By: Grant Dewell, Iowa State University Extension beef veterinarian
The Sand Hills Calving System has demonstrated an effective way to reduce calf diarrhea by decreasing the buildup of pathogens in the environment and breaking the transfer of pathogens from older calves to young susceptible calves. Unfortunately, most producers do not have access to eight calving pastures to implement the Sand Hills system. However, the principles involved with decreasing exposure of neonatal calves to pathogens can be utilized.
The reason that the Sand Hills system works is that late pregnant cows are moved to a new clean pasture while pairs which have already been exposed and are potentially shedding pathogens are left behind in the pasture they have already contaminated.
For producers with limited pasture opportunities I recommend having three different calving facilities available. Rather than moving pregnant cows every 7 days into a new pasture according to the Sand Hills method, pregnant cows are moved when calf diarrhea becomes a problem. Once several calves have begun to shed high levels of pathogens from a bout of diarrhea then every calf in the area will have been exposed and pathogens levels will increase in the environment. By moving pregnant cows we can break the exposure to the new calves that are born.
Some potential scenarios for cattle producers may be to start in a calving barn early in the year when weather is more of an issue. After scours start you would start calving in a dry lot facility, and if you have to move again the third area may be pasture or hay field.
In a good year you may be able to stay in the first facility the whole time and never need to utilize the pasture. However, during a severe outbreak pre-planning to have a place to move calving areas to can save a numerous calves from neonatal diarrhea. Other options for calving areas include stubble field before planting, machine or hay storage barn, or a sacrifice pasture. The main point to remember is that we are better off moving pregnant cows to a new pasture rather than moving pairs.