Dry Period Bunk Space & Economic Returns
Numerous publications highlight the importance of the transition period in milk production and disease risk. During the last 3 weeks of the dry period and the first 3 weeks of lactation, dairy cows experience challenges with feed intake, an increased risk of metabolic disease such as ketosis and milk fever, and an increased risk of infectious disease such as metritis and mastitis
One of the keys to reducing the risk of transition health issues is to minimize the drop in feed intake that occurs just prior to calving and to maximize feed intake after calving. Many factors influence this drop in feed intake but one of the most important is the stocking density of the close-up dry cows. Separate work by Norlund et al. and by Overton et al. have shown that the optimal level of bunk space is about 30" per cow during the close-up and fresh periods.
Overcrowding close-up cows reduces early lactation milk production by 2 to 20 lbs per day during the first 30-60 days in milk, depending on the level of overcrowding. For example, providing 30" of bunk space vs. a more traditional 24" is predicted to yield about 2 lbs more milk per cow per day after adjusting for the effect of season and lactation number. If milk is valued at $18/cwt and feed costs are $250/ton, the net value of this additional milk is $15/cow over 60 days in milk.
In addition, work by Huzzey et al. at the University of British Columbia found that for every 10-minute decrease in average daily feeding time during the week before calving, the odds of severe metritis nearly doubled and for every 2.2 lb decrease in dry matter intake during this period, cows were nearly 3 times more likely to be diagnosed with metritis. If the $15 in extra profit per cow does not provide sufficient motivation, consider that the cost of metritis is approximately $350 per case.
Managing the stocking density prior to calving can pay huge dividends by way of a reduction in the direct treatment costs of metritis, reduced culling risk in early lactation, improved reproductive performance, and greater returns per cow.
Article by Dr. Mike Overton, University of Georgia, College of Veterinary Medicine
