[This is from an article in the December 2013 issue of CowManagement]
Albert Einstein is frequently credited with saying that
“Everything should be made as simple as possible, but not simpler.” While the
composer Roger Sessions appears to be the actual author of this quote, it
accurately captures the sentiment of a statement that Einstein did make
describing the role of true scientists as they state hypotheses for testing.
“It can scarcely be denied that the supreme goal of all
theory is to make the irreducible basic elements as simple and as few as
possible without having to surrender the adequate representation of a single datum
of experience.”
Peter Ballerstedt, Barenbrug USA’s Forage Product
Manager, believes that the failure to observe this advice has produced the
epidemic of chronic disease facing America today and has limited the use of
grass in rations for today’s high-producing dairy cows. “We’ve misunderstood
the role of carbohydrates in both cases,” Ballerstedt explains. If that’s hard
to follow, perhaps some of Ballerstedt’s experiences will make it clearer.
“Six years ago at Christmas, I took a family portrait.
When I looked at myself in that picture, I didn’t like what I saw.” He was “an
obese, prediabetic, balding 51 year-old.” Today, he says, “I’m just balding.”
What changed? His diet. Today he eats a diet that is high in fat (primarily
from animal products) and low in carbohydrate. “The official dietary policy and
advice is based upon two overly-simplistic and unfounded hypotheses,” he says.
Replacing dietary fat
First, that the heart-healthy diet is one that is low
in fat, low in cholesterol, with restricted consumption of full-fat dairy and
other animal products. “Since the arterial plaques of atherosclerosis contained
cholesterol, it was speculated that the solution was to limit dietary cholesterol
and saturated fat intake,” Ballerstedt adds.
“Second, that since fat contains almost twice as many
calories per gram than carbohydrate, replacing dietary fat with carbohydrate
would prevent obesity,” he continues. Despite the fact that dietary
carbohydrate was understood to be “uniquely fattening” in the human diet,
Americans were directed to consume diets where the majority of their calories
would be supplied by carbohydrates. “A calorie is a calorie, we were told,
despite the fact that isocaloric amounts
of fat, carbohydrates and protein produce different hormonal responses.”
Both these hypotheses were adopted despite the lack of
proof and the presence of conflicting evidence. Thus the products of forage
agriculture, red meat and full-fat dairy products, were falsely accused of
promoting obesity and cardio-vascular disease. “Now that I understand these
erroneous oversimplifications, I want folks in animal agriculture, especially
ruminant agriculture, to become familiar with the information I’ve learned over
the past six years.” Ballerstedt concludes by saying, “We are not what we eat.
We are what our body does with what we eat!”
So, what’s this got to do with the role of grass in
today’s dairy rations? Unjustified oversimplifications have unfairly penalized
cool season grasses. First, there’s the current understanding of forage
quality. “Our concept of forage quality has been, basically, that lower neutral
detergent fiber (NDF) means higher quality.” This was an unjustified
over-simplification.
Cool season grasses
The fact that cool season grasses have higher NDF was
assumed to mean that they were lower quality than alfalfa. But NDF readings
cannot be compared between grasses, legumes and corn silage. “Despite this,
relative feed value (RFV) and relative feed quality (RFQ) values have been used
to compare different forage species,” according to Ballerstedt. “The key fact
is that the digestibility of cool season grass NDF is higher than NDF from
alfalfa or corn.”
Italian ryegrass and alfalfa
Another oversimplification was relying on a single
laboratory parameter to predict animal performance from forage samples. Work
conducted by dairy scientist, David Combs and his colleagues at the University
of Wisconsin, has produced an improved assay that incorporates the rate of
fiber digestion, the rate of passage and the total fiber digestibility. This
new assessment of forage quality, called total tract neutral detergent fiber digestibility
(TTNDFD), allows comparisons across forage species and can be used to balance
rations.
Selection criteria in grass
Not only can TTNDFD be used to balance rations, it can
be used as a selection criteria in developing new grass varieties. “All grasses
are not created equal!” Ballerstedt states. “Barenbrug has developed varieties that
have the highest NDFD and TTNDFD of their species.” Up to ten percentage point
differences between grass species and varieties within a species cut at the
same growth stage have been documented. “Remember, a two percentage point increase
in TTNDFD can produce an additional pound of milk per day from an already high-producing
cow! Barenbrug’s NutriFiber brand assures the farmer of the greatest genetic
potential for the highest NDFD and TTNDFD.”
Jersey Cows. They are NOT what they eat!
Ballerstedt finds it ironic that his personal and
professional interest should be so tied to carbohydrates. “In humans, there’s
no such thing as an essential carbohydrate. Dairy cows, on the other hand, must
have two types of carbohydrate: non-fiber carbohydrate (NFC), starches and
sugars, to support high levels of milk production; and digestible NDF to
promote rumen health, butterfat production and animal well-being.”