Dairy farming case study

1. Dairy farming case study

2. Learning objectives • To recognise that the farmer considers the health and • welfare of the dairy cows during different aspects of • farming. • To recall the key stages in milk processing and • Cheddar cheese production.

3. Dairy farming in the UK The population of the UK drinks around five billion litres of milk each year, the equivalent of 2,000 Olympic sized swimming pools. This is an average of 1.6 litres of milk each week. In addition, seven billion litres of milk is used in the production of dairy products such as cheese, butter, yogurt and dried milk powder.

4. Dairy farming: case study For three generations a family have farmed dairy cows and produced Cheddar Cheese in the West country. On this farm, each cow produces about 7,000 litres of milk per year, which in total supplies the cheese dairy with just over 7 million litres of fresh milk to be made into traditional farmhouse cheese. This volume of milk equates to an annual cheese production of 6,000 tonnes.

5. Life cycle on a dairy farm The production of milk requires dairy cows to be in lactation, producing milk, to do this she must have given birth to a calf. The cycle of calving, lactation, insemination and pregnancy, then a ‘dry’ period, tends to work in 12 month cycles. The ‘dry’ period is similar to an adult going on maternity leave, where the cow will rest and prepare for the birth of her calf. Dairy farms are reliant on the production of calves for the production of milk.

6. Cow housing Like most dairy farms across the UK, the cows on this farm graze outdoors during the summer and are housed during the winter. This farm uses a cow shed with a free stalls system, with individual beds for each cow. Elastic stall segregation is used to prevent cows from harming themselves. The cows are able to rest, stand and move around freely.

7. Animal health and welfare Herd health checks are carried out regularly and the farmer works closely with a veterinarian and animal nutritionist to ensure the highest quality of health and welfare for the dairy cows. Each dairy cow also has an animal passport identifying the origin of the cow and any other locations it has been transported to.

8. Milking The cows come in from the fields or the barn into the collecting yard twice a day. From the yard a number of cows are taken into the ‘herringbone style’ milking parlour.

9. Milking The herdsman or farmer firstly uses a clean paper towel is to wipe each udder. Foremilk is stripped. This is where a little bit of milk is squeezed from each teat to ensure the milk looks clean and healthy. One cup (flexible rubber) is applied to each teat from the cluster. The vacuum draws the milk from the udder, in a similar fashion as a baby calf's mouth massaging the teat.

10. Milking To prevent over milking the cluster automatically detaches itself. The udders are checked by hand to ensure the cow has been milked out properly. Antibacterial spray is applied to each teat to prevent infection, such as mastitis, and keep the skin healthy. Once the cows in that row have been milked, they are let out of the parlour to go and eat and drink.

11. Milk storage The lift pump draws the milk through large diameter stainless steel piping into the dairy. The milk passes through a plate heat exchanger to reduce the temperature of the milk to between 1-4 ºC before being stored in a refrigerated bulk tank.

12. Transport A milk tanker calls at the farm daily or every other day to collect the milk. The driver checks the temperature of the milk before transporting it to the processing dairy. This farm will process the milk to produce cheese in a factory on the farm. Other farms will transport the milk to a processing dairy further away.

13. Selection: Production and processing Select a product to investigate. Milk Cheese

14. Pasteurisation Pasteurisation is a process used to kill harmful microorganisms, such as certain pathogenic bacteria, yeasts and moulds, which may be present in the milk after initial collection. This process extends the shelf life of milk. The basic process for whole milk involves heating the milk to a temperature of no less than 71.7ºC for 25 seconds. This process is known as High Temperature Short Time (HTST). The milk is then cooled for packing, storage and transportation.

15. Homogenisation Homogenisation of milk involves the milk being pumped at very high pressures through narrow tubes, breaking up the fat globules in order for these to disperse through the liquid. This process produces milk of a uniform composition and palatability, without removing or adding any constituents. Most milk available for us to purchase is homogenised.

16. Packing The milk is then packaged into bottles and labelled. The packaging helps to increase the shelf-life of the milk.

17. Selection: Production and processing Select a product to investigate Milk Cheese

18. Delivery and pasteurisation In this cheese factory, up to 25,000 litres of milk can be delivered from dairy farms at any one time. The milk is unloaded and literage is checked before the milk is transferred into silos.

19. Pasteurisation The first process the milk goes through is pasteurisation. Pasteurisation reduces the number of spoilage microorganisms and provides a good environment for the starter cultures to grow. Milk is cooled in a vat after pasteurisation to 32 °C, an ideal temperature for the starter culture to grow.

20. Curdling A starter culture, similar to freeze dried natural yogurt, is then added to the pasteurised milk. This begins to acidify the milk. The curlding step allows the bacteria to grow and begin fermentation. Rennet, an enzyme that acts on the milk protein caesin, is added and the milk coagulates, forming lumps. The milk is mixed and then left to settle, while the junket forms, where the milk curdles and separates into curds and whey.

21. Cooling tables and draining whey The curds and whey run from the cheese vat onto the cooling tables. The cooling tables are used to: 1) cool the curds and whey; 2) separate the curds from the whey. The whey is drained off for further processing where cream is removed from the whey by centrifuge and made into butter. Protein is also extracted from the whey for different ingredients. In addition, lactose is removed from the water and then used for animal feed.

22. Cheddaring The mixture is moved around on the cooling tables allowing the whey to drain out through a central perforated channel. As the liquid is drained off a solid mass is created, called curd mats.

23. Cheddaring The curd mats are cut into sections and piled on top of each other and turned periodically. This step is called ‘cheddaring’. The protected name is West Country Farmhouse Cheddar and the conditions are that it is made in the four Counties (Cornwall, Devon, Summerset, Dorset), on a farm, using in part or whole milk produced on that farm supplemented where necessary by other locally produced milk, cheddaring by hand, matured for at least 9 months.

24. Salting Around 1,900 kg of cheese can be made on the cooling table within an hour. The curd pieces are fed into a mill and sliced into pieces about half the size of a thumb. This ensures the salt can be uniformly mixed throughout the curd. Salt is added to act as a preservative and prevent the cheese from going rancid during the maturing process. It also adds flavour to the cheese.

25. Cheese blocks The mixture is then taken into a six metres high tower to form rectangular shaped cheese blocks, weighing 20 kilograms each. After confirming the weight, these blocks are individually identified, ensuring traceability. Following this, the blocks are vacuum packaged and encased in six or seven wooden boards. They are then taken to the cool room and are chilled to a temperature of 10-12°C.

26. Cheese ripening In the cool room, acidification of cheese continues at a much slower rate during this period known as ripening. When it is time to select the cheese, the grader decides which cheeses are the best eaten young and which should be left to ripen (for up to 18 months) developing the special features and flavours associated with West Country Farmhouse Cheese.

27. Cheese packaging The final stage in cheese production is slicing and packaging. The cheese blocks are then cut into specific sizes, packaged and labelled. These products are sold via retailers large and small throughout the UK, as well as in the farm shop.

28. By-products from the farm In addition to the cheese, there are other products produced on the farm. The male calves are kept to form a herd of beef animals supplying quality meat to the farm shop. Arable crops, including wheat, barley, oats, oilseed rape and maize is grown. Some of the grain is used to feed the stock, such as dairy cows and pigs, while the rest is sold. Pigs are fed on whey from the cheese production and cereals grown on the farm.

29. Slurry lagoon The farm has a slurry lagoon which stores the slurry, a mixture of dairy cow manure and the water used to wash out the cow barn. This is used as fertiliser and spread over the fields at certain times of the year. The fields are used for grazing or growing crops such as wheat and barley.

30. Acknowledgement: Lye Cross Farm For further information, go to: www.foodafactoflife.org.uk