For much of the year, beef cattle can meet their protein requirements from the forage they consume. However, the quality of forage can vary significantly and there are times when it simply isn't enough to meet a cow's protein needs.
Understanding how to assess forage protein content and recognize when supplementation is necessary is key to maintaining a healthy and productive herd.
Estimating Forage Protein Content
The protein percentage in various types of forage can differ widely based on factors such as plant maturity, species, soil fertility and environmental conditions. Still, you can use use these general estimates of protein levels in common forage sources:
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Early Season Pasture: Lush, rapidly growing forage is typically the richest in protein estimated at 20.0% or even higher. Young, tender plants contain a higher concentration of crude protein and will often not require additional protein supplementation.
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Feeder Alfalfa: Alfalfa is renowned for its high protein content, but protein levels can vary wildly based on the feed’s condition. Good quality feeder alfalfa generally provides around 17.0% protein and is an excellent source of protein.
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Grass/Alfalfa Mix: A balanced blend of grasses and alfalfa offers a moderate protein level that can also vary wildly. A good quality mix is estimated at 14.0%.
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High Quality Grass Hay: When harvested at an optimal stage of maturity, high-quality grass hay can contain about 10.0% protein. This hay is usually leafy with a green color that indicates good nutrient retention.
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Average Grass Hay: As grass matures, its protein content declines. Average grass hay typically drops to approximately 8.0% protein. This is often the result of delayed harvesting or less favorable growing conditions.
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Low Quality Forage: This category includes late-season range, late season dry pastures, oat hay, straw and corn stalks. These forages are characterized by high fiber content and significantly lower protein levels, sometimes as low 5.0%. At this stage, plants are largely mature and have translocated most of their nutrients to seeds, leaving behind structural carbohydrates and little protein.
When to Consider Protein Supplementation
As a general rule, any forage below 12% protein may require supplemental protein depending on the cow's condition and stage of production. Cattle protein requirements and nutritional demands vary significantly throughout the production cycle.
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Dry, Mature Cows: These cows have the lowest protein requirements and may be able to maintain condition on forages with protein levels around 7-8%.
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Lactating Cows: Producing milk is highly demanding and lactating cows require significantly more protein (typically 12-14% of their diet) to support milk production and maintain their body condition.
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Pregnant Heifers and First-Calf Heifers: These cattle are still growing while also supporting a pregnancy, making their protein needs higher than mature cows. They often require 10-12% protein.
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Growing Calves: Young, growing calves have high protein requirements for muscle and skeletal development often needing 14-16% protein in their diet.
Low-quality forages, especially those below 8% protein, will almost certainly need supplementation if they are fed for more than a few days regardless of the cow's stage of production. Relying solely on such forages can quickly lead to nutritional deficiencies and economic losses when nutrition does not meet cattle protein requirements.
The Impact of Low Dietary Protein
When dietary protein is deficient, it not only means the cow isn't getting enough direct protein, but it also reduces the amount of internal microbial protein produced in the rumen. Cattle that are not receiving enough protein, either in their forage or through a cattle protein supplement, can experience a loss of body condition and negative impacts to overall health and fetal development.
The consequences of this dual deficiency can include:
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Loss of Body Condition: Cows will start to mobilize their own body protein and fat reserves to compensate, leading to a noticeable decline in body condition score. This can manifest as prominent ribs and hip bones.
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Reduced Forage Intake: A lack of protein can also reduce the cow's ability to digest and utilize low-quality forage leading to decreased forage intake. This creates a vicious cycle where the cow eats less and extracts even fewer nutrients from what she does eat.
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Negative Impact on Overall Health and Immunity: Protein is essential for immune function. Deficient cows are more susceptible to diseases and may take longer to recover from illness.
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Impaired Reproduction: For breeding cows, protein deficiency can lead to delayed estrus, reduced conception rates and even abortions. Poor body condition is directly linked to reproductive performance.
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Compromised Fetal Development: In pregnant cows, insufficient protein can hinder the proper growth and development of the fetus, potentially leading to calves with lower birth weights, reduced vigor and lifelong health issues.
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Decreased Milk Production: For lactating cows, protein deficiency directly impacts milk yield and quality which negatively affects calf growth and weaning weights.
The Best Approach: Laboratory Analysis
While general forage protein estimates can provide a useful starting point, the most accurate way to determine the protein level of your specific forages and make confident supplementation decisions is through a laboratory analysis.
By understanding the protein content of your available forage and recognizing the signs of deficiency, you can make informed decisions about when and how to supplement and ensure the health and productivity of your beef cattle herd.
Your local IFA salesman is available to assist you with forage sampling and analysis to provide certainty in your feeding program.
Work with an IFA Expert
Effective beef cattle nutrition hinges on understanding and managing forage protein. While forages form the backbone of a cow's diet, their protein content fluctuates throughout the year and across different types.
To eliminate guesswork and ensure optimal herd health and productivity, talk to your local IFA Feed Expert about a laboratory analysis. By combining knowledge of forage quality with precise data, you can make informed decisions about when and how to supplement beef cattle protein to safeguard the health and profitability of your herd.
Information provided by Marty Short, IFA Commercial Feed Marketing and Business Development, and TBD (Jim, Dennis, Bryce, Other?). We want to cite all of our experts involved in providing info.