By Janet McNally, Hinckley, Minnesota — In the previous two issues I examined late-gestation ewe rations: and ewe lactation/early-lamb growth rations using conventional hay/grain and pasture-based solutions. In late gestation, the relatively little grain required had only a small impact on total feed cost. Pasture presented a much larger cost-saving advantage over grain/hay during the lactation phase. This month, let’s look at finishing, taking the lamb from weaning at 120 days of age (75 lbs.) through to 110-120 lbs.
As the accompanying table (made from available data and personal experience) indicates, there is potential for substantial savings with pasture finishing. Yet this stage and the relative benefits of alternative rations are difficult to analyze, because the number of possible options is so great.
Finishing systems should capitalize on the resources available to the producer, as lambs are capable of turning a very wide variety of high-energy feedstuffs into growth. Finishing rations that utilize grazing are almost unlimited in number. Crop residue (corn, canning crops like peas, oilseed residue such as canola, beet tops); crops planted for finishing purposes, such as turnips, corn, and millet; forages such as ryegrass pastures and alfalfa – all can work. A great publication reviewing alternative feedstuffs for lamb finishing is AS 1182, “Alternative feeds for Ruminants,” published by North Dakota State University, which can be found at: http://www.ag.ndsu.edu/pubs/ansci/beef/as1182.pdf
There are two chief challenges to pasture finishing of lambs in the U.S. One is that with the exception of some areas of the South and Southwest, lamb finishing typically occurs in the fall in a grazing operation, which is the time when most plants are preparing for winter. Sugar content (which affects palatability and digestibility) of pasture plants declines, resulting in lower intake just when you would like to have the animal eating more.
Challenge number two is that for graziers in the northern half of the U.S., the growing season is just too short. As the table shows, it takes longer to reach finishing weights on pasture. Countries such as Australia and New Zealand have considerably longer growing seasons, and lambs are marketed at close to eight months of age, which makes it possible to finish a lamb on a lower-energy diet.
+ Based on 12% crude protein. Grain ration priced at $180 per ton, hay or haylage at $80 per air-dry hay ton.
*Assumes first and second crop taken as hay, thus sharing the land and crop cost of $60 to $90 per acre. Five pounds dry matter per lamb pasture allowance required.
Lambs must be at least 66 pounds to effectively utilize a high-roughage diet. Total digestible nutrients (TDN) of the complete diet must be 70% or greater to achieve finish. Late-summer and fall pastures have less digestible dry matter than spring forages: many forages in late summer range from 45-65% TDN. Therefore, very few forages are suitable for finishing lambs without supplemental grain. Forages that have been used for this purpose include high-quality alfalfa (third or fourth crop), well-managed ryegrass of a palatable grazing variety, turnips, and any grain grazed as a whole crop before maturity (wheat, oats, triticale, corn, millet).
In northern climates where freezing temperatures come early, alfalfa and ryegrasses are not viable options for most grazing operations. High-energy, “planted for the purpose” crops are more suitable in these regions. (With such a wide variety of annual grazing crops, I can’t do the subject justice in this article. I intend to address these crops in the future.) Orchardgrass and fescue do maintain a fair energy content into the late fall, but are prone to rust, and are usually not sufficient to finish lambs without added grain.
Most crop residues, such as corn stalks and just about any kind of stover, are relatively low-quality forages that require additional energy (and sometimes protein) supplementation, usually in the form of grain. (An exception can be regrowth of canola oilseed residue.) Crop residues are thus probably better utilized by the ewe flock, unless there is a significant amount of dropped grain available.
A wide variety of human food byproducts can be fed to sheep, and many of them are great for finishing in combination with pasture, or in a feedlot. For instance, a combination of potato waste and wet brewery distillers grains can make a nearly perfect lamb finishing feed. For a producer close to processing plants, a ration can be made for pennies per day if a way to ensile and utilize truckloads of product can be managed.
As each situation is unique, it is impossible to cover all the various combinations here, other than to encourage producers to investigate local food processors and find out what and if there are byproducts available.
For many, feeding grain is the only way to provide sufficient energy while pasture quality is declining in the fall. Transitioning to grain requires good management skills to avoid putting lambs off feed, and to minimize losses due to chronic acidosis. Begin by feeding 0.2 lb. of grain per day (whole shelled corn is sufficient) while lambs are still on pasture, and increase feeding by 0.2 lb./head every two to three days. By 21 days, lambs should be consuming approximately 2 lbs. of whole, shelled corn in addition to pasture, at which point they can be brought into the feedlot and moved onto self-feeders over the next 10 days. Grain fed during the 21-day transition totals 11 pounds, or 78 cents at $4.00/bushel corn.
On reasonably abundant, leafy fall pastures, it is possible to continue feeding two pounds of shelled corn (or barley, or DDGS or other palatable seed crop) through to finishing. Moving into the feed yard is only necessary when pasture quality and quantity are limited. By staying out on pasture (or crop residue) and feeding two pounds of shelled corn daily, about 1.5 lbs. per day of grain will be saved over a period of approximately 69 days, resulting in grain savings totaling 103 lbs., or approximately $5/head. Compared to corn, DDGS has been found to be more compatible with fresh forage diets, so producers should consider using DDGS in the ration where the price justifies its use.
When feeding grain on pasture, it is best to feed it just before lambs are to be moved to a fresh break. Feeding grain just after a move results in uneven intake and the possibility a few lambs will overeat.
Maximizing the quantity and quality of fall finishing pastures requires planning for everything from planting suitable species, to managing the crop all summer with the goal of preparing a suitable forage for finishing lambs. It is necessary to back off on grazing pressure after mid-summer and leave a bit more residual.
While a pre-grazing height of about 2 inches was adequate in early summer, lambs need to be allowed a greater pasture allowance later in the season to account for less-digestible plant material. A minimum grazing height of closer to 3 inches, or 5 lbs. DM allowance/lamb per day, is recommended, as anything less will reduce lamb growth.
Successful pasture finishing of lambs requires putting together four cornerstones: the right genetics, good growth and health prior to weaning, a proper introduction to grazing (i.e., reared with the dam on pasture), and a palatable pasture that is at least close to 70% TDN. If any one of these cornerstones is missing, lambs will fail to reach a slaughter weight with proper finish. Let one thing slip, such as parasite management, forage management, or use the wrong genetics, and the lamb crop will fall short of the goal.
While it can be a challenge to properly build these four cornerstones, the reward is a very significant savings in feed costs, coupled with lower labor. For most producers with unimproved pastures on non-tillable land, it is the last cornerstone (70% TDN pasture) that is the most difficult to achieve. In these situations, a suitable grain supplement or transitioning to the feedlot may be the best fit. I might argue, however, that leasing some nearby tillable land could be well worth the trouble.
So, if we figure on $4.00 corn, what’s the potential total feed savings from late lactation through lamb finishing that can be attained by utilizing pasture instead of grain? I come up with $68 per ewe with twins. Multiply that by the number of ewes you’re managing, and you can see the benefits of becoming a better pasture manager. As corn prices rise, the incentives become more obvious.
Janet McNally grazes sheep near Hinckley, Minnesota.