Brady Campbell, Program Coordinator, OSU Sheep Team
To capitalize on the niche market of grass-fed lamb products, have you ever considered placing a group of feeder lambs on pasture? The utilization of pastureland and the financial return from grass-fed products makes this type of production system profitable. However, grass-fed lamb production does not come without challenges. According to the USDA, in order for a product to be labeled as grass-fed, the animal must be fed solely forages, with the exclusion of its mother’s milk prior to weaning. From a production standpoint, this can be a difficult as research has shown that lambs finished on pasture take a longer period of time when compared to their counterparts fed grain. Lambs on pasture also face the challenge of parasitic infection. In an effort to decrease the effects of parasites and increase lamb body weight gain on pasture, producers may choose to supplement lambs while on pasture. However, supplementation of grain or grain by-products is not permitted by the USDA label of grass-fed. However, these lambs could be marketed as pasture-raised or housed on pasture in order to request a premium. Therefore, in using this marketing strategy, producers must choose which supplement is suitable for increasing animal gains while decreasing the effects of parasitism. Thankfully for us, Felix and colleagues (2012) conducted a series of experiments that outlined which supplements may be most beneficial while grazing lambs on pasture.
Over the course of four consecutive years, four experiments using a total of 312 Dorset x Hampshire crossbred lambs were conducted in order to determine the effects of supplementation on the health and performance of grazing lambs. Each year, lambs were grazed approximately for 70 days. In experiments 1 and 2, lambs were placed in one of two treatment groups: 1) lambs grazed on pasture with no supplement (control) or 2) lambs grazed on pasture offered supplement (dried distillers grains with solubles – DDGS) at 2.5% live body weight. In experiment 3, treatment groups 1 and 2 remained the same as previously described with the addition of a third treatment group: 3) lambs grazed on pasture offered supplement (soybean hulls – SBH) at 2.5% live body weight. In experiment 4, treatment groups remained the same, with the adjustment of adding additional phosphorus (P) to the SBH diet to match the P levels found in the DDGS diet. Lamb health was determined by evaluating at FAMACHA© eye scores, packed cell volume (PCV), and fecal egg counts (FEC) whereas performance was based upon average daily gain (ADG). Anthelmintic treatment was based upon PCV, where lambs demonstrating a PCV of 20% or lower received anthelmintic treatment.
In experiment 1, of the non-treated lambs (i.e. lambs, regardless of treatment group, during the grazing period that did not receive and anthelmintic treatment), DDGS lambs had a greater ADG (0.55 lbs./day) as compared to control lambs (0.29 lbs./day). Although not significantly different, yet worthy of noting, DDGS lambs were heavier at the conclusion of the grazing period (91 lbs. vs. 77 lbs.) and had fewer lambs treated with an anthelmintic when compared to control lambs (40.0% vs. 65.6%).
In experiment 2, DDGS lambs were heavier at the conclusion of the grazing period (92 lbs.) as compared to the control lambs (73 lbs.). In addition, DDGS lambs had a greater ADG (0.49 lbs./day) when compared to control lambs (0.22 lbs./day). From a treatment perspective, more than 90% of the control lambs required anthelmintic treatment whereas only 18.7% of DDGS required treatment. In comparing the ADG of both treated and non-treated lambs, DDGS lambs demonstrated greater gains as compared to control lambs (treated: 0.42 lbs./day vs. 0.22 lbs./day; non-treated: 0.50 lbs./day vs. 0.26 lbs./day). Interestingly, the only differences shown in PCV parameters were seen on day 21 of the grazing period where DDGS lambs demonstrated a greater PCV value compared to control lambs.
In experiment 3, DDGS and SBH supplemented lambs were heavier at the conclusion of the grazing period (90 lbs. and 86 lbs.) when compared to control lambs (70 lbs.). In addition, DDGS lambs had the greatest ADG (0.49 lbs./day), whereas control lambs were the lowest (0.21 lbs./day) and SBH lambs fell intermediate (0.41 lbs./day). From a treatment standpoint, control lambs had the greatest percentage of lambs requiring anthelmintic treatment (81.3%), whereas treatment of SBH and DDGS lambs remained low (31.2% and 9.4%). Furthermore, control lambs required a total of 1.27 treatments per lambs whereas SBH and DDGS lambs required only 1 treatment per lamb. In evaluating health parameters, over the entirety of the grazing period control lambs demonstrated greater FAMACHA© eye scores as compared to SBH and DDGS lambs.
In experiment 4, DDGS and SBH supplemented lambs were heavier at the conclusion of the grazing period (81 lbs. and 77 lbs.) when compared to control lambs (62 lbs.). In addition, DDGS and SBH lambs had a greater ADG (0.50 lbs./day and 45 lbs./day) when compared to control lambs (0.23 lbs./day). The ADG of treated lambs were also greater for DDGS and SBH lambs (0.52 lbs./day and 0.43 lbs./day) as compared to control lambs (0.23 lbs./day).
Overall, this series of experiments has illustrated that supplying supplement to grazing lambs can improve body weight gains on pasture and reduce the need for anthelmintic treatment. Keep in mind that these supplements were offered at 2.5% live body weight. At this feeding rate, some may argue that you are simply feeding lambs that are housed on pasture. In addition, you must also consider what your end goals are. In using this type of strategy, pastures may not be utilized efficiently. In using this strategy as a means to reduce the use of anthelmintics in pasture raised lamb, you have also excluded yourself from the grass-fed labeled market. Before implementing this tactic in your operation, be sure to do your research on the cost of each supplement and what type of market you may be able to enter with the unique diet of forage and byproducts. Who knows, you may be the next producer that creates the next niche market label of sustainable lamb.
Felix, T. L., I. Susin, L. M. Shoup, A. E. Radunz, and S. C. Loerch. 2012. Effects of supplemental dried distillers grains or soybean hulls on growth and internal parasite status of grazing lambs. Sheep and Goat Res. 27: 1-8.