June 4 2013 06:29 AM

Transition cows need more than just a separate pen during this time of weakened immune response.

On dairy farms, we tend to group our animals in an attempt to offer more specialized care. For example, some farms will have separate housing for their dry cows and transition cows (defined as 21 days prior to and 21 days after calving).

The transition period is a time of great change in hormonal profile, feed intake, nutrient requirements, metabolism and energy balance. These changes dramatically affect immune function. Unfortunately, even when we try to house these cows in special groups, limitations in facilities or management can further aggravate the weakened immune system.

Ricardo Chebel, D.V.M., University of Minnesota College of Veterinary Medicine, shared a paper titled, "Transition Cow Grouping Strategy Effects on Cow Health." According to Chebel, four areas for consideration when grouping transition cows are as follows:

Separation of prepartum heifers and cows
First-lactation heifers perform better when they are housed alone rather than with multiparous cows. In work done by Grant and Albright in 1995, first-lactation heifers ate more, ate more frequently, had more lying time and produced more milk when housed alone rather than with older cows.

Chebel recommends separating primiparous cows from mature cows for at least 21 days before and 21 days after calving with an 80 percent stocking density rate.

Do not overstock prepartum cows
For cattle of any age or stage of lactation, limited space or access to feed exacerbate aggressive or submissive behaviors. Two studies conducted at the University of British Columbia found that limited bunk space and less space per cow resulted in decreased overall feed intake, faster rate of feed intake, fewer meals per day, more feed sorting, more standing time and a higher rate of displacement from the feeding area. To read more about this study, take a look at our May 22 HD Notebook blog Avoid overstocking in the transition period.

Other studies echoed these results. Therefore, the current recommendation is one headlock, 30 inches of bunk space and 3 inches of water trough space per cow.

Limit social disruptions
Small studies done at the University of British Columbia have found that social interruptions cause reduced feeding time, greater rate of displacement from feedbunk and stalls, and reduced milk yields on days of regrouping.

Although there is no definitive answer, data collected by Grant and Albright (1995) estimated it may take 3 to 14 days for a group to re-establish stability after regrouping. This can be especially difficult in transition cow pens if cows are coming and going almost daily.

Achieve appropriate body condition score (BCS) at dry-off
Immune function at calving is impacted by dry matter intake, or more specifically reduced dry matter intake. In fact, past studies have found that dry matter intake during the last 21 days of gestation declines more in cows that are obese (BCS of 4.4 or greater) than in thin (BCS 2.8 or less).

Research from Chebel and others showed that BCS in excess of 3.25 at dry-off increased the risk of BCS loss during the dry period, and a BCS of 4.0 or greater at dry-off resulted in almost a 100 percent likelihood for BCS loss during the dry period. They found this also upped the incidence of postpartum diseases.

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The author is an associate editor and covers animal health, dairy housing and equipment, and nutrient management. She grew up on a dairy farm near Plymouth, Wis., and previously served as a University of Wisconsin agricultural extension agent. She received a master's degree from North Carolina State University and a bachelor's from University of Wisconsin-Madison.