|SYSTEM OF MILKING HAND MILKING is a labour intensive system in which capital investment, running costs, labour productivity and milking performance are minimal. Clean milking clothes, buckets, udders and hands are essential for good hygienic quality milk.|
|COOL the milk by immersing the cans of milk in clean, running water or by inserting an in-can turbine cooler. Alternatively, use a corrugated surface cooler connected to the water supply.|
|CLEAN the milking bucket and cooler by rinsing in clean water, scrubbing in hot (≥45°C) detergent/ disinfectant solution and finally rinsing in chlorinated (50 ppm) water. Alternatively, after scrubbing in hot detergent solution, disinfect by immersion in hot (≥75°C) water for at east 3 minutes. Afterwards treat ancillary equipment similarly and allow all equipment to drain dry in a clean place.|
SYSTEMS OF MILKING
Statistics from all major milk producing countries indicate an annual decline in the number and size of hand milked herds. Labour productivity in these herds is low with very few cows per person involved. Duration of milking each cow and the whole herd is protracted because each person milks cows one at a time with a relatively slow milk extraction rate compared with machine milking. These are factors which contribute to lower average lactation milk yields in hand milked herds. Nevertheless, for small herds, hand milking will usually be the method chosen because where there is sufficient labour available it can provide a satisfactory way of milk removal with minimal capital investment, equipment maintenance and cleaning.
During milking, hygiene standards require clean milking clothes and hooded milking buckets to prevent dust, dirt and udder hairs falling into the milk. Udders and tails need regular clipping. Before milking begins the foremilk is drawn and examined and visible dirt removed from udders and teats by washing and drying with disposable paper towels. Milk with clean, dry hands using the full hand in preference to just finger and thumb, a practice which can lead to misshapen udders and teat injury. It is best to milk rear quarters first as they contain the higher proportion of milk.
Milk cooling methods will depend mainly on the local water supply. If the quality, quantity or temperature are unsuitable or unreliable, then the milk should be taken, within 3 hours of production, to a central depot for cooling. Where an unlimited free supply of clean, cold (below 15°C) water is available, the cans of milk can be immersed in running water. Water usage can be reduced and cooling rate increased by inserting a turbine in-can cooler into the cans of milk. Alternatively, the milk may be tipped and allowed to flow over a corrugated surface cooler connected to the water supply.
Cleaning the milking bucket and cooler is best done by an initial rinse in clean water immediately after milking, followed by scrubbing in a hot (45°C or above) detergent/disinfectant solution before finally rinsing in chlorinated water (50 ppm). Alternatively, after scrubbing the equipment in hot detergent solution, disinfect by immersing it in hot (above 75°C) water for at least 3 minutes. The foremilk cup, stool and udder washing equipment should be treated similarly afterwards. All equipment must be drained dry during the interval between milkings. (See page for further details).
|BUCKET MACHINE MILKING was developed to mechanise cowshed milking. The units and ancillary equipment are carried from cow to cow and the milk transported, lifted and tipped manually. Therefore, although each operator uses 2 or 3 units, the system is laborious, restricting milking performance to about 30 cows per hour unless a trolley is used to enable an additional unit to be used.|
|COOL the milk either by inserting an in-can turbine cooler as soon as the milk cans are full or by carrying the milk to the dairy and pouring it over a surface cooler. Cooling efficiency can be improved and water saved by coupling the cooler to a chilled water unit.|
|CLEAN the milking equipment and cooler by rinsing in clean water, scrubbing in hot (≥45°C) detergent/disinfectant solution and finally rinsing in chlorinated (50 ppm) water. The ancillary equipment is treated similarly afterwards. Allow all equipment to drain in a clean place.|
Bucket milking machines were the first major development in the mechanisation of milking systems and were designed particularly for herds kept in cowsheds. Each portable unit, consisting of a 15 litre capacity lidded bucket, pulsator and teat-cup assembly or cluster, requires manual attachment to a vacuum supply when it is moved from cow to cow during milking. Milk is tipped from the buckets into milk cans positioned in the dairy (milk room) or in the cowshed. The system is mechanically simple with relatively low investment, running and maintenance costs compared with milking machines in parlours. Milking performance is restricted in terms of cows milked per hour by the amount of work that must be carried out on each cow (the work routine). A high proportion of time and effort is spent walking from cow to cow and manually carrying equipment and transporting, lifting and tipping milk. (See page for further details). As a result, each operator is unlikely to be able to use effectively more than 2 or 3 bucket machine units and, consequently, will not milk more than about 30 cows per hour. A better performance will be achieved by using a trolley carrying the milk cans, spare milking machine bucket and udder preparation equipment. The trolley is moved along the cowshed as milking proceeds. The consequent reduction in time and effort will allow an additional unit to be used thus raising potential performance to about 40 cows per hour.
Milk tipped direct to milk cans during milking is cooled by inserting an in-can turbine cooler when the cans are full. Otherwise, it will be necessary to carry the buckets of milk into the dairy and pour the milk over a corrugated surface cooler coupled to the water supply. Both methods are equally effective although using a surface cooler is more laborious. In either case, cooling efficiency is improved and water requirements reduced by connecting the cooler to a chilled water unit.
Cleaning bucket milking machines and the ancillary equipment is a three-part manual operation using detergent/disinfectant solutions. Immediately after milking, visible dirt and milk deposits on the outside of the equipment are removed with clean, cold water. Each unit is then connected to the vacuum supply and 10 litres of clean water drawn through the teat-cups into the unit bucket. This initial rinsing is followed by scrubbing all the milking equipment (except pulsators and pulse tubes) in a hot (not less than 45°C) detergent/disinfectant solution using 45 litres per 3 milking units. Volumes of water and quantities of chemicals used must be carefully measured (see page for further details). Finally, the equipment is rinsed in chlorinated water (50 ppm) and allowed to drain dry in a clean place. Ancillary equipment is treated similarly afterwards.
|DIRECT-TO-CAN MILKING is a very simple, low cost system of milking, cooling and cleaning specially devised for abreast parlour milking. Milk is drawn directly from udder to milk can, eliminating milk lifting, carrying and tipping and thus enabling each operator to manage 4 or 5 milking units effectively.|
|COOL the milk by inserting an in-can turbine cooler connected to the piped water supply or to a chilled water unit.|
|CLEAN the equipment by removing visible dirt and deposits by rinsing in clear water, then loading the component parts (up to 3 units maximum) in a specially designed basket and lowering into a bin containing 3%–5% caustic soda solution which cleans and disinfects and also defats the rubberware. Before milking drain and remove all traces of solution by rinsing in chlorinated (50 ppm) water. Renew the solution monthly, adding EDTA to prevent hard water deposits. Caustic immersion cleaning can only be used with stainless steel clusters and lids|
About 1950, many herds increased in size and moved from cowsheds to abreast parlour milking. The direct-to-can milking system was devised to meet this change and, consequently, it is applicable to this particular parlour. Compared with bucket machines, the capital investment, running costs and labour input are lower. As a complete system of milking, cooling and cleaning it is very simple indeed.
Milk is drawn direct from the udders to the milk cans via a specially designed lid which connects the milk can to the vacuum supply. Manual lifting, carrying and tipping of milk is eliminated with a consequent improvement in milking efficiency and performance. Therefore, each operator is able to manage a 4 unit, 8 stall or a 5 unit, 10 stall abreast milking parlour effectively. When full, the milk can is replaced with an empty one and milk cooling may begin. Cooling milk produced with the direct-to-can system is done simply by inserting an in-can cooler into the cans of milk and connecting it either to a clean, cold water supply or to a chilled water unit.
Cleaning direct-to-can milking equipment also provides substantial economies in labour and other costs of cleaning using a method developed specifically for the purpose. In addition to being bactericidal the cleaning treatment prevents milk fat accumulation in natural rubber components. When milking is finished, all visible dirt and milk deposits are removed from the milking equipment by rinsing in clean water. Next, the component parts of each unit, namely, the stainless steel lid and rubber gasket, two long rubber tubes and a stainless steel teatcup assembly are loaded into a purpose designed steel-mesh basket (up to a maximum of 3 units). The parts are positioned in the basket in such a way as to avoid any airlocks when lowered into a rubber or mild-steel bin containing a 3% to 5% caustic soda solution. A rubber lid covers the bin and the equipment remains in the solution until the next milking when it is lifted out to allow surplus solution to drain back into the bin. Before use, the equipment is removed from the bin and all traces of caustic soda solution removed by thorough rinsing in chlorinated (50 ppm) water. At monthly intervals the solution is renewed and ethylene diamine tetra-acetic acid (EDTA) added at the rate of 60gms to 45 litres of solution to prevent hard water deposits. After each milking the cooler and ancillary equipment are cleaned in the way described for bucket milking machine (See page 93). SEE PAGE 42 FOR SAFETY PRECAUTIONS.
|PIPELINE MILKING is a high investment, low labour cost system, originally installed in cowsheds and milking barns but particularly suited to large and medium sized herds milked in parlours with bulk milk collection. Milk is transported direct from udder to refrigerated bulk milk tank for cooling and storage, and plant cleaning is done in-situ.|
|COOL the milk either by discharging it over a corrugated surface cooler, connected to the water supply or a chilled water unit, to gravitate to milk can underneath, or pump it direct from a milk receiving vessel to a refrigerated bulk milk tank in the dairy.|
The introduction of bulk milk collection and refrigerated milk tanks on farms, together with the development of large static and rotary parlours for milking big herds, gave an impetus to pipeline milking systems which hitherto had been installed in large cowsheds and milking barns. The main advantages are that the milk is transported under vacuum from udder to dairy for cooling and storage and the cleaning and disinfection of the milking equipment can be done in-situ with very little manual involvement. In addition, devices can be inserted into the milking pipeline to reveal clinical signs of mastitis, indicate the milk yield from each cow, allow samples to be taken and automatically remove the cluster when milk flow ceases (thus eliminating overmilking). Internationally agreed standards prescribe the minimal diameter of pipelines to enable the milk to be transported without adversely affecting vacuum stability at the cluster. These comparatively high investment, low labour cost systems are the only practical alternative for large and medium sized herds milked in parlours, particularly where bulk milk collection is involved. During milking, operator work routines can be reduced to assisting cow entry and exit, udder preparation and cluster attachment so that milking performances of more than 85 cows per manhour can be achieved.
Milk cooling can be done by discharging the milk over a corrugated surface cooler connected to the water supply or a chilled water unit and collecting it in milk cans underneath. Alternatively, the milk can be pumped direct from a milk receiving vessel to a refrigerated bulk milk tank or via a pre-cooler to an insulated milk storage tank.
CLEAN and disinfect the pipeline milking plant in-situ by first removing manually any visible dirt and milk deposits from external surfaces and making the necessary adjustments to form a complete circuit between milking and milk transfer pipelines. Recirculate hot detergent/disinfection solution when the initial hot water rinse reaches 65°C at the discharge point, for 10–15 minutes at 10–15 litres per unit. Finally rinse with chlorinated water at 50 ppm.
Alternatively, use a single, once-through circulation of near boiling water at 15–20 litres per unit, and maintain a temperature of not less than 77°C FOR AT LEAST 2 minutes. During the first 2–3 minutes of flow, entrain 1 litre of diluted nitric or sulphamic acid
Cleaning and disinfecting pipeline milking equipment in-situ can be manually controlled or automatic using sequence timers which initiate the selected programme. Both the two available methods begin with the manual removal of visible dirt and milk deposits. Simultaneously, adjustments are made to enable a complete circuit to be formed incorporating the milking and milk transfer lines. Recirculation cleaning is a three-stage process incorporating a hot water pre-rinse which is discharged to waste until the water at the discharge point reaches 65°C. Detergent and disinfectant is then added to the hot water and the solution re-circulated (at 10–15 litres per unit) for 10– 15 minutes. Finally, chlorinated water is circulated once and discharged to waste. Acidified Boiling Water (ABW) cleaning relies solely on heat disinfection. It consists of a single, once-through circulation of near boiling water (at 15–20 litres per unit), maintaining a temperature above 77°C on all milk contact surfaces for at least 2 minutes. During the first 2–3 minutes of flow 1 litre of dilute acid (70% w/w nitric acid or sulphamic acid crystals) is drawn into the boiling water to prevent deposition of hard water salts. Simple modifications are inserted into the pipeline circuitory to ensure a balanced flow of the hot solution at the desired rate to all milk contact surfaces. The refrigerated bulk milk tank is cleaned manually or mechanically.