Monday, January 30, 2017

How do Calf Caregivers Spread Diseases?

It seems like a contradiction to suggest that calf caregivers spread diseases. Nevertheless, research has conclusively shown that caregivers often are the culprits when calves get sick.

Let's look at three examples how this takes place.

EXAMPLE #1
Calves are housed in individual hutches outdoors where they are fed six quarts of pasteurized milk daily from 3-Qt. bottles. At feeding time a wagon full of these bottles is towed between the rows of hutches. Two workers scoop up arm loads of four three-quart bottles and go from hutch to hutch dropping a bottle in each bottle holder. I noticed that one worker managed to carry an extra bottle by holding the last two by the nipples. As the routine proceeded I also observed that not every bottle settled evenly into the bottle holders - some adjustment was required [note: this is where the worker's gloved hands came in contact with the contaminated bottle holder]. Then the same worker went back to the wagon, picked up three bottles tucking them  under her arm and grabbed two more bottles by their nipples [note: point of contact between contaminated glove and nipples].

EXAMPLE #2
Calves are housed in individual pens in a calf barn where they are fed six quarts of pasteurized milk daily from pails. These same pails are used to feed water. The feeding routine is to first go along each row dumping any left over water from the liquid feeding pail into a waste container. Then, milk is fed to individual calves.
You noticed, right? That is correct, as the water is dumped the worker's gloved hand touched one liquid feeding pail after another - very effectively passing pathogens along the row of pails. A few Strep. species bacteria probably don't make any significant difference. However, passing along Cryptosporidia parasites and highly contagious Salmonella bacteria should be avoided. 

EXAMPLE #3
Calves are housed in individual pens in a calf barn where they are fed three quarts of pasteurize milk three times daily from liquid feeding pails that are also  used to feed water. As I observe calf care after feeding I noted that several sick calves needed to be treated. The calf care person stepped into the first pen, gave the treatment to the sick calf, left this pen and promptly opened and stepped into the pen of the next calf to be treated. Boots, Boots, Boots. Feces on boots are a very effective way to carry pathogens from one pen to another.

BEST MANAGEMENT PRACTICES

Another of my clients has a little low tow-along cart. The cart has a place for extra disinfectant solution and a brush. A low plastic container allows the caregiver to step in and brush her boots. The solution is dumped out between calves. The routine is step in before entering the pen, step into the container upon leaving the pen, brush to remove an manure, dump the disinfectant solution, go on to the next calf. 

I saw a similar set up for a dairy using outdoor hutches. They carried the container in the back of a 4-wheeler, set it out on the ground, sprayed disinfectant on their boots while standing in the container, stepped into the wire pen, treated the calf, stepped out into the container brushing their boots off while being sprayed with disinfectant, changed gloves and on to the next calf. 

Note: Footbaths are particularly ineffective for controlling pathogen movement. In "Best Management Practices" above both calf enterprises dumped the foot bath between  uses. Research has demonstrated that even well-maintained footbaths often fail to control the spread of pathogens, especially Salmonella. 

Reference: Gardner, C.E. and Others, "Case Report: Management of an Outbreak of Salmonellosis on a Commercial Calf Raising Unit." The Bovine Practitioner, vol. 38, no. 2, pp147-154.

No comments:

Post a Comment