LINCOLN, Neb. — We ask a lot from our cows come breeding season. We expect her to be providing adequate nutrients for calf growth (lactating), we expect her reproductive tract to repair and return to estrus prior to the start of breeding. All these expectations are within 90 days after calving to maintain a yearly calving interval.
So, what are some considerations that we can think about to meet nutritional requirements in our cows at breeding and have a successful breeding season? Those considerations may include quality and quantity of the consumed forage, nutrient requirements, and understanding what feed resources options we may need to consider helping meet those requirements.
Evaluate your Forage Base
When evaluating your forage base, we need to think about two things: 1) Can a cow eat all she wants in a given day? 2) What is the quality of forage she is consuming? During drought or drought conditions, we may see reductions in both quality and quantity of your forage. More resources related to forage management during a drought can be found on our drought page: https://beef.unl.edu/cattleproduction/drought.
Depending on when your breeding season occurs, knowing the quality of your forage and body condition of your cows will be key in knowing how to proceed. Forage quality of native range tends to peak around June and starts declining in July until November. More information on the dynamics of forage quality can be found here: https://beef.unl.edu/documents/2019-beef-report/MP106_pg021_Mulliniks_Adams.pdf.
Cow’s Requirements and Strategic Supplementation
Typically, when cows are moving from mid- to late gestation, energy requirements will increase by 25% and protein requirements by 10%. However, post-calving is where the greatest nutrient demand is occurring due to lactation. Table 1 illustrates the increased energy and protein intake differences to meet late gestation and early lactation requirements for a 1,200-pound mature beef cow with 20 pounds of milk production.
|Table 1. Maintenance requirements for a 1,200-pound mature beef cow with 20 pounds of milk
Generally, weight loss occurs after calving due to an inadequate supply of nutrients to support milk production. To overcome some of these hurdles, supplementation is generally recommended if forage protein and energy are inadequate.
Developing an effective supplementation strategy that meets the needs of the lactating cow is critical to improve performance. One thing to keep in mind is that protein sources are not all created equal for a beef cow (https://beef.unl.edu/beefwatch/2022/protein-not-protein-not-protein). During early lactation and throughout the breeding season, we find that cows are often consuming diets that are insufficient in metabolizable protein, but not insufficient in overall dietary crude protein. To increase the supply of metabolizable protein to the cow, a protein source high in rumen undegradable protein may need to be utilized. Historically, research over the last 40 years have shown that feeding rumen undegradable protein sources to lactating cows has resulted in increased pregnancy rates, increased calf weaning weight, and cows cycling sooner after calving.
Strategic supplementation with rumen undegradable protein may have the greatest promise in two- and three-year-old range cows after calving due to their high lactational and growth requirements. Beginning supplementation soon after calving and continuing through breeding may be a good strategy if forages are lower quality and nutritional demands are higher. These first calf females need to consume a diet that is at least 62% TDN and 10 to 11% CP, depending on the level of milk production expected after calving. Keep in mind that a good energy source (like distillers or an RUP supplement) will be important to think about during this stage of production.
Other Management Options
Perhaps we have evaluated our forage base and realize that we may not have enough grass available to get us through the fall. What are some management considerations that we may need to think about? The first that comes to mind would be early weaning. Implementing early weaning with our young (two and three-year old) cows may be advantageous if they are losing condition. This would allow for lactational demands to be reduced and reduce the amount of forage consumed. The difference in forage intake among our lactating versus a non-lactating cow is about 5 pounds of forage per head per day. Additionally, about 10 pounds of forage is conserved for each day a calf is weaned. To learn more about management strategies related to early weaning, check out these additional resources in a past BeefWatch article: https://beef.unl.edu/beefwatch/2021/managing-early-weaned-calves. In addition to early weaning, confined feeding may also be an option if resources allow. Learn more about confined feeding options from a past webinar: https://youtu.be/PBFA-F6sc7k.
Interviews with the authors of BeefWatch newsletter articles become available throughout the month of publication and are accessible at https://go.unl.edu/podcast.
— Kacie McCarthy, UNL Cow-Calf Specialist; Travis Mulliniks, UNL Beef Cattle Nutritionist, Range Production Systems