Prenatal nutrition and health of the cow
The health and well-being of the nursing calf starts with the health and nutritional status of the cow prior to the birth of the calf. Nutrient needs of the cow increase during the last trimester of gestation and, by the last month prior to calving, the fetus is gaining approximately 1 pound per day.
In addition to this late-term fetal growth, the cow is also preparing for lactation. Research has shown cows that are thin (body condition score of 4 or less) have a decreased concentration of immunoglobulins in colostrum compared to cows in a body condition score of 5 to 6 (1-to-9 scale). Additionally, calves born to very thin cows may be weak and slow to nurse, also reducing the colostrum they consume and making them more susceptible to disease.
A healthy start for the newborn calf
In addition to a healthy mother, the newborn calf needs a clean environment. Healthy adult cattle often shed very low levels of bacteria and viruses that cause scours and other diseases in calves. Manure and mud provide an ideal environment for disease-causing bacteria and viruses.
Early in the calving season, calves are exposed to these pathogens and often develop minor, undetectable infections; however, these young calves amplify the pathogen load in the environment faster than adult cattle do.
As the calving season progresses, newborn calves are challenged with increasingly higher levels of pathogens. Infection with high doses of bacteria or viruses combined with other risk factors like overcrowding, temperature extremes and precipitation can quickly overwhelm calves’ defenses, and clinical cases of scours may develop.
Long calving seasons further exacerbate the situation by providing a steady supply of new calves susceptible to infection over a long period of time. These conditions often lead to scours outbreaks which cause great financial loss due to increased labor, reduced weight gain and even calf death loss.
Segregating cow-calf pairs by age of the calf has helped reduce the incidence of scours outbreaks. When possible, calving areas should be divided into large lots. After a week to two weeks of calving, cows which have not calved should be moved to the clean area.
This process should be repeated every week to two weeks so older calves are not housed with younger calves, as it is the older calves that infect younger calves. After the youngest calves are 4 weeks old, all calves can be commingled.
Colostrum consumption
The timing and the amount of colostrum consumption is critical for the newborn calf as well. Ideally, newborn calves need to stand and nurse within the first few hours of life to maximize colostral absorption and immunity. The best-case scenario occurs when a cow in good body condition gives birth to a vigorous calf in a clean environment and promptly stimulates the calf by licking it clean.
Vigorous calves quickly nurse a large colostrum meal. The first meal a calf consumes is one of the most important meals of its life because a sequence of gut changes begins with that meal.
To protect the calf from pathogens, the gut begins to “close” (loses its ability to take contents directly across into the blood) as soon as the calf’s first meal is introduced to the intestinal tract. As a result, less and less antibody can be absorbed from each subsequent meal until gut closure is complete.
Timing of colostrum delivery is critical
A common misconception about the time window available to deliver colostrum to calves is: A calf always has 24 hours. In reality, the window depends on when the calf first consumes any kind of meal. If a calf has nothing to eat, it can still absorb some antibody at 24 hours, but if the calf consumes anything, gut closure begins immediately and can be complete before 24 hours has passed.
Unfortunately, “anything” can be a dose of colostrum that is too small, milk replacer or debris nursed from a dirty udder or environment. All of these meals will initiate gut closure and decrease the amount of antibody absorbed. Worse yet, bacteria nursed from a dirty environment, including the udder, can be directly absorbed into the blood and cause severe disease.
Prevention is the best cure
Good passive transfer is accomplished most effectively by implementing preventive management strategies. These include maintaining adequate body condition score in cows, providing a clean calving environment and routinely observing calves to make sure they have paired up and nursed.
Calves born following prolonged labor, especially if the calf had to be pulled or removed via caesarian section, are at high risk for failure of passive transfer. Calves born to first-calf heifers are more vulnerable as well. Close observation of these pairs can allow early intervention to maximize passive transfer.
Intervening when necessary
Interventions depend on producer preferences as well as recommendations from local veterinarians. In cases where the calf cannot nurse colostrum from its own dam, the following options are available:
1. Milk out the dam and feed with bottle or tube feed.
2. Feed colostrum banked from other cows that have lost their calves.
3. Feed commercial colostrum replacement product.
4. Feed colostrum banked from neighboring herds (beef or dairy if available).
5. Feed colostrum supplement.
These options are listed in order of decreasing efficacy and increasing risk of introducing new diseases. Resident cattle have the ideal colostrum for their own calves because the antibodies match the pathogens present in the herd and the surrounding environment.
Disease transmission is also less likely if colostrum from within the herd is used. Commercial colostrum replacers are available, are effective and come from carefully tested herds. These products are usually costly and must be mixed carefully according to provided instructions.
Feeding colostrum banked from neighboring herds can be effective but dramatically increases the risk of introducing diseases into a producer’s herd. Colostrum supplements are relatively safe in terms of disease transmission but typically do not contain a high enough concentration of antibody to guarantee adequate passive transfer. Visit with your local veterinarian when considering these options.
Weather stressors
Regulating body temperature can be a challenge for the very young calf. Depending on the time of year a calf is born, and the current weather conditions, the challenges can vary. Calves born in cold and wet conditions may need a dry, warmer place to acclimate.
Initially, this may be a barn with the dam. However, many ranchers have devised innovative ways to make a shelter or hutch calves can access without their dams to reduce cold and wind stress. Conversely, calves born in the summer months may need access to shade and plenty of easily accessible water to combat heat and humidity. 
PHOTO 1: Providing proper nutrition and a clean environment prior to and after calving helps ensure a healthy, thriving calf crop.
PHOTO 2: The optimal situation is for a cow in good body condition to give birth to a vigorous calf in a clean environment and promptly stimulate the calf by licking it clean.
PHOTO 3: Ideally, newborn calves need to stand and nurse within the first few hours of life. Staff photos.
For more in-depth information on managing not only the newborn, but the nursing calf throughout the period prior to weaning, see NebGuide G2293 Health and Management of the Nursing Calf.
Brian Vander Ley is a veterinary epidemiologist.
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Karla Jenkins
- Cow-Calf Specialist
- University of Nebraska – Lincoln Panhandle Research & Extension Center
- Email Karla Jenkins
