Optimal nutrition management targets for the transition ewe: Lessons learned in the lab and field
1. “Optimal nutrition management targets
for the transition ewe: Lessons learned in
the lab and field”
Richard Ehrhardt
Small Ruminant Specialist
Michigan State University
2. Overview:
• Flock nutrition in the 21st century
• Opportunities for high performance and profitability with
optimized nutritional management
• Importance of forage quality
• Energy intake issues observed in the field
• Feeding recommendations to optimize
productivity and maternal health
3. Precise nutrition management:
Nutritional investment at critical stages can
reap large dividends!
What stages and type of investment?
•3 critical stages:
flushing
late pregnancy
early lactation
•Invest in energy, particularly that from highly digestible
forage sources!
4. Precise nutrition management allows:
• Improved out of season conception
• Larger litter sizes (birth percentage)
• Higher colostrum and milk production
• Reduced incidence of metabolic disease
• Improved postnatal lamb/kid survival
• Improved postnatal lamb/kid growth
7. Forage Quality: determined by composition
and digestibility of cell wall fraction
Cell wall component: Digestibility:
Cellulose 50-90%
Hemicellulose 20-80%
Lignin 0-20%
Fiber digestibility determines the amount
of energy and protein available to the animal
8. Factors that determine fiber digestibility:
•Plant maturity
Vegetative to mature
•Growing conditions
Temperature
•Plant species
Grasses (C3 vs. C4)
Legumes
9. How do can you manage plant maturity?
•Time of cutting/harvest!!!!
Grazing: length of pasture rotation
Machine harvest: time of cutting
•Timing of forage harvest is the most critical factor
to manage in optimizing animal health and
performance in most sheep and goat farming
systems!
10. Barriers to control of harvest timing:
•Stored forage:
Lack of awareness!
Great lakes weather: lack of lengthy drying periods!
Silage harvesting systems allow much greater control over
harvest timing!
Need only 6-24 h of dry weather in most instances
Cost of silage harvest equipment/farm scale
•Grazing systems:
Lack of awareness!
Lack of pasture infrastructure
Subdivision fencing, water
11. Feeding issues encountered with silage
systems on sheep and goat farms:
• Quality and freshness: is the feeding rate sufficient to keep
silage from spoiling?
• Animal number needed to keep silage sources fresh during
cold weather (Dec to March):
Corn silage Haylage
Doe (125 lb) Ewe (170 lb) Doe (125 lb) Ewe (170 lb)
Silage bunk 1.86/ft2 1.37/ft2 2.92/ft2 2.15/ft
24 ft W, 6 ft T: 268 197 420 309
8 ft Ag bag: 94 68 147 108
Baled silage
(4x4 ft bale for 4 days: 39 28
* Need twice as many animals during warm weather!!
12. Important measures of fiber quality:
•NDF=neutral detergent fiber (cell wall fraction)
Negatively correlated with DM intake
•NDF digestibility =% of NDF digested in rumen
Best indicator of DM intake
•ADF=acid detergent fiber (cellulose and lignin)
Negatively correlated with DM digestibility
A primary goal is to maximize dry matter
intake during critical production phases
16. Feeding issues encountered with fermented
feeds (silages!) on sheep and goat farms:
• Obesity in low productivity states!
Non-pregnant ewes outside of the breeding period
Pregnant ewes: day 0 to day 100 of pregnancy
• Management solutions to prevent obesity in late pregnancy
1.Identify non-pregnant ewes with ultrasound (day 40-70) and sort
them out of the late pregnancy feeding group.
2. Feed a diet lower in energy (60% TDN) in the day 40-100 period.
3. Alter diet energy density for the 40-100 day period according to
body condition status.
17. Fetal and placental growth in single and triplet births
Triplet
Single
0
200
400
600
800
0 30 60 90 120 150
Gestational age, d
Placentalweight,g
Triplet
Single
0
1000
2000
3000
4000
5000
Fetalweight,g
Early LateMid
19. Prevention of ketosis:
• Key concept is to increase energy density of
diet in last 30 days
• Risk factors:
Plane of nutrition and body condition
Thin ewes in general-underfeeding exacerbates the
problem
Fat ewes-that cannot consume enough energy in late
pregnancy
Stress-winter storms, shearing, etc.
20. Evaluation of transition diets and their
relationship to health status and performance
in large sheep flocks in 2014
• Health status recorded by flock owners and CVM “Small ruminant
production medicine” clerkship students
• Feed intake recorded by flock managers during late pregnancy and early-
mid lactation
• Diet components and complete total mixed rations were sampled
• Diet samples were analyzed by NIR methodologies to estimate dietary
energy and protein concentration and to characterize fiber fractions
• 8 farms evaluated, results from 4 farms during the late pregnancy period
will be presented
• All flocks were “prolific” with lamb drop >200%
• Average ewe mass (parity 2+ in average body condition- BCS 3) ranged from
165-180 lbs between flocks
• All flocks fed some form of silage as the main source of dietary dry matter
21. 0
1
2
3
4
5
6
7
A B C D NRC
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
A B C D NRC
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
A B C D NRC
Energy intake
ME, (Mcal)
Feed dry matter intake,
% of bodyweight
Diet energy
Concentration
ME/lb.
22. 0
5
10
15
20
A B C D
0
5
10
15
20
25
30
A B C D
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
A B C D NRC
Feed intake,
% of bodyweight
Diet Starch, %
Diet ADF, %
23. 0
10
20
30
40
50
A B C D
0
20
40
60
80
100
A B C D
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
A B C D NRC
Feed intake,
% of bodyweight
Forage NDF
Digestibility, % (48 h)
Diet NDF
Concentration, %
24. Body condition score, incidence of ketosis and energy intake
in large flocks during 2014
Energy intake
ME, (Mcal)
0
1
2
3
4
5
6
7
A B C D NRC
0
2
4
6
8
A B C D
Incidence of ketosis,
% of late pregnant ewes
0
1
2
3
4
5
A B C D
Flock body condition score
(1=thin, 5=fat)
25. Improvement of dietary NDF digestibility in
flock D and its impact on feed intake and
incidence of ketosis in late pregnancy
• Flock D had a high incidence of ketosis , 5.8%, during the April
lambing period
• Ewes in flock D were also obese, BCS 4.0.
• Recommendations were made to improve dietary fiber quality
and to reduce energy concentration of diet prior to late
pregnancy
67% of poor quality “husklage” was replaced with a 50/50
mix of high quality corn silage and alfalfa haylage
Ration cost increased by 33%
26. 0
1
2
3
Old silage New silage
0
10
20
30
40
50
Old silage New silage
0
20
40
60
80
Old silage New silage
0
0.2
0.4
0.6
0.8
1
1.2
1.4
Old silage New silage
Diet energy
Concentration
ME/lb.
Diet NDF
Concentration, %
Forage NDF
Digestibility, % (48 h)
Feed intake,
% of bodyweight
0
2
4
6
8
Old silage New silage
Incidence of ketosis,
% of late pregnant ewes
27. Improvement of dietary NDF digestibility in flock D
and its impact on feed intake and incidence of
ketosis in late pregnancy
• Projected flock income due to reduction in ketosis
• 400 ewes @ 5.8%=22.4
• 400 ewes @ 1.0%=4.0
• 18.4 ewes and 32 lambs saved
18.4x$275 plus 32x$50=$6660
• Cost of preventative treatment:
• Feed cost differential = $3564
• Benefit of changing feed to reduce ketosis= $3096
• Additional benefits not assigned a $ value:
lambs grew faster
lamb mortality was reduced (birth to pre weaning)
Improved conception in next breeding cycle
Improved sheep welfare!
30. Summary of protein nutrition during
late pregnancy:
•Fetal growth is optimized at a protein plane (% crude
protein) of 11% and 13%, for single- and twin-pregnant
animals, respectively.
•Supplementation of protein above these thresholds will
improve maternal muscle protein retention during late
pregnancy
Will supplemental protein increase milk production?
Is supplemental protein cost effective in terms of milk
production and lamb growth?
31. Nutritional targets for late pregnancy:
• Manage body condition before late pregnancy,<3.5 BCS
• Target ration NDF <40% unless forage NDFd >70%
• Maximize use of highly digestible fiber sources
Target intake= 3% of non pregnant BW
Maximizes dry matter intake, maintains steady intake
• Limit use of high starch energy sources (i.e. corn and barley)
<50% of energy content( <30% dietary starch)
Minimizes acidosis, “going-off feed”
• Energy and Protein density targets
(TDN, %) Crude Protein (%)
Single 58 11
Twin 66 13
Triplet 73 15
• Alter targets based on BCS and production system
32. Summary:
• Forage quality is key to maximizing performance and profit in
prolific animals in high performance management systems
(accelerated, machine milking, etc.).
• The timing of forage harvest is the most critical management factor
in controlling forage quality.
• Silage harvest systems allow much greater control over the timing
of forage harvest but silage feeding systems must be matched to
farm size and may not be feasible for small flocks/herds..
• Energy form is especially important during late pregnancy as diets
high in fermentable fiber will allow a steady, high level of intake
thereby minimizing risk for metabolic disease.
• Managing body condition prior to late pregnancy will minimize
incidence of metabolic disease (target of 3-3.5 BCS)
33. Contact information:
Richard Ehrhardt Ph.D.
Small Ruminant Specialist
Animal Science / Large Animal Clinical Sciences
1287F Anthony Hall
Michigan State University
East Lansing, MI 48824-1225
Email: ehrhard5@msu.edu
Office: (517) 353-2906
Cell: (517) 899-0040
