With the start of spring calving season upon us, cow-calf producers (as well as we veterinarians) are knee deep in one of the most stressful, yet exciting times of the year. Although I always look forward to seeing healthy baby calves out on pasture, calving season is generally an exhausting and sometimes frustrating whirlwind season. To avoid some of the stress and frustration, I like to adhere to the adage ‘an ounce of prevention is worth a pound of cure,’ especially when dealing with one of the first health challenges a rancher faces – calf scours.
Calf scours prevention is a year-round effort that centers on the management of the health, nutrition, environment, and sanitation of the herd. Prevention efforts should consider the entire herd as well as that of the newborn calf. There are a variety of factors that affect the rate of occurrence of scours in calves from year to year and from ranch to ranch. Some of these factors can take years to influence, such as genetic makeup of the cowherd (indeed, some lines of cattle produce a ‘˜heartier’ calf) and age of the dams (calves born to heifers are at a higher risk for developing scours). Producers have little control over some factors, including cold and wet weather. Yet, with a little planning, there are many factors that a producer can control in a short time frame. Some of these factors are discussed here.
Optimize gestating cow and heifer nutrition
Cow and heifer rations should be well managed in terms of energy, protein, minerals, and vitamins until calving to account for increased gestational and seasonal requirements. The most critical period in the nutritional lifetime of a cow is 50-60 days pre-calving. This is when the placenta and fetus grow rapidly (up to two-thirds of calf growth occurs in the last third of gestation) and the cow is preparing to lactate. In the few weeks before calving, feed intake capacity of the rumen may decrease as the reproductive structures and fetus occupy a majority of the abdominal cavity. Typically, loss of body weight in the last third of gestation can be attributed to insufficient protein and energy intake. Adequate protein in the cow diet is especially essential for the cow to produce high-quality colostrum for the newborn calf.
A good rule of thumb is cows and heifers should calve in a body condition score of 5/9 to nourish a healthy calf and breed back quickly. Another rule of thumb is that replacement heifers should be at 80% of their mature body weight by the time they have their first calf. This means that heifers require a higher nutritional plane during gestation compared to mature cows to account for growth. If you haven’t already, I encourage you to develop a close relationship with a beef nutritionist to review your gestating ration and ensure the optimal condition of the herd.
Ensure a clean calving area and pair pasture or lot
A calf contracts scours by consuming fecal matter in the environment (whether that be from a dirty udder or directly from the ground). Thus, limiting the stocking rate and amount of time a pair is in the calving area reduces the amount of fecal exposure to newborn calves, thus diminishing their chances of developing scours. It’s important to try to segregate cow-calf pairs from pre-calving cows in order to decrease the environ-mental contamination to which newborn calves are exposed. Ideally, producers should bring close-up cows into the calving area/pasture and move older pairs out of the calving area into a clean area as soon as possible.
If providing calf shelters, these areas should be draft-free, yet well-ventilated to reduce humidity and improve air quality. Dry, comfortable bedding (such as straw, chopped cornstalks, or poor quality hay) is important to encourage calves to nest. Maintenance of calf shelter hygiene is critical, as baby calves love to chew on bedding and can easily consume environmental microbes that contribute to calf scours.
Implement pre-calving vaccination
Another prevention strategy that producers may consider is providing pre-calving vaccinations to gestating cows and heifers. Sometimes referred to as ‘scour shots’, these vaccines aim to program the dam’s immune system to produce protective antibodies against the most common scour-causing agents (including clostridium spp., rotavirus, and coronavirus). These antibodies will concentrate in the colostrum the calf receives within the first 24 hours of life. Like every vaccine, the timing of dam vaccination is very important to realize the maximum benefit from these vaccinations. In heifers, it is optimal to administer two rounds of pre-calving vaccinations 3 weeks apart, with the final vaccine given no later than 3 weeks prior to calving. In cows that have been vaccinated in previous years, one vaccination 3 weeks prior to calving is sufficient.
Start the calf off right with high-quality colostrum
The immune system of the newborn calf immune system is naïve as it is equipped with little to no defense against disease. For this reason, the dam provides the calf colostrum (the high-energy, ‘first milk’ loaded with disease-fighting antibodies). A calf needs to consume at least 2 quarts of high-quality colostrum within the first 2-6 hours of life, in addition to an-other 2 quarts over the next 6-12 hours in order to absorb the antibodies necessary to fight disease in the first few weeks of life. After the first 24 hours of life, a newborn calf is unable to absorb antibodies from colostrum and is essentially at a much greater risk to becoming sick during the first months of life.
Ideally, a calf will have the innate drive to nurse on its own and will easily consume the required amount of colostrum. However, it is imperative for producers to ensure a cow has milk and observe the calf nursing. If there is any question whether or not the calf has nursed, I suggest that the pair be stanchioned and the calf either helped to nurse from the teat, or the udder be stripped out and that colostrum is bottle-fed to the calf.
The best source of colostrum is from the dam, as this contains antibodies specific to the environment the calf is in. If the dam does not have colostrum, or it is not attainable, the second-best source would be colostrum obtained from other cows in the herd. If this is also impossible, a colostrum replacer (note, this is not a supplement) may be used. I suggest speaking with your veterinarian on what constitutes a good colostrum replacer in this situation.
A little planning and preparation can make calving season the perfect time of year to renew spirits and bolster enthusiasm for the cattle business. Producers who are anticipating calf scours, or have dealt with scours in the past, should contact their local veterinarian to develop a prevention program specific to their herd and management style. As always, may the weather soon warm up, the ground dry up, and your cattle be healthy!