particles lignin as a percent of cell wall followed a "U" shaped pattern of declining then increasing as size decreased. Patterns were sinusoidal for eating and ruminating long and chopped hays and total chewing (eating and ruminating) of long hay. Our results suggest a gradual effect on chemical degradation and physical detrition of digesta particles and chewing behavior as forage particle size decreased.

Animal Feed↗
PubMed1983

Effects of various forage feeding programs during dry period on body condition and subsequent lactation health, production, and reproduction.

During 3 yr, 289 Holstein cows prior to being dried off were assigned randomly to one of three diets: all long hay, 50% hay and 50% corn silage, and limit-fed corn silage plus 1.1 kg liquid protein supplement added per cow per day. Body weights, condition scores, and calving difficulties were recorded. Calf weights were recorded at birth. All cows were distributed across eight postpartum experiments. Body condition was similar for all cows at termination of dry period. Cows fed limited corn silage plus liquid supplement gave birth to heavier calves and had greater calving difficulty. Diet for dry period had little effect on health in the subsequent lactation. Cows fed long hay while dry consumed more dry matter, produced more milk with lower milk fat percent, and were not different for 4% fat-corrected milk compared to cows fed the other two diets in dry period. Days open were greater for cows fed long hay while dry. In general, as long as the ration is nutritionally balanced and fed in amounts to achieve or maintain adequate body condition, forage programs ranging from all hay to all corn silage can be fed successfully during the dry period.

Animals↗
PubMed1983

Early lactational response to supplemental protein by dairy cows fed grass-legume forage.

A total of 24 primiparous and 46 multiparous Holstein cows were in two trials to determine the influence of concentration of dietary protein on performance during early lactation. Treatments were 13.5 or 16.5% dietary crude protein for the first 12 wk of lactation. Complete mixed diets of grass-legume forage and concentrates were fed for ad libitum consumption. Treatment patterns repeated across trials. Yields of milk and 3.5% fat-corrected milk, intake of dry matter, and returns over feed costs were improved by feeding the diet with 16.5% crude protein. Percent milk fat, body weight change, and reproductive performance were unaffected by treatment. The results demonstrate benefit, during early lactation, from supplementing protein to grass-legume based diets containing 13.5% crude protein. Performance responses to increased concentrations of dietary crude protein during early lactation appear greater for multiparous than primiparous cows.

Animals↗
PubMed1987

Performance of lactating dairy cows fed tall fescue forage.

Two trials were conducted during consecutive summers to compare performance of lactating cows fed four varieties of tall fescue soilage. The first trial was conducted in 1983 and the second in 1984 using 25 midlactation Holsteins. Treatments included endophyte-free Kenhy; 8.1% endophyte-infected Johnstone (a prevarietal release); endophyte-free Kentucky 31; 63% endophyte-infected Kentucky 31; and orchardgrass or alfalfa as controls. In 1983, concentrate was fed twice each day at the rate of 4.1 kg per feeding, and in 1984, 4.5 kg were fed twice daily for first 4 wk and 4.1 kg per feeding thereafter. Intake of Kenhy was higher than all other tall fescue treatments when data for both trials were combined. Means of the high endophyte Kentucky 31 group were lower than all other treatments during both trials for milk yield, dry matter intake, body weight change, and serum prolactin in 1984 while higher for rectal temperature. Improved intake and performance of the cows consuming Kenhy compared with those consuming endophyte-free Kentucky 31 indicated the improved forage quality of this variety. Decreased performance of dairy cows consuming endophyte-infected tall fescue, even at a relatively low infection, was evident.

Animal Feed↗
PubMed1988

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 3.12 mm. 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.

Animal Feed↗
PubMed1988

Effect of forage physical form on chewing activity, dry matter intake, and rumen function of dairy cows in early lactation.

To examine the effects of reducing forage particle size on production, chewing, and digesta kinetic parameters in early lactation, 42 Holstein cows (9 ruminally cannulated) were assigned 14 d postpartum to one of three experimental diets with concentrate: alfalfa haylage: alfalfa pellets ratio of A) 60:40:0;B) 60:28:12; and C) 60:12:28 on a DM basis. The trial ran through the 12th wk postpartum, and measurements of chewing activity and rumen parameters were made during the 4th, 8th, and 12th wk postpartum. Dry matter intake (kg/d), milk production (kg/d), and milk fat percentage for diets A, B, and C were 23.1, 23.0, 18.8; 33.7, 35.5, 31.8; and 3.1, 2.9, 2.6, respectively. Rumen parameters and chewing activities were linearly related to haylage in the diet. Ruminal fluid dilution rate (%/h), volume (L), and outflow (L/d), rumination (min/d), total chewing (min/d), total chewing (min/kg DM intake), ruminal acetate (molar %), and NDF digestibility (%) were 16.6, 13.8, 10.0; 62, 58, 54; 243, 193, 137; 437; 367, 204; 649, 566, 376; 28.2, 24.1, 20.0; 58.6, 56.3, 53.8; and 32, 37, 23, respectively. These results suggest that dairy cattle in early lactation require a minimum amount of effective fiber to optimize production and intake. This requirement was met when 28%, but not 12%, of dietary DM was alfalfa haylage.

Animal Feed↗
PubMed1989

Comparative digestion in sheep and cattle fed different forage to concentrate ratios at high and low intakes.

Effect of maintenance and ad libitum intakes on digestibility of different feed fractions was studied with six ruminally fistulated cows and six ruminally fistulated wethers to validate the use of sheep as a model for cattle. Complete diets were made up of ratios of alfalfa:cracked corn and soybean meal of 80:20, 55:45, and 30:70. The regression coefficient of the line relating organic matter digestibility with proportion of concentrate in the diet was smaller for the cows at ad libitum intake than for the other groups. Increasing the intake caused a decrease in digestibility of different fractions. The depression in digestibility was greater for the 30:70 forage:concentrate diet than for the others. At high intake, digestion values in the cows were less than those in the sheep for all diets. An increase in intake depressed the digestion of cell wall fractions and cell solubles including starch in cows, whereas in sheep, an increase in intake reduced cell wall digestion and to a lesser extent cell solubles, without affecting starch digestion. The digestive physiology of these species is sufficiently different to preclude the use of sheep data in formulating nutrient requirements for cows.

Animal Feed↗
PubMed1991

Effects of protein level and forage source on milk production and composition in early lactation dairy cows.

Twenty multiparous and 12 primiparous Holstein cows were assigned at calving to one of three grass hay-based diets containing either 14, 18, or 22% CP or an alfalfa hay-based diet containing 22% CP to examine the effect of protein level and forage source on milk yield and composition. The diets contained 23% ADF during wk 1 to 4 postpartum, which was lowered to 11% for wk 5 to 12 postpartum. Cows fed the 18 and 22% CP grass-based diets produced higher yields of milk, 4% FCM, fat, protein, and SNF than those fed the 14% CP diet during the high fiber period. In addition, cows fed the 22% CP grass-based diet had higher milk fat tests than those fed the 14% CP diet during the high fiber period, due primarily to an increase in short-chain fatty acid synthesis. Milk fat depression was more severe when cows were changed to low fiber diets while fed the 22% CP alfalfa-based diet than when fed the 22% CP grass-based diet. Depression in milk fat content was 15.0, 17.0, 15.6, and 27.0% for 14, 18, and 22% CP grass-based and 22% CP alfalfa-based diets, respectively. Cows receiving the 18 and 22% CP grass-based diets exhibited higher blood NEFA during the high fiber feeding period than those fed the 14% CP diet. After fiber was lowered, changes in rumen acetate:propionate ratios were unaffected by treatment. Lowering fiber level resulted in an increased milk CP percentage regardless of treatment. Grass hay appeared to be more effective than alfalfa hay in preventing depression in milk fat test upon the change to a low fiber diet.

Animal Feed↗
PubMed1991

Lactation response and body composition of cows receiving somatotropin and three ratios of forage to concentrate.

Ninety multiparous Holstein cows were used to determine the effect of ration energy density and bST on lactation performance and whole body chemical composition. Seventy-eight cows, averaging 43.6 d postpartum, were assigned for 168 d to TMR with forage: concentrate ratios of 40:60, 50:50, and 60:40 (DM basis). Half of the cows on each ration received subcutaneously either 0 or 640 mg bST/28 d. Whole body chemical composition was determined by comparative slaughter in 12 cows (means = 35.9 d postpartum) prior to initiation of treatment and in 35 cows after either 84 or 168 d of treatment. Net energy intake was greater for 40:60 and 50:50 than for 60:40. Milk fat percentage was reduced in cows fed 40:60. Ration did not affect milk, 3.5% FCM, and DMI. There were no differences among rations for total body fat, protein, water, and calories. The bST increased milk and 3.5% FCM but had no effect on DM and net energy intakes. Yield of 3.5% FCM by cows receiving bST and fed 40:60 was 1.9 kg/d more and for 50:50 it was 2.7 kg/d more than for those fed 60:40. Administration of bST reduced total body fat and calories but did not affect protein and water. Partitioning of calories to milk at the expense of fat deposition is the primary mechanism for the galactopoietic action of bST.

Adipose Tissue↗
PubMed1992

Replacement of forage or concentrate with combinations of soyhulls, sodium bicarbonate, or fat for lactating dairy cows.

A lactation study was performed from wk 4 to 19 of lactation to evaluate the ability of soyhulls with or without 1% sodium bicarbonate to replace corn silage and the ability of soyhulls, roasted soybeans, and rumen-inert fat to replace concentrate. All diets contained similar concentrations of NE(L) (tabular value), CP, and degradable protein. When forage NDF was reduced to 62.5% of total dietary NDF (32 to 36% NDF, depending on analytical method) with soyhulls, milk production and total tract nutrient digestibility were unaffected. Addition of sodium bicarbonate to the soyhull diet reduced milk production, but other production aspects were similar. As evaluated using body condition scoring, cows fed soyhulls with buffer appeared to lose less condition before the trial and to recondition earlier and more during the trial than did those fed soyhulls without buffer, which explains differences in milk production. Buffer did not increase digestibility of OM and NDF, perhaps because the high rate of passage of soyhulls limited digestibility more than did ruminal pH. Replacement of concentrate with soyhulls and fat tended to increase milk and FCM production, resulting in improved efficiency of milk production. However, fat fed to cows reduced the percentage of milk protein. As evaluated during the last 4 wk of a 6-wk posttreatment period, fat fed to cows had no residual effects on any production aspect measured.

Animal Feed↗
PubMed1993

Computerized monitoring of gas production to measure forage digestion in vitro.

The techniques reported in this paper were developed to facilitate the study of the kinetics of forage digestion in vitro by measuring gas production. Fiber disappearance as a measure of the reaction rate has been replaced by the use of computerized pressure sensors to monitor the gaseous products (CO2, CH4) of microbial metabolism. The recording system described requires a computer, pressure sensors, an interface card, and appropriate software to monitor gas production continuously. Several variables, including sample size, inoculum size, vessel size, and type of pressure sensor, have been investigated to determine ranges within which gas production can be measured accurately, and the reproducibility of the results has been established. Because this technique uses small (100-mg) samples, a modified NDF method has been introduced that allows determination of extent of digestion at the end of an incubation in which gas production has been monitored. A strong linear relationship existed between NDF disappearance and gas production.

Acetates↗