Fall Cow/Calf Producer Herd Check Up
Fall is the time 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 sufficient.
Producers have other issues they should consider this time of year as well, according to North Dakota State University Extension livestock specialists.
“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 North Dakota State University Extension’s Carrington Research Extension Center. “Pregnancy checking heifers provides the opportunity to market open females directly off pasture. If pregnancy rates are lower than expected, it is important to evaluate parameters such as the bull-to-cow ratio, vaccination program and length of the breeding season.
“It is also important to factor in the age of open cows,” Hoppe adds. “If most of the open cows are young, there could be a nutritional issue affecting pregnancy rates.”
Assessing body condition score (BCS) in cows nursing calves also is a good management practice this time of year.
“Although rainfall and forage production were abundant in many areas of the state, declines in forage quality as plants mature can result in condition losses,” says Janna Block, Extension livestock systems specialist at NDSU’s Hettinger Research Extension Center. “It is important to remember that for spring-calving herds, the cow is not only providing for the calf at her side, but also entering the second trimester of gestation with next year’s calf.
“Although nutrient requirements for the fetus at this time are low, critical developmental events such as muscle fiber and organ development are occurring,”
Block notes. “Research indicates that severe nutrient deficiencies during this period could impact offspring birth and weaning weights, feedlot performance and even carcass quality.”
If cows are thin now, producers should consider weaning calves, particularly from first-calf heifers or old cows. A March-calving cow with a body condition score of less than 4 at weaning will have to gain approximately 1.5 pounds per day to achieve a recommended condition score of 5 at calving. Reducing the need for nutrients required for lactation is the most efficient way to put condition back on cows, the specialists say.
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. Sorting and vaccinating calves while they still are 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 says.
“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 at this time 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.
• External parasites such as horn and face flies – These populations have decreased dramatically and treatment for them 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.
Stokka also recommends commingling calves from different pastures prior to weaning if possible. This may seem unnecessary; however, calves at this stage are much like preschool children, he 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.”