It is customary to replace 20% of the flock or herd each year through culling and deaths. The most common reasons for culling ewes include age, failure to lamb, teeth problems, and mastitis. Producers should cull animals that have health issues like lost udder function, oversized teats, or chronic infections. When selecting replacement females, producers should evaluate them visually for structural correctness and performance based on traits like weights and mothering ability. Raising replacements allows breeding for important traits, but purchasing replacements allows using a terminal sire. Producers must manage replacement females separately with adequate nutrition to support their growth.

1. SUSAN SCHOENIAN
Sheep & Goat Specialist
University of Maryland Extension
sschoen@umd.edu – sheepandgoat.com

2. It is customary to replace 20 percent
of the flock (or herd) each year.
Reasons for culling % of ewes
Age 55.6
Failure to lamb 7.7
Teeth problems 7.6
Hard bag syndrome 7.1
Mastitis 6.7
Poor mothering 4.7
Other 3.7
Chronic weight loss 2.1
Economic issues 1.7
Other illness 1.2
Single births 1.1
Other repro problems 0.9
Death (5%) + Cull (15%) = 20%
A death loss of 4-6% is common. This
figure may be skewed in small flocks.
USDA APHIS NAHMS (2014)
10
years

3. Who should be culled?
Females that
• Have lost all or part of their udder function.
• Have oversized teats.
• Have pendulous udders.
• Prolapse their rectum or vagina (uterus?).
• Are chronically infected with hoof disease and/or
fail to respond to treatment(s).
• Require frequent hoof trimming.
• Require frequent deworming.
• Have unidentified weight loss.
• Are unable to maintain their body condition.
• Are open (fail to get pregnant)
• Fail to meet minimum standards for structural
correctness and soundness.

4. Who else should you cull?
Females that
• Lamb/kid late (fail to conceive during
first two heat cycles, 34-42 days).
• Miss more than one breeding
opportunity in accelerated birthing
programs.
• Fail to conceive as ewe lambs or doe
kids (@ 7 to 9 months of age), if that is
a goal.
• Give birth to small, weak offspring that
are slow to suckle.
• Reject their offspring.
• Wean poor quality offspring.
• Fail to wean offspring.
• Have fleece defects or wool quality
issues (wool emphasis).
• Fail to shed (hair sheep)
• Fail to meet standards for breed
character (registered breeders).

5. Consider culling . . . Hmm.
Females that
• Require any deworming.
• Require any hoof trimming.
• Experience dystocia
(difficult birthing, esp. ringwomb).
• Have singles more than once.
• Miss breeding opportunity in
accelerated birthing scheme.
• Sero-positive females for diseases
that you’re trying to eradicate (CAE,
OPP, Johne’s, CLA).
• Are over the age of 6 (?)
• Have bad temperaments.
• Are fence jumpers and escape artists
(mostly goats).

6. You have a choice.
You can raise or purchase your replacements.
Raise replacements
• Closed flock/herd
Better biosecurity
• Can breed for traits that are
most important to you.
• Can manage replacements
the way you want to.
• May be cheaper to raise
than purchase
replacements.
Purchase replacements
• Can breed all of your ewes
or does to a terminal sire.
– Superior market lambs/kids
– No risk of inbreeding
– Fewer ram/buck purchases
• Can purchase replacements
from farms that specialize in
their production.

7. Percentage of females required to
produce replacements
• Depends upon replacement rate and lambing/kidding
percentage (# lambs/kids raised per female exposed)
Flock size # needed Lamb % ♀ lambs % flock
100 20 80 40 50
100 20 100 50 40
100 20 120 60 33
100 20 140 70 29
100 20 160 80 25
100 20 180 90 22
100 20 200 100 20

8. Breeding for replacement
• It is generally recommended that
the top ~30% of the flock be bred
for replacement.
Example: Polypay x Polypay
• The other ~70% of the flock can
be bred to a terminal sire for
market animal production.
Example: Suffolk x Polypay
• An alternative is to use dual-
purpose breeds in a rotational
crossbreeding system.
Example: Kiko x Boer x Spanish
I make
market
lambs.
I make
replacement
ewe lambs.

9. Sires of replacement females
• Desired breed or breed
cross.
• Breeds and individuals
that excel in maternal
and fitness traits.
• Desired coat or wool
type.
• Desired level of
reproduction.
• Desired level of fitness.

10. Selecting replacement females
Need to select replacements that suit production system and intended markets for progeny.
1. Visual appraisal
2. Performance
3. Genotype or
serotype

11. Visual appraisal
• Establish minimum standards for
structural correctness and
soundness.*
– Feet and legs
– Teats
– Testicles (SC)
– Mouth - bite - teeth
– Conformation
– Hoof growth and morphology
– Shedding (hair sheep)
• Do not keep or sell animals with
known genetic defects or disease
issues (e.g. abscesses, hernia).
*Standards may be higher for seedstock producers and show flocks/herds.

12. Performance evaluation
• Select animals that are genetically
superior for traits of economic
importance to your enterprise.
 Estimated breeding values (EBVs)
 Adjusted weaning weights
– Raw data
• Weaning weights
• Post-weaning weights
• Carcass measurements
• Wool measurements
• Milk production
• Fecal egg counts
– Subjective scoring systems
• Birthing ease
• Mothering ability
• FAMACHA© score
• Body condition score (BCS)
• Hoof growth and disease status

13. Genotype
• Scrapie resistance
• Spider syndrome
• Hairy lamb syndrome
• OPP susceptibility
• Alpha S1 Casein
Serotype
• OPP
• CAE
• Johne’s disease
• Caseous lymphadentitis

14. Management of replacement females
• Identify early and separate
from mature ewes and market
lambs.
• Feed for moderate growth;
frame more important than
fat.
– May need to prevent winter
born (creep fed) lambs and
kids from getting too fat.
– May need to supplement
spring-born lambs and kids.
• Ensure exposure to parasites
so they can develop immunity.

15. Breeding for the first time
Lambs/kids (7-9 months) vs. yearlings (19 months)
PROS
• First year income $$$$$
• Greater lifetime production
• Potential to increase genetic
gain, if progeny are saved.
• Better mothers and milkers
next go-round.
• Ewe lambs/doe kids failing to
conceive can be sold as market
animals.
CONS
• Require better feed and
management than mature
females.
• Should managed as a separate
group from mature females.
• More likely to have problems as
compared to mature females.
• It “stunts” their growth [?]

16. Breeding ewe lambs and doe kids
• Favor early-born females;
however, size is more important
than age.
• Ewe lambs and doe kids should
achieve 60-70% of their mature
weight (avg. weight of 3-4 year
olds) before being bred.

17. Mating ewe lambs and doe kids
• Mate ewe lambs and doe kids to males
with same or smaller mature size.
• Avoid heavy fronted males and those
that sire offspring with above average-
birth weights.
• Mate ewe lambs and doelings
separately from mature females.
• Use pen or small paddock for breeding
(instead of big pasture).
• Consider breeding later than mature
females, so feeding and management
can be differed.
• Option of pregnancy scanning and
selling those that do not conceive.

18. Management of ewe lambs and doe kids
• Manage as a group; (ideally) keep
separate from mature females until
they are joined for the second time.
• Ewe lambs and doe kids have different
nutritional requirements as compared
to mature females.
– Primarily, ewe lambs and doe kids need to
consume more nutrient dense diets (i.e.
higher percentage of energy/TDN/ME).
– Ewe lambs and doe kids are generally less
competitive for feeder space.
• Feed according to NRC requirements.

19. Lambing yearlings
Ewe lambs and doe kids bred to lamb/kid at 12-14 months of age.
• Reproductive rate varies by breed and
flock.
– Often have singles.
– Many have twins.
– Some have triplets.
• More likely to experience problems
(but that doesn’t
mean they will).
• Usually do not have as much milk as
mature females (but that doesn’t
mean they won’t have enough milk to
feed their lambs).
• Feed according to NRC requirements.
• Consider weaning lambs early to allow
them to rebuild their body reserves
for second joining.

20. Your replacement females should be
the best females in your flock/herd.

21. Thank you for your attention. Questions? Comments?
SUSAN SCHOENIAN
Sheep & Goat Specialist
University of Maryland Extension
sschoen@umd.edu - sheepandgoat.com
My “yearling house”