Successful calving seasons are the result of good management decisions and hard work. Cows should be checked at least daily during the calving season, and heifers should be checked more frequently, perhaps several times a day. Having the cows and heifers in an easily accessible pasture will make this task more manageable.
As new calves arrive, so does the threat of calf scours. Allowing cows to calve in clean pastures is better for the health of the calf and the cow or heifer. Application of a pasture rotation system can greatly reduce the occurrence of scours in your calf crop. One such system is the Sandhills Calving Method.
Calf scours are caused by a variety of infectious microorganisms, including bacteria (E. coli, Salmonella, Clostridium perfringens, Campylobacter). Viruses such as (coronavirus, rotavirus, bovine viral diarrhea virus), as well as protozoan parasites (giardia, coccidia, Cryptosporidium). Johne's disease is an adult diarrhea (Mycobacterium avium subspecies paratuberculosis) that is commonly contracted through a calf nursing a manure-contaminated teat. The infected animal does not show any clinical signs until after a prolonged incubation period, usually two to five years post exposure. Typically, the environment becomes contaminated with these pathogens and then serves as sources of infection.
The Solution to Pollution is Dilution
Exposure to pathogens may occur through direct contact with other cattle or via contact with contaminated environmental surfaces. For that reason, keeping the environment clean is recognized as important for controlling calf scours. Disease caused by exposure to pathogens can be prevented by physically separating animals, reducing the level of exposure, or minimizing contact time. Reducing crowded conditions decreases opportunity for contact with infected animals or contaminated surfaces.
Separation is the key
Key components of the Sandhills Calving Method are segregation of calves based on their age, and the frequent movement of pregnant cows to clean calving pastures. Age segregation prevents the serial passage of pathogens from older calves to younger calves. The routine movement (every seven to 10 days) of pregnant cows to new calving pastures prevents the buildup of pathogens in the calving environment over the course of the calving season. This prevents exposure of the latest born calves to an overwhelming dose-load of pathogens. The objective of the system is to:
- Inhibit passage of pathogens
- Avoid contact between calves
- Prevent younger calves being exposed to a build-up of pathogens
The Sandhills Calving System uses adjacent pastures for calving, rather than high animal-density calving lots.
Steps of the system are:
• Cows are turned into the first calving pasture (pasture 1) prior to calving and
continues in pasture 1 for 2 weeks.
• After two weeks, the cows that have not yet calved are moved to Pasture 2.
Existing cow-calf pairs remain in pasture 1.
• After a week of calving in pasture 2, cows that have not calved are moved to
Pasture 3 and cow-calf pairs born in pasture 2 remain in pasture 2.
• Each subsequent week cows that have not yet calved are moved to a new
pasture and pairs remain in their pasture of birth.
The result is cow-calf pairs distributed over multiple pastures; each containing calves within one week of age of each other. Cow-calf pairs from different pastures may be commingled after the youngest calf is four weeks of age and all calves are considered low-risk for neonatal diarrhea.
Since this program is based on a well-defined calving system, veterinary involvement is essential for the program to be successful. Herd pregnancy exams can help to sort cows by gestational ages. These cows can then be separated into the proper group to enter the correct pasture at the beginning of the calving season.