Maximizing beef calf health

Maximizing calf survivability is crucial to economic success of beef producers. But having healthy calves starts many months before calving season. Proper herd nutrition impacts calf survivability more than any other factor. Proper environment/facilities also are important. If these two factors are under control, herd outbreaks of calf diseases will be minimized.

Calf losses are greatest in the first week of life, and most of these are a direct result of dystocia. Some causes of dystocia, such as fetal malpositioning, are impossible to control. However, other causes of dystocia, such as poor nutrition due to under or overfeeding and poor heifer and bull selection, can be minimized with proper management.

Nutrition

Underfeeding late-gestation cows can have a major impact on calf survivability for two reasons. First, stillbirths will increase, probably due to failure of the cow to go into labor or prolonged labor. Second, birth weights of calves might decrease, as will calf vigor. The producer might not notice this unless records are maintained of cow body-condition scores and calf birth weights and survival. This slight decrease in calf birth weight and vigor increases failure of passive transfer, increases cold stress and hypoglycemia, and decreases disease resistance, all of which decrease calf survivability.

Overfeeding, although less common, can be as damaging as underfeeding. Excess fat in the vaginal cavity can cause dystocia. Overfeeding of heifers can increase fat in the udder, and impact milk production later. Nutrition also impacts vaccine response due to its impact on the immune system—both humoral and cell-mediated immunity. Cows can respond to a vaccine only if they have proper energy, protein and mineral levels in the diet. For example, if a cow isn't taking in enough protein to maintain her body condition, she can't make antibodies. Therefore, vaccinating cows to protect calves through colostral transfer of immunity will only work with proper cow nutrition.

Historically, focus has been placed on the influence of nutrition in the third trimester on calf health. A newer focus is the influence of nutrition in early gestation and its impact on placental weight and subsequent fetal growth, neonatal weight and conformation, and body fat makeup and metabolism. Subsequent growth later in life and long-term reproductive health of calves could be impacted by nutrition in these early stages of gestation in their dams.

Failure of passive transfer

Many immune-system defense mechanisms are lacking or deficient in the neonatal calf. Therefore, intake of high-quality colostrum to provide adequate passive transfer of immunity is one important factor in protecting calves from disease. Besides providing circulating immunoglobulins, colostrum provides local immunity in the gut, WBC's that also contribute to local immunity and stimulate cell-mediated immunity if fresh, and nutritional elements. Calves that receive colostrum might have higher growth rates than calves that don't receive colostrum, even if those calves don't become ill. This increase in growth rate carries over even into the feedlot.

Several factors can contribute to failure of passive transfer (FPT). Low immunoglobulin concentrations in colostrum of beef cows usually are a result of poor nutrition, especially in heifers. Weak calves and poor udder conformation or a poor environment can all interfere with the calf's ability to ingest colostrum. Even if calves ingest adequate amounts of good quality colostrum at the appropriate time, sometimes they do not absorb enough of the immunoglobulins. Dystocia leading to hypoxia and acidosis likely is the most common cause of poor absorption. Other causes that are implicated, but difficult to prove, are placental insufficiency due to fetal oversize and/or poor nutrition in early gestation.

Prevention of FPT in an individual calf involves ensuring that 100 grams of immunoglobulins is ingested. Two liters of beef or four liters of high-quality dairy colostrum is recommended. High-quality dairy colostrum is hard to find and should come only from farms on a Johne's control program. The colostral supplements available at this time are very poor substitutes for real colostrum, and do not warrant the purchase cost.

Prevention of FPT on a herd basis involves providing adequate nutrition, providing an environment that allows the calves to stand and nurse without difficulty, minimizing dystocia and culling cows with poor udder and teat conformation.

It's important to remember that FPT is not a death sentence. On any one farm, there are going to be a few calves that have FPT, even if these farms are well managed. Disease outbreaks in the calf herd start to arise when the numbers of FPT calves increases, usually due to poor nutrition. The more FPT calves on a farm, the more likely a calf will become ill with a contagious disease, such as infectious calf diarrhea. Calves are amplifiers of disease because they shed more organisms than the adults, even if not clinically ill. So one ill calf can be the start of a vicious cycle of disease transmission that spreads throughout the herd.

If a specific infectious organism is identified in a calf-disease outbreak, vaccination of the cow a month prepartum to passively protect the calf can be considered. But because outbreaks are more common at the end of the calving season, vaccinations rarely help prevent disease in the current year, but it could help prevent cases the following year.

Sanitation

It's also important to remember that the adequate passive-transfer status of the herd can be overwhelmed by a dirty, contaminated environment. Feed troughs and hay racks should be moved periodically and placed away from water and shelter to discourage congregation of cattle in one area, and subsequently dissuade the concentration of pathogens. If a disease outbreak occurs in the calves, move pregnant animals to a clean pen, and leave sick animals in the already contaminated pen. Healthy calves should not move with pregnant cows because they could be incubating the disease and risk contaminating another pen. If possible, move healthy calves to a third pen. Cattle should be segregated in groups according to calf age so young calves are not exposed to older calves.

Other preventive strategies

Umbilical infections can be a problem in some herds, especially during wet years. Dipping navels with 7-percent tincture of iodine at birth, as well as controlling cattle movement and congregation as discussed earlier will help decrease the number of umbilical infections in a herd. I prefer 7-percent tincture of iodine.

Proper heifer development and selection, and bull selection are beyond the scope of this article but are extremely important in decreasing dystocia, weak calves and FPT.

Heifers should be bred to calve early in the calving season so they can be observed more closely for dystocia. In some years, early weaning of calves born to heifers—and cows if necessary—might make maintaining proper body condition in these heifers easier as they continue to grow.

If embryo transfer is employed, selection of good embryo recipients is crucial. Heifers should be avoided, as should cull dairy cattle, such as mastitis, Johne's disease, poor udder conformation, etc. Producers should be encouraged to select proven dams from their own herds as recipients. An alternative is to lease good, proven cows from other producers. Cows should be leased from farms with BVD and Johne's control programs in place, as well as other biosecurity measures. Embryo recipients are more likely to have large, overdue calves, so close observation during calving is very important.

Feeding at night or even in the afternoon increases the likelihood of daytime calving. On-farm lay help and veterinary services are more likely to be available during the day, so dystocia problems and weak calves are more easily handled and treated more promptly.