The reason for a dry period of the dairy cow is two-fold
1.    Recovery of the rumen and the udder from the previous lactation
2.    Preparation for the forth-coming lactation.
 
Studies have been done to compare total milk yield on cows with no dry period and dry periods up to 120 days. These show conclusively that the ideal dry period is 45 – 65 days; this is the period that gives an overall best lifetime producton, while maintaining the health status of the cow. Dry periods of less than 40 days or more than 80 days show a drop in production in the subsequent lactation of 5 – 10%
 
Management Principles
1.    Dry Cow Therapy – for udder protection
2.    Health of cow and calf
3.    Adequate nutrition for maintenance of cow and growth of the foetus.
 

Dry Cow Therapy

 
Dry cow therapy is a long-acting mastitis treatment and preventative in an oil base. It is not intended to cure clinical mastitis at drying off. Dry cow therapy is intended to treat sub-clinical mastitis and prevent mastitis-causing bacteria entering the teat canal and causing mastitis during the dry period. If a cow has clinical mastitis at drying, she should be treated with a lactating cow treatment until the clinical mastitis is cured before drying and treating with dry cow therapy. All cows in the herd should be treated, It is false economy to only treat those that have a clinical case of mastitis as some farmers do.
 

Health

 
•    Dosing – The dry period is a good time to dose the cow for roundworm and fluke to avoid losing milk due to withdrawal periods. The cow does not have to cope with the added stress of worm burden at calving and beginning lactation.
•    Vitamins – The cow will benefit from injection of vitamins A, D and E and Selenium at drying off. This protects the calf and helps prevent retained placenta and other calving conditions.
•    Vaccination – Vaccination of the cow with preparations such as SCOURGUARD 4 KC will give the new-born calf protection against scours. This is also the time to vaccinate the cow against bovine viral diarrhoea if using the killed virus and Corybacterium pyogenes if that is a problem in your herd. (See Vaccination of the Dairy Herd)
 

Nutrition

 
The cow should be dried off with a body condition score of 3.5 – 4 and fed during the dry period for maintenance of that condition and foetal growth. The cow should calve in the same condition she was dried at. Over feeding the dry cow is as bad as underfeeding her.
 
Overfeeding leads to
o    ‘Fat cow’ syndrome
o    Depressed appetite at calving
o    Impaired liver function
o    Lower resistance to disease
o    Long calving interval
o    Poor fertility
o    Problems associated with calving such as milk fever, retained afterbirth, mastitis, udder oedema, downer cow syndrome, displaced abomasums, metritus.
o    Drop in milk production
 
Underfeeding leads to
o    Dystocia – weak cow
o    Weak or dead calves
o    Low fertility
o    Production drop
o    Long calving interval
 
Nutrients are required for 
1)    Growth of the foetus (most growth takes place in the last three months of gestation)
2)    Regeneration of milk producing cells in the udder
3)    Building up of tissue reserves, especially protein and minerals to meet the demands of milk production after calving.
 

What to feed ?

 
Feed as much good quality roughage as possible. This is cost effective and allows for regeneration of rumen bacteria. If silage is fed it should be limited to 10-12 kgs/day.
Levels of concentrate feeding will depend on time of year and availability of good roughage, but should not exceed 3.5 kgs/day. The ration should contain 10-12% CP and ME of 8.5-9.  It is essential to feed dry cows on the correct ration and not on a lactating cow ration as their requirements for essential nutrients, especially protein, calcium and phosphorus are very different. Plenty of fresh water and a certain amount of exercise is also essential.
 
In Summary
•    Feed the cow during her lactation to dry off in calving condition. Cows are able to use food more efficiently during lactation than during the dry period.
•    Aim for a dry period of not less than 45 days and not more than 65 days.
•    Dry cows off abruptly. If necessary, for high-producing cows remove concentrates and/or restrict water to bring production down.
•    Use dry cow therapy with an effective antibiotic and teat dip after last milking and for the next few days.
•    If necessary, divide dry cows into groups ‘fat’ ‘thin’, ‘close to calving’ and feed each group accordingly.
•    Cow comfort is important. Provide adequate water, shade and exercise.
•    Observe dry cows daily, manually examine udders weekly.
•    Bring cows in for calving +/- 10 days before due date, allow a clean, dry area to calve, start feeding small amounts of the lactating ration to enable the rumen to become accustomed to it and observe at least twice daily for beginning of labour.
•    Vaccinate and deworm cows as recommended.
 
A Dry Cow in reasonable condition