Developmental
Stages of Lambs
Dr. Dan Morrical
Iowa State University

Development Stages of
Lamb Digestive System
Birth - 3 weeks pre-ruminant
3-8 weeks - psuedo ruminant
8 weeks & on - ruminant

Birth: Solely dependent on milk
Composition of ewes milk:
18.2% dry matter
5-7% fat
24.7% crude protein
26.4% lactose
7.5 mg/lb Vit E
11 IU /lb Vit E

Milk Yield and Composition
Impact Lamb Performance
•Higher milk fat leads to increase energy intake
•ISU creep trials: 16, 21 & 26% CP
No variation in performance
•Megalac increases milk fat

Creep Diets
Palatable
-Corn
-Soybean meal
-Molasses
Roughage is of minimal value
Lambs get adequate roughage intake from ewe diets

Creep Diets
•Easily digestible
•15-20% crude protein
•Added fat

Creep Ration
Corn
SBM 49%
Molasses
Limestone
TM salt
Ammonium sulfate
CTC
Selenium
Vitamin A
Vitamin D
Vitamin E
Zinc
Crude protein
TDN
Calcium
Phosphorous
1470
370
100
40
10
10
50 grams
.2 grams
1,000,000 IU
100,000 IU
35,000 IU
136 grams
16.7%
83.4%
.84%
.38%

Ration Physical Characterics
Very young lambs
3-8 weeks
8-12 weeks
>12 weeks
Meal form
Medium grind
Coarse grind
Whole grains

Nutrient Requirements
Factors :
Sex
Lean Growth Potential
Weight

Composition of Gain
Rams Lambs
Wethers
Ewe Lambs
Superior
Intermediate
Poorest

Mature Size
Lambs are market ready at 65% of average mature weight of ewes of parent breeds.
220 lb. sire + 180 lb. dam = 400 ÷ 2 = 200.
200 x .65% = 130.

% Protein Concentration of Lamb Rations
Lamb Wt.
.50
40
55
70
85
100
115 10.8
15.9
13.4
12.8
12.0
11.4
ADG
.60
.70
.80
17.0
18.6
20.4
14.7
15.8
16.9
13.9
14.7
15.5
12.7
13.4
14.3
11.9
12.6
13.3
11.4
11.9
12.5

Protein Quantity and Quality
Very young lambs solely dependent on feed protein for quality and quantity
Ruminant
-Protein quality depends on
Feed origin
Bacterial origin

Ruminant - Protein Quantity
•Intake
•Microbial yield
-impacted by energy intake
-rumen ammonia level
-liquid dilution rate

Rumen Bacteria
Cellulolytic - Fiber digesters
Amylolytic - Starch digesters
Proteolytic - Bacterial protein digesters

Lamb Intake
Controlled by:
Fill
Energy
Low concentrate diets -- fill
High concentrate diets -- energy

Specific Nutrients
Vit E.
Se
Ca
P
Salt
30,000 IU/ton
.3 ppm
.48
.24
.5-1.0%

What Type of Ration
1. Targeted marketing date.
2. Relative costs of nutrients.
3. Compositional goal.
4. Facility size.
5. Feed processing equipment & storage.
6. Feeding system.

Simplest System
Whole corn: Pelleted Protein Supplement.
Advantages:
-Superior feed efficiency
-Self fed
-Low processing costs
-Low cost diet
-Acidosis risk

Simplest System...
continued
Disadvantages:
-Sorting
-Slower gains
-Quality of protein supplement
-Cash expense for protein

High Hay Rations
Advantages:
-Minimal cash outlay
-Value added to hay crop
-Improved composition
Disadvantages:
-Lower ADG
-More facilities, bunks and pens
-Hay waste

Weaned Lamb
Performance on Grass
Factors - Forage Species
Grass vs. legumes
-Age of lamb
-Health of lambs
-Condition of lambs

Lamb Gains on Straight Grass
.20 - .25 pounds per day
.35 - .50 w/pound supplementation
Conversion 1:10 t0 1:5

Escape Protein for
Pasture Lambs
Sources:
•Blood Meal
•Fish Meal
•Corn Gluten Meal

Nursing Lamb Performance on Grass
Milk Production is Key
1. Rotational grazing a. high quality and quantity of forage b. reduced competition between ewe & offspring
2. Creep Feeding a. improved growth b. allows coccidia control c. increases cost of production