Calf Diseases, Immune Systems & Nutrition

By Roy Williams, DCHA Leadership Class Member

Most of us are aware that, in many parts of the world, there are serious issues with malnourished children and very high rates of mortality among those young children. There is a strong connection between nutrition and the ability of the body to fight off disease.Calves' immune systemsare affected by nutrition, too.

Within the dairy industry, there is a lot of talk about "accelerated" milk feeding programs for calves.Dairy calves are typically fed at much lower rates than are naturally raised beef calves (8 lbs of milk per day vs. 30 lbs), and dairy calves (on average) suffer 3 to 4 times more mortality than beef calves.

Here are some documented trials that support the hypothesis that the amount we feed calves has a lot to do with the mortality and morbidity rates we see in dairy calves.

Two significant disease agents in calves are Cryptosporidium and Salmonella. In a research trial at Cornell University, two groups of calves were fed an infectious dose of Cryptosporidium parvum at age 2 days. One group of calves was fed a "standard" milk replacer ration (20-20 at 0.13 Mcal per kg of body weight per day, or roughly 1 lb of powder for a 100 lb calf), the other group was fed an "accelerated" milk replacer ration (28-20 at 0.30 Mcal per kg of body weight per day, or about 2.5 lbs/day for a 100 lb calf). At the end of the 21-day trial, it was found that the calves fed the "standard" ration had lost a small amount of weight, while the "accelerated" group had gained almost 1 pound per day, and experienced a much quicker recovery as measured by fecal scores. At the end of the 21-day trial, the "standard" fed calves were still scouring (their fecal scores improved by only 0.2), while the "accelerated" fed calves had mostly quit scouring (their fecal scores had improved by 2.0).

Land O'Lakes provided this author with information on a field trial that was done on Jersey calves. In the first phase, half of the calves were fed a 20-20 milk replacer at the rate of 1.1 pounds per day; the other half of the calves received a 28-25 milk replacer at the rate of 1.4 pounds per day. As expected, the "accelerated" calves were somewhat larger than the "standard" calves after 9 weeks. However, after these calves were sent to a grower, the experiment did not quite go as planned. A Salmonella dublin outbreak occurred at the grower's facility after the calves had been there several months, with the outcome that 34% of the "standard" fed calves died, and only 16% of the "accelerated" fed calves died. (All calves were fed the same amount at the grower.)

These two reports illustrate the significant effect of nutrition on the immune system. Calves fed a little more thantwice as many calories (about 4 bottles, high protein) per day had half the death loss as calves fed 2 bottles to a Salmonella outbreak months later; and well-fed calves (3 bottles, high protein and fat) recovered from Cryptosporidium infection, while calves fed 2 regular bottles did not.

The author wishes to thank Dr. Tom Earleywine of Land O'Lakes for some of the information contained in this article. The author also wishes to acknowledge the assistance of DCHA president, Dr. Bob Patrick, Shamrock Animal Health Services, Inc., in developing the content of this article.