Feeding Dry Cows
Dairy Pipeline: November 1998
Gerald M. (Jerry) Jones
Extension Dairy Scientist, Milk Quality and Milking Management
Over a 6-week period, 104 Michigan dairy herds with DHI averages above 19,300 lb., were visited four times and 1,170 cows were blood sampled and body condition scored in a study to identify risk factors for displaced abomasum. Cows of greater risk to having DAs were those receiving high energy rations during the dry period, high body condition scores (above 4), poor feed bunk management (more than 24" per cow if fed in limited amounts or more than 12" per cow if fed free choice so that all feed was not consumed by the next feeding and bunks were cleaned at least once a day), and negative energy balance prior to calving. These cows may have had reduced dry matter intakes before calving, which may have been caused by lack of sufficient fresh feed throughout the day or high levels of concentrate intake which cause rumen acidosis and depressed appetite. The authors refer to one study where first lactation cows fed to maintain a body condition score of 4.0 for the last 60 days before calving experienced a high incidence of subclinical ketosis and a 50% incidence of DA within the first 30 days after calving. In Dairy Guideline 404-212 I have recommended that dry cows should be limited to 30 lb. per day of corn silage but also should consume at least 10 lb. hay, preferably grass hay or grass-legume mix and should be balanced for mineral needs. Rotational grazing would provide excellent feed to both dry cows and bred heifers, especially since both groups often need additional attention. Several types of pastures could be included in the rotation, such as cool season grasses, legume-grass mix, and sorghum-sudan for summer months. Small amounts of hay (3-4 lb.) should be available to prevent bloating. The amount of concentrate for dry cows should be limited to 4-8 lb. per cow daily, preferably fed in a total mixed ration. At 2-3 weeks before expected calving, offer limited amounts of corn (35-40 lb.) or hay crop silage (30-35 lb.) and continue with at least 10 lb. hay. Vitamin E should be supplemented at 1,000 IU/day during the dry period and 500 IU/d during lactation and selenium should be added to the ration at the maximum amount allowed (3 and 6 mg/head daily, respectively) because shortages in these nutrients have left cows less resistant to environmental mastitis.