Recent research and producer initiatives have caused the industry to challenge conventional wisdom about the dry period. Traditionally, we have believed that a dairy cow requires a 60-day vacation from milking to reach maximum productivity in the next lactation. However, it’s time to rethink the length of that rest period.
A new strategy
While the grouping and feeding strategies of milking cows became simplified, the dry period was subdivided to allow for rumen adaptation prior to calving. Often, animals are moved three times to new social groups and receive three new rations during this time. However, in the last two years, we’ve discovered that cows and heifers benefit from a rumen adaptation period longer than three weeks.
In addition to lengthening the close-up stage, the industry has looked at decreasing total days dry. A retrospective analysis of our clients’ herd records showed no advantage to a 60-day dry period. As a result, we have been targeting 45 total days dry for the last 10 years.
Research has shown that eliminating the dry period results in a drastic reduction in milk yield after calving. However, reducing the duration of the dry period to 30 days did not significantly reduce yield in most studies, and resulted in more total milk revenue — even when subsequent yield was reduced.
In addition, animals with shorter dry periods fed the equivalent of a close-up ration the entire time had higher feed intakes before calving and improved reproductive performance after freshening. Some of the reproductive benefit was due to decreasing the magnitude and duration of negative energy balance because of lower production. However, the extra month of milk production more than paid for the difference.
Combining these two principles has led us to recommend a 30- to 45-day dry period with only one ration and pen move. The merit of this strategy from a cow health perspective is multi-fold:
By not feeding a far-off ration, the rumen is less at risk of acidosis from drastic changes in carbohydrate levels.
Less group changes mean less social changes and higher feed intakes during this critical period.
A shorter dry period means less total dry cows to house. This increases the likelihood that a
producer can optimize living conditions, often making free-stalls and cooling available throughout the dry period.
We also know that a shorter dry period means less risk of subclinical mastitis, especially due to environmental streptococci.
The cow stays productive during a greater percentage of her lifetime.
Do not try this at home unless you have excellent information about calving dates and enough housing to avoid overcrowding. Experience in client herds has led us to recommend this practice only in herds with the best control of these factors.
When calving dates are inaccurate, cows may calve early and have reduced yield, or calve late and suffer from obesity and its consequences. Overcrowding of a facility designed for a 21-day-close-up period results in dirty housing, increased mastitis, decreased intakes and eliminates all of the benefits we anticipate from a shorter dry period.
In order to get the most out of a shortened dry period, you need to have good management already in place.
Marguerita B. Cattell is a consulting veterinarian in Fort Collins, Colo.