Nutrition is especially important before and after calving

Published on Feb. 15, 2020

Meeting a cow’s nutritional needs during late gestation and early lactation is absolutely critical according to Dr. Katy Lippolis, Extension cow/calf specialist and assistant professor at Iowa State University. Lippolis offers nutritional suggestions for late gestation and early lactation during an Iowa State University webinar published Dec. 20.  

Developing a nutritional program

            “When I go about developing a nutritional program there are a few steps I like to think about,” Lippolis explains. “First of all, I need to know what my cows nutritional needs are, the feedstuff available to me, the base diet I have and what the nutritional content of it is.” 

            From here Lippolis says it is important to figure out what deficiencies exist on the operation, identify the availability of supplemental feed and determine what requirements need to be met in the cow.

            “There are a lot of things that determine a cow’s nutrient requirements,” Lippolis states. “These include weight, frame size, age, stage of production, body condition score (BCS) and the environment.” 

            Lippolis notes the stage in biological cycle also plays a significant role in a cow’s nutritional requirements.

 Pre and post-calving

            “Pre-calving and post-calving are the most critical time periods of the cow’s cycle,” Lippolis states.

            “Pre-calving is the second most critical nutritional period,” she notes. “During this time there is nearly 75 percent fetal growth and the cow is beginning to prepare colostrum.” 

            She continues, “Once the cow gets a calf on the ground, she enters the post-calving and early lactation period, which is the most crucial period of a cow’s lifecycle because she is not only nursing a calf and entering peak lactation, but we are also asking her to rebreed within at least 80 to 85 days.” 

            Lippolis also says during this time producers may see a two-fold increase in a cow’s protein requirements as well as a 20 to 30 percent increase in her total digestible nutrient (TDN) requirements. 

            Lippolis then shows a graph depicting protein and TDN requirement changes based on months since calving.

            “This example is based on a 1,400 pound mature cow with a BCS of five, above average milking ability and weaning at six months,” Lippolis notes. 

            She walks through the graph, which shows during the first few months post-calving, the cow has the highest protein and TDN requirements. These slowly taper off as the cow transitions from peak lactation and her current calf begins to rely more on forages than her milk.

            Lippolis notes after weaning at six months, there is a fairly straight drop off in the cow’s protein and TDN requirements, as she no longer has to provide for her calf on the ground. 

From there, Lippolis points out her requirements slowly start to increase as the fetus starts to develop.

Nutrition in first-calf heifers

            Lippolis explains it is also important for producers to take extra considerations when creating a nutritional program for first-calf heifers.

            “First-calf heifers require more protein and energy than mature cows because they are not only going into peak lactation, but they are also trying to grow,” she says. “When looking at the physiological mechanisms of a cow, reproduction is going to be her last priority if her own needs are not being met.” 

            She continues, “Setting her back at this time will result in decreased lifetime productivity because she will rebreed slower and end up weaning fewer calves each subsequent year.”

            Lippolis gives the example of a 1,020-pound yearling who will mature to a 1,400 pound cow with a BCS of five and rebreed after the first three months post-calving. 

            “This heifer needs about 3.3 pounds of protein a day and 17.4 pounds of TDN a day. She needs a decent amount of about 12 percent protein and 65 percent TDN,” she says. “This is significantly higher than needed by mature cows.”

Effect of wind chill

Lippolis also points out the effect of wind chill on nutritional requirements is important. 

            “In general, we see about a 13 percent increase in a cow’s requirements for each 10 degree drop below critical temperature,” she explains. “For a moderate conditioned, dry, heavy winter coated cow, the critical temperature is about 18 degrees Fahrenheit.” 

            She continues, “If the wind chill is -10, it would drop about three times, which would increase the requirements roughly 40 percent.” 

Feedstuff considerations

            Lippolis points out the type and quality fo the feed during this time is important when it comes to meeting that cow’s higher nutritional needs. 

            “My first suggestion is to utilize higher-quality forages later in the year,” Lippolis says. “Some lower-quality forages can start to limit how much forage a cow can consume, which in turn limits the amount of nutrition she can get from that forage.” 

            She continues, “If a producer is utilizing lower-quality forages, they need to use some kind of supplementation to give their cattle additional energy and protein to boost the rumen microbes.”

            Lippolis notes a strategic supplementation practice producers should implement before calving is to sort heifers and thin cows from older cows in good condition. This way, producers can provide supplementation to younger, thinner cows and avoid having them bullied away from the supplement.

            Lippolis also mentions during calving season, cattle need to be kept on a high plane of energy so they have enough energy to calve and avoid dystocia issues.

“Some work has found in the last month of pregnancy when comparing a low-energy diet to a high-energy diet, those cows on a low-energy diet had a 30 percent reduction in calf survival, 58 percent more scours, 20 percent more deaths due to scours and 15 pounds less weaning weight,” she states.

BCS

            When looking at the effect BCS has on calves, Lippolis says data proves similar outcomes. 

“When comparing cows with a BCS of two through six, calves took almost twice as long to stand on the thinner cows,” she says. “Calves on thinner cows also have lower amounts of immunoglobulin in their serum than those on fatter cows.” 

Lippolis also notes cows with a BCS lower than four also have a 30 percent reduction in rebreeding rates and have longer post-partum intervals.

With this in mind, Lippolis points out it is important cattle aren’t too fat pre-calving either. She says an adequate BCS for pre-calving is a moderate 5.5.

            Hannah Bugas is the assistant editor for the Wyoming Livestock Roundup. Send comments on this article to roundup@wylr.net.