Herd health has become production medicine

By Ron Goble

The process for keeping your dairy herd healthy has changed dramatically over the years. It hasn’t been too long ago that veterinarians had a different vaccination for most every disease. Today, one vaccination may prevent up to 10 different diseases.

Pete Kistler, DVM, for Valley Veterinarians in Tulare, Calif. has seen the evolution of that phenomenon.

“When I was finishing up school in the mid-1980s, herd health changed to production medicine,” explained Kistler. “The idea was that we’ve pretty much cured all the diseases. The only time we have an outbreak is when someone forgets to vaccinate.”

All inclusive vaccination

Today, vaccinations tend to have 10 different antigens, usually IBR, BVD, PI3, BRSV and five of the Leptos. “Right now there are only a few companies from which you can purchase these vaccines,” he declared.

Kistler said their vaccination program is basically one shot with most everything in it. However, he added that they will boost a lot of the animals with a killed product during pregnancy sometimes and it probably does help the immune system, especially with BVD. “I think – of all those classical organisms – what we see most now is probably abortions due to BVD,” he said.

“All those viruses used to cause problems – and the bacteria like lepto. Of all those, what do we see today? We’ve pretty much wiped out all of the diseases. The only thing we seem to see consistently is abortions due to BVD,” Kistler said. “The problem is that the BVD virus mutates. So the vaccine might be effective for a year or two, and then you get a mutation that runs through the herd and you get a bunch of abortions.”

Kistler said their team of vets has always used live products on non-pregnant cows. “We think it works better, and believe you get a better immune response. Companies that produce the killed product say the advantage is being able to give it to pregnant cows while not risking abortion. But they were not as immunogenic,” he said. “That’s why we recommend live product on non-pregnant cows.

As dairies modernize

“Back in the 60s and 70s,” Kistler recalled, “contagious mastitis was a huge problem. Because when dairies and milk parlors were getting bigger and the same claw was used on 20 or 30 cows a day, you could transmit infection from one cow to another quite rapidly. As dairies modernized, you had a rise in contagious mastitis, until people figured out they needed to use teat dip to stop the spread in the parlor and dry cow therapy to kill any early infections to help control the problem.

“It’s really not a problem in most of our herds today,” Kistler said. “A 1,000-cow herd may have five staph cows a year and maybe one year they will get into trouble with mycoplasma.”

Kistler said they use computer benchmarks and look for significant variations in order to flag herd health issues before they become more problematic.

Like the annualized abortion rate in our herds, we have a variation from 9.7% to 13.7%, not too wide. However, if we look at the percent culled, we see a huge variation. “That’s where I think the most opportunity is right now,” the vet said.

The average culled prior to 60 DIM is about 10% in California. It may vary from a 5% to a high of 18%, said Kistler. Culling practices will impact the annual death rate, which ranges from 3.7% to 9.7% in the herds they service.

“An elevated cull rate probably has something to do with animal movement in the closeup cows, and the dry cows, losing weight. Anytime a dry cow loses weight, she’ll mobilize fat that gets infiltrated into her liver and she ends up with a fatty liver – Type 2 ketosis, they call it, which doesn’t respond well to treatment at all.”

While the computerized benchmarks are updated daily, the big updates are input from test days when they get milk weights and herd check days, when they get new herd pregnancy data.

‘The move of death’

Moving dairy animals can be very disruptive to their social standing in the herd and has often been called, “the move of death,” a phrase Kistler attributed to John Lee, a veterinarian for Pfizer Animal Health. Kistler talked about research conducted at a Wisconsin dairy that put numbers to the “move of death” theory.

Researchers looked at animals that got moved into the closeup pens. They followed what happened on the dairy. Some animals got moved into the maternity pen at 7 days before calving. Some got moved in at 12 days, and others at 20 days.

They looked at what the risk was of having type 2 ketosis and maybe going to beef. Animals that were moved three days prior to calving didn’t have any problems, Kistler said. However, those moved at 7 or 8 days before calving were hurt the hardest. Because that adjustment happened, those animals might not have eaten for two or three days. They started developing ketosis, which showed up really early in lactation when they really started milking hard.

Cows with Type 1 (classic) ketosis, is two weeks fresh and chewing on the pipes. She’s giving a lot of milk and just can’t eat enough to keep up with her production. Type 2 ketosis might show up in cows at 5 or 6 days fresh. She’s been working on this prior to calving. She’s got fatty infiltration in the liver and her metabolism is just wacko, Kistler stated.

Some dairies are going to the dry pen and pulling out animals that are 250 days with calf and put them in one pen and leave them there until they calve, with no pen movement and no social upheaval.

Kistler said his experience at one dairy showed that a group of cows that didn’t get moved into the maternity pen had 9% sent to beef. But of those animals moved into the maternity pens before calving, 18% were sent to beef. “You can look at these animals and they look gorgeous, but internally they’ve got fatty liver and are just ticking time-bombs,” said Kistler.

Preg rates rise and fall

He said preg rates (PR) at many of their dairies for first-calf heifers ranged from 28 to 24, and  19 to 25 for milk cows. PR measures the percentage of cows in a herd that become pregnant every 21-day period past the voluntary waiting period.

Kistler said they achieve these numbers by following a strict A.I. synchronization program in their herds. Of all their herds, average age at freshening for youngstock is 24 months, with a conception rate of 63% and first service conception rate of 65%.

But Kistler also pointed out that he has seen nutrition impact pregnancy rates when certain commodities are removed from the cows’ ration. To save on feed costs, one producer told his nutritionist to drop cottonseed from the ration. He saw his herd’s reproduction suffer. Some nutritionists will add a little corn and bypass fat to replace the cottonseed, but those who don’t represent the more severe examples.

Bunk space matters

Besides watching when to move animals or not move animals, Kistler stressed the importance of adequate bunk space per cow on the dairy. “Facilities often dictate what’s going to happen in your herd. It used to be that cows had 24 inches of bunk space. But those who provide 28 inches of bunk space per cow are doing better,” he said. “The highest producing herd in our practice has 28 inches of bunk space per cow. It’s not just fans and soakers; it’s bunk space. It may be difficult to measure, but give them the adequate space and reap the benefits.”

Bring in experts

Kistler stressed that many of their dairies lean on their nutritionists and occasionally bring in lameness experts to help fine tune herd care from a preventative perspective.

The 12 DVMs at Valley Veterinarians service approximately 250,000 milk cows in Central California – with most of those animals located in Tulare and Kings counties. Four lab technicians provide testing and analysis for their clients’ herds.

Valley Vets is also known for development of Dairy Comp 305, a very successful software program for individual, group or herdwide analysis. Dairy Comp is the heart of the firm’s dairy records analysis services.

Kistler said studying a dairy’s computerized statistics can answer a lot of questions concerning the operation. “You see where they are excelling and where they could use some help. Dairy Comp is an invaluable tool for us,” he said.


■  To contact Pete Kistler at Valley Vets, call 559-686-1447 or e-mail him at, pete@valley vets.com.

■  For information on Valley Veterinarians, Inc., visit their website at www.valleyvets.com.