DAIRY MANAGEMENT
The main reason why most farmers keep dairy cattle is the production of milk among others. Milk is the white nutritious liquid produced by a cow (lactating animals) after successful parturition. Usually after calving, the stomachs of these calves are not fully developed and largely depend on this liquid until when solid foods are introduced.
The lactating cow produces milk from the time of calving down to the period of drying off. A good cow should produce adequate amounts of milk during the lactation period. In order to produce enough milk, for a long time, the cow must be fed well and managed well.
Characteristics of a Good Dairy Breed.
• It is wedge-shaped that is thin at the head and wide at the rear.
• Having a pronounced milk vein such that there is a good supply of blood to the udder.
• Well spaced teats which are long enough.
• Well attached udder (not pendulous).
• Should have even sized teats.
• Large capacity of udder.
• Should be docile (have good temperament).
• Have a long lactation period.
• Should be able to produce a lot of milk.
• The teat orifice should not be large.
Benefits of Dairy Farming.
• The farmers will have a stable source of income and employment for the family.
• Cattle are able to convert fibrous materials which would be useless into high feed value products like milk and meat.
• They are more efficient producers unlike beef cattle, pigs or poultry.
• Source of farmyard and manure.
• After their production period, they are fattened to produce good quality beef.
Limitation of dairy farming.
1. High labour requirements
2 Requires a lot of capital investment.
3 Milk is highly perishable.
4 Calls for plenty of skills, knowledge and modern equipment.
5 Risk levels are high.
Milk composition
The composition of milk in any dairy cow is largely determined by many factors such as breed, season of the year, type and amount of feed, stage of lactation and temperament. Milk is composed of water, fats, proteins, sugars, minerals and vitamins.
The percentage composition in any breed is approximately;
Water 87.6%
Minerals (ash) 0. 7 %
Proteins 3.2%
Fats 3.7%
Sugar 4. 8 %
Proteins , mainly casein, are formed by combining amino acids, sugar ( lactose ) formed from two simple sugars glucose and galactose and fats formed from glycerol and acetic acid.
Qualities of Good Milk
• Good milk has a good flavour.
• Clean without foreign materials.
• Good keeping quality can stay for a long time without going bad.
• Safety to the consumer such that it has no germs to caused disease to man for example Tuberculosis.
• Nutritious containing all food values.
Why Milk is highly perishable
1. Contains fats which easily go rancid.
2. It contains many nutrients essential for multiplication of a wide range of micro-organisms.
3. Contains a lot of water.
4. Can easily absorb smell from the surroundings.
5. It contains fat, which easily goes bad.
6. It readily absorbs smell and bad odours.
Factors affecting milk yield and composition
1. Breed of the animal: - Friesians produce more milk with low butter fat while Zebu produces less milk with more butter fat.
2. Age of the animal: - Milk yield tends to increase with age up to either lactation. It remains steady until 10th lactation, after which it begins to decline.
3. Period of lactation: - Milk yield increase until the seventh week after which it begins to decline.
4. Health of the animal: - Healthy animals, as a opposed to diseased animals produce high quality and quantity of milk.
5. Temperament of the cow: - Quiet animals are the best milkers. Nervous cows and those that kick about produce less milk.
6. Feeding of the animal: - Proper balanced feeding leads to production of good quality and quantity of milk.
7. Season of the year: - Cows tend to produce more milk of better quality in rainy season compared to dry seasons, apparently due to presence of young slushy pastures.
8. Oestrous (Heat period):- Oestrous usually causes a slight restriction in milk yield and composition.
9. Handling of the animal during milking: - Gentle treatment of the animal during milking ensures high milk production.
10. Frequency of milking: - The more times the animal is milked per day, the higher is the milk yield.
Pasteurization and sterilization of milk
(a) Pasteurization
Its the process of killing micro-organisms in the milk by heating at controlled temperatures that do not considerably change the natural characteristics of the milk.
Objectives of pasteurization
- To reduce the milk micro-organisms to a safe level without destroying the nutrients.
- To increase the life or keeping quality of the milk.
Systems of pasteurization
1. Low temperature holding process (LTH):- it involves heating the milk to above 62oc and holding it there for about 30 minutes, then rapidly cooling it to 10oc.
2. High temperature- short term process (H.T.S.T):- milk is heat to above 30oc and held there for about 155 before rapidly cooling it to 10oc.
(b) Sterilization
It is the process of making milk completely free of micro-organisms by heating to very high temperatures. In this process, the quality of the various nutrients such as protein, vitamins and minerals is considerably reduced.
Methods of sterilization include
1. In bottle process: - The milk is heated to above 110o for about an hour.
2. Ultra high temperature process (U.H.T):- Milk is heated to about 150oc for 20seconds then immediately placed in completely sterilized bottle.
Milk products include cream, cheese, butter, yoghurts and ghee.
Milk synthesis, secretion, Letdown and Hold up
.
Milk Synthesis.
Milk of the constituents of milk come from the food the cow eats. These raw materials such as amino acids, sugars and glycerols are brought to the udder by blood vessels. The udder has secretary cells found in the alveolus and it is where materials are assembled into milk. The whole process is known as milk synthesis.
Milk secretion
Milk secretion (lacto genesis) begins some few months before calving. This is usually during the steaming up period. Milk secretion takes place in the udder under the influence of prolactin hormone controlled by the anterior pituitary gland. Notably a fall in the body level of progesterone initiates milk secretion and it happens just prior to parturition.
Milk secretion is the release of milk from the secretory cells, into the alveolar cavity, to the duct and then gland cistern. This is controlled by the luteinizing hormone. (L H) Secreted by the anterior pituitary gland.
As the process of digestion and absorption take place, more raw materials are brought to the udder by blood vessels. Therefore milk has to be removed from the alveolar cavities and gland cisterns during the process of milking. This ensures constant milk secretion. The more times the cisterns are emptied, the more milk will be synthesized.
The udder comprises of four quarters each independent of the others and is drained by its teat. It is supported onto the body by strong ligaments and abdominal muscles. The left quarters are separated from the right ones by the medial suspensory ligament. The secreting glands are surrounded by blood capillaries therefore well supplied with constituents of synthesizing milk. In the middle they open into tiny spaces called alveoli and these are lined by cells which secrete the milk.
The various alveoli converge into small ducts then eventually larger mammary ducts which open into the udder or gland cistern. The teat is connected to the gland cistern. At each convergence point is a sphincter muscle which holds milk until a stimulus occurs to the cow.
Qualities of a Good Udder
A good Udder has;
1. Four- well developed spaced teats.
2. Should be soft to touch.
3. Should be big enough to hold more milk.
4. Should not be liable to injection.
The udder
Materials that include proteins, vitamins, fats, urine, simple sugars and water are delivered through the blood to the alveolar cavity. The milk secreting cells limit alveoli extract these materials from blood and combine them through a sequence of biochemical process to provide milk.
Abnormalities of the udder.
1. Blood stains in milk usually due to mastitis.
2. Udder inflammation due to bacteria infections like mastitis.
3. Congestion; udder swells before calving as well as when milking is skipped.
4. Milk letdown failing especially in newly calved heifers.
Milk letdown and hold up.
Milk held in the alveolar cavity and ducts has to move down to the cisterns. The down ward flow of milk from the alveolar cavities, mammary ducts, into the gland and teat cisterns is known as milk letdown.
Milk let down is controlled by the hormone oxytocin, secreted by the posterior pituitary gland. In order for oxytocin to be produced, the animal has to be stimulated. The stimulus can be any of the following;
• Washing and massaging the udder with warm water.
• Sight of calf at milking time.
• Approach of milking time.
• Provision of feeds at milking time.
• Sucking by the calf.
• Noise made by knocking of milking utensils.
• Attachment of teat cups onto the teats.
When any of these happens, a massage is sent from the udder to the brain and the posterior pituitary gland secretes oxytocin hormone into the blood stream. Oxytocin is pumped to the udder and the effects are the contraction of udder muscles surrounding the alveoli and dilation of the annular fold.
Effects of oxytocin in the udder
(i) It contracts the alveolar muscles thereby forcing milk through the ducts down to the a stems.
(ii) Stimulates the production of more milk by alveolar cells.
N.B Influence of oxytocin lasts for about 7 minutes thus milking should be done very fast within this time limit.
Milk hold up
However, it is worth noting that once the animal is excited, the opposite occurs, that is, milk hold up. Milk hold up is a situated whereby milk letdown is stopped due to the secretion of a adrenaline hormone by the a adrenal gland. Poor handling during milking such as unusual noise, pain due to poor milking techniques and beating, lead to milk hold up(the prevention of down flow of milk from the udder In other words, Udder conditions of excitement such as rough handling, strange sound or otherwise, a hormone called adrenalin is produced by the adrenal gland. Adrenalin contracts the muscles of the annular fold thereby preventing the release of milk from the udder.
Thus, for adequate milk yield, its advisable to have a gentle and quite handling of the animal during milking.
N.B:- Adrenaline opposes the influence of oxytocin.
Clean milk production.
Milking is a daily routine carried out on a dairy farm. Milking is the process of removing milk from the gland cistern and teat cistern into a container. It can be done by hands or machines. The milking process can conveniently be divided into the following stages;
(a) Preparation of the milking shed and milking utensils.
(b) Preparation of the cow.
(c) Preparation of the milker
Preparation of the milking shed and milking utensils..
• The milking shed should be scrubbed clean before actual milking starts and allowed to dry.
• In case of machine milking, the teat cups and milk storage tank should be washed clean.
• Also ensure that the whole milking machine is in good working condition.
• The feed trough should be cleaned and later filled with concentrate feeds..
• Any material that can taint milk should be removed from the shed.
• The milking utensils such as pails, churns, strainer and strip cup should be washed clean and any dust removed.
• The utensils should be within easy reach.
Preparation of the cow.
• Animal should be allowed to assemble within the milking area in a good time. This allows them to settle down.
• The hind legs are tied with the help of a milkers rope and the udder washed with warm water mixed with a disinfectant.
• The udder is then wiped dry with a clean disposable towel
• The hind quarter is brushed or groomed to remove loose hair or dust.
Preparation of the milker
The milk man / woman should do the following before milking starts.
• Wash hands with soap and dry them with a towel.
• Cut his / her finger nails clean.
• Put on a cap
• Should be healthy and not suffering from infectious diseases such as tuberculosis and typhoid.
Procedure of clean milk production
In order to produce clean hygienic milk on the farm, the following procedures should be followed.
1. Ensure that the milking par lour or shed is cleaned before milking starts.
2. The milking utensils should be washed with a disinfectant and sterilized in the sun to kill germs.
3. Healthy cows which are free from mastitis should be milked.
4. The milker should wash his / her hands and dry them before milking.
5. The milker should cut his or her finger nails short.
6. The milker should put on clean clothes.
7. The milker should put on a clean cap.
8. The udder of the cow is washed with warm water mixed with a disinfectant and dried with clean towel which is disposable to prevent the spread of mastitis.
9. The hind quarters are brushed to remove loose hair and dust
10. Feeds are put in the trough so that the animal is not excited while being milked.
11. A few streams of milk are drained from each teat into a strip cup to detect mastitis. Animal with mastitis should be milked last and their milk poured away. Draining helps to get rid of first milk which has many bacteria and is also known as stripping.
12. A milk salve (jelly) is smeared onto the teats to reduce friction and cracking of teats.
13. Use clean utensils to avoid contamination of milk.
14. Use milking utensils with smooth inner walls for ease of cleaning.
15. Use aluminum or plastic utensils to avoid contamination.
16. Do not feed cows on silage before and during milking to prevent tainting of milk.
17. Filter milk after milking to remove foreign materials such as flies or hair.
18. Cover the milk well to prevent dust and flies from falling into the milk.
19. Keep milk in a cool place to reduce the multiplication of micro organisms. Where possible, milk can be boiled and allowed to cool down.
20. Wash all the utensils used in the milking process with a disinfectant and put them under the sun to dry. They should be dried on a rack while facing upside down.
21. Keep utensils in a clean store upside down to prevent dust/ dirt settling in them.
22. Scrub the shed clean.
23. Record the milk produced in litres.
Reasons for using a strip cup.
• To detect mastitis in milk.
• To remove milk in Beef Fat content before actual Milking.
• To remove milk high in micro-organisms usually found in the teat cistern.
Activity one.
• Visit a near by farm or go to a school dairy unit and participate in preparing clean milk production.
• Prepare the milking shed and utensils.
Methods of milking.
There are two methods used to remove milk from the udder of the cow and these are; Hand and machine milking.
Hand milking;
The milker squatrts and ties the hind legs with a milkers rope, washes the udder with warm water and dries it up with a clean towel. He then applies the teats to avoid cracking.
The thumb finger is placed along the teat and the index finger closes the top of the teat. Then pressure is exerted on the teat by squeezing the teat rhythmically.
Milk trapped in the cistern is drawn down words into the container.
Avoid pulling the teats during milking as may lead to milk holdup.
The system is quite slow, inefficient and tiresome.
Its however cheap, easier to practice and facilitates easy control of mastitis.
Machine milking involves the use of a milking machine.
Advantages
- Its so quick and works within the influence of oxytocin.
- It improves on quality and quantity of milk produced on the farm.
- It requires less labour.
- Theres easier handling of livestock.
Disadvantages
- The purchase and installation of the machine is very expensive.
- The operation of the machine requires technical know how.
- It can lead to a high incidence of mastitis on the farm.
- Power failure can greatly affect the milking process.
- A faulty machine may cause injury to animals.
Activity two
Visit a near by farm and dry to practice hand milking.
Machine milking
A milking machine is common equipment on large dairy farms where hand milking may be possible. A milking machine is composed of vacuum supply unit, the pulsator, the vacuum controller, the teat cup liner and milk receiving unit.
Vacuum supply creates vacuum within the entire system and this is the principle on which the machine works. When the teat cups are put on teats, re put on the teats, the vacuum pump creates a vacuum inside the rubber teat cup liners as well as between the rubber liners and the metal shells. As a result, the vacuum created holds the teat cups in place the teat canal opens up and milk flows out.
The pulsator dries air atmospheric pressure into the chamber between the rubber liner and the metal shell. The air is then drawn into the vacuum system. The pressure created massages the teat and draws milk from it .differences in air pressure occur during pulsation between the vacuum level within the liner and the normal air pressure outside the liner and this causes it to shrink.. The end result is the re- establishment of the vacuum level and milk is drawn from the teat canal. This is the actual milking phase. When massaging is not properly done by the teat liner, injury to the teat is likely to occur.
In order to avoid injury to the animal. The pulsation ratio ( Pr) should be set according to the manufacturers instructions. PR is the time the inflation is in the milking phase compared to the resting phase. The vacuum controller is a valve in the vacuum supply unit, which performs the following during milking.
1. Regulates the amount of air in the vacuum level so that it is not high or low. Too high vacuum causes injury to the teats and at a low vacuum level, milking will be slow and teat cups will fall off.
2. The milking unit is made up of four teat cups, pulse tubes and milk collecting tubes. The teat cups are attached on to the on the teats and once the machine is switched on, there is synchrony between the vacuum supply unit and pulsator. If the machine is in good working condition, milking will start (that is resting phase and milking phase)
3. Milk receiving unit. It is made up of glass and calibrated. Milk is directed through the milk line via the pump into the milk storage tank.
Machine milking has the advantages of clean milk production, saving labour and it is quick. However, costs of installment are high, faulty machines can injure the animals, there are higher chances of mastitis spread through teat cup and power failure can affect milking.
Milking Techniques
• Before milking starts, wash the udder with warm water, dry it with a towel and provide the cow with dairy meal.
• Tie the hind legs with a milkers rope.
• Wash hands and dry them with a clean towel.
• Squat or sit on a milkers stool on the side of the cow near the udder.
• Apply milk salve on the teats, do not use water, milk or saliva to lubricate the teats
• Rinse your hands with clean water.
• Draw streams of milk from each teat into a strip cup to detect mastitis. Animals with mastitis should be milked last and milk poured away.
• Place the thumb finger along the teat and index finger above the teat and squeeze rhythmically downwards. Avoid pulling teats.
• Milk quickly but gently within 5-8 minutes to maximize the effect of Oxytocin.
• Strip the udder to get the last milk by massaging the udder quarters as far as possible progressively and squeezing out the milk.
• Avoid exciting the animal during milking.