Boosting Feedlot Lamb Growth and Profitability Through Rumen Optimization

Effective rumen management in cattle and sheep is essential for achieving optimal growth rates. Multiple studies have shown that a well-developed and healthy rumen is linked to higher average daily weight gains, making it a crucial focus for livestock management. This becomes even more important during stressful periods like weaning and should be maintained throughout the fattening phase to ensure livestock meet their target slaughter weights. 

Recently, a trial by Vitam International was conducted in South Africa, to study the impact of feedlot systems on the rumen health of fattening lambs. The findings highlight important insights into managing rumen health and improving lamb growth and profitability in feedlot systems.  

Why Rumen Health Matters for Fattening Lamb  

The rumen plays a vital role in the performance of fattening lamb, similar to its function in dairy cows and beef cattle. It not only facilitates digestion and nutrient absorption but also acts as a barrier that prevents bacteria and toxin coming from the gut to enter into the general body circulation. 

Rumen microbes break down dietary polysaccharides into volatile fatty acids (VFAs), such as propionate, acetate and butyrate. These VFAs provide up to 75% of the metabolizable energy in ruminants. Well-developed rumen papillae are essential for maximizing the surface area for VFA absorption, which directly impacts lamb growth and health. 

However, maintaining rumen wall integrity while providing a diet that generates sufficient VFAs for growth can be challenging. High starch diets allow important growth rate but also orientate the rumen microbiota toward acid-producing species leading to a decrease of ruminal pH, potentially leading to sub-acute ruminal acidosis (SARA), which may ultimately damage the ruminal epithelium and can create a disbalanced rumen microbiota. This, in turn, reduces feed intake, impairs microbial balance and energy production for daily gain. 

Challenges in Feedlot Lambs 

Lambs are particularly susceptible to stress, especially during the transition to a feedlot system. They are initially fed high-fiber diets and dam milk, but as they move to finishing pens, their diet shifts to one that is high in starch and low in fiber. This rapid change, combined with the stresses of weaning and transport, can increase the risk of SARA and ultimately to acidosis.  

Acidosis in lambs can range from mild drops in performance to severe rumen inflammation. This not only affects growth and feed efficiency but can also harm production margins, a key concern for feedlot operations. 

The benefits of feeding Rumen-Specific Live Yeast 

To mitigate the risks of ruminal SARA (and try to avoid acidosis) while promoting growth, Lallemand Animal Nutrition selected LEVUCELL SC, a rumen-specific live yeast feed additive. This live yeast helps stabilize rumen pH, protecting the rumen lining and papillae from the harmful effects of low pH. By maintaining a healthy rumen environment, LEVUCELL SC allows lambs to handle high-starch, low-fiber diets without compromising growth rates. 

Feedlot Lamb Trial Results 

In a trial conducted in South Africa in 2022, 600 Dohne Merino lambs were divided into a control group and a treatment group. The treatment group received LEVUCELL SC in their grower and finisher feeds. The results showed that adding LEVUCELL SC to the diet delivered clear benefits to lamb health and growth. 

The treatment group experienced a 2% increase in average daily gain and an improved feed conversion ratio of 4.8 compared to 5.1 in the control group. This led to an increased margin over feed cost of 10.35 US$ per lamb in the treatment group versus 8.09 US$ per lamb in the control group. The return on investment was 3:1. 

Furthermore, the treatment group showed a reduction in severe ulcers, and hyper-keratinized rumen papillae compared to the control group. Which shows that feeding LEVUCELL SC helped keep lambs health. 

Figure 1: Trial design

Figure 2: Rumen scoring results 

A Healthy Rumen Leads to Better Growth and Profits

Feedlot lambs face environmental and dietary stresses that can compromise rumen health and growth rates. By feeding a rumen-specific live yeast like LEVUCELL SC to help stabilize rumen pH, lambs experience less rumen damage associated with low pH. This positively impacts lamb performance through better average daily weight gain, improved feed conversion rates (FCR) and higher returns on feed investments.

Protecting the rumen is crucial for achieving optimal health and growth in feedlot lambs. The use of LEVUCELL SC has been shown to enhance lamb performance, leading to greater profitability in feedlot systems.