Nutrition and Feeding
Systems for Market Lamb Finishing
Table of Contents
- Grain Feeding Strategies for Lambs
- Free-choice versus Restricted Feeding
- Textured Diets versus Pelleted Diets
- Lamb Feeding Systems for Finishing
The purpose of market lamb feeding is to cost-effectively produce
a product of marketable quality and quantity. Keeping this objective
in mind will help you make good business and animal management decisions.
The rumen, the largest of the four stomach compartments in ruminant
animals, is a fermentation organ, not an acidic stomach. This means
digestion depends on the microbes that live inside the rumen. Maintaining
the health of this environment is therefore critically important
when you are finishing lambs.
Sheep and lambs need several nutrients and nutrient classes for
optimum growth. They are listed below in order of importance.
- Water - The majority of a lamb's gain comes from water. Proper
hydration also improves growth. As a result, it is crucial to
have clean water constantly available. Waterborne minerals may
interact with dietary compounds, which may improve or inhibit
the uptake of some nutrients.
- Carbohydrates - In a typical ration, energy is usually the limiting
factor. This means the volume of rations the lambs will need is
determined by how much energy they need. In modern farm rations,
carbohydrates are the prime energy source. There are two major
- Non-structural carbohydrates include starches and sugars.
In a grain ration, starch is the primary source of energy
and is the part of the feed that is likely to be associated
with acidosis - an undesirable condition where the rumen becomes
- Structural carbohydrates include the fibre and cell walls.
These are found in forages and the hull of grains. Fibre is
less digestible and lower in energy than starch but is usually
less expensive. Digestibility is largely determined by how
mature the forage is.
- Protein - In livestock nutrition, the terms "protein"
and "crude protein" (CP) are typically used interchangeably.
CP is an estimate of the amount of protein in a feedstuff. CP
assumes that most proteins have a similar nitrogen content. For
most feedstuffs, CP = nitrogen content (%) x 6.25.
In mature animals with fully functioning rumens, lower-quality
protein or non-protein nitrogen (NPN) can be converted to high-quality
bacterial protein. However, in young lambs under 27 kg (60 lb)
liveweight, the rumen may not be fully developed. As a result,
young animals depend on higher-quality protein in the ration.
- Vitamins, minerals and additives - Good lamb diets include numerous
vitamins and minerals. These are usually included in commercial
mineral/vitamin packages. To improve meat quality, give lambs
50-75 IU or more of vitamin E per day and the recommended levels
of minerals. Coccidiostats are recommended. Note that ionophore
coccidiostats can improve feed conversion if delivered in an appropriate
range. Consult your flock veterinarian and mineral supplier to
ensure your needs are met.
- Fats - Fats are an alternate form of energy. Due to cost, they
do not usually play an important role in lamb feeding.
Feed conversion targets (ratio of feed to liveweight gain)
- Grass-fed lambs introduced to a grain diet: 8.5-6.0:1
- Lambs that are grain-fed from post-weaning (approximately 50
days old) to market weight:
- lambs up to 36 kg (80 lb) liveweight: 4.0-3.0:1
- lambs over 38-55 kg (85-120 lb) liveweight: 7.0-5.0:1
Days to market (DTM) and average daily gain (ADG) targets
Table 1 outlines the DTM and ADG for different feed systems assuming
a market liveweight of 43-48 kg (95-105 lb). For grass-based systems,
it assumes a May/June lambing.
Table 1. Days to market and average daily gain for different
|| 50-250 g
|| low rate of gain often under-finished for some
Ontario markets without grain feeding
|Grass and finishing
|| 50-250 g
|| 150-250 (plus 3-6 weeks of grain feeding)
|| required if grass lamb is under-finished poor
utilization of grain compared to the grain-based system described
Grain-based confinement system
|| 325 g
|| grain-only diet from weaning to market weight
4,0:1 feed conversion risk of over-finishing if corn is the
|Grain and hay
|| 250 g
|| 6.0:1 feed conversion
Grain Feeding Strategies for Lambs
As with all ruminant livestock, lambs require transition diets
when introduced to a new ration. The transition period allows the
microbe population in the rumen to adapt to the new feedstuffs.
Grain-based feeding system
If lambs have been creep-fed and are weaned at approximately 50
days and 18-27 kg (40-60 lb) liveweight without having consumed
appreciable amounts of forage, the following recommendations can
- Continue feeding a creep diet for 2 weeks after weaning, where
the creep and "receiving" or "starter" rations
are the same: 17% CP, 85% total digestible nutrient (TDN), plus
- Use a growing/finishing ration for lambs that are over 27 kg
(60 lb): 15%-16% CP, 80%-85% TDN
- Use a separate ration for animals over 40-45 kg (90-100 lb):
13%-14% CP, 75%-85% TDN
As animals make the transition from one level in the grain feeding
program to another, blend the new diet into the previous one at
increasing rates for 3-7 days (Table 2).
Table 2. Example of a transition diet
|1 and 2
|3 and 4
|5 and 6
Grass (forage)-based system
If lambs are coming off an all-grass or forage program and need
additional finishing, the transition period required is much longer.
In this case, the following recommendations can apply:
- Have a "receiving diet" that is at least 90% forage
(less than 0.25 kg [½ lb] grain per head per day). If possible,
use the same forage the lambs have been eating, or a similar one.
- Provide the receiving diet for 1 week.
- Assuming the desired finishing diet is 80% or more concentrate,
allow at least 3 weeks (or preferably 4 weeks) to switch the lambs
from the receiving diet to the new diet. Gradually increase the
proportion of concentrate over this time.
Free-choice versus restricted feeding
Regardless of what equipment is used, there are typically two
strategies for feeding grain. One is free-choice feeding (also known
as ad libitum, ad lib or full feeding). The other is restricted
feeding (or limit feeding). Each has benefits and drawbacks, and
the producer must decide which strategy is most appropriate based
on his or her equipment and management ability.
Free-choice feeding often uses a hopper-type feeder, where a continuous
supply of feed ensures the hopper is never empty. This allows for
constant storage and frees producers from making or delivering feed
on a frequent basis. However, there is a risk that lambs will eat
more of one diet component and less of another, and there is no
control over intake patterns. This makes lambs on free-choice feeding
programs more susceptible to overeating, irregular intake and acidosis.
For this system, allow 10 cm (4 in.) of feeder space per lamb, and
ensure feeders do not go empty.
This strategy is a powerful animal management tool because it
allows producers to dictate when and how much feed animals receive.
It allows more control over intake, more equal consumption of various
diet components (e.g., grains vs. pellets) and frequent assessment
of feed intake and conversions. Its major drawbacks are the increased
labour required to deliver feed at least twice per day and the need
for additional bunk space to allow all animals to eat at one time.
To avoid trampling during feeding, allow 12-25 cm (5-10 in.) of
feeder space per lamb, and watch the animals diligently.
Restricting feeding to 90%-95% of the ad lib intake improves feed
efficiency. This is known as "slick bunk management,"
"23-hour feeding" or "target feeding," and is
a strategy that is gaining popularity in the beef feedlot industry.
Textured Diets versus Pelleted Diets
Once the decision to feed grain is made, a ration type must be
chosen. Both textured and pelleted diets have advantages and disadvantages
in terms of what feeds can be utilized, equipment requirements,
cost and convenience.
- allow the use of commodities, such as whole-shelled corn, soybean
meal (SBM), etc.
- allow for the use of molasses in dry rations to:
- stimulate intake
- prevent sorting
- ensures that minerals and medications and other powders
bind to larger feed particles
- may be purchased or home-made
- allow the possibility of total mixed rations using silages and
- may cause serious handling issues
Pelleted supplement + grain
In this diet, small grains and corn comprise 70%-90% of the total
grain, while pelleted supplements comprise 30%-10% of the total
- all vitamins, minerals and additives are properly included
- according to research, intake may be lower on pellets
- sorting of ingredients may occur
- because this diet includes purchased materials, feed costs may
"Processing" means milling or rolling grain. It is also
referred to as cracking, grinding and hammer-milling. Pelleted diets
use grains that have been processed before pelleting. Generally,
processing adds about $10 per tonne to the diet cost, due to labour,
power use and machinery upkeep.
Sheep are ruminant animals. They can utilize forages, fermenting
them in the rumen. Unlike our acidic stomachs, a sheep rumen uses
bacterial fermentation and requires a neutral pH (a balance between
acidity and alkalinity). Sheep secrete bicarbonate from the salivary
glands while chewing. Thus, cud-chewing (rumination) promotes saliva
production and rumen health.
In most cases, coarser grains are better because this promotes
rumination and extends the amount of starch that is available for
digestion over a longer period. This helps prevent acidosis.
In sheep, whole grains are large enough to be ruminated and chewed
and do not require processing, except in young lambs (creep feed).
Processing grains creates smaller particles that are more palatable
to lambs, thus increasing intake. General processing guidelines
- For lambs less than 9 kg (20 lb) liveweight, process all grains.
- For lambs less than 22-27 kg (50-60 lb), corn should be processed.
- For lambs over 27 kg (60 lb), all grains can be fed whole, reaping
the benefits of whole grain without compromising intake.
Avoid processing unless required. In most cases, this means only
processing young lamb rations. A whole grain diet produces better
rumen health in lambs compared to processed feeds. Improved rumen
health means improved performance. However, in some cases, the handling
benefits of all-pelleted diets may outweigh their biological drawbacks.
Lamb Feeding Systems for Finishing
Many producers consider mixing their own finishing rations when
their lambs reach a size they feel might justify it. To determine
if mixing lamb rations on-farm is economical, consider the following
- Calculate the cost of a farm-made diet, based on ingredients
alone. Determine the cost of the commercial alternative. If the
difference between the two indicates that on-farm mixing may be
economical, estimate the tonnage that could be mixed per year.
- Calculate the cost of all necessary mixing/delivery equipment
that are above and beyond what is needed for purchased, complete
feeds. This could include commodity storage bins, augers, complete
diet bins, feed carts and the mill. Possible systems include:
- Total Mixed Ration (TMR) - With TMR systems, silages, hay
and grain are fed at the same time. Stationary and mobile
mixers are available. TMR mixers use a batch-mixing approach.
They require specialized feeding arrangements (drive-through
feeders for mobile units, conveyor belts or wagons for stationary
units). Daily time requirements include loading, mixing and
- Tractor-drawn mix-mills - These are large-batch mixers,
which can grind dry hay into concentrate rations. They are
run off PTO power and have their own dispensing auger. These
allow bins to be filled at one or more locations. Daily time
requirements include loading, mixing and dispensing.
- Stationary volumetric mills (for example Farmatic,
Modern Mill, etc.) - These use feed proportioners and
overhead gravity flow bins to deliver feed into the four to
six compartments on the top of the mill. These compartments
can be "mini-bins" serviced by augers. Stationary
volumetric mills control ingredient flow rate and produce
a steady flow of one desired ration. However, they require
calibration when a new load of the same ingredient is received
or the diet is re-formulated, and they can only be used for
concentrate. That said, stationary volumetric mills are cost-effective,
and pre-owned systems are readily available. A schematic for
set-up is given in Figure 1.
- Automated, continuous mini-batch mixers (for example, Precision)
- Although it appears to perform the same function as stationary
volumetric mills, this system (Figure 2) offers a huge advantage.
Instead of volumes, this system uses ingredient and ration
weights in batches of approximately 30 kg, so re-calibration
is not required for each lot of ingredient. It can be programmed
to build several rations at one time in sequence, without
re-calibration. For example, one Precision system can
feed up to four rations to four different delivery auger systems
at all times. It creates complete feed logs in the programmable
control centre. If there are any problems with intake, ingredient
levels or power supply, it sends a pager alert. These are
primarily used in hog barns that use the puck-style conveyer
to drop feed, so it is easily converted to flex augers. The
cost to install this system is about $15,000.
- Blending boxes - Like stationary mills, blending boxes use
the volumetric principle. Unlike stationary mills, they have
no motorized parts. They are based on flow rates through slides.
Blending boxes are less accurate and have no potential for
rolling or grinding.
- Decide on an appropriate amortization period for the extra
equipment. It should reflect the lifetime of the machinery (typically
about 5-10 years).
- Calculate any additional costs of feeding equipment. For example,
a TMR feeding system needs enough bunk space, which may be limited
if you are using an all-grain system fed in hoppers. Two hopper
types are pictured in Figures 3a and 3b.
- Multiply the differential calculated in step 1 by the tonnage
over the amortization period to see if it covers the entire cost
related to farm mixing. (Note: Remember to factor in additional
Figure 1. A schematic view for volumetric feed proportioner
setup. The number of bins or bin compartments is flexible. These
can be constructed from wooden materials as described, or prefabricated,
commercially available overhead bins may be used. The size and number
of mill compartments can be adjusted to suit specific situations.
Complete feed can be delivered to either side, the front or back
of the machine and connected to other feed delivery systems.
Figure 2. Feed mixing system showing four input flex augers
to deliver ingredients and four output flex augers to deliver rations.
Pictured to the right is the control unit.
Figure 3a and 3b. Two types of hog hopper feeders used by some
sheep farmers in Ontario.
In certain situations, specialized feeding programs for market
lambs are ideal. These include situations where extra value can
be gained by investing in the additional feed and labour. The producer
must moderate his or her expectations according to the flock production
system. Various aspects of diet preparation must be considered to
optimize the delivery of nutrients and to ensure lamb health. Producers
are encouraged to implement market feeding programs in consultation
with nutrition providers and veterinarians to ensure all aspects
and information are taken into account.
This Factsheet was written by Christoph Wand, Beef Cattle, Sheep
and Goat Nutritionist, Economic Development Division, OMAFRA, Guelph.