Organic Acid Treatment of High Dry Matter Corn Silage Fed Lactating Dairy Cows,

In four experiments, lactating Holstein cows were used to evaluate the nutritive value of corn silages treated with organic acids. Propionic, formic, and acetic acid treatment of silage with medium dry matter (34 to 39%) in two experiments slightly increased silage intake but had little effect on milk yields. However, addition of propionic acid to silages with high dry matter (42 to 47%) in three experiments increased silage intake 12%, total intake 6%, and milk yields 5%. Formic acid added to high dry matter silages was less effective than propionic in increasing intakes. Decreasing dry matter of silage from 43% to 36% with water added at ensiling did not improve intakes or milk yields. Propionic treatment decreased silage temperatures during fermentation and feeding and lowered fungal counts of silage exposed to air. Normal concentrations of lactic and acetic acids and pH values resulted from propionic treatment. Propionic treatment of high dry matter silage appeared profitable.     

Alfalfa Silage or Hay Versus Corn Silage as the Sole Forage for Lactating Dairy Cows

In Trial 1, three rations were fed to 21 cows in a 3 × 3 Latin square: 60% alfalfa silage, 60% corn silage, and 79% corn silage (dry matter basis) with the balance from corn and soybean meal. Acid detergent fiber measures indicated alfalfa and corn silage were of excellent quality. Milk production was similar on 60% forage rations but lower on 79% corn silage. Milk fat was reduced on 60% corn silage. In Trial 2, four rations were fed to 16 cows in a 4 × 4 Latin square: 63% alfalfa silage, 60% alfalfa hay, 60% corn silage, and 76% corn silage. Alfalfa forages were higher in acid detergent fiber but corn silage was similar to Trial 1. Dry matter digestibility was highest on 60% corn silage, intermediate on 63% alfalfa silage and 76% corn silage, and lowest on 60% alfalfa hay. Milk production was similar on the diets containing 60 and 63% forage and lower on 76% corn silage. Milk protein concentration was reduced on the alfalfa diets. Highest protein secretion and feed conversion was supported by 60% corn silage. In both trials, potentially digestible neutral detergent fiber from alfalfa was more digestible than that from corn silage, and concentrations of urea in milk and blood were highly correlated. Results indicate high quality alfalfa silage is comparable to corn silage for milk production.     

Intake and Digestibility of Brown-Midrib Corn Silage by Lactating Dairy Cows,

Two short trials in 2 yr evaluated brown midrib-3 (bm3) mutant (low lignin) corn silage for Holstein cows in early lactation. In trial 1, five Holstein cows per group (bm3 or normal genetic counterpart) were fed individually a ration of corn silage and grain (60:40, dry matter) from wk 2 through wk 8 postcalving. Cows fed the bm3 ration consumed 19% more digestible dry matter and energy as a percent of body weight than cows fed the normal ration. Digestibilities of most components were 2 to 4 percentage units higher for the bm3 ration. Milk yield was not different between rations, but cows fed bm3 lost less body weight. In trial 2, five Holstein cows per group were fed individually a ration of either bm3 or normal silage supplemented with a concentrate mix at 85:15 silage to concentrate. The concentrate mix was formulated to meet needs for protein, minerals, and vitamins. Cows were on trial from wk 6 through wk 13 postcalving. All measures of daily intake of dry matter were greater for the bm3 ration while digestibilities of some components were reduced slightly. Digestible energy intake was 27% greater for the bm3 ration. Milk and milk component yields did not differ, but cows fed the bm3 ration gained more body weight. Total and individual ruminal volatile fatty acids were higher and pH lower with time after feeding for the bm3 ration.     

Corn Silage Partially Replacing Short Alfalfa Hay to Optimize Forage Use in Total Mixed Rations for Lactating Cows

We theorized that adding corn silage to a total mixed ration with alfalfa hay as the sole dietary forage would improve nutrient intake and chewing activity and thereby improve rumen fermentation and milk production. The objective of this research was to determine the effects of partial replacement of short alfalfa [physically effective (pe) neutral detergent fiber (NDF) >1.18 mm (peNDF_>1.18) = 33.2%] with corn silage (CS, peNDF_>1.18 = 51.9%) in yellow grease-supplemented total mixed rations on feed intake, chewing behavior, rumen fermentation, and lactation performance by dairy cows. Four multiparous (138 ± 3 d in milk) and 4 primiparous (115 ± 10 d in milk) Holstein cows were used in a 4 × 4 Latin square design experiment with four 21-d periods. Each period had 14 d of adaptation and 7 d of sampling, and parity was the square. Treatments were diets [dry matter (DM) basis] with 1) 40% alfalfa hay (ALF), 2) 24% alfalfa hay + 16% CS (CS40), 3) 20% alfalfa hay + 20% CS (CS50), and 4) 16% alfalfa hay + 24% CS (CS60). Diets had a forage-to-concentrate ratio of 40:60 on a DM basis. Cows had greater intake of DM and thus greater intakes of net energy for lactation, NDF, and peNDF when CS partially replaced alfalfa hay. Replacing alfalfa hay with CS increased daily eating and chewing times in all cows, and increased rumen pH at 4 h postfeeding in multiparous cows. Apparent total-tract digestibility coefficients for crude protein (CP) and NDF were not different among cows fed ALF, CS40, and CS50, but were lower for CS60 than for ALF. Energy-corrected milk yield was greater for CS40 and CS60 than for ALF. Milk protein yield was increased when CS replaced 40, 50, and 60% of alfalfa hay. Milk lactose was greater only for CS60, but milk lactose yield was greater for CS50 and CS60 than for ALF. Milk percentage and yield of fat did not differ among treatments. Therefore, CS partially replacing short alfalfa hay increased DM intake, consequently increased net energy for lactation and physically effective fiber intakes, and thus, improved milk and milk protein and lactose yields.     

Feeding Value of Dry Corn,Ensiled High Moisture Corn,and Propionic Acid Treated High Moisture Corn Fed with Hay or Haylage for Lactating Dairy Cows

Trial 1. Fifty lactating Holstein and Brown Swiss cows were assigned to six groups in a 3 × 2 factorial design and fed one of six diets for 16 wk: (1) dry corn + hay, (2) dry corn + haylage, (3) ensiled high moisture corn + hay, (4) ensiled high moisture corn + haylage, (5) propionic acid treated corn + hay, and (6) propionic acid treated corn + haylage. Quantities equal in dry matter of dry corn, ensiled corn, and acid treated corn were offered in the ratio of 1 kg concentrate (corn and supplement) for each 2.75 kg milk produced. Forage was fed free choice. Means adjusted by covariance for cows fed diets 1 to 6 averaged: dry matter intake (kg/day), 16.7, 20.0, 17.4, 20.6, 17.1, 20.0; 4% fat-corrected milk (kg/day), 21.8, 21.1, 22.6, 23.5, 22.4, 23.4; milk fat percent, 3.54, 3.45, 3.63, 3.53, 3.62, 3.80; and acetate to propionate ratio 3.53, 3.85, 3.73, 3.66, 3.13, 3.32. Cows fed ensiled corn and acid treated corn produced more 4% fat-corrected milk than did cows fed dry corn. The molar percent acetate to propionate ratio in rumen fluid of cows fed acid treated corn was lower than for cows fed dry corn or ensiled corn.Trial 2. Dry corn or propionic acid treated corn was fed to 12 cows in combination with a supplement, 4.54 kg of hay, and ad libitum haylage. Means adjusted by covariance for cows fed dry corn and acid treated corn averaged: dry matter intake (kg/day), 18.2 and 17.7; 4% fat-corrected milk (kg/day), 20.6 and 20.1; and total digestible nutrients (%) 63.7 and 58.7.Any of these methods are acceptable for storing corn, and feeding this corn in properly supplemented diets will yield acceptable lactation performance.     

A Computer Ration Evaluation Program for Heifers,Dry Cows,and Lactating Cows

A computer program designed to calculate ration dry matter, crude protein, total digestible nutrients, acid detergent fiber, cost, macrominerals, and microminerals was developed. Feeds, designated by number, and amounts fed are entered by the program user. A library file contains feeds and their standard laboratory analytical concentrations for all nutrients to be evaluated. Modification of Standard nutrient concentrations is made via screen editing. Three screens are used to accommodate all nutrients. The first screen contains dry matter, crude protein, total digestible nutrients, acid detergent fiber, and cost. Screens 2 and 3 contain, respectively, the macrominerals (calcium, phosphorus, sodium, magnesium, sulfur, and potassium) and microminerals (iron, cobalt, copper, manganese, zinc, and selenium). National Research Council's nutrient requirements are calculated and printed on the screen, and the percent of the requirement met by the ration being fed is displayed. This program has been used extensively by extension personnel, faculty, and students for ration evaluation, problem solving, trial-and-error ration balancing, and instruction to demonstrate the principles of ration balancing.     

No Associative Effects Between Corn and Haycrop Silages Fed to Lactating Dairy Cows

Four first-lactation Holstein cows were used 65 to 177 days postpartum in a 4 × 4 Latin square trial to evaluate possible associative feeding effects between corn and haycrop silages. Nutrient digestibility and nitrogen and energy balances were studied. Diets were concentrate mixture, urea-treated corn silage, and early-cut, wilted haycrop silage in dry matter ratios of 55:45:0, 55:30:15, 55:15:30, and 55:0:45. Rations were offered just below energy balance in each 28-day period. Ration components were fed separately, concurrently, and twice daily. Crude protein in concentrate, corn silage, and hay crop silage dry matter was 16.9, 11.1, and 12.5%. Milk yield (18 to 19 kg) and ration dry matter intake (2.61% body weight) were not significantly different among diets. Apparent digestibility of gross energy, dry matter, protein, and fiber was not different among diets, but fat was more digestible in corn silage. Partition of ingested energy and nitrogen was not affected by treatments except that urine nitrogen was higher in corn silage. No associative feeding effects were significant. The two silages were equivalent in supporting milk production when fed in equal dry matter amounts.     

Cubed Complete Rations for Lactating Dairy Cows

Production by cows fed cubed complete rations as compared to the same ration components fed separately as long hay and concentrate was determined in two experiments. The cubed rations reduced milk fat percentages in both experiments and total fat production in one experiment. Solids-not-fat was increased slightly by cubed rations. Lower efficiency of feed utilization for the production of 4% fat-corrected milk was evident for cows fed cubed rations. Losses of body weight following parturition were reduced, and subsequent weight recoveries were more rapid in cows fed cubed rations. Also, molar ratios of acetic/propionic acids in the rumen were reduced. Effects of rations on milk composition, changes in body weight, and ratios of volatile fatty acids appear to be related to differences in coarseness or texture of the roughage components of cubed and baled hay rations. The results of these feeding experiments indicate complete rations prepared by cubing chopped alfalfa hay and concentrates in conventional hay cubing equipment have limitations as the sole rations for high producing dairy cows.     

不同长度玉米秸秆青贮对奶牛生产性能的影响

将玉米秸秆以10、26 mm两种不同长度切碎后青贮,分别以直接和全混合日粮(TMR)揉碎两种形式饲喂奶牛进行比较研究.结果表明:两种切碎长度对玉米秸秆青贮质量无明显影响;但无论采用何种饲喂方法,将切碎长度为26 mm的青贮玉米秸秆饲喂给奶牛,奶牛产奶量提高,胎衣不下减少,空怀母牛降低,各种疾病发生减少;同时切碎长度增加还可以提高青贮劳动效率.     

Sodium Cloxacillin for Treatment of Mastitis in Lactating Cows

Sodium cloxacillin was used to treat 107 cows affected with acute mastitis and 138 affected with subclinical mastitis. Based on the application of conservative bacteriologic criteria, the cure rate was 53% for acute staphylococci mastitis and 65% for subclinical staphylococci mastitis. The cure rate for Streptococcus agalactiae infections was 91% in acute conditions and 92% in subclinical conditions. The cure rate was 73% for the acute infections and 88% in cases of subclinical infections when Streptococcus spp. “non ag” was the cause. Daily milk production had no effect on response rate. No adverse reactions due to treatment were reported by any investigator.     

Mammary Extraction of Propionate in Lactating Cows

Four cows with exteriorized carotid arteries were in an intensive study of concentrations in plasma and mammary extraction of propionate. A restricted-roughage, high-grain diet produced higher arterial propionate concentrations and larger carotid-subcutaneous abdominal vein (arteriovenous) differences than the control diet. Concomitant changes in acetate, β-hydroxybutyrate, and glucose in plasma and in fat and protein in milk were measured. Mammary arteriovenous difference in propionate was correlated negatively with milk fat percentage. However, since arterial propionate and β-hydroxybutyrate also were correlated negatively, evidence of a direct inhibitory effect of propionate in mammary gland is equivocal.     

Effects of Silage Fermentation and Post-ruminal Casein Supplementation in Lactating Dairy Cows: 1—Diet Digestion and Milk Production

Two silages were prepared from the first-cut sward of timothy-meadow fescue and wilted to a dry matter (DM) content of 300 g kg^-1. One was ensiled with the addition of a formic-acid-based additive (4 litres formic acid (FA) per tonne) and the other with the addition of a bacterial inoculant (LAB) at a rate of 5×10⁶ colony forming units g^-1. Both silages were well preserved, but the extent of fermentation was greater in LAB-silage than in FA-silage as indicated by a lower concentration of water soluble carbohydrates (68 vs 177 g kg^-1 DM) and a higher concentration of lactic acid (147 vs 32 g kg^-1 DM). Four Ayrshire cows were used in a 4×4 Latin square experiment with 21-day periods to study the effects of silage fermentation and postruminal casein supplementation on silage intake, nutrient supply and milk production. The four treatments were FA-silage without casein (FA-0), LAB-silage without casein (LAB-0), FA-silage with casein (FA-C) and LAB-silage with casein (LAB-C). Both silages were given ad libitum with 8 kg day^-1 of barley without or with 400 g day^-1 of casein infused into the duodenum. Organic matter digestibility was lower (0·723 vs 0·753; P<0·01) for FA-silage than for LAB-silage. Cows offered FA-silage had a higher molar proportion of acetate and a lower proportion of propionate in ruminal fluid than cows offered LAB-silage. Microbial protein synthesis estimated from the output of purine derivatives in urine was greater (288 vs 260 g N day^-1; P<0·05) for cows given FA-silage compared with LAB-silage. Feeding LAB-treated silage tended (P<0·10) to decrease silage DM intake compared with FA-treated silage (10·61 vs 11·77 kg DM day^-1). Silage composition did not affect significantly milk yield or milk composition. Casein infusion increased milk yield (25·1 vs 27·1 kg day^-1; P<0·05), milk protein content (32·4 vs 33·8 g kg^-1; P<0·05) and protein yield (808 vs 905 g day^-1; P<0·01). The responses were similar for both silages. © 1997 SCI.     

Comparison of Low Alkaloid Tall Fescues and Orchardgrass for Lactating Jersey Cows

Johnstone (prevarietal release) and Kenhy, new varieties of tall fescue (Festuca arundinacea Schreb), were compared with Boone orchardgrass (Dactylis glomerata) in 2 yr. Cultivars were maintained in a vegetative stage by removal of excess growth. Johnstone seed and the resulting cultivar were 6.7% infected with endophyte fungus (Acremonium coenophialum). Forage from each cultivar was chopped daily and fed individually to five lactating Jersey cows for 12 wk in 1983 and to eight cows for 9 wk in 1984. Cows were fed 6.8 and 4.5 kg daily of a 16% crude protein concentrate in 1983 and in 1984, respectively. No evidence of fescue toxicosis was observed in 1983, but a trend toward depressed prolactin occurred in 1984 for Johnstone tall fescue. Daily dry matter intake, intake as percent body weight, and daily milk production were significantly higher on orchardgrass than on tall fescues. Intake as percent body weight, daily milk, milk protein, and fat-corrected milk were significantly higher on Johnstone than on Kenhy tall fescue. Although the experimental design did not allow direct comparison, performance appeared to be as good on Johnstone fescue as on orchardgrass. The inferior animal performance on fescue compared with orchardgrass seems to be due entirely to Kenhy.     

Palatability of Methionine Hydroxy Analog or DL-Methionine for Lactating Dairy Cows

A decrease in grain intake occurred initially after feeding supplemental methionine hydroxy analog (top-dressed or mixed with concentrate) but top-dressing DL-methionine did not affect intakes. After initial adjustment (1 to 3 d), cows generally returned to normal grain intakes on diets supplemented with methionine hydroxy analog. Intake patterns were similar at all methionine hydroxy analog levels, which attained three to four times that recommended for supplementation. Increases in plasma free methionine at methionine hydroxy analog intakes above 40 g/d suggest bypass of additive for intestinal absorption.     

Effects of Silage Fermentation and Post-ruminal Casein Supplementation in Lactating Dairy Cows: 2—Energy Metabolites and Plasma Amino Acids

Four cows were used in a 4×4 Latin square design with a 2×2 factorial arrangement of treatments to examine the effects of the extent of silage fermentation and post-ruminal casein infusion on the arterial concentrations and mammary arterial–venous (A–V) difference of energy-yielding nutrients and plasma amino acids. Of the two silages one was preserved with formic acid (FA-silage) and the other with an inoculant of lactic acid bacteria (LAB-silage). Both silages were given ad libitum with 8 kg day^-1 of barley, without or with duodenal casein infusing (400 g day^-1). Blood was sampled from the coccygeal vessel and milk vein. FA-silage less fermented than LAB-silage as indicated by higher concentration (g kg^-1 dry matter) of water soluble carbohydrates (178 vs 68) and lower concentration of lactic acid (32 vs 147). Plasma concentration of glucose was lower (P<0·05) and concentrations of essential amino acids (P<0·001) and blood β-hydroxybutyrate (BHB) (P<0·01) were higher with FA-silage than with LAB-silage. There was a strong linear relationship between arterial concentration and mammary A–V difference of blood metabolites, except BHB, and amino acids. The relationship between arterial concentration and mammary A–V difference of glucose was different between the silages. Mammary extraction rates of glucose, BHB, histidine, leucine and lysine were affected by their arterial concentrations. The interaction between silage fermentation and casein infusion was significant (P<0·05) in arterial concentration of branched-chain amino acids, the increase being greater with FA-silage than with LAB-silage. The results suggest that the supply of glucose may limit milk synthesis in cows given restrictively fermented grass silage and barley, whereas the supply of amino acids may be more limiting with extensively fermented silages. It is further suggested that the mammary gland has a capacity to adapt it's efficiency of nutrient uptake according to the supply and mammary demand of nutrients. © 1997 SCI.     

A Blend of Essential Plant Oils Used as an Additive to Alter Silage Fermentation or Used as a Feed Additive for Lactating Dairy Cows

A blend of essential plant oils was evaluated for its effects on silage fermentation and animal performance. In the first experiment, the blend of essential oils was mixed with freshly chopped whole-plant corn to achieve a concentration of 0, 40, or 80 mg of active product per kilogram of fresh forage weight. Whole-plant corn was also mixed with a buffered propionic acid-based product at 0.2% of fresh forage weight. The blend of essential oils did not affect the populations of yeasts, molds, lactic acid bacteria, or enterobacteria; the fermentation end products; or the aerobic stability of the corn silage. Addition of the buffered propionic acid additive moderately reduced the production of acids during fermentation and resulted in a small reduction in the numbers of yeasts after ensiling, but did not affect aerobic stability. In a second experiment, 30 Holstein cows (4 primiparous and 26 multiparous) averaging 118 ± 70 d in milk and producing 38 ± 16 kg of milk/d were fed a total mixed ration, once daily, that consisted of (on a DM basis) 25% corn silage, 15% alfalfa silage, 10% alfalfa hay, and 50% concentrate. One-half of the cows were fed a blend of essential oils that was mixed directly into their total mixed ration to provide 1.2 g/cow per d for 9 wk. Cows fed the essential oils ate 1.9 kg more dry matter/d and produced 2.7 kg more 3.5% fat-corrected milk/d than did cows fed the control diet. The percentages of milk fat and protein, the somatic cell count numbers, and the concentrations of milk urea nitrogen were unaffected by treatment. Feed efficiency, change in body weight, and change in body condition scoring were also similar between treatments. After 12 h of incubation, the addition of a moderate dose and a high dose of essential oils to in vitro ruminal fermentations had no effect on the concentration of total VFA compared with the control treatment. However, they decreased the molar proportions of acetic, butyric, and valeric acids and increased the proportion of propionic acid. The blend of essential oils evaluated in this study altered in vitro ruminal fermentation and improved animal performance when fed directly to cows, but it did not affect the fermentation or aerobic stability of corn silage.     

Plasma Concentration and Lipid Composition of Lipoproteins in Lactating Dairy Cows Fed Control and High Grain Diets

Six multiparous Holstein cows ranging from 7 to 19 wk postpartum were in a switchback design to determine effects of feeding high grain diets on lipoprotein concentration and composition in blood. Percents concentrate, alfalfa haylage, and corn silage of control and high grain diets were 50, 83; 25, 9; and 25, 8 dry matter. Milk yield (kg/day), milk fat percentage, and fat yield (g/day) averaged 27.7, 3.58, 997 and 30.2, 2.45, 729 for control and high grain treatments. Very low density, low density, and high density lipoproteins were isolated by gel filtration of total lipoproteins obtained by ultracentrifugation. Lipoprotein concentrations in blood plasma of cows fed the control or high grain diets were similar. Triglyceride, phospholipid, cholesterol, and cholesterol ester contents of each lipoprotein class were not altered by treatment. High grain feeding increased octadecadienoic fatty acid content of low density and high density lipoprotein cholesterol esters and decreased octadecenoic and octadecatrienoic acids. The trend was similar for the very low density lipoprotein fraction. Phospholipid octadecenoic acid decreased in all lipoprotein fractions but only significantly for high density lipoproteins. It is unlikely that differences in lipid composition of plasma lipoproteins caused alterations in lipoprotein metabolism leading to fat depression in this and other similar studies.     

Aerobic Storage and Utilization of Ammonia-Treated Distillers Wet Grains for Lactating Dairy Cows

Two experiments were conducted to determine the influence of NH₃ treatment on the aerobic stability of distillers wet grains and value of the NH₃-treated grains as protein supplements for lactating cows. In Experiment 1, fresh distillers wet grains were treated with NH₃ at 0, 1.57, 3.14, or 4.71% of DM, compacted in polyethylene bags, and kept in aerobic storage at 16, 27, or 38°C for 14 d. Intermediate and high NH₃ reduced temperature increases, mold growth, and spoilage and improved DM recoveries. Low ammonia grains were less stable and deteriorated faster than untreated grains.In Experiment 2, lactating Holstein cows were supplemented with NH₃-treated distillers wet grains (13.8% of total DM) or soybean meal (10.1% of total DM) for 70 d. Intakes of DM tended to be lower on ammoniated grains (19.4 and 17.6 kg/d). Milk yields (27.1 vs. 27.9 kg/d) and composition were not significantly different among treatments, but efficiency of converting feed to milk and income over feed costs were greater for ammoniated grains than soybean meal.