Like most conscientious cattle producers, Zizzy Osborne made fetal programming a key part of herd management years ago. He just didn't know what to call it at the time.
"Cows can't make good babies if they aren't in good shape," the Eden, North Carolina, cattleman says. "That counts for dry cows, too."
When mature cows in his commercial Angus herd calve, he targets a body condition score (BCS) of 5.5 to 6.0. That focus on the dam's condition is important, not just to get a healthy calf on the ground but for good milk production to grow that calf and to set that cow up to breed back on time.
South Dakota State University Extension meat scientist Amanda Blair says Osborne's home-spun explanation is another way of explaining a scientific concept called "fetal programming."
"It centers on the idea that what the cow eats and what she endures during pregnancy can impact the lifetime performance of the calf she is carrying," Blair explains. She adds this carryover effect can include the immune system, reproduction, performance and even meat quality.
LESSONS FROM WWII
The concept of fetal programming first came to light in human research. At the end of World War II, while Nazis occupied the Netherlands, an embargo was placed on food shipments to that country. Coupled with a famine, this resulted in severe food shortages where residents were getting just 400 to 800 calories a day.
Babies born to women who endured semistarvation had light birthweights. Once grown, they had higher rates of diabetes, obesity and heart disease. The theory is they were programmed in utero with the human equivalent of what cattle producers call the "easy keeping" gene.
Blair compares DNA, or the animal's genotype, which is set at conception, to a script that can be modified. Alterations to the uterine environment can modify the expression of genes, altering the outcome, or phenotype. These changes to the gene script are thought to help the fetus prepare for conditions after birth.
In the bovine world, timing plays a critical role in this gene expression. For example, a heifer calf is born with all the eggs she's ever going to have, and those are formed early in gestation.
North Dakota State University Extension livestock specialist Janna Block explains, "The process of follicular development is extremely critical to the reproductive capacity of that female. Similar to follicles, beef cattle are born with all the muscle fibers they'll ever have." Early and mid-gestation are also when the placenta, which supplies nutrients to the fetus, does most of its growing. Shortchange the dam nutritionally at this stage, and the placenta isn't able to do its job when the fetus has its huge growth spurt in late gestation.
Block adds, "75% of calf growth occurs in late gestation. An 80-pound calf will weigh approximately 20 pounds at the start of late gestation."
South Dakota's Blair adds the majority of fat cell formation also occurs at this time. "This can affect not only intramuscular fat, or marbling, but brown and white fat used for thermoregulation when the calf hits the ground. That affects its ability to deal with temperature swings."
Block cites a University of Wyoming study on heifers restricted to 65 to 70% of their energy needs during late gestation compared to those receiving 100% of their requirements. Along with a slight reduction in birthweight, there was a 7% increase in death loss for calves from dams that received restricted energy. Calves that did survive had a decreased weaning weight of 26 pounds, a loss that can really play into the bottom line.
BODY CONDITION AND REPRO
Studies have shown cows with a BCS of 3 can take 90 days to return to estrus, while those in a moderate to higher BCS averaged 60 days to return.
South Dakota's Blair adds it is especially important to keep the BCS up on heifers and young cows.
"Heifers and young cows have a higher nutrient requirement due to their growth, which continues until they are 4 years of age. Younger cows are more susceptible to nutrient restrictions and don't have the ability to buffer the effects to the gestating calf," she explains, adding most of the research to this point has focused on understanding what occurs when negative factors are applied to a system, such as a nutrient restriction. It's the kind of information geared to "help us stay out of the ditches."
Osborne is definitely staying out of the ditches. Heifers are in better shape than cows, with target BCSs of 6 to 7 at calving.
"Our heifers get the best grass, and we supplement them with 2 pounds a day of a 14% crude protein, 70% TDN (total digestible nutrients) commercial feed," he says.
His cows are by no means ignored, either. While he says fescue, bermudagrass, crabgrass, dallisgrass and gamagrass pastures usually keep these girls in good condition year-round, he supplements them all with dry hay and, if needed, small amounts of commercial feed should their BCS start to dip.
Along with his team, which includes manager Daniel Stewart and herdsman Salvador Perez, as well as Dean Askew, beef network coordinator for Firsthand Foods and Joe French, superintendent of the Upper Piedmont Research Station, he is seeing payoffs. Ten years ago, he started the herd with 23 cows and an aggressive AI (artificial insemination) program, and he and his team have grown it to 190 females. It isn't uncommon for him to average an 80% conception rate with two rounds of AI. Overall rates for his fall and spring 65-day breeding seasons easily hit the 90% mark.
Osborne markets the top end of his steer crop to Firsthand Foods as pasture-finished beef, a choice that allows him to keep close tabs on carcass quality. The Durham, North Carolina, company targets the equivalent of middle Choice. Buyer Askew says, "Zizzy's cattle are above the average from a carcass quality standpoint."
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