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PubMed2000

Grazing methods and stocking rates for direct-seeded alfalfa pastures: II. Pasture quality and diet selection.

A 2-yr study was conducted to determine the effects of two grazing methods (GM) and two stocking rates (SR) on alfalfa (Medicago sativa L. var. WL225) pasture quality and diet selection by Holstein steers. Eight pasture plots (.76 ha) were seeded in 1988 and divided into two blocks of four pastures each. Pastures were managed to allow a 36-d rest period with an average grazing season of 105 d. Before steers entered the next paddock, canopy heights (CH) of alfalfa plants were determined and pasture-forage samples were collected. Forage samples were analyzed for DM, OM, CP, and in vitro OM digestibility (IVOMD). At 12-d intervals beginning with the second grazing cycle, extrusa samples were collected from steers with esophageal fistulas. Extrusa samples were frozen, freeze-dried, and analyzed for OM, CP, IVOMD, in situ ruminal DM degradation, and ruminal undegradable protein. There were no effects of GM on alfalfa CH or pasture DM, OM, CP, and IVOMD. Increasing the SR increased pasture CP content in both years and increased DM, OM, and IVOMD in the 2nd yr. There was no effect of GM or SR on the quality of forage selected by esophageally fistulated steers. Esophageally fistulated steers selected forage that had greater OM, CP, and IVOMD than the average nutrient content of the forage. Although forage quality was greater when stocking rates were increased, the quantity of forage available per animal may have limited gains.

Animal Husbandry↗

PubMed2004

Effects of cereal grain supplementation on apparent digestibility of nutrients and concentrations of fermentation end-products in the feces and serum of horses consuming alfalfa cubes.

Twenty geldings (five groups; similar age and BW) were used in a completely randomized design experiment to determine effects of grain supplementation of an alfalfa-cube diet on apparent nutrient digestibility and hindgut fermentation. The geldings were housed individually, fed their diets in two equal meals (0600 and 1800), and adapted to five dietary treatments over 6 wk. The treatments were alfalfa cubes (1% of BW; DM basis) without (control) or with one of four rolled cereal grains (i.e., barley, corn, naked oats, or oats) to provide a target level of 0.4% of BW as total nonstructural carbohydrates (TNC). Due to acute laminitis, three geldings (one in the control group and two in the barley group) were excluded. Because of this and multiple incidents of gas colic, TNC level was decreased to 0.2% of BW to ensure the geldings' health throughout the adaptation (7 d) and sample collection (5 d) periods. Grain intakes varied (P < 0.05) and reflected the different TNC concentrations. Apparent digestibilities of DM, OM, CP, NDF, ADF, and cellulose were not affected (P > 0.05) by grain supplementation and averaged 63.2, 63.1, 79.5, 42.7, 39.9, and 50.3%, respectively. Regardless of the source, grain supplementation increased (P < 0.05) apparent digestibility of TNC (from 85.6 to 94.6%) and decreased (P < 0.05) fecal pH (from 7.04 to 6.74). Fecal concentrations of total VFA (mg/g of DM) were greatest for the barley and naked oats diets (averaging 11.73), intermediate for the oats diet (8.00), and least for the control and corn diets (averaging 5.00; P < 0.05). Fecal concentrations of lactate (microg/g of DM) were greatest for the barley diet (254), intermediate for the oats diet (138), and least for the remaining diets (averaging 100; P < 0.05). Fecal concentrations of NH3 N (mg/g of DM) were greatest for the naked oats diet (1.68), intermediate for the barley and oats diets (averaging 0.86), and least for the remaining diets (averaging 0.63; P < 0.05). Serum concentration of lactate was 46% higher (P < 0.05) for the control than for the grain diets (averaging 0.05 mg/100 mL). Feeding barley, corn, naked oats, and oats contributed to 13, 15, 8, and 20% higher (P < 0.05) serum NH3 N concentrations than the control diet (0.25 mg/100 mL). Higher (P < 0.05) serum concentrations of urea N (mg/100 mL) were detected for the control, barley, and naked oats diets (averaging 25.28) than for the corn or oats diets (averaging 22.21). Results suggest that horses consuming alfalfa cubes could be supplemented with rolled barley, corn, naked oats, or oats at levels not exceeding 0.2% of BW as TNC without affecting nutrient digestion or overall health negatively.

Animal Feed↗

PubMed1981

Millet and alfalfa hays alone and in combination with high-energy diet for receiving stressed calves.

Calves subjected to stresses of weaning, marketing, shipping and processing ate more feed, gained more weight and gained more efficiently when fed a 75% concentrate receiving diet, alone or with free choice hay, than when fed hay alone (P less than .01). Diets with greater bulk or lower energy densities did not promote higher feed intake in these stressed calves, as would be the case in unstressed animals. No differences due to receiving diets were observed in number of calves treated, days treated per sick calf, death loss or relapses. There was a trend (P less than .1) for calves on hay diets to have fewer total sick days than those fed a 75% concentrate diet alone or with free choice hay. Feed intake, weight gains and conversion of feed to gain for calves on alfalfa hay alone were superior (P less than .05) to the corresponding measures for calves on millet hay alone. Both hays fed alone were inferior (P less than .01) to a 75% concentrate diet alone or in combination with either hay in promoting weight gains and conversion of feed to gain. Gastrointestinal tract fill estimated from apparent and predicted gains amounted to 93 and 76% of apparent gains for calves fed millet or alfalfa hay respectively, but only 58% or less for those fed diets containing the 75% concentrate milled feed. Growing lambs were in negative N balance when fed millet hay alone but retained approximately 15% of N intake when fed diets containing the 75% concentrate milled feed. N retention on alfalfa hay alone was intermediate. The data indicate net tissue growth in calves fed millet hay alone is near zero during a 28-day receiving period. No differences were noted between calves receiving grubicide as a dip and those given grubicide as a pour on.

Animal Feed↗

PubMed1983

Plasma clearance of L- and D-lactate in steers fed alfalfa hay or high concentrate diets.

Experiments were conducted with 40 steers to evaluate the effects of diet (alfalfa hay vs high concentrate) on the rates of elimination of D- and L-lactate from plasma. Plasma L- and D-lactate clearance rates were determined before (Period I) and 114 d after (Period II) an abrupt switch from the alfalfa hay to the high concentrate diet. One group of steers received the hay diet throughout the experiment. Diet or period did not alter the rate of disappearance of L-lactate from plasma; the half-life was 13.5 to 15.5 min. D-lactate disappearance from plasma followed an exponential decay curve with at least two components; however, diet or period did not alter the calculated rates of disappearance. The half-life of the first component was 9 to 28 min and the second component was 207 min. Characteristics describing D- or L-lactate metabolism were not highly correlated with lactate utilization for fatty acid synthesis. These data demonstrate that, in steers adapted to a high concentrate diet consuming 18.2 Mcal ME X head-1 X d-1, clearance of D(-)- or L(+)-lactate is not different from that in steers fed alfalfa hay consuming 23.1 Mcal ME X head-1 X d-1.

Animals↗

PubMed1985

Interaction of molybdenum, sulfate and alfalfa in the bovine.

Thirty-two weanling Hereford heifers were assigned to treatments in a 2(3) factorial arrangement involving two levels of Mo (0 and 100 ppm added inorganic Mo), two levels of SO4 (0 and .5% added inorganic SO4) and two levels of alfalfa pellets (0 and 2.72 kg daily). A basal diet of hay and salt ad libitum and 454 g milo pellets (92% milo and 8% molasses) was fed daily. All animals were fed individually for 11 mo. Added dietary Mo created severe symptoms of Mo toxicity that included scouring, achromotrichia, anemia and weight loss. Five of the 16 animals that received Mo died within 2 wk after the study was terminated. Molybdenum accumulated in all tissues sampled during the first 8 mo and decreased thereafter. Molybdenum also elevated plasma Cu. Balance data indicated that 100 ppm of added dietary Mo led to daily retention of 105 mg Mo and reduced the rate of liver Cu depreciation. Added Mo did not influence feed intake, digestibility or metabolizable energy (ME) when calculated per unit of metabolic size. Added inorganic SO4 lowered plasma Cu and Mo, but did not alter digestibility, ME or Cu and Mo balance. Added protein supplied by alfalfa pellets increased feed intake and digestibility of dry matter, crude protein and energy but did not prevent Mo toxicity symptoms. Alfalfa also increased ME, P, S and N balance and was involved with certain interactions with both Mo and SO4. Plasma Mo is a good indicator of Mo intake and is more useful than tissue Cu levels. Urinary Mo may also be useful to evaluate Mo intake under field conditions.

Animals↗

PubMed1986

Ruminal changes in monensin- and lasalocid-fed cattle grazing bloat-provocative alfalfa pasture.

Microbial and fermentation changes in the rumen in monensin- and lasalocid-fed cattle grazing bloat-provocative alfalfa pasture were studied using genetically bloat-susceptible, ruminally-cannulated adult cattle. Monensin at .66 and .99 mg/kg body weight daily reduced the severity of legume bloat by 41 and 73%, respectively. The same doses of lasalocid reduced bloat by 25 and 12%. Comparison of ruminal contents from animals before treatment with ruminal contents from antibiotic-treated animals showed no differences in pH, ammonia, soluble N, soluble carbohydrate, ethanol-precipitable slime and anaerobic bacterial counts. Monensin treatment decreased protozoal numbers and microbial activity, as evidenced by lower gas production from in vitro fermentation of ground alfalfa hay when compared to pretreatment. Lasalocid had no effect on protozoal counts and in vitro gas production. Addition of monensin or lasalocid (12 micrograms/ml) to in vitro fermentation of chopped, fresh alfalfa reduced microbial activity as evidenced by higher soluble N, lower ammonia concentration and decreased gas production. Monensin reduced the amount of ethanol-precipitable slime and protozoal numbers. Reduction in the severity of bloat when monensin was fed appears to be due to decreased protozoal numbers, which resulted in decreased gas production. Lasalocid did not reduce legume bloat because of its minimal effect on the ruminal protozoa.

Animal Feed↗

PubMed1986

Responses to dietary additions of fiber (alfalfa meal) in growing pigs housed in a cold, warm or hot thermal environment.

Five trials involving 112 individually-penned animals were conducted to determine the effects of dietary fiber additions (0 or 10% dehydrated alfalfa meal) on the rate and efficiency of growth and carcass characteristics of growing pigs housed in a cold (10 C), thermoneutral (22.5 C) or hot (35 C) thermal environment. Cold exposure (10 C) depressed efficiency of feed and energy utilization, carcass length, backfat, cold carcass dressing percentage and percentage lean cuts. Exposure to the hot environment resulted in depressed live weight gains but did not alter the efficiency of feed utilization. Dietary additions of alfalfa meal depressed daily gains by 1, 3 and 5% in pigs housed in the cold, warm and hot environments, respectively, and gain:feed ratios by 1, 7 and 10%. Ingestion of the fibrous alfalfa meal depressed cold carcass dressing percentage in the 10 and 22 C environments as compared with the basal diet. Based on these data, the nutritional value of fibrous feedstuffs (15% total dietary neutral detergent fiber or less) for growing pigs allowed to consume feed ad libitum is greater in animals housed in a moderately cold vs a warm or hot thermal environment.

Animal Feed↗

PubMed2000

In situ disappearance of malate from alfalfa and bermudagrass hay.

The objectives of this study were to determine the rate of malate and dry matter disappearance from different forages in the rumen. Four nonlactating, ruminally cannulated Holstein cows were fed a hay-based diet. Samples of early and late harvested alfalfa, Coastal bermudagrass, and Tifton 85 bermudagrass hays were ground, placed in nylon in situ bags, and ruminally incubated for 0, 0.5, 1, 2, 4, 8, 12, 24, and 48 h. After incubation, samples were rinsed, freeze-dried, extracted, and analyzed for malate content by HPLC with an organic acid column. When forages were incubated in the rumen, malate concentrations were less than 0.55 mg/g of dry matter at 0.5 h and remained low for the 48-h incubation period. These results suggest that malate was solublized and utilized within 30 min after reaching the rumen. Dry matter digestibility of both forages increased with time and was different across forages. Both alfalfa samples were digested to a greater extent between 0.5 and 24 h than either type of bermudagrass, but after 48 h the early maturity Tifton 85 digestibility was similar to alfalfa. Even though it is more common to feed unground forages to ruminants, these in situ results suggest that once malate is available in the rumen it will disappear quickly.

Animal Feed↗

PubMed2000

Enzyme, bacterial inoculant, and formic acid effects on silage composition of orchardgrass and alfalfa.

We evaluated the effects of cellulase (from Trichoderma longibrachiatum) application rates on neutral detergent fiber (NDF) concentration and fermentation products of orchardgrass (Dactylis glomerata L.) and alfalfa (Medicago sativa L.) silages harvested with decreasing dry matter (DM) digestibility. Additionally, the impacts of inoculant (Lactobacillus plantarum and Pediococcus cerevisiae), pectinase (from Aspergillus niger), or formic acid on silage composition were studied. Forages wilted to a DM content of about 320 g/kg were ensiled in laboratory silos for 60 d. Cellulase, combined with inoculant, was applied at 2, 10, and 20 ml/kg of herbage (at least 2500 IU/ml). Cellulase at 10 ml/kg was also applied alone or in combination with pectinase and inoculant or formic acid. The NDF concentration of orchardgrass silage decreased with increasing cellulase up to 20 ml/kg, at which NDF content was decreased by 30%. The NDF concentration of alfalfa silage decreased with increasing cellulase application up to 10 ml/kg, at which NDF content was decreased by 13%. Immature plants were more responsive to cellulase treatment than mature plants. Cellulase at 2 ml/kg combined with inoculant improved fermentation characteristics of the silages but generally, there was no effect on silage fermentation by higher cellulase applications, resulting in an accumulation of sugar. The improved fermentation of orchardgrass treated with cellulase and inoculant was mostly related to the effect of inoculant, whereas cellulase alone improved fermentation characteristics of alfalfa silage and this effect was enhanced by addition of inoculant. Decreased NDF and increased sugar concentrations did not improve the in vitro DM digestibility of cellulase-treated silages.

Aspergillus niger↗

PubMed2001

The effect of a dry or liquid application of Lactobacillus plantarum MTD1 on the fermentation of alfalfa silage.

Alfalfa was wilted to 30 and 54% dry matter and was untreated or treated with Lactobacillus plantarum MTD1 applied either as a liquid or dry inoculant to determine whether form of inoculation affected silage fermentation. In silages with 30% dry matter, both forms of inoculation resulted in silages with more lactic acid and a lower pH than in untreated silage after 2 d of ensiling. In addition, both forms of inoculation resulted in silages with lower concentrations of acetic acid between 8 and 45 d of ensiling than in untreated silage. The ammonia-N content was also lower in silages that had been treated with both forms of inoculation during the early and intermediate stages of ensiling, but not after 45 d of ensiling. In silages containing 54% dry matter, dry and liquid inoculation produced a more rapid decrease in pH from d 4 to 14 when compared with untreated silage, but the effect was greater when the inoculant was applied in water. In contrast to findings from 30% silages, the inoculated silages with 54% dry matter had lower concentrations of ammonia-N than untreated silage from d 8 to 45, and both forms of inoculation were equally effective. The results of this study agree with previous research that shows that microbial inoculation can improve the fermentation of alfalfa silage. However, this report shows that a microbial inoculant was more effective when applied in a liquid- rather than a dry-form to alfalfa with a high DM content.

Acetic Acid↗

PubMed2006

Effect of chestnut tannin on fermentation quality, proteolysis, and protein rumen degradability of alfalfa silage.

Two experiments were conducted on alfalfa to investigate the effects of the addition of commercial chestnut hydrolyzable tannin at ensiling on 1) silage fermentation quality in lab-scale silos and protein degradation in the rumen, and 2) silage fermentation quality and proteolysis in bale silages. Wilted alfalfa was prepared with 4 tannin levels (0, 2, 4, and 6% on a dry matter (DM) basis; T0, T1, T2, T3, respectively) and ensiled in lab-scale silos. Silages (33% DM) were analyzed for fermentation quality, protein rumen degradability in situ, and organic matter digestibility in vitro through gas production after 120 d of conservation. Wilted alfalfa containing 0 and 4% tannin (T0 and T2) was harvested at 40% DM (wilting level I) and 53% DM (wilting level II) for bale (600 mm diameter) silage. Silages were analyzed for fermentation quality after 78 d of conservation. All the silages were well fermented with no butyric acid. Lab-scale silages showed reductions in ammonia, nonprotein nitrogen (NPN) and DM losses in T2 and T3 treatments, while the fermentation acid profiles were unaffected. In experiment 1, the untreated silage (T0) had the highest protein degradability after being incubated in the rumen. The addition of tannin reduced crude protein ruminal disappearance in a dose-dependent manner. However, the tannin reduced the organic matter digestibility by 5.1% for all of the tannin addition levels. The tannin positively affected the silage quality in the round bale silages, in particular reducing ammonia and NPN in the lowest wilting level. In both experiments, T2 treatment reduced proteolysis without any influence of DM on the binding reaction and reduced the NPN by 15% in comparison to the control.

Ammonia↗

PubMed1984

Effect of sodium bicarbonate addition to alfalfa hay-based diets on digestibility of dietary fractions and rumen characteristics.

Three trials were to evaluate effects of sodium bicarbonate in alfalfa hay-based diets. In Experiment 1, four Jersey cows were fed diets of 40:60 chopped alfalfa hay:grain with either 0, .25, .5, and .75% sodium bicarbonate in a 4 X 4 Latin square digestion trial. Dry matter and fiber digestion were unaffected. Volatile fatty acids of ruminal fluid and milk fatty acids were not different. In Experiment 2, two rumen fistulated cattle were fed diets of Experiment 1 for changes of ruminal fluid characteristics at -1, 2, 4, and 8 h postfeeding. Volatile fatty acids of ruminal fluid and hydrogen ion concentration were not different across time with sodium bicarbonate. In Experiment 3, four Holstein cows with rumen cannulae were fed diets of 30:70 chopped alfalfa hay:grain with 0, .4, .8, and 1.2% sodium bicarbonate in a 4 X 4 Latin square. Dry matter and fiber digestion were unaffected. Ruminal fluid samples were collected at -1, 3, 6, and 9 h postfeeding. Volatile fatty acids were different only at 6 h with 0 and 1.2% sodium bicarbonate diets displaying lower concentrations. Rate of increase of hydrogen ion concentration was greater for diets containing 0 and .4% compared with .8 and 1.2% sodium bicarbonate between -1 and 6 h. Milk fatty acid composition, ruminal liquid dilution rate, and dry matter disappearance from nylon bags suspended in the rumen were not affected by sodium bicarbonate.

Ammonia↗

PubMed1985

Methionine deficiency in early-weaned dairy calves fed pelleted rations based on corn and alfalfa or corn and soybean proteins.

Holstein bull calves weaned at 4 wk of age were assigned to one of three replicated 4 X 4 Latin squares at 5 to 6 wk. Trials were abomasal infusion of 0, .30, .60, and either 90 (Trials 2 and 3) or 1.20 g (Trial 1) L-methionine/kg pelleted starter ration consumed. In Trials 1 and 2, ration ingredients of the ration contributed the following percentages of total crude protein: corn meal 39, alfalfa meal 48, and soybean meal 12; dry matter of rations contained 13.6 and 13.9% crude protein and .26 and .32% sulfur. Infusion of .60 g methionine in Trial 1 tended to depress excretion of nitrogen in urine and increase nitrogen retention. In Trial 2, urine nitrogen excretion and retained nitrogen responded in a quadratic fashion; infusion of .30 and .60, and either .90 (Trials 2 and 3) or 1.20 g (Trial 1) L-methionine/kg pelleted starter ration consumed. In Trials 1 and 2, ingredients of the ration contributed the following percentages of total crude protein: corn meal 39, alfalfa meal 48, and soybean meal 12; dry matter of rations contained 13.6 and 13.9% crude protein and .26 and .32% sulfur. Infusion of .60 g methionine in cretion 9%. Relationship between plasma methionine and infused methionine was linear for all trials. Methionine is the first limiting amino acid for early-weaned calves fed complete pelleted rations based on corn and either alfalfa or soybean proteins.

Amino Acids↗

PubMed1985

Addition of buffers to high quality alfalfa hay-based diets for dairy cows in early lactation.

Beginning 4 wk postpartum, 14 Holstein cows were paired according to expected calving date and lactation number and assigned randomly to one of two treatments in a single reversal experiment designed to study the effects of added buffers to high quality alfalfa hay-based diets. Cows were offered daily 14.5 kg of concentrate containing 0 or 2% sodium bicarbonate and .5% magnesium oxide (as fed), plus free choice high quality alfalfa hay in a ratio of forage:grain approaching 50:50 (dry matter). No differences were in milk production, milk fat percentage, fat-corrected milk, or dry matter intake. Dry matter intake of grain was decreased with addition of buffers. Kilograms fat-corrected milk per kilogram of dry matter intake were 1.41 and 1.45 for control and buffered diets. No differences were significant for rumen pH, ammonia concentration, molar proportions of acetate and propionate, or ratio of acetate: propionate. Concentrations of total volatile fatty acids were higher for cows fed the buffered diet. No differences were in blood acid-base status or in various serum metabolites. Urine pH was 8.11 and 8.20 for control and buffered diets. Fractional urinary excretion of magnesium and sodium was greater when cows consumed the buffered diet. Diet digestibilities and rate of passage were not affected by dietary buffers. Addition of sodium bicarbonate plus magnesium oxide did not improve performance of early lactation cows fed high quality alfalfa hay as the sole forage.

Animal Feed↗

PubMed1986

Sodium bicarbonate and alfalfa hay additions to wheat silage diets fed to lactating dairy cows.

Two experiments were conducted to examine dietary effects of .8% sodium bicarbonate and 1.4 kg/d of alfalfa hay on performance and rumen metabolism of lactating dairy cows fed 50% wheat silage and 50% concentrate (dry basis). In Experiment 1 with 12 midlactation Holsteins in a 4 X 4 Latin square design, intake, milk production, and milk composition were not affected by treatment. Dietary sodium bicarbonate and alfalfa hay did not alter blood, rumen, or fecal pH. Rumen volatile fatty acid pattern was not affected by sodium bicarbonate, but addition of hay resulted in higher molar percentage propionate and lower acetate: propionate ratios. In Experiment 2 with 32 early lactation cows (20 Holsteins and 12 Jerseys) in a complete randomized block design, supplementation of sodium bicarbonate, alfalfa hay, or both did not affect intake, milk production, or milk composition in the first 8 wk of lactation. Blood, rumen, and fecal pH were not affected by treatment. Dietary sodium bicarbonate did not alter ruminal volatile fatty acid profile, whereas addition of hay increased molar proportion acetate and decreased molar proportion butyrate. A shift in rumen fermentation was observed across treatments from wk 1 through 8 postpartum with molar proportions of acetate and butyrate increasing and molar proportion of propionate decreasing.

Animal Feed↗

PubMed1989

Microbial inoculation of alfalfa haylage: ensiling characteristics and milk production response when fed to early lactation dairy cows.

Third-cutting alfalfa hay harvested at bud stage and wilted to approximately 65% moisture was treated with a live bacterial inoculant at the rate of 300,000 cfu/g fresh alfalfa. Treated alfalfa was packed in polyethylene bags. Samples were taken at time of ensiling and d 1, 2, 3, 4, 7, and 28 postensiling. Mean pH was lower in the treated haylage (5.09 and 5.71 for treatment and control, respectively). Mean temperatures were higher in the treated haylage (30.0 and 28.0 degrees C for treatment and control, respectively). Mold count, water-soluble carbohydrate, alpha amino nitrogen, CP, and ADF were not affected by treatment. Regardless of treatment, pH, mold counts, and water-soluble carbohydrates declined with time. There was no significant difference between treatments for DM intake, milk production, and milk composition.

Analysis of Variance↗

PubMed1990

Effect of alfalfa maturity on fiber utilization by high producing dairy cows.

Six ruminally cannulated cows were used in a replicated 3 x 3 Latin square to study the effect of alfalfa maturity on utilization of DM and fiber. Cows were fed three diets based on alfalfa hay at early vegetative, late bud, or full bloom maturities. Forage:concentrate ratios were: 68:32, 53:47, and 45:55 for diets with early vegetative, late bud, and full bloom hays. Concentrations of NDF in the early vegetative and late bud diets was higher (32.6%) than NDF in the full bloom diet (27.9%) after accounting for feed refusals. Fat-corrected milk yield was similar, but fat percentage was higher for the diet with early vegetative hay than the diets with late bud or full bloom alfalfa. Dry matter intake was higher for the diet with early vegetative hay than the diets with late bud or full bloom hay (26.1, 24.4, and 24.8 kg/d). Ruminal dacron bag incubations of the three hays suggest that the high digestibility of the early vegetative hay was due to more soluble DM, more potentially digestible DM and fiber, and a faster rate of digestion. These factors compensated for the faster passage of the early vegetative hay and resulted in a higher intake and better utilization of DM and fiber.

Animals↗

PubMed1991

Wheat straw or alfalfa hay in diets with 30% neutral detergent fiber for lactating Holstein cows.

Twenty-four Holstein cows near peak lactation were fed diets formulated to contain 30% NDF with forage NDF from chopped wheat straw or chopped alfalfa hay in proportions of 0:3, 1:2, 2:1, and 3:0 in an 8-wk trial to evaluate effects of fiber source on lactational performance. Concentrate was based on highly degradable carbohydrate in steam-flaked sorghum grain. Forage to concentrate ratio decreased from 49:51 to 28:72 when straw was substituted for alfalfa hay. Milk yield (38.4 kg/d) and DMI (23.1 kg/d) were not influenced by forage source. Milk fat percentage decreased and milk protein percentage increased linearly with increasing straw. Yields of 3.5% FCM and fat showed linear and quadratic responses, because they appeared to be reduced only on the 0:3 diet, and protein yield showed a quadratic response and was highest for the 1:2 diet. Digestibility of NDF averaged 43.5, 45.4, 40.7, and 31.2%, and acetate to propionate ratio was 3.0, 2.4, 2.2, and 1.9 with increasing dietary straw. Passage rates were not influenced by diet and averaged 9.3, 7.6, 6.1, and 4.7%/h for fluid, grain, alfalfa hay, and wheat straw, respectively. It is suggested that the ratio of forage NDF to ruminally degradable starch be maintained greater than or equal to 1:1 when diets based on low quality forage are fed to cows in early lactation.

Animal Feed↗