Connecting the dotsWritten by Saige Albert
Lake looked into feed efficiency, its implications in selecting bulls and the importance of feed efficiency as a one of a variety of tools in herd improvement at WESTI Ag Days in Worland on Feb. 8.
“As producers, an efficient cow is one that stays in good condition, weans a calf and breeds back in time,” said Lake. “I think we do a good job in selecting for that type of cattle.”
He continued, explaining that efficiency is a ratio that looks at inputs compared to outputs. Residual feed intake (RFI) is one tool that producers and researchers utilize to describe feed efficiency in many cases.
However, Lake mentioned that it is important to understand the RFI information provided before utilizing it to make selection decisions.
Residual feed intake
Residual feed intake is one method of measuring efficiency of animals and is calculated by subtracting the expected feed intake from the actual feed intake of a livestock animal.
“Some animals eat more than expected for the level of productivity, and they have a positive RFI,” explained Lake, noting that many people get confused in distinguishing good and bad RFI. “Think of it like a test from the doctor – positive is bad.”
He also noted that, because RFI doesn’t account for growth, two animals with the same feed intake and average daily gain may be very different in size and growth.
The order of energy partitioning
Using the example of two cows with identical body weight, diet and consumption rates, Lake said that one animal would likely gain more than the other.
Lake added that research shows the order of energy partitioning accounts for the differences. Energy partitioning is where the energy from feed intake is applied in a cow, and at what priority her energy needs are addressed.
“When a cow assimilates energy, the first priority is maintenance, second is growth, third is lactation and fourth is reproduction,” explained Lake. “Maintenance and growth will always be the number one priority.”
Because reproduction is the lowest priority on a cow’s survival list, if her other needs are not met, she will not put energy toward reproducing.
Lake questioned that, if producers select for only efficiency, or the maintenance and growth aspect of a cow’s development, are they sacrificing reproduction?
“Is the really efficient animal putting more emphasis on the individual and putting less on the reproduction and lactation?” he asked. “Is she sacrificing reproduction for gain?”
While the question remains unanswered, the consideration of energy partitioning should help producers realize that selecting for efficiency alone is not effective.
“We don’t want efficiency to come at the expense of reproduction,” said Lake. “We have been trying to connect the dots to determine the effects of efficiency.”
Profitability and efficiency
“Efficiency does not equal profitability,” added Lake.
Using an example of two bulls from the Wyoming Beef Cattle Improvement Association Bull Test, the lowest RFI animals and the second worst bulls on the test, Lake proposed that production may ultimately be more important.
The difference in the animals’ consumption was three pounds of feed per day, and Bull A, the most efficient bull, produced 20 percent less than the worst bull on test, Bull B.
“Three pounds per day over a six month winter feeding period, at a price of $200 per ton of hay would cost $54 per head more, over six months, to feed the less efficient bull,” said Lake. “That would be a huge savings with Bull A.”
Using the 20 percent size difference, Lake also mentioned that performance may be very important. If Bull A weaned a 500-pound calf, then Bull B would theoretically wean a 600-pound calf, and in today’s cattle market, Lake noted that the calf from the less efficient bull would be worth nearly $100 more.
“When we subtract out the hay savings, the calf from Bull B is more profitable by about $42,” explained Lake. “Growth is what really drives profitability.”
The perfect combination?
“Very rarely is an effective breeding program based solely on a single trait,” commented Lake, adding that bull selection is perhaps one of the most critical decisions made on operations. “In three generations, the bulls’ genetics will make up 85 percent of the herd.”
“It seems like it takes a while to make progress, but it doesn’t take very long to turn an operation into a disaster,” said Lake.
To achieve whole system efficiency, Lake noted that cow longevity, weaning calf percentages, weaning weights and average daily gain are all important, and improving all those criteria may be achieved through crossbreeding.
“If we made our bull decisions based on performance and efficiency, and we put them in a crossbreeding program, then we might capture additional benefits and even more value,” he explained.
Because reproduction is an important aspect of operations, Lake encouraged producers to look at selecting for reproductive traits, rather than carcass quality and size alone, saying, “It is extremely important to not ignore the foundation of the operation – the maternal side. Let the carcass take care of itself.”
Continuing research to develop understanding of the many traits affecting bull selections is ongoing, said Lake, but selecting based on feed efficiency alone may be dangerous for producers.
“There are more and more dots that we are connecting,” said Lake. “Maybe we’ll find what’s really important. I don’t want to say any one trait is not important, so use caution when making selections.”
Does cow size correlate with efficiency?
“We have a big concern about cow size,” said University of Wyoming Livestock Extension Specialist Scott Lake. “Smaller cattle aren’t necessarily more efficient, and, in fact, generally, larger animals are more efficient.”
Lake spoke at the Feb. 7-8 WESTI Ag Days in Worland.
Larger cows have a higher production potential and are more difficult to maintain, said Lake, while smaller cows with the lower production potential are low maintenance and require less feed.
Environmental factors play an important role in the efficiency of small or large cows, added Lake, who noted that, in areas where it is possible to meet the needs of larger, high maintenance animals, they might be more efficient.
“With a lower production potential animal, such as the traditional Angus or Hereford, in a low energy system, we can meet the maintenance needs of the animal, and they can still grow well,” explained Lake. “They don’t have the higher production potential so they will milk and raise a calf, keep in good condition and breed back.”
In a low production system, higher maintenance cattle aren’t being fed to their potential so they aren’t milking to their potential and may breed back at a lower rate, he explained.
However, in a high feed environment, utilizing low production animals will result in fat cows, according to Lake, and large amounts of waste can be expected.
“In a high production system, a higher producing cow is more efficient,” added Lake. “Those cows are able to produce a lot more milk, maintain their weight and still breed back.”
He added the caveat the high producing cow should also result in a calf with a heavier weaning weight, or it is not more efficient.
At the end of the day, depending on the maintenance requirements that forage or rangeland can support, the most desirable and efficient cow size is a function of region.
“The practical implication is that low maintenance doesn’t necessarily mean efficient cows, and high maintenance cows are not necessarily inefficient,” said Lake. “Maintenance energy alone is not a measure of biological efficiency.”