MANAGEMENT COMPONENTS

SECTION 5. DRY COW CARE

A "dry" cow is a cow that is not producing milk (lactating). Daily milking is usually ceased abruptly after a dairy cow has been lactating for 10 to 12 months. The dry period (non-lactating) ideally begins 40 to 60 days prior to the next calving.

The dry period allows for involution and regeneration of milk secretory tissue in the udder. This process takes 3 to 4 weeks. Cows which are given a dry period of less than 30 days will produce less milk in the subsequent lactation. A minimum dry period of 55 to 60 days after the first lactation, and 50 to 55 days after the second lactation is recommended. Older cows require a minimum dry period of 40 to 50 days. A dry period of more than 70 days can contribute to obesity at calving. Obese cows are more likely to have calving difficulties and metabolic disorders.

Dry cows are usually housed in groups. Corral space, loafing area size, and protection from weather depends on cow numbers, climate, and waste management considerations. In unpaved, earthen corrals under semi-arid conditions, approximately 500 to 600 square feet of loafing area and 40 to 50 square feet of shade per cow are recommended.

Freestalls are becoming more common in California. These are individual stalls which are open in the back so cows can freely enter and exit. If freestalls are used, there should be one stall per cow. If overcrowding is unavoidable at times, cow numbers should not exceed available freestalls by more than ten percent. Freestalls should allow 25 square feet per cow. Exercise pens should allow 100 to 200 square feet per cow. These recommendations are important for both waste removal and cow comfort.

Corrals should be free from standing and running water and graded to an approximate slope of 4 percent for drainage. Surfaces may be concrete or earthen. Corrals should be cleaned and scraped regularly. Clean, fresh drinking water must be accessible at all times. An overflow drain and a 10-foot concrete apron around the water supply is desirable. Shade should be provided in outside corrals. Trees and other natural objects can provide adequate shade. Feeding locations should be designed to encourage adequate exercise.

The feeding program during the early part of the dry period is aimed at stopping milk production. Eliminating grain concentrates, high-quality legume forage, and corn silage from the ration reduces milk production. These feedstuffs can be replaced with lower-energy, high fiber forages such as grass or oat hays. Rations should meet National Research Council's Nutrient Requirements for Dairy Cows (1989).

Nutrient and energy requirements for dry dairy cows are lower than for lactating cows. The feeding program during the dry period will vary depending upon the cow's calving date, but should be designed to adjust body condition, provide for growth of the fetus, and prepare for lactation. The energy requirements of the dry cow are lower than the lactating cow. Forages, such as hay, can be used as the primary feedstuffs in dry cow rations and are usually the least expensive source of required nutrients. These fibrous feeds help maintain the strength of ruminal muscles and general rumen health.

Cows entering the dry period in proper body condition (body condition score of about 3.5) should be fed only roughages such as hay, pasture, greenchop, and silage until about three weeks before calving. Mineral supplementation may be necessary with some roughage sources. These dry cows should gain 1 to 1.5 pounds per day to allow for the growth of the fetus. Thin (condition score below 2.50) dry cows should be grouped separately and fed a higher energy ration to allow them to regain optimal body condition. Obese cows (condition score of 4.00 or above) will have more calving and health problems. These cows should be grouped separately and fed low quality forages with protein supplemented separately. All dry cows should be fed diets with crude protein levels of at least 15% of dry matter intake.

The total intake of calcium, phosphorus, and potassium during the dry period is critical. These three minerals must be fed in amounts very close to animal requirements to keep the gut absorption mechanisms active. Excess quantities of any of these minerals will predispose the cow to milk fever (parturient paresis or periparturient hypocalcemia), downer cow syndrome, and other related problems. Milk fever will predispose the cow to other serious health problems such as dystocia, prolapsed uterus, retained placenta, uterine infection, and mastitis.

The recommended feeding program for dry cows during the last 10 to 16 days before calving is described in Section 3, "Care of Cows During the Periparturient Period."

Cows recently dried off should be carefully monitored until their udders no longer produce milk. Cows developing hard, swollen quarters should be milked out. This will help remove the bacteria and toxins responsible for the inflammation. Approximately half of all new mastitis infections occur in the early dry period. Cows are also particularly susceptible to new infections when milk is present in the udder. Therefore, it is important to keep dry cows in clean corrals or pastures especially close to calving.

Dry-cow therapy is an important component of a mastitis control program because it reduces the number of persistent udder infections and new dry period infections. Dry-cow therapy consists of infusing at the end of a lactation each quarter of the udder with a registered, Food and Drug Administration approved, long-lasting antibiotic. It is most beneficial if all four quarters of all cows undergo treatment at the end of each lactation. If the herd level of contagious mastitis is low, the producer and the veterinarian may consider treating only cows that have a record of mastitis infection or high somatic cell counts.

Dry-cow therapy has several advantages over treatment of mastitis during lactation. During the dry period, higher drug dosages can be used safely since the antibiotics remain in the udder of the non-lactating cow which increases the cure rate and reduces the risk of milk contamination from drug residues compared to lactational therapy. A sterile, individual syringe should always be used to avoid introducing infectious organisms into the udder. Always read and follow the manufacturer's label instructions. Observe withdrawal times to avoid residues in meat and milk. Immediately after administering dry treatments, the cow should be removed from the milking string. Cows should be observed for any complications for 7 to 10 days after treatment .

Other health treatments may be administered at this time, depending upon local disease problems and specific herd problems. Any necessary vaccinations should be scheduled well in advance of calving to allow the production of desired immunoglobulins in the colostrum. Cows with diagnosed parasite infections can also be treated during the dry period. Directions should be carefully followed on all vaccines and medicines, as certain modified live virus vaccines and some drugs can cause abortion.