饲料学粗饲料（中英文）

1、Chapter 5 Roughages （粗饲料） 干草（Hay）藁秕饲料（Crop Residues）Animal Nutrition and Feed Science5.1 干草（hay）Hay - produced by dehydrating green forage to moisture content of 15% or less Allows forage supplies to be distributed throughout year winter feeding dry-season feedingAnimal Nutrition and Feed Science(1)

2、To reduce the moisture content of green forage crops sufficiently to permit their safe storage without spoilage or serious loss of nutrients.(2)The maximum water content for baling hay is about 18% to 22%, depending on the fineness of the hay, the rightness of the bale, the prevailing humidity, and

3、the amount of air movement. 5.1.1 Object in hay making Animal Nutrition and Feed Science(3)Freshly mown hay that is stored before it is sufficiently dry can be destroyed by fire resulting from spontaneous combustion（自燃）.(4)Stored hay that contains excessive moisture may tend to mold, making it unsui

4、table for feeding purpose. 5.1.1 Object in hay making Animal Nutrition and Feed Science(5)Hay that is improperly harvested may suffer losses due to :1. Shattering. This is the loss of leaves. Legumes lend to shatter badly. Raking and baling tend to increase leaf shattering.2. Leaching. Rain on hay d

5、uring the curing periods tends to leach out and cause the loss of the more water-soluble nutrients, especially protein and carbohydrate.3. Bleaching. Excessive exposure to sunlight will cause heavy losses of certain nutrients .5.1.1 Object in hay making Animal Nutrition and Feed Science5.1.2 Proper

6、hay-making procedures(1)A forage crop to be harvested for hay should be mowed just as soon after reaching an early bloom stage of maturity as circumstances will permit. Undue（不适当的） delay in harvesting hay will result in lower quality hay. Animal Nutrition and Feed Science(2)Every effort should be ma

7、de to select periods of rain-free weather for harvesting hay. A minimum of 1 and normally 2 days of good drying weather are required for curing hay. Weather forecasts can be of great assistance in this regard.5.1.2 Proper hay-making proceduresAnimal Nutrition and Feed Science(3)“Conditioning” （压裂草茎）

8、will reduce the curing time required for certain crops, especially crops with coarse sappy（汁液多的） stems, by as much as 50%. 5.1.2 Proper hay-making proceduresAnimal Nutrition and Feed Science(4)A forage crop to be harvested for hay should be raked（耙） before it is completely dry to avoid excessive sha

9、ttering and overexposure to the sun.(5)Turning of a windrow, when necessary to facilitate drying, should be done when the dew is on,especially with hays subject to serious shattering.5.1.2 Proper hay-making proceduresAnimal Nutrition and Feed Science(6)Baling should be carried out just as soon as th

10、e hay is sufficiently dry. Square bales should be stored as soon as possible and, in any event, before they are rained on. Round bales, however, will shed rain（流下） and may be left in the field for extended periods without serious damage to the hay .5.1.2 Proper hay-making proceduresAnimal Nutrition

11、and Feed Science5.1.3 Nutritive value of haysHay is classed as dry roughage and is used as a source of bulk in the ration primarily, and as a source of nutrients secondarily. Hay is a cattle, horse, and sheep feed. Very little hay of any kind is ever fed to swine .However, dehydrated alfalfa meal so

12、metimes makes up 5% to 10% of swine rations.Animal Nutrition and Feed Science5.1.3 Nutritive value of haysHay are primarily a source of energy, although high quality grass and legume hay may be excellent sources of protein, minerals and vitamins.Hay of average quality usually will contain from 25% t

13、o 32% crude fiber and 45% to 55% TDN.Digestibility of most hays is within the range of 50-60%TDN as compared to 75-90%for the cereal grains. Animal Nutrition and Feed Science5.1.4 Use of hay preservativesAdded to forage material at baling time, might permit the forage to be baled safely with as much

14、 as 25% or more moisture without heating and resultant quality loss .Inhibit microbial growth.Sodium diacetate（双乙酸钠）, propionic acid, acetic acid, and anhydrous ammonia（液氨）.Greater percentage of leaves saved, thereby increasing the total yield of more nutritious hay.Animal Nutrition and Feed Science

15、5.1.5 Hay desiccants（干燥剂）Increase drying rate when applied at time of mowing（割草）Alter the waxy materials of the cuticle layer（角质层）and allow moisture to pass throughDrying agent is typically water solution of potassium carbonate, sodium carbonate, and sodium hydroxideAnimal Nutrition and Feed Science

16、Animal Nutrition and Feed ScienceAnimal Nutrition and Feed ScienceAnimal Nutrition and Feed ScienceAnimal Nutrition and Feed ScienceAnimal Nutrition and Feed Science5.1.6 Hay storage(1) At best, storage losses are about 5% for 15% moisture hay, wetter hay losses increase 1% for each 1% moisture, for

17、age quality is reduced in hays above 20% moisture.(2) Rectangular bales usually stored inside, round bales often stored outside with resulting losses.Animal Nutrition and Feed Science5.1.6 Hay storage(3) Weathering（风化） dramatically reduces digestibility, compounds lost are highly digestible.(4) Unpr

18、otected, storage losses often 40% or more.(5) Tarps（油布） restrict air movement, use for hays 30% of total N = lowered digestibility and feeding value5.1.7 Losses in storageAnimal Nutrition and Feed ScienceThe local environment (temperature, humidity) will affect how fast hay dries and how much moistu

19、re can be present without heating. Storage of hay at 36 with 18%moisture causes losses in dry matter as high as 8% over 9months of storage.The losses were primarily sugars and other soluble carbohydrates. 5.1.7 Losses in storageAnimal Nutrition and Feed ScienceExcessive heating of stored hay results

20、 in formation of brown and black hays, usually with much mold which reduces the palatability and nutritive value. Digestibility of protein and energy of the hay is usually considerably less than for good quality hay.5.1.7 Losses in storageAnimal Nutrition and Feed ScienceIf storage of hay is not com

21、plicated by excessive moisture, hay protected from the weather changes very little in composition and it can be stored for several years with little loss in nutritive value.5.1.7 Losses in storageAnimal Nutrition and Feed Science5.1.8 Changes during dryingRapid drying results in the least changes in

22、 chemical components of herbage.During respiration there is an appreciable loss of the soluble carbohydrates, particularly glucose, fructose and sucrose. There is generally some loss of N; this is due to action of plant protease enzymes which result in a decrease in protein N, but an increase in sol

23、uble N including peptides, AA, amides（酰胺）and other compounds. Animal Nutrition and Feed ScienceSlow drying results in loss of as much as 80% of the carotene when herbage is exposed to the sun.The vitamin D content of fresh herbage is very low. Curing in sunlight or ultraviolet light results in a mar

24、ked increase in vitamin D activity as a result of synthesis of it from plant sterols, especially in the leaves.5.1.8 Changes during dryingAnimal Nutrition and Feed Science(1)Stage of harvestConsidered to be the most important quality factor.Grass should be cut in the boot（孕穗） to early seed-head stag

25、e. Good grass hay does not have many seed-heads.Alfalfa should be cut in the late bud（含苞未放） to early bloom stage. There should not be many blooms or any seed pods.Clover should be cut between the 20 to 50% bloom stage. 5.1.9 Hay Quality FactorsAnimal Nutrition and Feed Science5.1.9 Hay Quality Facto

26、rs(2)Leafiness As plants mature, increase in fiber , lignification and the ratio of stems to leaves.Leaves are critical to animal nutrition: 60% TDN, 70% protein, and 90% vitamins. Leaves higher in energy and DMD (dry matter digestibility), lower in fiber than stems (80% of nutrients in leaf)Animal

27、Nutrition and Feed Science Visual appraisal is the initial approach to determining hay quality (Courtesy of Iowa State University)Animal Nutrition and Feed Science(3)Colorthe most desirable hay is bright, natural greenyellowing, especially in grasses, is often an indicator of over-maturity.hay that

28、is rain damaged, sun bleached, moldy, or heat damaged during storage will be off color（不好）.rain damaged hay tends to make hay dark brown or black, stems will often become very brittle.heat damaged hay will often be brown5.1.9 Hay Quality FactorsAnimal Nutrition and Feed Science(4)Odor the smell of f

29、reshly mowed hay is the standard for evaluating hay with the nose.odor is the primary reason for animal rejection.odor is a good indicator for molds.5.1.9 Hay Quality FactorsAnimal Nutrition and Feed Science(5)SoftnessPlants will become more fibrous as they mature.Is a factor in animal acceptance an

30、d palatability.Another indicator of hay making technique.(6)Trash and foreign material5.1.9 Hay Quality FactorsAnimal Nutrition and Feed Science(7)EnvironmentHigh heat causes more lignin productionHigh moisture makes drying a problem(8)Soil fertilityFertilizer affects yield more than quality. Weeds

31、more likely in low fertility fields.5.1.9 Hay Quality FactorsAnimal Nutrition and Feed Science5.2 藁秕饲料（Crop residues） Straws and chaff(谷壳) from the cereal grains-rice, wheat, barley, etc.Grass straws, stover（秸秆）from corn and sorghum, corn cobs, cottonseed hulls, cotton gin trash ,hulls of various ty

32、pes. Sugar cane bagasse (甘蔗渣) and pineapple stumps.Animal Nutrition and Feed ScienceForage crops are harvested directly for animal feed.Animal Nutrition and Feed ScienceAnimal Nutrition and Feed Science5.2.1 Nutrition Characteristics Low crude protein content. High in cellulose and other structural

33、carbohydrates (crude fiber, ADF, NDF)and highly lignified . Usable nutrient content is low. Animal Nutrition and Feed ScienceLower in Ca than high quality sources, especially legumes, and they are invariably low in P. For a roughage such as straw, the carotene content is nil. The content of vitamins

34、 D and E would also be extremely low and that of the B-complex vitamins would be nil.5.2.1 Nutrition Characteristics Animal Nutrition and Feed Science5.2.2 Processing method(1)Grinding or choppingTends to decrease wastageIncreases bulk density, which facilitates transport and storageIncreases surface area available for digestion Increases rate of passage from the rumenAnimal Nutrition and Feed Science(2)Alkali treatment solubilizes lignin and increases fiber digestibilitybreaks lignin-carbohydrate bonds to increase digestibility5.2.2 Processing