Bred cow nutrition: Experts discuss nutritional requirements for cattle during late gestation
Cows have different nutritional needs at different stages of gestation. Nutrient requirements in early gestation are not much different from maintenance requirements, unless the cow is lactating. However, as the fetus grows larger, the cow’s nutrient needs increase.
If a cow is lactating, she needs a much higher level of protein and energy.
Timing is key
Dr. Travis Mulliniks, beef cattle nutritionist and range production systems specialist at the University of Nebraska-Lincoln, says there are two key time points.
“On the pregnancy side, we see a big increase in nutrient requirements during late gestation. There’s been a lot of research on supplementation and management focused on late gestation and lactation, but it mainly boils down to how it all fits a producer’s environment,” Mulliniks says.
“When we think of beef production across the U.S., the timing of when we have high-quality forages or feedstuffs affects our nutritional plan,” he adds.
In some environments, forage quality is high enough, even during late gestation, to meet those requirements, while semi-arid and arid environments may only have quality forages for three months of the year.
This makes a difference in how cows should be managed, what type of cows a producer should run and when producers should calve. Most producers in the U.S. still calve in the spring, but in the South and Southeast there are a growing number of fall-calving herds.
“Here in Nebraska and in some areas in Montana and the Dakotas, as well as several other regions, many producers are moving to summer calving because nasty spring blizzards can cause high death losses in spring-calving herds,” says Mulliniks.
Understanding nutrient requirements
“Understanding nutrient requirements and timing of forage quality in a production system is very important. Producers need to do some fine-tuning and have a good nutritional plan throughout gestation to have the optimal production outcome,” Mulliniks explains.
“Some of this research started back in the 1960-70s and focused on providing adequate nutrients for the pregnant cow and making sure she was in good enough body condition to make it through the stress of winter,” he says.
In the 1980-90s, many producers progressed to thinking about nutritional requirements for the calves cows are carrying, in addition to the requirements for the cows.
In Idaho, a lot of research was conducted in the 1970s on weak calf syndrome due to low protein levels in cows’ diets throughout the winter.
“And now, we talk about fetal programming. We may put too much emphasis on this,” states Mulliniks.
“When we look at the data and a large number of production studies, there’s not a huge difference in calf performance by maternal nutrition during late gestation. But, when we have extreme events, such as extreme cold weather like a bomb cyclone – a rapidly intensifying storm associated with a sudden and significant drop in atmospheric pressure in which weather is extremely cold and extremely wet – this can create a negative impact on the fetus and on baby calves, resulting in higher-than-normal calf losses,” he says.
“Providing correct nutrients to the fetus is like an insurance policy so it doesn’t have poor growth, poor health or nutritional deficiencies,” Mulliniks adds.
Producers need to enable their cows to deal with calving and recover quickly enough to get pregnant in a timely manner. Open cows or late-bred cows cause big losses to cow/calf producers.
“This fits into the idea of fetal programming – making sure we’re providing the correct insurance policy so there won’t be a negative effect on the cow or calf. We want to have a good impact on performance and do it in a cost-effective way,” says Mulliniks.
Achieving proper BCS
A person doesn’t want to overfeed and have cows too fat over winter, since this can also have a negative effect on performance.
Having cows with a body condition score (BCS) of six or seven usually means they’ll lose weight after they calve and start lactating. Often, these cows have the lowest pregnancy rates in the next breeding season.
“Nutrient requirements for a cow with a BCS of seven is much higher than a cow with a BCS of five,” he explains. “If she is losing weight after calving, she is less apt to cycle and breed back than if she’s maintaining weight or slightly gaining.”
“Cows with a BCS of seven at calving sometimes lose much more weight than cows with a BCS of five. It’s easier to get thin cows gaining weight and bred back up. So, producers need to think about optimizing the whole system and not just pregnancy in late gestation,” he says.
Some producers overdo it on one end of the spectrum and underdo it on the other. There should be a balance, which can be hard when making sure there aren’t thin cows while also being flexible enough when extreme events occur.
“We don’t want to be so far behind the ball that we have a major wreck with thin cows, a huge calf loss or a negative impact on future calves’ performance,” says Mulliniks.
There are many different factors to take into account.
“It involves monitoring and reading cows and knowing their BCS. Producers need to know the extent of their forage supply and feed quality and recognize how much time they have left between now and when they will see a big increase in nutrient requirements with lactation,” Mulliniks explains.
“We have to allow enough room so we don’t get too far behind, and we can’t afford to catch up. This happens when requirements are high and we don’t have high enough quality of feed,” he says.
Be prepared, be flexible
Producers always need to have a plan and be flexible in case Mother Nature throws a curve ball. They need to be able to make decisions quickly and stay ahead of the game so they don’t wake up and suddenly realize their cows are too thin.
“We don’t want to be stuck in the traditional mindset of starting to feed hay on a certain date instead of starting when the cows need it,” states Mulliniks. “We must allow enough room to make adjustments when needed.”
“I tell producers to use weaning data to formulate a plan for supplementation in late gestation, especially with young females because they are still growing while lactating for the first time,” he continues. “They are more susceptible to negative impacts from lack of nutrients, whereas a mature cow has more of a buffer.”
Mulliniks encourages producers to check BCS early and possibly consider weaning earlier if necessary so cows can regain condition before winter.
“Sometimes, producers get in wrecks if they always wean on a certain date and don’t leave themselves enough room for the uncertainty of a bad winter. In those situations, they often can’t afford to put enough energy into their cows to get them caught up before calving. If they wean earlier, thin cows can be gaining longer and, most likely, doing better,” he explains.
“This is where some producers got into trouble two years ago,” he adds. “We had a lot of rain in the spring, which caused forages to grow faster and therefore mature earlier than usual. By July and August, forage quality was more similar to forage quality in October and November.”
“We’d set ourselves up for problems because cows were thinner than usual when they went into winter, and then a bomb cyclone hit. We had serious issues with very thin cows due to lack of flexibility in management systems,” says Mulliniks.
Producers also hadn’t increased nutrient supplies in their supplementation strategy or changed their weaning date, and cows were not prepared to handle the extra stress.
“There are no specific guidelines on when or how to supplement cows, but BCS tells us a lot. We can utilize BCS with direction – knowing where we are headed – and work with a nutritionist to fine-tune our plan. We need to know what feeds are available and when to start increasing or decreasing nutritional requirements. We also need to know what to supplement our cattle with to make it all work,” he says.
Feed testing is important, yet most people don’t do it.
“Producers can run into wrecks thinking their forage is higher quality than it actually is – their cows will slowly become thinner. It can happen at such a slow rate, they don’t see it until cows are suddenly too thin and there is no time to fix the situation,” Mulliniks concludes.
Heather Smith Thomas is a corresponding writer for the Wyoming Livestock Roundup. Send comments on this article to roundup@wylr.net.
