Plant Pathology Commons^™

Simulation Of Complementary Forage Cropping By Feeding Oat Grain To Ewes, J L. Wheeler, D A. Hedges, C Mulcahy

IGC Proceedings (1977-2023)

In many parts of the world where year-round grazing is feasible, complementary forages such as oats or sorghum are sown to impove the quantity and quality of the forage available at specific periods. Experiments in which these crops complement well­fertilized grassland have generally not shown an increase in animal production compared with all-grassland systems. The pres­ent experiment aimed to determine the effects of a simulated complementary forage crop on pasture yield and on the production of breeding ewes. Eight groups of 10 sheep grazed 0.6-ha plots of Phalaris aquo.tica L.-Trifolium repens L., and eight groups of 10 sheep grazed 0.8-ha …

Effect Of Feeding Level And Forage: Concentrate Ratio On The Digestibility Of Pelleted Diets By Sheep And Cattle, G.M J. Horton, M J. Farmer, B E. Melton, S Sklane

IGC Proceedings (1977-2023)

Sheep are frequently used to determine the nutritive value of cattle feeds. However, there is some evidence that digestion coef­ficients for cattle and sheep may differ and that digestibility may be influenced by feeding level. The purpose of this study was to investigate the effects of feeding level and animal species on the digestibility of pelleted diets containing different ratios of alfalfa hay to barley grain. Five 4O-kg yearling crossbred lambs and four 35O-kg yearling steers were used to evaluate each diet. The six diets were isonitrogenous, containing the following proportions of barley grain and alfalfa hay (percentage as fed …

Effect Of Supplements On The Live-Weight Gain Of Beef Cattle Given Forage During The Dry Season, C Thomas, P N. Mbugua

IGC Proceedings (1977-2023)

The low quality of standing pasture grasses in the dry seasons presents a major problem in the intensification of beef produc­tion in the tropics. The objective of this research was to examine the role of maize and grass silage or standing napiergrass (Pen­nisetum purpureum) as sources of forage when given alone or with supplements to beef cattle. In the first of three trials conducted at the National Agricultural Research Station, Kitale, Kenya, 36 Friesian castrates, initially 249 kg live weight (LW), were given silage of whole-crop maize either alone or supplemented with corn-and-cob meal. Each of these two basal diets …

Intake Of Grass Silage By Dairy Cows And Its Potential To Meet Requirements Of Maintenance And Milk Production, J P. Dulphy, C Demarquilly, J P. Andrieu

IGC Proceedings (1977-2023)

The main objective of our research was to measure the :intake and digestibility of grass silages in order to estimate their poten­tial for meeting requirements for maintenance and milk production. Twelve silages were prepared by the following three techniques, which considerably improve the intake compared with those used 10-20 years ago: (1) fine chopping (1-3 cm), (2) add­ing formic acid as an efficient preservative (3.5 I/ton), and (3) covering the roughages with plastic to prevent oxygen from enter­ing the silo. Three other silages were made simultaneously with 3 of the same forages, but without formic acid. All forages were directly …

Utilization Of Energy Of Fresh Pasture By Lactating Dairy Cows, T E. Trigg, C R. Parr, N R. Cox

IGC Proceedings (1977-2023)

The New Zealand dairy industry is almost totally reliant on grazed herbage for the production of milk solids, but few data ex­ist on the efficiency with which lactating cows utilize energy of fresh herbage offered as the sole diet. One hundred thirty-two energy balances have been conducted by indirect calorimetry using cows at two levels of feeding and at two stages of lactation over 3 years. Mixed pasture suitable for grazing and cut twice daily was the sole diet. Data for the utilization and partitioning of energy have been subjected to regression analysis on a within-cow basis. Efficiency of utilization …

Energy Balance Studies With Lactating Cows Fed Fresh Or Frozen Grass From Pasture Suitable For Grazing, Y Van Der Honing, A.J H. Van Es

IGC Proceedings (1977-2023)

Information on feeding value and energy utilization of grass consumed by grazing cattle, especially lactating cows, is limited. It is nearly impossible to perform calorimetric studies with grazing dairy cows. Similar studies indoors often show low intakes of fresh grass and require much labor. Still, in much of the world, cattle graze at least half the year; therefore, knowledge of the feeding value of grass is important for practice. In the Netherlands, each year (1973-1974) each of four permanent pastures in the grazing stage of maturity was cut twice daily and either fed fresh or stored at - 20°C to …

Long-Term Feeding Of Corn Silage As The Sole Forage In Diets Of Lactating Dairy Cows, C H. Noller, N J. Moeller, C L. Rhykerd

IGC Proceedings (1977-2023)

The long-term feeding of corn silage as the sole forage to lactating dairy cows has had only limited success due to problems with production, reproduction, and health after one lactation. Consequently, a long-term study was begun in August 1975 with two groups of 19 cows, 15 2-year-old heifers, and 4 3-year-old cows assigned at random to each group as they calved. One group was fed a diet with corn silage as the sole forage and the other group a diet with a 50: 50 ratio of forage as corn silage (CS) and low-moisture alfalfa-orchardgrass ( AO) silage. Both rations contained …

Top Grazing High Protein Forages With Lactating Cows, H R. Conrad, R W. Van Keuren, B A. Dehority

IGC Proceedings (1977-2023)

Two grazing systems, top-grazing of alfalfa (Medicago sativa L.) and high-intensity grazing of orchardgrass (Dactylis glomerata L.), were investigated with three and four levels of concentrate, respectively. The concentrates consisted of corn, oats, and minerals. High dry-matter (DM) alfalfa silage fed in the barn with 40% concentrate by weight was used for a positive control ra­tion. Three- or 4-day grazing periods/paddock were used with 16- and 24-day rotation cycles for orchardgrass and alfalfa, respectively. Using alfalfa without concentrate resulted in mean daily yields of 20.2 kg of milk and 0.65 kg of protein. As amounts of concentrates were increased, daily …

Nutritive Value Of Cattle Diets On Fertilized And Unfertilized Blue Grama Rangeland, J D. Wallace, F J. Cordova, G B. Donart, R D. Pieper

IGC Proceedings (1977-2023)

Low levels of nitrogen (N) fertilization can substantia1ly increase forage production on native rangeland if adequate precipita­tion is available. The objective of this study was to_ compare nutritive value of diets selected by Hereford steers grazing unfer­tilized and N-fertilized (45 kg N/ha) rangeland in south central New Mexico. The study area consisted of two adjacent pastures of approximately 60 ha each, containing comparable areas ofbottomland, upland, and hillside sites. Stocking rates were 4.8 and 2.4 ha/yearling steer for control and N-fertilized pastures, respectively. Dietary samples were collected from esophageally fistulated steers (average weight 308 kg) during early, middle, and late …

Seasonal Changes In Botanical And Chemical Composition And Digestibility Of Diets Of Large Herbivores On Shortgrass Prairie, G M. Van Dyne, J D. Hanson, R C. Jump

IGC Proceedings (1977-2023)

Studies were conducted from 1969 through 1974 on northeastern Colorado shortgrass prairie during different grazing seasons and under different grazing intensities to evaluate bison, cattle, sheep, and pronghorn antelope diets. The purpose was to ex­amine seasonal changes in chemical and botanical composition and digestibility of diets of large herbivores. Bison, cattle, and sheep diets were obtained from esophageal fistula samples. Fistula samples were analyzed microscopically to determine botanical composition. Pronghorn antelope diets were obtained by bite-count methodology. Data, presented for im­portant plant species and species groups, were averaged for 28-day intervals to show typical seasonal trends in diets. During all …

Diet Selection By Cattle On Tropical Pastures In Northern Australia, B Walker, M T. Rutherford, P C. Whiteman

IGC Proceedings (1977-2023)

Diet selection by steers in northern Australia on a continuously grazed pasture of Setaria sphacelata var. sericea (Kazungula), Macroptilium atropurpureum (siratro), and Stylosanthes guianensis var. guianensis (Schofield) was studied. The pasture treatment that supported the highest annual weight gains (254 kg/steer) in a stocking-rate experiment had 1.7 steers/ha. Mean annual rain-fall was 1,490 mm, with 70 % falling from December to March. Monthly average temperatures are highest in December (30 .1 °C) and lowest in July (11. 9°C). Pastures were sampled in 1973 (seven 3-day periods) and 1975-1976 (six 3-day periods) with three esophageal fistulated steers. Extrusa samples were analyzed …

Relationship Between Botanical Composition Of Herbage On Offer And Herbage Eaten By Grazing Beef Cattle, R.D H. Cohen, D L. Garden

IGC Proceedings (1977-2023)

The relationship between botanical composition of the herbage ori offer and herbage eaten is a key link in the modeling and simulation of grazing systems, yet there appear to be no data describing this relationship for multispecific or nontemperate swards. This paper describes one such relationship for cattle grazing multispecific swards in the subtropics. Native or improved pastures were grazed by Hereford heifers fistulated at the esophagus. The native pasture, which had never received fertilizer, contained mixed grasses and no legumes. One of the improved pastures consisted of native pasture fertilized

with superphospbate, and the other improved pastures were fertilized …

Cattle Preference And Plant Selection Within A Hybrid Grass, P O. Currie, R S. White, K H. Asay

IGC Proceedings (1977-2023)

Recent development of hybrid forage grasses shows promise for advancing grassland agriculture. Previous selections within these hybrids have been based on morphological, reproductive, and adaptive attributes with only limited testing of animal ac• ceptability. Testing of animal preference and selectivity was the primary purpose of the present study. Yearling cattle were tamed and observed for their selectivity in grazing individual plants and genetic lines of F6 crosses between quackgrass (Agropyron repens) x bluebunch wheatgrass (Agropyron spicatum). Animals showed definite preference for individual plants within genetic lines and for different genetic lines. Different animals frequently preferred the same plant or lines …

Combination Range-Pasture Management In South Florida For A Low-Energy Grassland Program, L L. Yarlett

IGC Proceedings (1977-2023)

The semitropical environment of south Florida is favorable for coordinated management of a wide variety of native grass species and improved pasture forages. The decade of the 1980s will emphasize change from forage programs of high energy utilization to those with a low requirement of fossil fuels. For 4 decades, grassland management in south Florida has been primarily pasture establishment created from the rangeland resource. The establishment and management required substantial inputs of fossil fuel. Use and management of rangeland was largely neglected. Ecological concepts as a basis for managing semitropical ranges were not accepted. In recent years practical programs …

Forage Intake Of Cattle As Affected By Grazing Pressure, C D. Allison, M M. Kothmann, L R. Rittenhouse

IGC Proceedings (1977-2023)

A series of trials was conducted in 1977 to determine the effect of level of grazing pressure on organic-matter intake and the relationship between intake and forage disappearance. Levels of grazing pressure studied were 10, 20, 40, and 50 kg forage allowed/animal unit/day (kg/AU/day) for 14-day trials in April, July, and September. A standing crop of forage was measured before, in the middle of, and immediately after each trial. Organic-matter intake was estimated by the fecal output: indigestibility ratio technique. Organic-matter intake was highest in April; cattle also consumed Dlore forage in September than in July. The combination of forage …

Effect Of Herbage Mass And Allowance Upon Herbage Intake By Grazing Dairy Cows, J.A C. Meijs

IGC Proceedings (1977-2023)

An adequate supply of nutrients for grazing animals depends on the intake and nutritive value of herbage. Little information is available on factors affecting herbage intake of grazing cows, particularly for grazing systems that do not involve daily change of animals to a new pasture. Our objectives were to determine the effects of variation in herbage mass ( due to variation in stage of maturity) and of herbage allowance on herbage intake by grazing dairy cows and on efficiency of consumption (herbage con­sumed as a proportion of herbage accumulated). From 1976 to 1979 the herbage intake oflactating cows was determined …

Relation Of Animal Production To Stocking Rate On Cultivated Pastures In Cerrados Areas Of Brazil, C J. Escuder

IGC Proceedings (1977-2023)

The relationships among stocking rate, gain/animal, and gain/ha were compared on six grazed pastures. The experiment was established on an oxisol acrustox in Brazil. The pasture consisted of (1) jaraguagrass (J); (2) jaraguagrass plus legumes (J + L); (3) molassesgrass (M); (4) molassesgrass plus legumes (M + L); (5) pangolagrass (P); (6) Pangolagrass plus legumes (P + L); (7) mixture of grasses (jaragua, molasses, and pangola) plus legumes (JMP + L). Pasture of pangolagrass alone was discarded because of poor establishment. Four stocking rates were applied on each pasture, from 1.0 to 3.4 animals/ha. For all pastures, gains/animal decreased linearly …

Evaluation Of Forages Ensiled In Concrete Stave And Oxygen-Limiting Silos, J O'Leary, R W. Hemken, L S. Bull

IGC Proceedings (1977-2023)

This study evaluated corn silages stored in concrete stave and oxygen-limiting silos during 1978-1980. Factors considered in­cluded the effect of environmental conditions in each silo on silage stability and feeding value. Milk production was evaluated using Holstein cows, intake studies used Holstein heifers or steers. Weekly measurements of intake, milk production, silage temperature, pH, and yeast and mold content were made for each silage. Aerobic stability was determined monthly. Silo type had no effect on intake or milk production. Silage temperatures from the oxygen-limiting silo were higher, and the silage was less stable than that from concrete stave silos. No …

Round Baling From Field Practices Through Storage And Feeding, W L. Kjelgaard, P M. Anderson, L D. Hoffman, L L. Wilson, H W. Harpster

IGC Proceedings (1977-2023)

A model analysis compared labor and fuel requirements for round and rectangular bale systems. Round baling reduced harvesting, transport, and handling labor by one-half but increased fuel use by a factor of 1.6. When data from field studies of all dry matter (DM) losses were included, round baling required 80 % as much labor and 200 % as much fuel as did rectangular bal­ing. Baling losses for round balers and stackers averaged 10 % compared with 3 % for rectangular balers. ·Dry-matter losses from mowing through feeding of field-cured round bales, including 6 months of outdoor storage, totaled 41 % …

Harvesting And Processing Effects On Alfalfa Protein Utilization By Ruminants, R Britton, D Rock, T Klopfenstein, J Ward, J Merrill

IGC Proceedings (1977-2023)

Alfalfa (Medicago sativa) is an efficient and important means of producing supplemental protein for ruminants. This research was undertaken to characterize the value of alfalfa protein for ruminants and to show how the protein is affected by different harvesting or processing regimens. The effects of maturity (prebloom, one-tenth, one half, and full bloom) and processing method (freeze dried [FD], sun cured [SC], and oven heated [HJ), on percentage of nitrogen (N), acid detergent insoluble N (ADIN), in-vitro rumen ammonia release (NH3), and in-situ rumen protein degradation, using dacron bags (BAG), were studied on irrigated alfalfa harvested over 2 years. …

Comparison Of Conservation Methods Under Controlled Practical Conditions, H Honig, K Rohr, E Zimmer

IGC Proceedings (1977-2023)

The most common forage conservation methods (direct-cut and low-moisture silage, barn,dried hay, and dehydration) have been compared under practical, but strictly controlled, conditions to determine their relative value for meeting the increasing demands of high-yielding ruminants. A grass mixture was used as forage, at different stages of maturity in different ex­periments. Parameters determined were changes of nutrient content; losses of DM and net energy; and, in three experiments, forage intake by dairy cows. From the results of the experiments, the following conclusions could be drawn: (1) roughage quality is influenced more by cuttng time than by preservation methods; (2) low-moisture …

Wet Fractionation Of Alfalfa: A Direct Forage-Harvesting System, M Collins, R G. Koegel, N A. Jorgensen, H W. Ream

IGC Proceedings (1977-2023)

In this syst􀀇m, termed wet fractionation, fresh forage is macerated and pressed to remove approximately 50 % of the moisture. The result is a forage product containing 32 %-38 % dry matter (DM) that can be ensiled directly. In addition, the protein con­tained in the plant juice can be coagulated and removed. The remaining deproteinized juice contains large quantities of mineral nutrients that can be returned to the soil. This process has several potential advantages: (1) less weather-dependent harvesting, which minimizes harvest losses; (2) reduced harvesting time; (3) reduced fertilizer requirements; and (4) ability to harvest protein from land unsuited …

Hastening Hay Drying, J W. Thomas, T R. Johnson, M A. Wieghart, C M. Hansen, M B. Tesar, Z Helsel

IGC Proceedings (1977-2023)

The objectives of these studies were to increase the drying rate of cut alfalfa (Medicago sativa) by treating with chemical solu­tions and to examine factors that influence drying. Time to dry and drying rate of cut alfalfa were studied under laboratory and field conditions. Treatment consisted of spraying the cut alfalfa with methyl esters of long-chain fatty acids, an emulsifier alone, or a combination of an emulsifier and a potassium carbonate solution. Alfalfa sprayed with solutions of each chemical under specified conditions increased drying rate and decreased drying time to 60% or 75 % dry matter (DM) or …

Alternative Treatment Systems To Increase The Drying Rates Of Green Forage Crops, W E. Klinner, O D. Hale

IGC Proceedings (1977-2023)

Forms of conditioning treatment are being developed that aim to minimize the barrier effect of the crop cuticle without sacrificing too much of the structural strength of the herbage. Effective surface abrasion and favorable windrow structure can be achieved with steel-spoked rotors, which are now beginning to be offered commercially. More recently, plastic brushes have been developed because the higher population density and yielding ability of the crop-engaging elements, plus the absence of metal components, appeared to offer additional advantages. Four different brush conditioner systems have been evaluated in the laboratory and in replicated field experiments. Tufted brushes using trilobar …

Effects Of Microwave Treatment On Drying And Respiration In Cut Alfalfa, S A. Seif, D A. Holt, V L. Lechtenberg, R J. Vetter

IGC Proceedings (1977-2023)

After forage crops are cut mechanically, they usually undergo some degree of natural drying before being stored or further processed. During early stages of drying, plant respiration continues. Treatments or management practices that hasten drying and reduce postharvest respiration are desirable, because they minimize quantity and quality losses. Our objective was to determine the effects of brief microwave treatment on subsequent natural drying rate and respiration of alfalfa (Medicago sativa L. ). Duplicate samples of field grown Apollo alfalfa were subjected to focused microwave energy (2,450 MHz) generated at 0.25, 0.50, or 1.0 kilowatt of power for 3, 6, …

Effect Of Formic Acid- Formaldehyde Treatments On The Nitrogenous Constituents In Annual Ryegrass Silage, M L. Fishman, F Mchan, D Burdick

IGC Proceedings (1977-2023)

Prevention of proteolysis during ensiling is important in preserving the nutritive value of silage. Hence, the mechanism by which silage protein is protected against degradation was studied in wilted annual ryegrass (Lolium multiflorium Lam.) silage pretreated with formic acid, formaldehyde, and a formic acid-formaldehyde mixture. Raw-wilted ryegrass, control ryegrass silage, and treated ryegrass silage were extracted and fractionated under conditions previously found to maximize yield of nitrogenous constituents and minimize proteolysis during the extraction of fresh grass. Extractions were by boric acid-borate buffer at pH 8.0 with and without detergent (1 % sodium dodecyl sulfate). Sodium metabisulfite, an antioxidant, was …

Addition Of Lactobacillus Sp. To Aid The Fermentation Of Alfalfa, Corn, Sorghum, And Wheat Forages, N J. Moon, L O. Ely

IGC Proceedings (1977-2023)

As preservation of forage by ensiling has increased, so has the use of additives to enhance acid fermentation. Many of the fermentation aids currently on the market contain microflora to insure a lactic acid fermentation. The objectives of this study were to characterize the basic patterns of fermentation in a variety of crops and to evaluate the effects of adding selected microflora to forages to enhance the fermentation. Four crops were ensiled in each of three seasons. Alfalfa was harvested at 20 %-40 % bloom, second cut; wheat was cut in the early dough stage; corn was cut in the …

Interrelationships Between Pattern Of Fermentation During Ensilage And Initial Crop Composition, J M. Wilkinson, P F. Chapman, R J. Wilkins, R F. Wilson

IGC Proceedings (1977-2023)

Relationships between crop composition and silage composition were examined for 231 silages made at the Grassland Research Institute from 1968 to 1978 without additives. A test was made of the model of Weissbach et al. (1974) in which silage characteristics were related to the percentage of dry matter in the crop (OM) and the ratio of sugar (Z) to buffering capacity (PK). Although these factors accounted for significant variance, the percentage accounted for was low at 36 % for lactic acid (percentage of total acids), 26 % for Flieg's score, 22 % for ammonia N (percentage of total N), and …

Effect Of Delayed Sealing During Ensiling On Fermentation And Dry-Matter Loss, N Takano, Y Masaoka, T Manda

IGC Proceedings (1977-2023)

Two experiments were carried out from 1976 to 1980 to ascertain the effect of delayed sealing of silo on fermentation, dry· matter (DM) loss, digestibility, and silage intake. The effect of delayed sealing (up to 72 hours) of grass and corn silage was tested in laboratory silos on fermentation quality with storage temperatures at 15°C and 30°C, moisture content from 49% to 85 % , water-soluble carbohydrate (WSC) content ranging from 11.1 % to 17.5%, and with and without an addition of 0.25% formic acid. In all cases, delayed sealing resulted in poor-quality silage with high pH values and low …

Improving Hay Quality By Ammoniation, K J. Moore, V L. Lechtenberg, K S. Hendrix, J M. Hertel

IGC Proceedings (1977-2023)

Experiments were conducted to determine the effect of hay ammoniation on hay consumption and weight gain by steers when the hay was fed unsupplemented and supplemented with energy and protein. Mature orchardgrass (Dacrylis glomerata L.) hay was baled in early June 1979 and treated with anhydrous ammonia at 30 g/kg of hay. Seven weeks after treatment the hay was uncovered and allowed to aerate for 3 days. It was then fed to weanling steer calves weighing approximately 225 kg each. Similar hay baled from the same field but not ammoniated was fed to separate groups of steers. Both the treated …