Pasture, animal feeds and nutritional disorder in agriculture

Terminologies

1. Pasture is land covered with grass and other low plants suitable for grazing animals, especially cattle or sheep.
2. Fodder is a grass or legume that is cut and carried to the stall for indoor feeding.
3. Forage is a plant grown primarily for feeding livestock.
4. Hay is feed produced by hydrating green forage to a moisture content of 15% or less.
5. Silage is type of fodder made from green foliage crop  which have been preserved by fermentation to the point of acidification.
6. Palatability is the relative attractiveness of feed to an animal.
7. Herbage refers to leaves, stems and other succulent part of forage plant that animals can feed on.
8. Stocking rate is the number of animal grazing in unit area of pasture land irrespective of reliable or available herbage.
9. Carrying capacity is the number of animals a given pasture is able to support for a given period of time.

Types of pastures

There are two main types of pasture i.e.

Natural

Ley

Natural pasture

This is open area with a dense cover of native grasses and other plant species.

Advantages of natural pasture

• forage plants found in natural pasture are well adapted to natural condition hence can survive even under poor management,
• Natural pasture contains a variety of forage plant needed in the animal diet.
• They are found in areas that are difficult to cultivate hence help in the utilization of such idle places.
• They can support a large population of local livestock species like goats, sheep, and cattle.
• They are cheap to maintain since they do not require a lot of care.
• They require fewer inputs during improvement.

Disadvantages of natural pasture

• They are less productive in terms of herbage yields and nutritive value.
• The grasses mature very fast becoming stemy and coarse hence reducing palatability and nutritive value.
• They are usually grazed communally hence high chances of more livestock using it leading to overgrazing.
• Due to poor management of natural pasture livestock diseases spread very fast from herd to herd.

Ley pasture

These consist of improved grasses and legumes that provide high quality forage.  Ley pastures are used for intensive farming and particularly for dairy cattle.

Limitations of ley pasture

1. High cost of establishment i.e. money is needed to prepare the land, buy seeds and fertilizers.
2. Lack of viable seeds – seeds are not readily available on a commercial basis for Ley pastures.
3. Poor quality animals – Most farmers rear poor quality animals which cannot give profitable returns to cover the cost of leys.
4. Poor managerial skills – Most farmers lack basic knowledge and skills of managing Ley so that they can be productive for a long period of time.
5. Poor soil – Most farmers are not willing to surrender their fertile soil for Ley pasture production.
6. Unreliable rainfall – Ley pasture production requires rainfall which is not less 800mm annually and must be well distributed.

Importance of pastures

1. They provide organic matter to the soil after rotting.
2. They provide a wide range of nutrients to grazing animals.
3. They help in utilizing idle land.
4. Deep rooted pasture plants recycle plant nutrients from deeper layer to soil surface for rooters to use.
5. They can break life cycle of pest when planted in a rotation with crops.
6. They can reduce water evaporation from the so acting as a cover.
7. Pastures are the cheapest source of feeds for animals
8. The root of pasture plant will bind soil particles together hence reducing soil erosion.
9. Pasture plant, particularly legumes improves the soil fertility by fixing nitrogen into the soil.

Improvement of natural pastures

1. Fencing – The area should be fenced to exclude wild animals and intruders.
2. Remove bushes and dense tree canopy so that the pasture grasses can receive enough light.
3. Weeds control – Poisonous and notorious weeds should be removed.
4. Provision of water to animals – Watering points should be well distributed to avoid over grazing and trampling on pastures in some places.
5. Erosion control – Stolonferous grass spp should be planted on bear surface or in over grazed area to reduce soil erosion.
6. Over sow – this is the introduction of improved forage spp more especially legumes in natural pasture to improve nutrient content.
7. Control grazing / rotational grazing / strip grazing – This encourages efficient forage utilized and reduces over grazing.
8. Establishing fodder bank that can be fed to animals when fresh herbage is scarce.
9. Distribute salt licks evenly in a pasture to stop animals from creating small path in a pasture as they move to the point with the licks.
10. Practice control burning so that all pasture with parasites are got rid of to give way for the young and nutritious forage.
11. Draining water logged area so as to encourage proper forage growth and control parasites

Factors to consider before establishing a pasture

1. Type of soil – A farmer should consider a good soil with a good ability to retain moisture
2. Topography – pasture land should have a gentle slope which allows easy use of machines during seed bed preparation and planting.
3. Climate – The area should have adequate rainfall with about 800mm during dry periods.
4. Planting materials – There should be good quality planting materials that ensure good pasture establishment.
5. Cost of production – The farmer should make sure that the expense involved in pasture establishment can be met from the income of the animals.
6. Availability of pasture seeds – The pasture under consideration should have readily available seeds with in the environment.

Characteristics of a good pasture species

1. It should be easy to establish hence reducing cost involved in replacing the seeds that failed to establish.
2. It should be able to provide herbage even in times of scarcity
3. It should be drought resistant. In order to meet this deep rooted species are always preferred.
4. It should be easy to manage i.e. easy to plant, weed and harvest.
5. It should be highly palatable so that the animals can take it.
6. Should match with the nutrient requirement of animal.
7. It should show a high resistance to grazing i.e. the species should be able to regenerate after grazing and persist for at least three years.
8. It should be highly resistant to pest and diseases that can attack the pasture.
9. Should be able to produce a large quantity of dry matter in a year for the animals to graze on.
10. It should have a suitable height from the ground to allow easy grazing by the animal.
11. It must be a pasture that can be easily mixed with other pasture species without having any effect on them or being affected.
12. It should have readily available seeds that can be used for propagation.

Types of pastures

Pasture is divided into two broad groups. i.e.

• Pasture grasses
• Pasture legumes

Examples of pasture grasses

• Guinea grass –              Panicum maximum
• Rhode grass –              Chloris gayana
• Congo Signal grass                 –   Brachiaria ruziziensis
• Elephant grass                         –  Pennisetum purpureum
• Kikuyu grass                            –   Pennisetum clandestinum
• Nandi grass                              –  Setaria anceps
• Thatch grass                             –   Hyparrhenia rufa
• Star grass                                   –   Cynodon dactylon

Examples of common pasture legumes

• Green leaf Desmodium                 –              Desmodium intortum
• Silver leaf Desmodium                –             Desmodium uncinatum
• Stylo                                                –              Stylosanthes gracilis
• Glycine                                           –              Glycine wightii
• Centro                                            –              Centrosema pubescens
• Lucerne                                        –          Medicago  sativa
• Clovers                                          –          Trifolium spp

 

Advantages of including legumes in a pasture

1. They fix nitrogen into the soil hence improving soil fertility for other plant species.
2. They show a high resistance to drought hence can be relied on during the dry season.
3. They increase the palatability of the pasture since they are highly palatable.
4. Since they are deep rooted, they help in recycling plant nutrients for use by other plant species.
5. They reduce cases of bloat in animals since they are not very succulent.
6. A good number of them have broad leaves hence have the ability to control soil erosion.
7. The legumes supply protein to the animals which supplement the grass.
8. They give longer grazing period since they mature at different times.
9. They produce better quality and quantity of foliage for the animals.

Adaptation of forage plants to the environment

1. They produce very many feeds which increases their chances of survival
2. Their seeds are light hence can be easily dispersed by wind.
3. they can withstand defoliation and regenerate quickly
4. They have short life cycle hence able to utilize the shortest period of good conditions
5. some have thorns and hair which discourage animals from eating them
6. Some species produce chemicals which keep off animals
7. Some have under ground stem (rhizomes) which will sprout when the leaves and stems are destroyed.
8. Some grass seeds posses hard seed coat that can not be destroyed by the animal digestive system.

Conservation of herbage

Herbage can be conserved into two major ways i.e.

• Hay
• Silage

Hay

Characteristics of a good hay

1. Good hay should be leafy since leaves are richer in food value compared to other parts of the plant.
2. Should be prepared out of herbage cut at the stage near flowering when the plant is highly nutritious.
3. It should be green in colour since the green colour signifies the presence of Vit .A
4. It should be free from dust and moulds which reduce palatability
5. It should be soft and pliable for easy consumption by the animals.
6. It should be free from weeds and poisonous plants.
7. It should have a smell which is a characteristic of the plant from which it is made.
8. The moisture content of hay should not exceed 15% since high moisture may cause rotting.

Factors affecting the quality of hay

1. The species of grass – some grass species produce high quality hay since they can be easily turned and have nutrient content.
2. Storage – Proper storage of hay by protecting it from rain and sunlight preserve the quality.
3. Stage of cutting the grass – Grass cut before flowering produces high quality hay than that cut after flowering.
4. Level of drying – Poorly dried hay becomes moldy and over dried hay lacks Vit. A

Procedure of making hay

1. Select a suitable plant species with high nutrient to be used in the making of hay.
2. Cultivate the plant species on a good soil where it can obtain the required nutrients.
3. Harvest the plant species just before flowering when it contains a lot of nutrients.
4. Dry the hay to a moisture content of about 15%
5. Tie the hay in bales and prepare it for storage
6. The hay should be stored in a place well protected from rain and sunlight to preserve the quality.

Factors affecting the quality of hay

1. The species of the grass – Some grass species produce high quality hay since they can be easily turned.
2. Storage – Proper storage of hay by protecting it fro rain and sunlight preserve the quality.
3. Stage of cutting the grass – Grass cut before flowering produces high quality hay than that cut after flowering.
4. Level of drying – Poorly dried hay becomes moldy and over dried hay lacks Vit. A.

 

Silage

This is the herbage cut before flowering and converted into succulent feed through the process of fermentation.  It can be made from any succulent green material such as sweet potatoes vines, young maize, sunflower sorghum, young Guatemala grass and elephant grass.

N.B. High protein foliages mixed with starchy foliages in ratio 3:1 give well balanced silage.

The process of ensiling (making silage)

1. Cut the grass when it is about to flower and in case of legumes when they have formed pods.
2. Chop the grass into small pieces of about 4cm long that can be easily packed.
3. Park the material in the air tight chamber (silo) and compress it to exclude air.
4. Add fermentable water soluble carbohydrates like molasses which provide energy to the microbe during fermentation process.
5. Add urea at a rate of 5Kg per ton so as to increase nitrogen content of the silage.
6. When the silage chamber is full, seal it off from the atmosphere to exclude air and water.
7. Allow the materials to ferment for Atleast three weeks
8. Monitor the temperatures in the silo to ensure proper fermentation. When temperatures drop, molasses should be added to provide energy to the microbes carrying out fermentation.

Fermentation process of silage

1. The material is under fermentation through the action of lactobacillus bacteria.
2. Organic acids are produced and the major one being lactic acid
3. Lactic acid gives silage a good flavor, kills off the harmful microbes and acts as the preservative for silage.
4. The PH has to be low between 3.8 – 4.3 and the temperature must rise to about 37.8⁰C to encourage fermentation by lactobacillus.
5. If the temperatures are low, add more molasses into the silage.
6. Add water to lower temperature in case they are high.

N.B.       Low temperature can be avoided by:

1. Partial drying of the material before ensiling to reduce moisture in the silage.
2. Filling the silage chamber rapidly but compressing the material lightly.
3. Sealing the silo immediately after the final packing to exclude air as much as possible.

N.B. Forage crops contain other species of bacteria such as clostridium ssp which convert sugars and lactic acid to butyric acid.

Butyric acid gives silage a foul smell and makes it less palatable.

Factors affecting the quality of silage

• The type of grass and legume species ensiled
• The stage of growth of the species ensiled
• The speed of ensiling
• The type and amount of additive used.
• Consolidation to exclude air from ensilage.
• The moisture content of the material ensiled
• The degree to which the temperature rises during ensiling.

Reasons for making silage

• For getting money
• Increase total amount of herbage produced per unit area
• Get feeds for use during periods of forage scarcity
• Conserve forage in succulent form
• Avoid forage wastage in periods of planting and abundance
• Increase number of livestock that can be kept per unit area
• Enables animals eat plant materials that they would not eat when fresh.

Advantages of silage.

• In increases the animal’s appetite since it is very palatable and so increases an animal’s intake of a feed.
• It is easier to store than the same quantity of hay since it requires less space per unit weight to store.
• The losses incurred during ensiling are less than those incurred in making hay.
• Many species that the animal cannot eat in fresh form can be eaten when ensiled.
• Under proper storage, silage can stay for several years without losing quality.
• Because the materials retain succulence, fire outbreaks during storage are avoided unlike in the storage of hay.
• There is increased efficiency of feed use since the animal rejects very little of the feed.

Problems of using silage

• Some nutrients are lost due to seepage in the process of silage.
• Its more laborious
• The plant materials are difficult to compact effectively and some rotting is inevitable.
• It is expensive in terms of preservatives used.
• It requires large quantities of materials for it to be economical
• Poorly fermented silage has a bad smell that it may be introduced into the animal products.

How to reduce losses during silage making

• Careful harvesting of the material to reduce losses of leaves and contamination by soil.
• Proper sealing of the silos to prevent re-entry of air into the silo.
• Proper fermentation of the material to exclude oxygen and acid fermentation.
• Proper chopping of the material to ensure proper fermentation.
• Wilting of the material before ensiling to reduce the moisture content and reduce the possibility of rotting.
• Addition of additives to increase the energy supply for the bacteria and preservatives.
• Quick use of the material once the silo has been opened to reduce the chances of spoilage due to exposure to the environment.

Forage utilization method

• Continuous grazing
• Rotational grazing
• Zero grazing
• Deferred grazing.
• Strip grazing

 Continuous grazing

This is an extensive system of grazing in which livestock remain on the same pasture for prolonged period.

Advantages of the system

1. Fencing costs are reduced or avoided completely.
2. It allows animals to have free access to any part of the pasture

• No costs are involved in improving pastures.

Disadvantages

1. It allows selective grazing which can lead to pasture wastage
2. It encourages the buildup of ticks and internal parasites within the grazing place.
3. It may result into under stocking or over stocking as plant growth and seasonal conditions change.
4. It’s difficult to control / diseases amongst animals since the system encourages communal grazing
5. Pasture improvement is extremely difficult as more people are involved in using the pasture.
6. May easily result into overgrazing and destruction of pastures

Rotational grazing

This is where pastures is divided into paddocks and animals are allowed to graze in one paddock at a time until the herbage is uniformly grazed to a given height then moved to another paddock.  High producers like lactating animals are allowed first into paddocks for it to graze the more nutritious herbage.

Advantages of rotational grazing:

1. Provides a uniform developed pasture due to uniform grazing
2. It allows maximum utilization of herbage by avoiding selective / spot grazing.
3. Forage yield is potentially higher since pastures are allowed to regenerate than in other systems.
4. Intervals between grazing allow for remediable practices like fertilizer application, weeding etc.
5. It’s a good method used in the control of parasites like ticks, roundworms, liver fluke.
6. It reduces instances of over grazing and under grazing hence controlling destruction of pastures
7. It makes management practices easy as animals are confined in one place.
8. It allows flexibility in the use of pasture land since crops can be planted in the idle paddocks.
9. It can allow higher stocking rate of animals.
10. Controlled breeding is easy to practice since animals can be grouped according to sex

 Disadvantages of rotation grazing

1. It requires a high initial cost of establishing fences on pastureland.
2. Requires a high level of managerial skills in terms of repairing the fences, improving the pastures etc.
3. Fences can easily injure animals.
4. Over trampling on pastures by animals leads to wastage
5. May require a lot of Labour for repairing farm structures and managing animals

 Zero grazing

This is where animals are confined in structures / stalls where they are fed on fresh forages cut on a daily basis.

Advantages of zero grazing

1. Animals are protected from adverse climatic conditions
2. Feed taken in by each animal is easily known hence easy to keep feeding records.
3. it’s easy to identify sick animals since they are in close observation
4. it’s easy to collect manure from the animals since they are confined in one place.
5. Disease spread is reduced since animals are not in contact with others from another herd.
6. There is high production since animals do not spend a lot of energy looking for pasture and water
7. Selective grazing and trampling on pastures is effectively controlled since animals are fed on pastures cut from the field.
8. it’s easy to carryout management practices on animals under this system as animals are under confinement.
9. The system permits high stocking rate since a large number of animals can be kept on a small piece of land

Disadvantages of zero grazing:

1. The method is capital intensive i.e. requires a lot of capital for constructing animal structures and feeding
2. It requires a lot of Labor which can be used in collecting fodder, cleaning the stalls etc.
3. It cannot support a large number of animals
4. The system is applicable economically in places where market for milk is readily available to cover the costs involved easily.
5. It may lead to loss of soil fertility if manure is not taken back to the fodder garden.
6. The animals lack exercise which can affect their health.

Deferred grazing

This is where a certain paddock is set aside to allow the accumulation of standing hay which can be grazed on during periods of pasture scarcity

Advantage of deferred grazing

1. Pasture seeds are dispersed for pasture stand improvement
2. It provides herbage during periods of scarcity.
3. It allows pastures to develop greater root and crown which is important for subsequent re-growth.
4. The pasture can be used in the control of soil erosion.
5. It allows for natural establishment of pastures

Disadvantages of deferred grazing

1. The pasture is not as nutritious as the fresh pasture hence a need to supplement it.
2. Requires a large piece of land for practicing deferred grazing
3. Does not permit high stocking rates

Strip grazing

This is where strips of fresh pastures are made available each day to animals by moving an electric fence forward.

The grazed area is sealed off for regrowth and excess pastures conserved.

Advantages of strip

1. The animals enjoy fresh grasses each day
2. The grass is eaten at its highest nutritive value
3. Allows intensive grazing hence utilizing pastures efficiently
4. It is highly flexible since it may allow more than one activity on the land

Disadvantages of strip grazing

1. Requires more Labor
2. Requires more skills in using an electric fence
3. Pastures may be destroyed as a result of overgrazing.
4. Ground where animals pass is destroyed and lost since pastures may fail to grow there

Establishing a pasture

1. Clear the land to remove trees and bushes that may interfere with pasture growth
2. Prepare a firm (for moisture conservation), fine (to bring small seeds in contact with soil) and weed free (reduce competition for nutrients) seedbed by burning, ploughing, and harrowing
3. Apply fertilizers to the seed bed to improve soil fertility more especially phosphatic fertilizers for proper pasture establishment
4. Select good quality seed for planting depending on the animal’s needs and environment
5. Treat the seeds to ensure uniform and proper germination by scarification, inoculation and pelleting
6. Sow the seeds shortly after the rains so as to take advantage of soil nitrogen made available by mineralization. Methods of sowing are drilling, broadcasting and row planting
7. Apply pesticides and fungicides to control pests and diseases in pastures

 

Principles of feeding animals

 Terminologies in animal nutrition

 Digestibility

It is the proportion of the feed absorbed by the animal’s body or the difference between the amount of feed ingested and amount of feces produced

Digestible energy

This is the portion of the total carbohydrate contained in the feed which an animal is capable of utilizing or the amount of energy in the feed minus the energy lost in feces.

Crude proteins

This the sum of total nitrogenous compounds contained in a feed.

Production ratio

It is the amount of feed an animal need to produce products such as milk, meat, eggs and offspring in addition to the maintenance ration required for basic functions.

Digestible crude proteins (DCP)

It is the amount of proteins which can be digested, or it is a measure of nitrogen in the feed consumed that is retained in the body of an animal after subtracting loses through feces.

Starch Equivalent (SE)

This is the measure of energy requirement which an animal can obtain from the food. Or it is the amount of pure starch which has the same energy as 100kg of a feed

Palatability of animal feed

Palatability refers to acceptability/preference of the feed by the animal,; it is associated with taste,  odor, texture, appearance and temperature

Ration

A ration refers to the total amount of feed consumed by an animal within 24 hours. It comprises all the nutrients needed for the animal’s well-being and provided for in sufficient amount.

The characteristics of concentrate feeds

• have low crude fiber content
• have high protein and carbohydrate contents
• are highly palatable to animals
• have high digestibility
• mainly derived from grain and their byproducts
• have low moisture contents
• have fairly constant food value

The factors that should be considered when formulating a ration for farm animals

• The nutrient requirement of for the animals whose ration is being formulated
• The palatability or acceptability of the final mixture of the feed
• Availability of ingredients and their cost
• Health status of the animal
• Nutrient composition of the final mixture
• Physical nature of feed
• The wholesomeness of the food stuff. The final mixture should not harmful to the animals
• Age of animal i.e. young animal requires high proportion of proteins
• Level of production for instance milk cattle and layer require high proportion of calcium.
• Type of animal for instance ruminant can digest cellulose

Nutrition and metabolic disorders in livestock

Milk fever

Causes

It is caused by insufficient calcium in the diet

Symptoms

• Loss of appetite, poor GI tract movement, and cold extremities
• Excitability, nervousness, hypersensitivity, and tremors
• Weakness, weight shifting, and shuffling of hind feet
• Inability to stand
• Coma and death if not quickly treated.

Control and treatment

• intravenous or subcutaneous injection of calcium gluconate
• giving calcium, vitamin D and phosphate supplements

Grass tetany (grass stager/hypomagnesemia)

Caused by magnesium deficiency

Symptoms

• The animal becomes nervous suddenly
• Twitching of muscles especially those around the head and the neck
• The head of animal is lifted high
• Accelerated respiration
• Over salivation followed by death

Treatment and control

Provide magnesium in the diet

 

Bloat

Causes

Accumulation of gases in the rumen due to fast fermentation of young succulent grass with high moisture content especially in some animal susceptible to bloat

Symptoms

• Loss of appetite
• Distention of the abdomen,
• Feeling fullness, pressure, uncomfortable/distress
• Rectal protrusion.
• Difficulty breathing due to pressure on the diaphragm.
• The animals stands with its legs spread wide apart and its head extended forward
• The animal lies down and fails to stand up due to distress.

Control and treatment

• control the amount of succulent feeds and younger pastures fed to the animals
• carry out drench using any vegetable oil
• use stomach tube to release gas from the stomach
• drenching using anti-bloat drugs, cooking oil or beer to stop production of acids
• use of trocar or cannula to puncture the lumen to allow escape of gases
• exercising the animal
• Use of broom stick method i.e. wooden rod is inserted across the mouth to keep the mouth open to allow escape of gases from the rumen
• avoid giving the animal cassava, excess grain and protein concentrate

Piglet anemia

Caused by iron deficiency in mothers milk

Symptoms

• Ears and belly of piglets become pale
• Body weakness
• Pale mucus membrane
• Rapid breathing

Treatment

• Inject with iron solution after birth
• Give mineral supplements rich in iron/anthill soil to the mother and piglet

Ketosis (acetosemia /pregnancy toxaemia)

Caused by high production exceeding feeding capacity leading to low glucose levels in the blood

Symptoms

• Emaciation
• Hypoglycemia
• Drop in milk yield in lactating animals
• Walking in cycles
• Apparent blindness
• Increased keto acids in blood due to malfunctioning of the liver

Prevention

• Adequate and proper feeding

Curled toe paralysis ( peculiar lameness)

This occurs in poultry due to insufficient vitamin B2 (riboflavin) in the diet

Symptoms

• Poor growth of feathers in chicks
• Retarded growth of chicks
• Diarrhea
• Poor hatchability

Control

Provide diet rich in vitamin B2

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Dr. Bbosa Science