Milking systems for dairy Cows
Hand milking
It is suitable for small herd size. It is of three types.
- Stripping: Holding the teats between thumb and forefinger and drawing it’s down the length. This Process to be repeated in quick succession. Both the hands are used for holding different teats and stripping down alternately.
- Full hand milking: Whole teat is held first with the thumb and the index finger encircling the base of the teat. Teat is squeezed between the hollow of the palm and with the middle, ring and index finger. This process is repeated in quick succession. Full hand method is better than the stripping because it is quicker, produce natural suckling stimulation by the calf and causes less irritation to teat by repeated sliding of fingers on teat.
- Knuckling: Many milkers tend to bend their thumb against the teat canal and drag the milk out. This practice should be avoided as it is injurious to the teat
Machine milking
In large dairy farms machine milking is more suitable than hand milking because milking consumes maximum labour hours. Machine milking ensures comparatively clean milk production. Animals are milked smoothly and quickly and in uniform way thus increases milk production thereby income. It requires less time for milking a large number of milk animals. Milking machines work on the principle of vacuum.
Basic components of milking machines:
- Vacuum system: vacuum pump and reserve tank, vacuum regulator, pipelines and long pulse tube(s) forming an enclosed space.
- Pulsators: that alter the vacuum level around the teat so that milking occurs without fluid congestion and edema of the teat tissues;
- Milking units or cluster: The assembly of four teat cups connected to a claw and mounted with a valve that admits and cuts off the vacuum to the unit.
- Milk removal system that transport the milk away from the milking unit toward a storage unit: the milk tube and receiver (bucket, recorder jar, milk pipelines, milk pump, etc.)
Portable milking machine system
It is ideal for small herds (upto 20 cows). It can be used when the use of static milking machines is not possible (in the field or barn) or while attending agricultural shows, if the size of herd is small and for sick animals in remote pens. It can also be used in the fields with no electricity as a diesel engine may be attached.
Milk is collected in a stainless steel bucket for further transportation. Options with one or two buckets are available and portable milkers come with one or two clusters. All parts are mounted on a lightweight trolley which can be easily transported and requires minimal maintenance.
Recommended vacuum level for milking a cow with a portable milker is 48-50 kPa and the pulsation rate is set to 60 ppm with ratio 60:40.
Barn Milking System
Barn milking systems are installed on the farms where the cows are kept tied in their cubicles. The milking takes place at the place where the cow is standing. The milking is carried out using a portable milking unit which provides pulsation and delivers vacuum to the teat end.
The milking unit is plugged into the milking station fitted on the milk line. One milking station is usually installed for every two cows. The milk then flows to the milk receiving set. From the milk receiving vessel the milk pumped into the milk cooling tank.
Cleaning-In-Place automated washing system can be installed for efficient cleaning after milking. Good quality washing is achieved using a water slug technique. This water slug is created in the milk line by the air injector valve. The system is easily scalable. A separate milk and vacuum line loop is installed for every 50 cows in the barn.
Milking Parlour System
- Herringbone milking parlour
Named herringbone as the linear layout and angle of the stalls mimic the shape of the backbone of the herring fish. Cows enter in single file, and line up almost perpendicular to the central passage on both sides, facing outwards. After washing the udder and teats the cups of the milking machine are applied to the cows, from the rear of their hind legs, on both sides of the working area. There will be one milking control for each stall. Large herringbone sheds can milk up to 600 cows efficiently with two people. Typical sizes range from a Double 8/8 through 20/20 which means an identical number of stalls on each side of the parlour. The stall angle ranges from 30 to 90 degrees.
- Swing-over milking parlour
Swingover parlours are the same as herringbone parlours except they have only one set of milking cups to be shared between the two rows of cows, as one side is being milked the cows on the other side are moved out and replaced with unmilked ones; with the notation 8/16 or 20/40. The swingover style uses half the number of milking controller as one control is used for both sides of the parlour. It is a cheaper option to a doubled up parlour.
- Rapid exit parallel milking parlour
The Rapid Exit stall work is growing in popularity as they allow fast throughput by locating the exit gates in front of the cow stall. Also the building does not need to be long as for herringbone, but needs to be wide. The vacuum operated gate lift allows cows to exit en-mass and aids fast reloading of the stalls.
- Rotary milking parlours
With growing herd size the efficiency of the herringbone parlour is reduced when the size goes beyond 20 points per side due to the length of the parlour. The most efficient parlour for the large herd is the Rotary Platform parlour. A turntable with about 12 to 100 individual stalls for cows around the outer edge. The turntable is turned by an electric-motor drive at a rate that one turn is the time for a cow to be milked completely.As an empty stall passes the entrance a cow steps on, facing the centre, and rotates with the turntable. The next cow moves into the next vacant stall and so on. The milker, cleans the teats, attaches the cups. The milker, or an automatic device, removes the milking machine cups and the cow backs out and leaves at an exit just before the entrance. The rotary system is capable of milking very large herds: over a thousand cows. It allows for only 2 operators to milk 250 cows per hour on a typical 60 point platform.
Automatic Milking Systems (AMS)
It involves complete automation of the milking process. AMS has been available commercially since the early 1990s. Most farms with AMS located in the Netherlands and Denmark. Milking unit consists of a milking machine, a teat position sensor, a robotic arm for automatic teat-cup application and removal, and a gate system for controlling cow traffic. Typical capacity for a AMS is 50-70 cows per milking unit. AMS usually achieve milking frequencies between 2 and 3 times per day, so a single milking unit handling 60 cows and milking each cow 3 times per day has a capacity of 7.5 cows per hour. When the cow elects to enter the milking unit (due to highly palatable feed that she finds in the milking box), a cow ID sensor reads an identification tag on the cow and passes the cow ID to the control system. If cow has been milked too recently, the automatic gate system sends the cow out the unit. If the cow may be milked, automatic teat cleaning, milking cup application, milking, and teat dipping takes place.
Advantages of Automatic Milking Systems
- Elimination of labour: The farmer freed from the milking process and associated rigid schedule, and labour devoted to supervision of animals, feeding, etc.
- Increased milking frequency: Milking frequency may increase to three times per day, however typically 2.5 times per day is achieved. Resulting in less stress on the udder and increased comfort for the cow, as on average less milk is stored.
- Perceived lower stress environment: There is a perception that elective milking schedules reduce cow stress.
- Herd Management: The use of computer control allows greater scope for data collection helping the farmer to improve management through analysis of trends in the herd, for example response of milk production to changes in feedstuffs.
Individual cow histories may also be examined, and alerts set to warn the farmer of unusual changes indicating illness or injury.
Disadvantages of Automatic Milking Systems
- High initial cost
- Increased complexity
- Difficult to apply in pasture systems
- Lower milk quality: higher Somatic cell count (SCC) than conventionally milked herds.
- Possible increase in stress for some cows: Cows are social animals, and it has been found that due to dominance of some cows, others will be forced to milk only at night.
- Decreased contact between farmer and herd