One of the primary challenges of bringing calves or yearlings into a feedlot is minimizing stress associated with shipping and processing.
Under non-stressed conditions, animals allocate nutrients in the following order - body maintenance, pregnancy, growth and then immune response. When an animal becomes sick or stressed, the order of nutrient use shifts to body maintenance, pregnancy, immune response and then growth.
That's why, when an animal is stressed, growth is reduced or stopped completely. Providing optimum nutrition to aid the animal to develop a strong immune response to disease pathogens and vaccination is the best opportunity to head off stress-related illness.
Nutrition And Immune Response That nutrition can affect a calf's immune response and increase vaccine efficacy is a widely accepted concept. It isn't, however, practiced as widely as most consultants would like.
Most producers are concerned with protein and energy, but many programs lack the proper vitamin and mineral supplementation or use the wrong recommendations. Feed salesmen should sell programs, not products, to the producer.
Vitamins such as A, E and the B-vitamins are essential to the immune response, as are the minerals copper, zinc, selenium, iron and manganese. Antibodies are made of proteins, so protein levels of 14-16% should be in the receiving ration.
Urea or non-protein nitrogen has no place in receiving rations. By-pass protein, however, has shown favorable results in a number of receiving rations.
Despite the general awareness of increased requirements and reduced animal performance during stress, the data doesn't detail precisely the specific needs of all stressful situations. The variety of possible scenarios in feed, water, cattle types, environment, handling, age, vaccinations, parasites and disease challenges makes a blanket recommendation impossible.
However, by using past experience, along with feed and water analysis and cattle history, nutrition consultants, in conjunction with the veterinarian, can put together a good receiving program for the producer.
In most weaning/receiving rations, I recommend 1.5 to 2 times the NRC recommended levels of minerals. This, of course, does not take into account any antagonistic levels in the water or feed and any problems particular to each individual producer.
I like to include chelated (organic) forms of copper, zinc, magnesium and possibly manganese and potassium at a level of 30% of the total mineral level. At this level, I feel I get the best response for the animal at the best cost for the producer.
These are the general guidelines I use for receiving diets. Most diets, however, are customized for each producer.
* Protein - 14 - 16%
* Concentrate - 50 - 55% ration (more for yearling cattle)
* P - 0.4 - 0.6%
* Mg - 0.2 - 0.3 %
* Cu - 12 - 15 ppm
* Mn - 40 - 60 ppm
* Zn - 75 - 100 ppm
* K - 1.2 - 1.4%
* Se - 0.1 - 0.2 ppm (max.)
* Vitamin A - 2,000 - 3,000 IU
* Vitamin E -100 - 400 IU
Medications such as Bovatec, AS-700 or Deccox may be included if problems are anticipated. Probiotics and yeast cultures also may be included to stimulate rumen activity.
A high level of potassium is of importance for incoming cattle because potassium and sodium are depleted by shrink, especially when it's more than 6-7%.
The immune system is one of the most complex and intricate molecular interactions in the animal's body. Proper trace mineral supplementation won't eliminate disease. It will, however, allow the animal's immune system to respond with efficiency to disease pathogens and vaccination programs and minimize the risk of economic loss.
David Wieland is a nutrition consultant specializing in cow/calf, feedlot and horses. Based in Shepherd, MT, Wieland also publishes a subscription newsletter. For more information, contact him at 406/373-5512 or e-mail at [email protected]