Minimizing risk

Andre Rigo AHV International B.V.

SIOUX FALLS, S.D. — As cows reach the end of their lactation and begin the dry-off period, Andre Rigo said this is more than a break between lactations; it is the beginning of the next.

Rigo is the director of technical services and products at AHV International B.V. Rigo spoke during the seminar “Dry off: The next lactation starts here,” March 18 at the Central Plains Dairy Expo in Sioux Falls.

During the dry-off period, Rigo said farmers should give cows proper treatment and rest. Cows will go through three phases — active involution, tissue regeneration and colostrum formation — to prepare for the next lactation.

Active involution is roughly the first two weeks into the dry-off period. Milk is accumulating, which can lead to udder engorgement, pressure and milk leakage. Rigo said this is a stressful moment for the cow and can make it easier for bacteria to set in and create mastitis or other problems.

In 1995, as cows neared the end of their lactation, milk production was 33-35 pounds per day. Today, Rigo said milk production in cows has almost doubled. This leads to a longer amount of time dedicated to phase one and less time for the cow to repair her mammary system in phase two.

“They (dairy farms) have high-producing cows with more than 60 pounds,” Rigo said. “That’s very common for our industry at this time (dry off). More than 70% (have) persistent leakage after three weeks. … The increase in production and leakage increases the risk for new intermammary infections at dry off.”

Research shows that 75% of new mastitis cases started during dry off, Rigo said.

Rigo attended a national dairy conference where they shared guidelines for what production should be near dry off. At the conference, presenters said the ideal production is close to 33 pounds.

Gradually drying off cows is a management strategy Rigo spoke about during the seminar. This strategy can help minimize risk and give more time for udder repair before the start of the next lactation. Within this strategy, Rigo said farmers should reduce milking frequency, lower dietary energy density by increasing fiber and decreasing starch, and remove concentrates from the ration 3-7 days before dry off.

Rigo referred to a 2024 paper that discussed the relationship between dry matter intake and production. It also talked about the direct relationship between pre-dry off, DMI and post-calving milk production.

“If we are doing gradual dry off, if we are doing reduction in energy in feed, for these animals they are ingesting less (so) they will produce less,” Rigo said.

The second phase is the steady state of dry off, which allows the udder to repair and regenerate itself for the next lactation. In the mammary system, epithelial cells are responsible for milk production, Rigo said. Adequate time in this phase determines milk production in the following lactation.

“If you have the first phase too long, we have less time for the repair and rejuvenation of the udder,” Rigo said. “If you have the first phase really short, we have more time for the rejuvenation and for the repair. Everything that starts in this phase, we will harvest in the next lactation.”

Although retaining milk in the first phase will help trigger the evolution of the udder to repair and rejuvenate cells, too much milk retention can cause risk, Rigo said. If too much milk is retained, the udder can have increased inflammation, opening the mammary system for bacteria.

“Every single time we increase inflammation in a milk lactation can lead to cellular apoptosis,” Rigo said. “If we are killing the epithelial cells that produce milk, … (that affects) the next lactation as well.”

The last phase of dry off focuses on colostrum formation for the upcoming lactation and the final stages of calf growth before calving. Within the last phase or final 30 days of the dry period, there is a high energy demand, Rigo said. With the transition of feed rations, there can be issues with negative feed management, creating another risk for cows during the dry period.

Rigo encourages dairy farmers and herdsmen to ask themselves, “How can I facilitate this transition and make this smooth for the cow?” Dairy producers can then dry off more efficiently.

During the seminar, Rigo shared information about a bolus developed by AHV called Stoplac. The bolus temporarily modifies fermentation in the rumen to reduce volatile fatty acid production, he said. By reducing VFA production, milk production will decrease faster, so they are not in phase one too long. This bolus should be administered after the last milking of the lactation and will facilitate dry off. Within five days, it will decrease production by 60%, Rigo said.

Minimizing risk factors during the dry period and decreasing milk production at dry off gives cows more time to prepare for the upcoming lactation.