A revised edition of the nutrient requirements of beef cattle has been released.
This is the eighth version published since 1944 by the United States’ National Research Council. It includes updated information on nutritional requirements, byproduct feeding and environmental impacts of all aspects of the beef sector. Feed products, cattle type and new research have changed since the last version was circulated in 1996.
“The book really goes into detail about the various nutrient requirements of the animal and then the second part is meeting the requirements by understanding the feed composition,” said Karen Beauchemin of Agriculture Canada.
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She was the only Canadian on the 10 member committee, which has been working on the 479 page book for three years. Portions of the new guide are available online, and the entire book is available for purchase.
Nutritionists, laboratories that test feed, researchers, producers who are formulating diets and the Canadian Food Inspection Agency rely on this information, she said.
One chapter with 170 feeds in a database describes nutrients.
“We always say, ‘get your feed tested,’ but it is always good to know facts,” Beauchemin said.
“It gives you an idea of what to be expecting and what the average range is for different nutrients in different feeds.”
Tables provide information on feed types, dry matter composition, energy, carbohydrates, protein macronutrients, calcium, phosphorus, manganese, potassium, sulfur and micronutrients such as cobalt, copper, iron, selenium and zinc .
Most of the basic concepts for nutrition information remains the same.
“It is refining what we have been doing and ensuring we are doing it better,” she said.
However, updates were needed because modern cattle grow faster and larger.
“There was actually data from Alberta that went into testing the robustness of those equations that were originally developed years ago,” she said.
A new system for feeding cows talks about using body condition scoring to show what those scores mean and how they can be used to assess the energy required or lost if the animal is losing weight.
“We don’t weigh mature cows, and it is really hard to know what they need,” she said.
“If you don’t know how heavy they are or how fat they are, those factors are really going to dictate what you need to feed them.”
There is also an animal welfare component, which includes how to feed stressed animals.
Another chapter on water requirements includes formulas to estimate intake, quality guidelines and information about what is acceptable in terms of salts, hardness, nitrates and contaminants.
Considerable attention was paid to feeding byproducts, especially those derived from the production of grain-based biofuel. Almost nothing was mentioned about these products in the 1996 version.
“Now byproduct feeding, especially those byproducts from the distilling industry, make up a large part of beef cattle diets,” she said.
The book focuses mainly on corn and soybean byproducts because they are available in large amounts and are commonly used.
“We did not exhaustively review all byproducts,” Galen Erickson of the University of Nebraska said during a July 12 webinar.
“For hundreds of years, distillers grains have been used as a protein source.”
The guide provides information on assessing protein content of these products.
“If you make corn into distillers grain, you increase the protein content by about threefold,” he said.
“If you look at individual amino acids, for instance, lysine in the original corn would be about two percent of dry matter. That is increased roughly threefold in distillers grains.”
Research information is also presented on dealing with the higher sulfur content of these products. Cattle that receive too much sulfur in their diet run the risk of polio unless the right balance of roughage is added.
Erickson said the guide will be updated as more research is conducted on the use of byproducts.
