ARTICLE FEED & ADDITIVE MAGAZINE August 2024 71 and diet transition during this period increase the risk of acidosis, which can result in decreased growth and feed efficiency, and ultimately production margins. RUMEN ACIDOSIS As ruminants, sheep have evolved to eat diets that are forage based. The inclusion of cereal in diets is necessary for feedlot lambs to grow at the required rate, but the high levels in their rations can result in acidosis. The signs of acidosis can vary from subtle drops in performance to more significant rumen inflammation caused by the acidic environment which can result in diarrhea, dehydration, and sometimes even death. Lallemand Animal Nutrition’s rumen specific live yeast, LEVUCELL SC, can support the feeding of a high energy diet while minimizing the risk to rumen. The yeast stabilizes rumen pH which protects rumen wall integrity and papillae length through reducing the risk of acidosis and the damage it can inflict on the lamb’s rumen. This allows lambs to cope with a high-starch, low-fiber diet to encourage rapid growth, without compromising the rumen. LEVUCELL SC FEEDLOT LAMB TRIAL The feedlot trial took place over a period of 32-46 days in October and November 2022 in Hartbeesfontein in the North West Province of South Africa. It involved 600 Dohne Merino lambs who entered the trial at between 90 and 150 days of age. The trial split the lambs into a control group of 300 and a treatment group of 300. Both groups were fed a basal feedlot ration, but the treatment group were also given the equivalent of 0.4g/lamb/ day of LEVUCELL SC 10 ME Titan in both their grower and finisher feeds. The lambs were all reared on ad-lib lucerne hay and adaptation TMR before transitioning to a grower feed for 8-30 days (Figure 1). Both the control and treatment group were split into three pens; one each of small, medium and large lambs with 100 animals in each pen. The trial weighed the lambs at day 0, the day before being transported off site, and at the slaughterhouse the day after transport. Dry matter intake per day was measured through weighing the TMR distributed and any refusals. Individual hot carcass weights were recorded after slaughter and evisceration. The rumens and livers of the slaughtered lambs were also scored and the average daily gain, feed conversion ratio, and return on investment calculated. LEVUCELL SC IMPROVES RUMEN HEALTH AND LAMB PERFORMANCE The trial showed that adding LEVUCELL SC to the diet delivered a clear benefit to lamb health and growth. It increased average daily gain by 2% across the recorded period and gave a better feed conversion ratio- 4.8 compared to 5.1- which increased the margin over feed from 8.09 US$ per lamb to 10.35 US$ per lamb. This gave a return on investment of 3:1 with an average feed cost during the trial of 317 US$ per ton. The increase in margin over feed cost is linked to improved rumen health supporting better nutrient absorption. The rumen scoring at slaughter showed a statistically significant reduction in star scars in the lambs fed LEVUCELL SC compared to the conAdaptation (lucerne hay ad lib + adaptation TMR) Control LEVUCELL SC Grower feed (8 to 30 days) D0 Slaughter Finisher feed (10 to 20 days) Figure 1. Trial Design
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