FARGO, N.D. — Fall is when beef cattle producers make many management and labor decisions, including repairing cattle-working facilities, moving cattle to fall grazing, assessing crop residue opportunities and wondering if winter feed supplies will be enough.
Producers have other issues they should consider this time of year as well, according to North Dakota State University Extension livestock specialists. One of those issues is assessing the body condition score (BCS) in cows nursing calves.
“Scheduling pregnancy checks for cows nursing calves provides a good opportunity to identify cows for market and to vaccinate calves preweaning,” says Karl Hoppe, Extension livestock systems specialist at NDSU’s Carrington Research Extension Center. “Pregnancy checking heifers provides the opportunity to market open females directly off pasture.”
Bulls also need to be evaluated in the fall for foot, leg and penile injuries, and BCS, Hoppe says. Mature bulls should have minimal weight loss during the breeding season, while yearling bulls will lose some weight during the breeding season and would benefit from improved nutrition when removed from the breeding herd.
Another key component of fall herd management is an assessment of the risk of certain diseases, and the efficacy and safety of specific products such as vaccines.
“The preweaning vaccination protocol provides an ideal opportunity to follow up on springtime vaccinations and enhance the immune response to respiratory pathogens,” says Gerald Stokka, Extension veterinarian and livestock stewardship specialist.
Respiratory disease is one of the primary risks to weaned calves. The bovine respiratory disease complex (BRDC) is associated with the stress of weaning, diet change, transportation or movement to new surroundings, and often the commingling of different pasture groups on the same ranch.
Enhancing the calves’ immunity to specific potential pathogens can decrease the risk of BRDC, Stokka says. Sorting and vaccinating calves while still nursing their dams reduces the stress of calf processing.
The infection risk is related to several viral and bacterial pathogens. Depending on a veterinarian’s assessment of the risk to the herd, calves may need booster doses at weaning or they simply may be separated from their dams without additional vaccinations.
Modified live virus vaccines (MLV), often called five-way viral vaccines, that are labeled for use on nursing calves can provide excellent protection when properly handled and administered according to label instructions, Stokka says. Mannheimia haemolytica infections often are implicated in pre and post weaning respiratory disease cases, and vaccines against this pathogen commonly will be included, very often in combination with the MLV virus vaccines.
In specific herds, other bacterial vaccines may be necessary, depending on herd history and risk.
“It is important to remember that killed/inactivated vaccines will usually require a booster dose to achieve an adequate level of protection,” Stokka notes. “Consult your veterinarian about specific products related to viral and bacterial vaccines.”
Other health risks to calves include:
- Clostridial diseases, commonly called “blackleg” – The risk of this infection is difficult to assess; however, the organism that causes these diseases lives in the soil and can cause severe illness and death in susceptible animals. A second vaccine dose administered in the fall will enhance protection against this family of pathogens.
- Internal parasites if cattle are on grass – Calves with internal parasites will have reduced feed/forage intake, resulting in reduced weaning weights. Internal parasites also can have a negative impact on the calves’ ability to respond to vaccination. If dewormer products are used at preweaning, calves should be moved to clean pastures to avoid re-infection. However, with the recent hard frost, the risk of re-infection is negligible.
- External parasites such as horn fly and face fly – These populations have decreased dramatically and treatment for these no longer is necessary. Treatment for biting and sucking lice is not recommended at this time. The feeding activity of lice will increase with colder weather, so hold off on treatments until signs of lice appear.
If possible, commingle calves from different pastures prior to weaning. This may seem unnecessary; however, calves at this stage are much like preschool children, Stokka says. Allow calves to share their bugs and develop a social order while still nursing their dams. This can greatly reduce the risk of postweaning respiratory diseases.
“Preweaning vaccination events, while stressful, can minimize pathogen stress that is normally associated with commingling of different pastures, separation from the dam and changes in diet that occur with weaning,” Stokka adds. “Work to ensure that all animal-handling events are conducted in a calm, low-stress manner to the extent possible.”
— NDSU Agriculture Communication
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