Wednesday, March 14, 2018

The Perfect Storm for Scours

With this spring's wet weather, the potential for
calf scours is an increasing concern.  Separating calves
by age and moving pregnant cows to clean calving pastures
is key to reducing scours potential.  Photo by Kari Lewis.

With this wet snow and rain we've been having (or if the weather warms up and our snow-covered pastures turn to soggy, muddy pastures), the potential for calf scours is becoming an increasing concern.  Calf scours is not a specific disease but is a clinical sign that can be caused by various infectious agents and predisposing factors.  Calf scours results in dehydration and potentially death.  Even if calves recover from scours, research has shown those calves have decreased performance throughout their lifetime.  A Colorado study showed calves with scours who recovered still weaned 23 pounds lighter compared to their herd mates that did not have calf scours.

The three main factors that determine the potential for a scours outbreak include the exposure rate of organisms affecting the calf, calf immunity levels, and stress on the calf.  Environmental conditions influence both the pathogen exposure level and the ability of the calf to resist disease.  Temperature extremes and moisture hinder the calf’s ability to resist disease.  Exposure to pathogens may occur from direct contact with other cattle or contact with contaminated environmental surfaces.  Crowded conditions increase the contact between infected animals and contaminated surfaces. 

When treating sick calves, a rancher’s hands, clothing, and equipment can be a source of contamination to healthy calves.  Work with the healthy calves first, and then treat sick calves.  And yes, those coveralls should be washed too!  If you are feeding scouring calves on a bottle or with a tube feeder, that equipment should be thoroughly disinfected before using on the next calf.  Washing equipment in hot, soapy water and soaking in a bleach solution is effective against many agents.  Several hours of bright sunlight is also an effective disinfectant. 

The Sandhills Calving System is likely the best management recommendation for preventing scours.  This calving system was developed in the Nebraska Sandhills to help minimize scours.  In one 900-head beef cow herd in the study there was typically a 6 to 14% calf mortality rate per year due to scours.  After switching to the Sandhills Calving System, they didn’t have any calves die from calf scours in the following years and they estimated a $40,00 to $50,000 per year savings due to the increased number of calves weaned, better calf performance and reduced treatment expenses.  That $40,000 to $50,000 was back in the early 2000’s, so likely would be an even greater number now. 

The Sandhills calving system is based upon two concepts – 1) Separate calves by age to prevent direct and indirect transmission of pathogens from older to younger calves and 2) Routinely move pregnant cows to clean calving pastures to minimize dose load and contact time.  Each week the cows that are still to calve are sorted out and moved to a new pasture, with the pairs that have calved being left behind in the original pasture.  If cows are calving in barn or shed situation, potential for contamination is increased and it is critical that clean, fresh bedding be supplied. 
Lastly, I know hay is costly, but don’t short your cows now.  I know there’s a hundred things to do this time of year but take the time to put the mineral out.  The cowherds that have been on a strong nutritional program with a consistent vitamin and mineral package and that are on a complete herd vaccination program are going to come through this winter and spring in much better shape. 

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