For Mid-Atlantic States Veterinary Clinic, May 19, 2016

1. SMALL RUMINANT REPRODUCTION
AND OPPORTUNITIES TO ENHANCE
REPRODUCTIVE PERFORMANCE
SUSAN SCHOENIAN (Shay-nē-ŭn)
Sheep & Goat Specialist
Western Maryland Research & Education Center
University of Maryland Extension
sschoen@umd.edu - www.sheepandgoat.com
http://www.slideshare.net/schoenian

2. SHEEP AND GOATS
REPRODUCTION BASICS
Sheep Goats
Average Range Average Range
Puberty 5-12 months 6-8 months 4-12
Estrus cycle 17 days 14-19 days 21 days 18-24 days
Standing estrus 30 hours 15-45 hours 36 days 24-48 days
Ovulation
(hours after estrus)
About 24 hours after onset 36 hours 9-72 hours
Gestation 148 days 144-150 days 150 days 145-152 days
Ovulation rate ~1.5 1-4 ~1.7 1-4

3. PUBERTY IN SHEEP AND GOATS
 Marked by first ovulation and estrus.
 Age at puberty is affected by species, breed, nutrition,
and season of birth.
 Size more important than age when deciding to breed
ewe lambs and doe kids.
 Ewe lambs and doe kids should achieve approximately
60-70% of their mature weight before being bred for the
first time.
 Ewe lambs and doe kids should be fed an managed
separately until they wean their first offspring, ideally
until they are bred for the second time.
 Well-grown ram lambs and buck kids can successfully
breed at 7-8 months of age (50% of their mature weight).
They can be expected to service 15 to 25 females.
 Don’t mix young males with mature males.

4. SEASONAL BREEDING HABITS
 Sheep and goats are seasonally polyestrous; short day
breeders.
Their cycling activity is triggered by photoperiod.
Normal breeding period is August-December
 Breeds originating further from the equator have shorter
breeding seasons; those from closer to the equator have
longer breeding seasons.
 There are species and breed differences
 Goats are generally less seasonal than sheep
 Tropical breeds tend to cycle throughout the year
 Some breeds have longer breeding seasons, e.g. Dorset
 Can extend breeding season with
 Ram/buck effect
 Hormonal treatments, e.g. CIDRs
 Light control
 Ewe lambs and doelings usually cycle their first fall and
don’t respond as well to artificial manipulation.

5. SIGNS OF ESTRUS (HEAT) IN SMALL RUMINANTS
Ewe
 More subtle in sheep than goats, cattle, and pigs.
 Practically non-existent in ewe lambs.
 More pronounced in hair than wooled sheep
 Seek out male
 Walk fence lines
 Increased vocalization
 Rapid tail movement; raised tail
 Decrease in milk production and appetite
 Reddened swollen vulva
 Teaser ram often needed to detect heat in
ewes.
Doe
 Similar to cattle, but goats less likely to
mount or stand to be mounted.
 Increased vocalization
 Restlessness
 Loss of appetite
 Rub up against other goats
 Reddened, swollen vulva
 Thin mucous discharge from vulva

6. REPRODUCTIVE EFFICIENCY IN SHEEP AND GOATS
 While the national average lambing
percentage is only 111 (NASS, 2016), there
are considerable differences among regions
and farms.
 NASS does not calculate a percentage for
goats (is it higher: ? birth rate (Y), survival
(N)
 The American Sheep Industry has identified
increasing the national lamb crop as a
priority.
 There is tremendous opportunity to
increase reproductive efficiency in sheep
and goats.

7. MANY FACTORS AFFECT REPRODUCTIVE RATE
 Species
Goats are generally more prolific than sheep, but offspring mortality is usually higher.
 Breed
Some breeds are more prolific, e.g. Finn, Romanov, hair sheep
Some breeds are less prolific, e.g. Angora, Merino, Texel
 Genetics
Selection for improved performance will increase flock/herd reproductive rate
Unproductive females should be culled
 Season
Fall breeding/spring birthing produces a larger crop than out-of-season breeding.
 Nutrition
Females in better body condition (or flushed) ovulate more eggs and produce more
offspring.
 Age
Females between the ages of 3 and 6 produce the most offspring.
 Survival
Anything that kills lambs and kids reduces reproductive rate: predators, parasites,
disease, etc.
 Birthing interval
Lambing or kidding more often than once per year can increase reproductive rate

8. BREEDING PRACTICES EMPLOYED BY SHEEP
PRODUCERS (NAHMS, 2011)
Practice % sheep farms
Flushing 52.8
Breeding marks 21.1
Teaser ram 9.7
Artificial insemination (AI)
Frozen semen
Fresh semen
1.4
79.3
28.6
Embryo transfer (ET) 1.5
Estrus synchronization 6.6
Ultrasound pregnancy scanning 7.1
Breeding soundness exam 23.4
Out-of-season breeding (February-
July)
Hormonal treatments
Light control
24.5
11.6
0.7

9. BREEDING PRACTICES EMPLOYED BY GOAT
PRODUCERS (NAHMS, 2010)
Practice % sheep farms
Flushing 10.4
Breeding soundness exam
Physical exam
Semen evaluation
2.5
3.3
Pregnancy scanning 3.6
Out-of-season breeding, with Light
control
1.8
Genetic selection to breed out-of-season 5.4
Synchronized estrus 39.1
Accelerated kidding 17.1
No defined breeding season 34.8
Artificial insemination 0.5
Embryo transfer 0.4

10. FLUSHING
52.8% OF SHEEP FARMS AND 10.8% OF GOAT FARMS
 A means to increase ovulation rate and embryo
survival in ewes and does; thus, increase birthing
percentage.
 Is accomplished by putting ewe or doe on a rising
plane of nutrition.
 Grain is usually fed (~0.5 lb. per head per day) but
ewes/does can also be moved to a better quality
pasture.
 Flushing works best with females in low body
condition,
< 2.5 BCS.
 Ewes/does already in good body condition may not
respond to flushing.
 May also be advantageous to supplement rams and
bucks during breeding season.

11. MONITORING BREEDING ACTIVITY
21.1% OF SHEEP FARMS
 Use marking harness or paint to monitor
breeding activity of rams and bucks.
 Forecast lambing/kidding date
 Identify sire (multi-sire matings)
 Identify barren females
 Identify breeding problems (semen, libido)
 Detect estrous (teaser ram/buck)
 Apply paint every 2-3 days
 Change crayon every 17 days (sheep) or
21 days (goats).
 Start with paler color first
 Allow male to get used to breeding harness for a
few days before joining females.

12. PREGNANCY DIAGNOSIS
7.1% OF SHEEP FARMS AND 3.6% OF GOAT FARMS
 Pregnancy diagnosis is beneficial to
both small and large producers
 Eliminate non-pregnant females from flock/herd
 Sell non-pregnant ewe lambs for lamb prices.
 Alter feeding of females
 Separate twin and multi-bearing females into
production groups for feeding management

13. METHODS OF PREGNANCY DIAGNOSIS
 Determine pregnancy status
 Heat checks (return to heat)
 Breeding marks (via marking harness or rattle paint)
 Udder palpation (2-4 weeks before lambing)
 PregTone (detects amniotic fluid, 60-120 d))
 Progesterone and blood test assays
BioPRYN® (detects Pregnancy-Specific Protein B, after 30 d)
 Ultrasound (after 35 d)
 Transrectal (can detect earlier pregnancies)
 Transabdominal (less risk to female)
 Determine fetal numbers
 Ultrasound (scan 35-90 d)
 BioPRYN® (?) - multi-bearing ewes may have higher concentration of
PSPB

14. BREEDING SOUNDNESS EXAM (BSE)
23.4% OF SHEEP FARMS AND 2-4% OF GOAT FARMS
 Up to 15 percent of rams and bucks are of unsatisfactory
reproductive breeding quality.
 A breeding soundness exam can help to eliminate males
with sub-par fertility.
 A breeding soundness exam should be done one month
before breeding and include:
1. Physical exam (body condition, structural soundness, health)
2. Inspection of reproductive organs (palpate scrotum and
testicles, evaluate epididymitis, measure scrotal size)
3. Collection and evaluation of semen (collect semen via
artificial vagina or electro-ejaculator, check morphology and
motility).
 Libido or sex drive is another important aspect of
breeding soundness. It is seldom measured. A marking
harness or painted brisket can be used to evaluate
breeding behavior.

15. ESTROUS SYNCHRONIZATION
6.6% OF SHEEP FARMS AND 39.1% OF GOAT FARMS
 There are many benefits to estrus
synchronization
 Schedule lambing and kidding
 Concentrate lambing and kidding
 Reduced labor
 Reduced mortality
 More uniform lamb/kid crop
 Reduced marketing costs
 For use with artificial insemination (AI)

16. OUT-OF-SEASON BREEDING,
24.5% OF SHEEP FARMS BREED OUT-OF-SEASON; 17.1% OF GOAT FARMS ACCELERATE KIDDING
 Seasonal breeding remains one of the biggest
obstacles to growing the sheep/goat industry
and demand for lamb and goat meat, as it
makes it difficult to provide markets with a year-
round supply of fresh lamb and goat.
 Seasonal breeding results in seasonal
fluctuations in prices, as most lambs/kids are
born in the first half of the year and marketed in
the second half.
 From a producer’s standpoint, out-of-season and
accelerated breeding can increase profits by
improving reproductive and marketing efficiency.
 There is less predator, parasite, and weather risk
with fall lambing/kidding.
0.0%
2.0%
4.0%
6.0%
8.0%
10.0%
12.0%
14.0%
16.0%
18.0%
20.0%

17. OUT-OF-SEASON BREEDING
INDUCING ESTRUS IN NON-CYCLING FEMALES
 Normal breeding season is July-
January
(more like September-December)
 Spring breedings (April-May) are
usually most difficult.
 Three methods to induce estrus in
ewes/does
 Ram or buck effect
 CIDRs
 Light control

18. RAM OR BUCK EFFECT
9.7% OF SHEEP FARMS USE TEASER RAM
 When a ram or buck is introduced to a group of
females, the reproductive cycle of those females
tends to synchronize.
 During the non-breeding season, some females may
be stimulated to ovulate and express heat.
 Silent heat is followed by fertile heat 10 to 14 days
later.
 Ewes/does must be isolated from males (sight,
smell) for at least 2-3 weeks before joining.
 The ram/buck effect is thought to be caused by
pheromones.
 Teaser rams/bucks can be used to induce the male
effect, which are then replaced by fertile males no
longer than 14 days later (1 male: 20 females).

19. OUT-OF-SEASON BREEDING WITH CIDR-G
11.6% OF SHEEP FARMS USED HORMONAL TREATMENTS FOR OUT-OF-SEASON
BREEDING
 CIDR is an intravaginal insert for delivery or progesterone
 Simple, easy-to-use device that is inserted into ewe for 5
days, with ram introduction immediately to follow.
 Some have found greater success leaving CIDRs in for
10-12 days (followed by injection of PG600- ELDU).
 Many have reused CIDRs with success.
 Ram fertility is key to success.
 Approved for sheep in 2009
 CIDRs cost about $6 each.
 Not recommended for ewe lambs.
 No other method of hormonal manipulation is approved
for sheep. No method is approved for goats. Hormonal
control of reproduction does not meet requirements of
ELDU.

20. OUT-OF-SEASON BREEDING WITH LIGHT CONTROL
0.7% OF SHEEP FARMS AND 1.8% OF GOAT FARMS USED LIGHT CONTROL
 Estrus in ewes and does is triggered by
photoperiod.
 Ewes/does are short-day breeders
 Modifying day length can induce sheep to ovulate
out of season.
 The change of day length from long days to short
days initiates estrus.
 Need light-proof barn, with adequate lighting
 Should expose females as well as males to
lighting program.

21. ARTIFICIAL INSEMINATION (AI) IN SHEEP/GOATS
1.4% OF SHEEP FARMS AND 0.5% OF GOAT FARMS
PROS
 Genetic improvement
 Introduce new breeds
 Introduce new bloodlines
 Export potential
 Disease management
Fewer diseases spread with semen
 Maintain fewer males
CONS - CONSTRAINTS
 Lack of identification of superior sires
 Lack of semen to purchase
 Smaller size of sheep and goats compared to cattle
 Cost of procedure
 Cost of semen (vs. natural mating)
 Difficulty with sheep AI (with frozen thawed semen)
 Complicated cervix
 Few visible signs of heat
 Poor conception rates with frozen semen except when
done laparoscopically under anesthesia

22. ARTIFICIAL INSEMINATION (AI) IN SHEEP AND GOATS
4 Methods
 Vaginal
Semen is deposited into anterior vagina
 Cervical
Semen is deposited in cervix
 Trans-cervical
Semen is deposited into uterus after cervix
is traversed
 Laparoscopic
Semen deposited into uterine horns
intrabdominally

23. EMBRYO TRANSFER (ET)
 Genetic improvement via eggs from
superior females.
 Not widely done in US sheep and goat
industry (NAHMS)
Sheep - 1.5% farms
Goats - 0.4% farms
 Primarily done with show flocks/herds.
 Means to export germplasm.
 Requires veterinary expertise

24. RECOMMENDED RESOURCE
 Sheep Production Handbook (2016)
American Sheep Industry Association
Revision currently in progress
http://www.sheepusa.org/sheep-production-
handbook
 Goat Science and Production (2010)
Sandra G. Solaiman