Finishing Lambs on Pasture
Finishing lambs on pasture can be a great way for producers to manage feed costs. However, producers should consider several questions as they develop their plan to finish their lambs.
One of their first questions should be how they plan to market their lambs. Do they have a specific date for marketing their lambs? Do their buyers require specific production practices, such as only grass-fed, or do buyers focus more on carcass characteristics? Then, second, what do they plan to feed them? If they choose to finish their animals on pasture, there are some considerations to keep in mind.
While forages generally mean lower feed costs, they also mean slower growth rates. Managing growth rates allows a producer to plan marketing to meet a particular weight range at a specific marketing date. A typical growth rate for lambs on pasture is 0.25 to 0.33 pounds per day, which can be achieved on cool-season grass-legume mix pastures commonly found across Pennsylvania. Pastures must be growing in a vegetative state and be of high quality. Pastures must also be rotationally grazed to maintain high-quality forage, and to help prevent internal parasite issues. One of the biggest challenges producers face is maintaining high-quality pastures throughout the grazing season, particularly during the summer slump.
As temperatures rise during the summer, forage quality normally decreases, as does forage growth rate. In addition, forage nutritional value decreases due to maturity. Producers can expect decreases in protein and energy content and increases in fiber. These factors make it difficult to plan for consistent-quality forage and thus consistent weight gains on pasture. If temperatures remain high and there is little cooling at night, this can also affect dry matter intake.
Producers can seek to manage this summer slump by incorporating forages less susceptible to it, such as perennials with deep tap roots and warm-season annuals. Penn State Extension's article "Grazing During the Summer Slump" states, "To supply summer forage, it is ideal to have a portion of the farm in warm-season annuals and/or perennials. These forages are adapted to high temperatures and dry soils. Examples are millets, sudangrass and sorghum-sudan hybrids, teff, Sunn hemp, cowpea, forage soybean, switchgrass, big bluestem, and Indiangrass." Forage chicory mixed with a legume is another option to provide high-quality forage during the summer months.
When grazing forage chicory, lambs should be moved every 3 to 5 days to prevent grazing the regrowth from plant crowns. According to Chicory: An Alternative Livestock Forage from the University of Kentucky, grazing studies in New Zealand have reported daily gains of 0.6 pounds per day for lambs. However, this can vary somewhat throughout the season and will decrease once the chicory plants mature and send up a seed stalk.
Producers grazing lambs on cool-season perennial pastures and who wish to increase daily gains may want to consider feeding a supplement, particularly when forage quality becomes low. The amount can vary, depending on the desired rate of gain, but should not exceed 1% of a lamb's body weight. For example, a lamb weighing 75 pounds should not consume more than 0.75 pounds of a supplement. Furthermore, the type of supplement can influence forage digestibility. According to Sheep 201, "Research with cattle suggests that supplementation with feedstuffs that are high in starch, such as grain, reduces forage digestibility, as compared to energy supplements with highly digestible fiber sources (soybean hulls, corn gluten meal)."
Research at the Eastern Ohio Resource Development Center looked at the effect of finishing lambs with a corn/soybean meal or soy hull supplement. Lambs had access to a self-feeder, and researchers looked at weight gains, carcass characteristics, and costs. They found that animal performance and carcass characteristics were similar for the two methods. However, they did find a difference in the amount of feed consumed and the cost to finish. Lambs consumed more feed per pound of gain, 5.6 pounds average for the soy hull supplement versus 4.28 pounds for the corn/soybean meal supplement, and the cost per pound of gain averaged $0.03 higher for the soy hull supplement. They noted that in the first year of their trial, soy hulls had higher feed waste, particularly if they got wet.
Overall, pasture can be a viable method to feed lambs in a finishing program. However, remember that supplement costs can vary greatly from year to year. Regardless of the method used to finish lambs on pasture, producers should be aware of their costs, including total feed costs, cost per pound of gain, and lamb value when marketed.
This article was first published in Lancaster Farming.
Resources:
Chicory: An Alternative Livestock Forage
