Managing cows through the end of the dry period and into their next lactation remains a challenge across many dairy farms. Much of this is driven by what we ask cows to handle throughout the weeks before and after calving.
While many of these stressors are somewhat unavoidable, there are strategies that can be used to help reduce their total impact.
How much space does a cow need during the transition period?
One of the primary housing stressors can be reduced by not overstocking the pens cows will progress through. Solid data and research support a few stocking recommendations and bunk space suggestions. Before, the general rule was to maintain the feedbunk at a stocking density of 85 percent.
However, the introduction of 30-inch headlocks has changed this a bit. With the wider option, one cow per headlock may not present any issues. The current Canadian Code of Practice recommends 30 inches per one headlock or space within a post-and-rail barrier. If using older 24-inch headlocks, then targeting 85 percent is suggested.
Recommendations for resting space are similarly limited. The Canadian Code of Practice suggests the provision of 160 square feet per cow within a maternity pen. The only other general recommendation for stocking density within these guidelines is to not exceed 120 percent stocking density of the freestall or 120 square feet per cow, which is more applicable for lactating cows rather than transition cows.
For transition cows, stocking densities closer to one freestall per cow, or 100 percent stocking density, will likely improve their ability to adjust. There are a variety of more specific recommendations within extension publications but nothing consistent or strongly supported by research.
Why does space matter during this time?
Because dry matter intake during the transition period is so important, much of the recent research on stocking density for dry and transition cows is focused on feeding space. In these studies, some consistent trends have emerged.
When feeding space is limited, cows respond by increasing aggressive behaviors to gain access to feed. Studies from the University of British Columbia and Cornell University suggest the increased aggression will occur regardless of when the overstocking occurs.
Interestingly, the overstocked cows in the Cornell study consumed about 2 pounds more dry matter per day on average but also had indicators of decreased energy balance. This suggests the demands of fighting for feeding space comes with an energy cost.
Mature cows will also increase their feeding rate in response to overstocking and to compensate for less feed access. This is important for two reasons. First, slug feeding can negatively affect rumen health. Second, heifers are unable to increase their feeding rate.
This behavioral limitation is one reason why heifers are not well equipped to thrive in an overstocked housing environment. While heifers may benefit from separate housing during this time, the question of when to commingle them remains unless the proper facilities are in place to manage them as a separate group through the transition and early lactation periods.
Changing pens is also problematic
Even if pens are correctly stocked, moving cows among pens is challenging. Studies from the University of British Columbia showed for the first one to two days following regrouping, there is about twice as much social aggression, an increase in feeding rates, decrease in rumination and decrease in dry matter intake. These rates typically return to normal in three to seven days depending on the severity of the disruption.
Limiting pen moves to once a week can help minimize the behavioral changes and lost dry matter intake. Making sure cows spend a sufficient length within a pen is also critical. Some evidence shows cows housed within the fresh cow pen for at least nine days may produce an additional 2,000 to 4,000 pounds of milk in their next lactation.
The greatest response is seen in heifers. This increase in milk production might be driven by a general improvement in overall health. In one study, the incidence of milk fever, retained placentas and uterine infections were reduced when cows spent at least 15 days in the close-up pen before calving.
If pens moves are unavoidable, then what can be done?
There are a few steps that can be taken to reduce the stress of moving to a new pen. First, moving animals, especially heifers, in pairs can help. Studies show heifers moved as pairs had greater lying times than those moved individually. This indirectly suggests the paired heifers were more comfortable in their new housing arrangement.
There is also a benefit to avoiding pen moves around the hours of feed delivery. The two hours following the delivery of fresh feed are when cows are highly motivated to eat and the activity level in the pen is at its greatest.
Avoiding this time will place cows in their new environment when activity is low, which may allow them more freedom to explore, consume a meal and settle in. Finally, moving between adjacent pens may make for easier transitions.
What to consider on the farm?
The best stocking density on any given dairy will need to be worked out by tracking the success of the dry cow and transition cow programs. While there is still a considerable amount of work to done to establish best management practices for stocking density and managing pen moves, steps can be taken to follow general recommendations.
Providing at least one freestall or a minimum of 150 square feet on a bedded pack and 30 inches of bunk space is a good place to start. Consideration also needs to be given to the heifers who will likely transition best in an undercrowded, noncompetitive environment when entering the lactating herd.
Paying attention to the timing of when you move animals should also help to ease the transition into a new group. 
PHOTO: Cows are moved to a bedded-pack barn three weeks prior to calving to allow acclimation to their environment. Photo by Erika Edwards.
-
Peter Krawczel
- Assistant Professor
- Department of Animal Science - University of Tennessee
- Email Peter Krawczel
