There are several principles for scour prevention in elk calves. These good management practices apply to all cervids and include the following strategies.
Removing sources of infection
High infection pressure is a major risk factor on many elk (and deer) ranches. A key management step is to reduce the environmental contamination to a level that will not overwhelm the natural defense mechanisms of the calf or fawn. Steps to achieve this are:
- Avoid overcrowding – We know that overcrowding increases the incidence of scours in beef herds, and this has also been observed in a clinical setting in elk herds. One different aspect in elk is that they tend to swap calves more if they are more heavily confined, which can leave some calves with inadequate colostrums. The amount of space needed varies depending on the quality of the calving grounds, but certainly more is better.
- Improve quality of calving grounds – The land should be dry and well-drained. Potholes with water can be a major problem. All water should be drained either naturally or with a pump, but should not be allowed to just evaporate. These water holes can be a major source of infection. Leaving the calving area clean and dry in the hot summer months will help reduce the number of bacteria in the soil.
- Change location of calving grounds – The calving grounds should not be in the same place year after year. This is especially important if diarrhea has occurred on this farm before. The bacteria and viruses that cause scours can be very hardy, and survive in the soil for a long time. Moving cows into the calving grounds one to two weeks prior to calving will prevent excessive accumulation of manure and decrease the pathogen loads.
- Isolate the calf from contaminated environments – This is not as important a factor in elk and deer herds as it is in beef herds, mainly because elk are calved in open paddocks. However, it still needs consideration.
- Split up the calving herd – Ideally the early calvers, the late calvers and the heifers should be separated and calved in different pens. If this is too difficult, separation of the heifers from the cows is the minimum. Studies in beef cattle have shown those herds calving heifers and cows together have an increased incidence of scours in all calves. A likely cause of this is inadequate colostrums intake in the calves born of heifers resulting in diarrhea and shedding of pathogens, and thus increased infection rates.
There are 3 reasons for splitting up the early and late calvers.
- Older calves can shed pathogens harmful to the naïve younger calves, who have variable immunity levels.
- Older calves have waning colostral immunity that makes them more susceptible to pathogens spread by stressed cows at calving.
- Older calves may steal milk and cross mothering may create confusion for some calves that end up not getting their due rations.
Stress is a major factor in disease. Handle the calves as little as possible in their first 30 days. Excessive human contact can be very stressful to the calves, and can greatly increase the incidence of disease. Check the cows no more than 3 times a day from the outside of the pen, and other than tagging shortly after birth, there should be no human contact.
Split up the early and late calvers as mentioned above. This will reduce the amount of stress on the younger calves.
Increasing nonspecific resistance
Colostral intake is essential in preventing both sickness and death due to scours. Absorption of colostrum from the gut ceases as early as 10 to 15 hours postpartum. Therefore, it is important to ensure that each calf gets at least 50 mls per kilogram, or just under a litre in the first 12 hours after birth. Assuming birth weights of about 18 kg, 2 litres of colostrum in 24 hours is ideal and approaches the mammalian norm of about 10% of body weight as fluids per day.
However, colostrum provides an important measure of local protection inside the gut lumen for much longer than 24 hours after it is absorbed. If you are bottle raising calves, and scours is a risk, you should consider obtaining colostrum from sheep or goats prior to the calving season and freezing it. It can be used later in calves where colostrum is not available from the mother for whatever reason.
Increasing specific resistance
Immunity to specific pathogens varies from herd to herd and within herds, depending on exposure to infectious agents. Therefore, vaccines are used in an attempt to boost immunity to specific pathogens. In the case of elk calves, these pathogens include E. coli, rotavirus, coronavirus, Cryptosporidium and Salmonella. These vaccines are designed to be administered to beef and dairy cows before calving, and the antibodies produced are passed onto the calf via the colostrum. So, colostrum intake is still crucial.
Many elk producers are using these vaccines in an attempt to reduce scour problems. This is an off-label use of these vaccines. We know very little about either the safety or efficacy in elk. The results are mixed.
On the plus side, there are some anecdotal reports of reduced morbidity and mortality in elk herds that have used vaccines. There are no reports (so far) of serious adverse reactions to the vaccines. Therefore, they may be safe, but without clinical trials we don’t really know.
The use of these vaccines also has a number of disadvantages. These include:
- Off-label use – These vaccines have only been tested for safety and efficacy in cattle and sheep. Elk producers assume all the risk for any losses that may occur from adverse reactions.
- Lack of research – There have been no controlled trials to see if the vaccines actually reduce problems related to scours. Research has been done with cattle, but do the findings apply to elk? There are cases of scours in herds that are vaccinated.
- Variability of pathogens – There is really no good information on what cause scours in elk calves, as opposed to bovine calves. Cryptosporidiosis is much more severe in red deer than it is in bovine calves, and has the same severity in elk calves. There is no vaccine available to control cryptosporidiosis.
Overall, we simply don’t know enough about this disease process or the vaccines to make an informed decision. However, some producers will continue to use the vaccines, with varying success.
Scours in cervid young is a management disease. With good management in the calving season, the incidence of this disease can be greatly reduced or eliminated in most elk and deer herds.
Source: Dr. Jerry Haigh