One thing leads to another
The lifetime event of perinatal nutrition
By Kylee Kohls
There’s a cause and a consequence for everything.
You can see it in cow herds just before and after calving, says Allison Meyer, animal scientist at the University of Missouri.
The 5.5% of calf deaths in the United States that occur prior to weaning add up to losses of at least $670 million per year, plenty of economic incentive to find answers. Meyer studies what cows eat in the perinatal period from last trimester to the first three weeks post-calving, and the transfer of nutrients from cow to calf.
“We’re particularly interested in how many nutrients are getting to the calf,” she says. “Then, how that affects its growth and development—and ultimately its long-term health, reproductive efficiency and carcass quality.”
Causes for a shift in nourishment available to the calf begin with dietary balance and intake for the cow. How is the forage quality? Is she being supplemented to meet requirements? Is she a heifer that’s still growing or a cow with high lactation potential? Is there heat or cold stress effecting her energy intake or needs?
“When the calf is a fetus, the cow provides all nutrients through the uterus and placenta,” Meyer says. “Certainly she has to consume the nutrients, digest them, then absorb them and transfer those to the calf. But once the calf is born, it is relying on the cow or the first-calf heifer to make colostrum and milk.”
The calf, in turn, has to be vigorous enough to get the colostrum or milk and have a good enough gastrointestinal (GI) tract or gut to digest and absorb the nutrients and use them.
“We know calves that don’t consume as much colostrum and get sick early in life are less likely to grade Choice and less likely to have a high weaning weight,” Meyer says. “It needs colostrum really early” and can only use available nutrients if the gut can digest and absorb those so the calf can “stay warm, finish development and grow up.”
We ask a lot of the newborn calf GI tract, she says.
“The gut is trying to deal with all the pathogens that are coming in from the outside, so it’s important to make sure it’s developed appropriately,” Meyer says, explaining why calves need colostrum to create passive immunity.
Newborn calves have few nutrient stores, relying on nutrients from the cow to ensure their vigor, development and production. That starts before birth, she says: “From the post-weaning period until the calving period, we need to make sure cows are maintaining or gaining body condition.”
Cutting back to where females lose weight risks creating runts that can’t fully express their genetics.
“We want calves to match their genetic potential as a fetus because the growth and development they’re doing then is setting them up for everything they will do after birth,” Meyer says.
“We don’t want to decrease fetal growth or decrease birth weight by restricting or taking feed away from a cow or heifer while she’s pregnant,” she says. “If we want to decrease birth weight because we’re worried about dystocia, we really need to make sure we do that genetically. We want the genetics of the calf to tell it how much to grow as a fetus.”
Feeding pregnant cows appropriately leads to their calves’ independent health.
“Our goal is for calves to be born alive,” Meyer notes. “How we keep them alive is to make sure they get the nutrients they need before they are born, and then continue to get the nutrients they need after they are born.”
In a lifetime of causes and consequences, she says, “It’s important to focus on the pre-weaning calf, because regardless of what type of beef producer we have, whether they’re trying to produce the next national champion bull or just calves to take to the sale barn at weaning, how many live to weaning and how ready they are for the next phase of their life matters to everybody.”