Cow comfort: 15) Milking

Frequency

Milking twice a day in a milking parlour has long been the common practice in most countries. More frequent milking results in higher milk production if adequate nutrition is provided, but the general economic benefit is dependent on labour costs, milk prices, milk quota and other factors.

For cow comfort, the most ideal way of milking is by a robotic milking system. The cows can choose their own time for being milked and keep to their own daily rhythm. Cows milked automatically are often milked between two and a half and three times per day, but that varies from two to four times per day depending on the lactation period of the cow.

Changing from milking twice a day to milking three times a day has a marked increase on milk production. In addition lactation becomes more persistent and prolonged. The reason why milk production increases with a more frequent milking could be more frequent exposure of hormones stimulating milk secretion to the mammary gland. However, milk contains an inhibitor with negative feedback control on milk secretion. A more frequent removal of this inhibitor therefore results in higher production. An interesting finding in this respect is that cows with a small udder cistern are more sensitive to the frequency of milking. The smaller the cistern the greater the effect of frequent milk removal on milk production, while with larger cisterns there is less response to frequent milking.

Parlour stress

When a cow is not standing comfortably in the milking parlour, she will be stressed. Stress factors in the milking parlour include flies, slippery floors, bad ventilation, small stands and a restless milker. Cow reactions to parlour stress include not entering the parlour voluntarily, kicking off the milking cluster, defecating in the parlour or refusing milk let-down. Clearly it is very important for the farmer and the cow to be less stressed during milking. Good milking starts with good equipment and a consistent milking routine within a well ventilated, comfortable and safe parlour.

Production

To illustrate an individual cow’s milk production, we normally plot the yields against time to get the lactation curve. Milk yield will rise during the first months after calving, followed by a long period of continuous decline. The shape of the lactation curve will differ from individual to individual and from breed to breed. Feeding and management will also influence the shape and have a significant impact on the total amount of milk produced. Lactation is ideally 305 days, but in practice it is usually more, followed by a two-month dry period prior to the next calving. A cow’s milk yield is influenced by many factors, which are described in more detail in, Efficient Milking.

A dairy cow's lactating curve:

 A dairy cow's lactating curve

Source: Efficient Milking

Peak yield

Peak yield is the point where the cow reaches the highest milk production level during the entire lactation. Heifers peak at 70 to 75 percent of mature cows and second lactation cows peak at 90 percent of mature cows. Normally the peak is reached four to ten weeks after calving. The time it takes to reach peak yield varies with many factors, for example breed, nutrition and yield potential. Higher producing animals tend to peak later than low producing ones. A high peak yield normally means a higher total yield. Research shows that each one kilogram increase in peak yield usually means an additional 100 to 200 kilograms of milk produced during the actual lactation. Reaching high peak yields requires a very well managed and balanced feeding programme.

Feeding during milking

When creating a good milking routine, it sometimes helps to start using routines which will create positive emotions for the cow. During the 1970’s, scientists demonstrated that feeding during milking resulted in more efficient udder emptying, a higher peak flow and a tendency towards increased production. The observation resulted in a recommendation to feed concentrates in the parlour in some countries.

But what was the mechanism behind this observation and is it worthwhile to continue feeding concentrate in the parlour? Interestingly, it was found that feeding during milking both prolonged and increased the milking related release of the hormone oxytocin. From a production point of view it was further indicated that milking and feeding simultaneously increased milk flow, decreased milking time and showed a tendency to increase milk production.

Cow moving and parlour traffic

When planning a new milking facility, a great deal of consideration should be given to the site of the building and to cow traffic routes. It is self evident that simple, easy, open routing will speed up cow flow. It will also reduce the risk of milkers upsetting the cows in the period before milking. It should be remembered that adrenaline release in the cow interrupts the oxytocin-based milk let-down response.

Twelve golden rules

There are many factors that affect milk quality. With good milking routines and adequate milking equipment, the risk of new mastitis cases will be significantly lowered. See 12 golden rules for milking.