The dairy cow has four main stages to its production cycle; these are early lactation, mid lactation, late lactation and the drying off period. The production cycle of the dairy cow is shown in diagram 1 below.

Diagram 1, the production cycle of a dairy cow. As you can see the dairy cow should be in milk for around 305 days a year and have a drying off period of around 60 days. After calving the cow should be back in calf after 85 days, this is to keep the ratio of 1 calf/ cow/ year. This ratio will get the highest yield out of the cow and keep a good profit margin for the farmer.

The cow will produce differing yields of milk throughout the year; the yield will follow what is called a lactation curve as seen below in diagram 2. This …show more content…

Source www.dairymaster.com

Late lactation and dry cow management
In the last 2/3rds of the lactation cycle the cow should be gaining weight. The condition score of the cow should be moving towards 3.0. If the cow is not responding to the feeding and stays skinny then it may be better to dry the cow off earlier, as this could end up having poor repercussion for the farmer later on down the line. It is considered better planning to have the cow hitting her target score in late lactation rather than in the drying off period. Cows can normally only 0.25 – 0.5 B.C.S during the dry period.

The dry period is necessary for the involution (repair and development) of the mammary gland. Correct management of the dry period will ensure that the cow will reach her full potential in the next lactation cycle. A short or absent dry period reduces the number of secretory cells in the mammary glands. A dry period of 40 days will cause a drop of 250kg of milk in the next lactation while a dry period of 60 days will cause an increase of 125kg of milk in the next lactation, figures found on www.ruralni.go.uk.

When bringing a cow into the dry period there are two main things to consider;
• Gains in profit to be achieved if you extend the current lactation of the cow.
• Losses in production and profit in the next lactation resulting from a shorter dry period.

If the dry period is poorly managed then the cow could suffer from Ketosis, acidosis and calving difficulties.