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Rumen Development of Young Calves: Preparing Replacement Heifers for Intensive Production

Replacement Heifers…the Future of the Herd

The average productive life of high producing dairy cows in today’s intensive dairy operations has decreased to less than 3 lactations. Cows are often replaced due to low production, but the shorter life span is mostly due to involuntary culling caused from health and reproductive issues. Nutritional management from birth through weaning and the growing period is critical for the development of the replacement heifer to handle the stress of intensive milk production for additional lactations and improved profitability.


Preparing replacement heifers for intensive production requires nutritional strategies that support improved digestive efficiency and nutrient intake during the weaning and growing periods. Growth and development are significantly impacted by the nutritional program and how we manage the young calf during the first few weeks and months of its life.


The First Two Weeks of Life

The most important time in the calf’s life is the first two weeks after birth. Born without a functional immune system, the calf depends on the mother’s colostrum to provide passive immunity protection from the harsh pathogenic challenges at birth. Passive immunity is provided when the calf absorbs the protective immunoglobulins in the colostrum. If the calf consumed sufficient amounts of colostrum before gut closure which occurs approximately 24 hours after birth, the passive immunity will last from five to 10 days depending on the immunoglobulin concentration and amount of colostrum fed.


Development of Active Immune Function

Once gut closure is complete, the passive immune function is significantly reduced, and the calf becomes dependent on a clean environment and the development of an active immune system able to fight its own pathogen challenges. Unfortunately, the active immune system does not become fully functional until after day 14 to 21. This period is when we often see significant health issues.  Calves develop scours at two-three weeks due to overload of pathogen challenge, underdeveloped and ineffective immune function.

The bioactive compounds in Excell™ will help support benifical microbial populations in the intestine and gut health which contributes to the development of intestinal and immune structures necessary for high milk production, reproduction and health.

Stimulation of Rumen Development

At birth, the calf has a non-functional rumen and is dependent on milk or milk replacer for nutrients for the first several weeks of life. Because liquid feed bypasses the rumen through the esophageal groove and directly into the abomasum, it does very little to stimulate rumen development. As the young calf begins to consume dry feed which enters the rumen, the influence of ingested bacteria and the anaerobic environment initiates rumen fermentation and production of volatile fatty acids (VFA’S) primarily acetic, propionic, and butyric acid. Propionic and acetic are primary energy sources for body growth but butyric is absorbed directly by the rumen wall and utilized for rumen development.


In vitro research has shown Excell™ increases the butyric acid levels in rumen fermentation which contributes to accelerated rumen development in weaned calves. The unique profile of bioactive compounds in Excell™ supports microbial populations and butyric acid production in the rumen which is directly utilized for development of rumen tissues.


Challenges of Weaned Calves in Transition and Growing Phases

If calves are weaned and moved to group housing before adequate rumen development has occurred, the calf will be challenged by the stress of the new environment. The calves typically will reduce feed intake and may even lose weight for several weeks.  Often health setbacks occur as well if active immune function is not developed fully. Complete rumen development will usually take 4 to 6 months and increasing grain levels will increase the rate of development. To avoid acidosis, high quality, mold free forage should be fed and carefully monitored for calves during 2 to 6 months.


To meet the demands of intense production, the replacement heifer must begin development of the bodily organs and tissues at an early age and transition into a strong and efficient forage utilizer.   When fresh, we want a cow with significant digestive capacity and production efficiency to have a long and successful lifetime in the herd. Developing optimum rumen function from birth through lactation is the key to maintaining the health, production and profitability of the herd. 

Excell™ supports rumen functon by supporting microbial populations in the digestive system of the rumen and intestine for efficient nutrient digestion and adsorption needed for productive lactations and animal health.

The Next Generation Of Animal Health!

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