Friday, July 31, 2015

Heifers and Worms

Lots of dairies have transition heifers on pasture and/or dry lots during temperate months. At some time in the fall they come off of these facilities into winter housing. 

If you dairy in western New York heifers usually come in when it gets both wet and cold; that is, sometime in September. It may sound somewhat insane to be thinking about this at the end of July. However, a little bit of planning may make parasite control six or seven weeks from now go smoother (especially if in September we are up to our ears chopping corn and trying to get in one last cutting of haylage).

Recall that the need for parasite control is related to risk of exposure. Calves and heifers in total confinement housing usually have low risk. In contrast, we have heifers that go out on the same "heifer pasture" year after year. The stocking rate may be high enough to support high levels of contamination. Thus, the risk may be high.

The economics of parasite control have been well demonstrated. Feed efficiency is lower and general health is suppressed among parasitic animals. At our vet clinic we sell pour-on wormer that will treat 550 pound heifers for less than $3.00 each. So, we are not talking about a huge expense.

Now is a good time to start talking with the herd veterinarian about the choice of wormer, method of delivery and timing. If the supplies are on hand (September is only 4 weeks away) the rainy-day job can be taking care of parasites in the heifers.

Thursday, July 30, 2015

Cryptosporidia can be Ubiquitous!

My impression about cryptosporidia oocysts is that they come close to being everywhere on the typical dairy farm. Tough to avoid exposure. 

In a recent research report on dairy calves [ T.M. Hill and Others, "Effect of feeding rate of milk replacer with early weaning and protocols for water treatment and sanitation on dairy calf growth and health." The Professional Animal Scientist, 31 (July 2015) 375-382] the calves with abnormal manure were checked for parasites. 

They had 48 bull calves on the feeding trial, all of them came from one dairy farm. Of these 22 had abnormal feces (46%). This diarrhea rate may have been expected given that the blood serum total protein levels averaged just under 5.0.

What percentage of these calves had cryptosporidia in their feces? ONE HUNDRED PERCENT!

This high rate of parasite presence was in spite of exceptional efforts at the research facility to prevent inoculation from water and feeding equipment. My best guess is that the calves had already been exposed to an infective dose of crypto oocysts before they left the host farm. You will recall that this parasite is autoinfective (that is, the oocysts do not have to leave the body in order to re-enter the g.i. tissues) so no additional exposure would be needed to reach a clinical level of infection. 

For a one-page summary about cryptosporidia click HERE

For a protocol for using chlorine dioxide for crypto control click HERE


Tuesday, July 28, 2015

Oh, For the Lack of a Brush!

It is true that one cannot brush if you don't have a brush!

A tube feeder used for feeding colostrum to calves.

The dairy had a brush that would clean the  inside of the esophageal tube.

Someone took the brush to clean something else and did not return it. 

The inside of the tube was then not brushed - just rinsed. 

Just like death and taxes, it was a given that "gunk" would start to build up inside the tube. 

The most recent check with a ATP monitoring unit turned up a value in excess of 5,000 (standard for this equipment is less than 50). 

Oh, for the lack of a brush!

Fortunately I had an extra brush in the truck and could leave it for the dairy. It's tough to brush if you don't have a brush!

Friday, July 24, 2015

How Does Much Bacteria Count in Air Vary?

In a presentation at this year's Dairy Calf and Heifer Association meetings Ken Nordland (University of Wisconsin School of Veterinary Medicine) reminded the audience about the variations of bacteria counts in various settings. 

Outdoor - can go as low as 100-1,000 colony-forming units per cubic meter.

Clean office air will have 1,000 - 2,000 cfu/cubic meter.

Well ventilated livestock barn 10,000 - 15,000cfu/cubic meter. 

Poorly ventilated livestock barn 25,000 to 3 million cfu/cubic meter.

How about that 3,000,000cfu/cubic meter! No wonder that an effective positive pressure ventilation system can reduce the treatment rate for pneumonia in calf barns.
Real Numbers Help Guide Actions

Best management practices are not always easy to communicate to workers on dairy farms.

Two recent experiences suggest that getting real numbers (quantifying) to describe a situation may help get the need for improvement across to persons responsible for dairy calf care.

I am using the Hygiena SystemSure Plus unit to do adenosine triphosphate (ATP) monitoring. The ATP test is a process of rapidly measuring actively growing microorganisms through the detection of adenosine triphosphate. An ATP monitoring system can detect the amount of microbial contamination that remains after cleaning a surface (for example, calf feeding equipment). 

Thresholds used in the food processing industry are less than10 RLU for direct food contact surfaces and less than 50 RLU for environmental surfaces. I have been using a reading of 100 RLU as realistic on-farm upper threshold for calf feeding equipment

On Farm A we were concerned with post-pasteurization of unsaleable milk being fed to calves. The source of contamination was hard to pin down. Back in April we brainstormed for all the places where bacteria could be coming from. One place we checked was the underside of the top of a milk transport tank - the tank was filled with pasteurized milk to feed the calves. BINGO! RLU reading of 6443!  We agreed that this surface would continue to receive regular attention in the future. A matching test in June resulted in a RLU value of 39. 

On Farm B we were concerned with inoculation of colostrum with bacteria during the collection process. Attention to teat preparation did not appear to decrease inoculation levels. Testing the collection bucket did not turn up contamination - RLU value of 29. I picked up the stainless steel lid and swabbed at the edge and under the gasket. RLU value of 2209! We agreed that in the future the gasket would be removed and cleaned as well as all surfaces of the stainless steel lid being scrubbed after each use. 


Thursday, July 23, 2015

Umbilical Cord Healing: Normal?

Sometimes it is good to have a sense of what is considered "Normal" for an event. One of these of interest to calf rearing persons in the healing rate of the umbilical cord among newborn dairy calves. 

Observations were made during an evaluation of four different compounds used for navel dipping. The umbilical cord diameter was assessed within 30 minutes after birth and again at 24 hours of age. [Robinson, A. L., L.L. Timms, K.J. Stalder and H.D. Tyler, " The effect of 4 antiseptic compounds on umbilical cord healing and infection rates in the first 24  hours in dairy calves from a commercial herd." Journal of Dairy Science 98:5726-5728 September 2015]. Sixty calves were observed.

Birth
Average umbilical cord diameter was 0.9 inches (22.8mm). Most calves fell in the range of 0.75 and 1.05 inches.

24 hours
Average umbilical cord diameter was 0.3 inches (7.6mm). Most calves fell in the range of 0.14 and 0.46 inches.

Normal healing rate (shrinking diameter)

From 0.9" at birth to 0.3" at 24 hours. 

Outlying cases that I would tag for watching

1. Diameter well over 1" at birth.
2. Diameter remains over 0.5" at 24 hours.

By the way, always remember to train and retrain all the folks doing the navel dipping to:
1. Dip umbilical cords soon after birth.
2. Use clean dip and a dip container.
3. Expose the entire umbilical cord to the dip.
4. If the dam has removed all the dip, re-dip the navel after removing the calf from the dam.

BTW you might be interested in the dollars and cents of navel dipping at this resource sheet: click HERE.


Tuesday, July 21, 2015

Looking for THE Bug
Denying the Obvious

Start with sick and dying calves. Jump to the most attractive explanation: "It must be a bug."

The "bug" in this case is some exotic highly pathogenic bacteria or virus that has invaded the dairy and is the sole cause the sick and dying calves.

Thus, when the dairy reaches out for professional assistance to solve the sick and dying calf problem the dairy already knows how to find the solution. That is, "Find the BUG."

At our most recent visit to a dairy with this situation we had difficulty walking across the bedding pack where calves are born. Why? Less than 50 square feet per cow stocking rate. And, none of us would want to kneel down on the bedding in this pen - ugh.

Blood agar cultures of colostrum being fed to the calves uniformly resulted in plates with too many colonies to count - well over 1/4 million per ml - with very heavy growth on the MacConkey plates showing heavy coliform contamination.

No interest in participating in blood sampling of youngest calves to check on immunity levels. 

Necropsy data from calves from a university laboratory failed to find "THE BUG."

What is the next step?

One alternative is to keep looking for "the bug." Send more dead calves to the lab. Find other professionals to help in the search for "the bug" since the ones involved so far were not competent enough to find "the bug."

Another alternative is to step back, assemble a "team," and assess the calf management program from top to bottom. Identify opportunities to reduce pathogen exposure and increase immune defenses. 

If you are interested, two web resources that provide checklists for these are:

and 

As a regular reader of this blog I do hope you are not among the "bug hunters."