Reproductive Physiology and Management Research Program

1
Reproductive Physiology and Management Research
Program

• Robert Dailey, Jorge Flores, Keith Inskeep,
  Marlon Knights, Paul Lewis and Matthew Wilson

2
Projects/Support

• Hatch 427/NE1007 - Ovarian and Environmental
  Influences on Embryonic/Fetal Mortality in
  Ruminants 10/1/02-9/30/07
• State 149 (Animal Health Funds) - Effect of
  Peptidoglycan-Polysaccharide (PG) Complex of
  Streptococcal Cell Wall on Reproductive
  Efficiency and Mastitis in Sheep, 10/1/00
  9/30/02 - Dailey
• State 170 (Animal Health Funds) Pattern of
  Cytokines in Uterine and Vaginal Tissue and
  Secretions during Discrete Stages of the Estrous
  Cycle of Sheep, 10/1/02 9/30/04 - Dailey

3
Projects/Support cont.

• State 140 (WV Legislature/WV Department of
  Education)- WV Sheep Improvement Project
  Increasing Farm Income by a Strategic Shift in
  Breeding Time for Ewe Flocks, 7/1/98 6/31/07
  Lewis and Inskeep
• NRSP-7 Effectiveness of Intravaginal
  Progesterone Inserts and FSH Ewes, 1998-2003 -
  Inskeep, Lewis and Knights
• USDA-NRI 2001 -35203-10982 Investigation of the
  Benefits of Early Gestational IGF-I in Sheep,
  9/1/01-8/31/04 Wilson

4
Support from industry and other sources

• Pharmacia Animal Health Nat. Inst. Occup. Safety
  Hlth.
• InterAg Division of DEC International The Ohio
  State University
• Vetrepharm Dept. of Pathology, W V U
• Elysian Fields Farm (PA) WV Sheep Federation
• University of Michigan Colorado State
  University
• ARS Forage Unit, Beaver, W V Impres Medical
  Corp.
• Intervet Dept. of Immunology, W V U
• Dept. of Biology, W V U Jeff Lawson Farm (VA)
• USDA Sheep Exp. Station, DuBois ID Dale Evans
  Farm (MD)
• Allen Pysell Farm (MD) Richard Blamble Farm
  (MD)
• Michigan State University University of
  Wyoming
• 20 W Va Sheep Producers Antonio Lopez S. -
  Spain

5
Philosophical Approaches

• Conduct basic research into factors that limit
  reproductive efficiency and management of sheep
  in West Virginia and the Appalachian Region.
• Conduct applied research to test concepts
  generated by basic research, to enable wide
  application of new concepts, and to identify
  other problems deserving basic studies.
• Collaborate to maximize understanding and output.

6
Research Areas

• Regulation of Luteal Function
• Induction Synchronization of Estrus
• Early Embryonic Mortality
• Late Embryonic and Fetal Mortality
• - Progesterone Metabolism
• Mastitis and Reproduction
• Embryonic and Postnatal Growth
• Regulation of Follicular Dynamics

7
Regulation of Luteal Function

• Current and Proposed Studies
• Changes in gene expression of the prostaglandin
  synthesis and endothelin systems, and of
  prostaglandin dehydrogenase activity in corpora
  lutea.
• Signal transduction mechanisms mediating actions
  of endothelin and prostaglandin in luteal cells
• - Changes in concentration of intracellular
  Ca
• - Role of protein kinase C isozymes,
  especially ?.

8
Induction Synchronization of Estrus

• Anestrous Ewes (Knights)
• Three studies evaluated the CIDR-G (to deliver
  progesterone) and single injections of FSH for
  out-of-season breeding. One goal was to maximize
  conception rates. The second goal was to
  increase ovulation rate and litter size (to
  2.0). (1392 ewes)
• Conclusions Progesterone increased pregnancy
  rates to two services from 45 with ram
  introduction alone to 62. Treatment for 5 days
  was as effective as treatment for 12 days. FSH
  marginally increased ovulation rate, but did not
  consistently increase litter size.
• These data have been reported to USDA-NRSP7 for
  submission to FDA for approval of the CIDR-G for
  anestrous ewes. Three papers published.

9
Induction Synchronization of Estrus

• Ewes during the breeding season (Knights and
  Dixon)
• Three studies were conducted with CIDR-G to
  synchronize estrus during the breeding season.
  Treatment with 2 CIDR-G for 12 days yielded
  pregnancy rate to first service and prolificacy
  of 90 and 1.9 vs 79 and 2.0, respectively, (ns)
  in control ewes. 401 ewes
• Treatment with CIDR-G for 5 days with PGF2a 24 h
  before insert removal increased pregnancy rate to
  first service (63) compared to ewes that
  received PGF2a only (44 P lt .05). 164 ewes
• Treatment with CIDR-G for 5 days with PGF2a at
  insert removal increased pregnancy rate to first
  and second services (71 and 72 P lt .05) compared
  to ewes that received PGF2a only (58 and 61
  Plt.01). 1014 ewes

10
Breeding Anestrous Ewes Using Ram Effect and GnRH
Ram is a powerful tool to induce ovulation in
anestrous ewes. - It can be enhanced by
injection of progesterone at ram introduction.
- Estrus can be synchronized with subsequent
injection of PGF2a (day 12-16), but pregnancy
rates to two services usually do not exceed 70.
Objectives Will more ewes ovulate if ram
introduction is followed by injection of GnRH?
Will GnRH enhance pregnancy rates in response
to the ram effect and PGF2a? In two trials to
date, GnRH has not increased estrous response or
pregnancy rate. (Jordan, Wurst and Knights)
11
Induction Synchronization of Estrus
Ewe lambs during anestrus (Knights and
Baptiste) Fall born ewe lambs were treated in
July. Groups were Control Used CIDR-G device
(progesterone) Used CIDR-G device and ram
introduction Used CIDR-G device, ram
introduction and 25 ?g EB 24 h after CIDR
withdrawal Ram introduction alone increased LH
pulse frequency, follicular development and
ovulation. Progesterone alone did not.
Progesterone and EB combined with ram
introduction increased estrous response.
12
Late Embryonic Fetal Mortality

• Studies in Ewes

13
Anestrous Ewes That Experienced Pregnancy Loss
From Day 25 to Lambing
_________________________________________________
1998
1999
Synchronization Studies - Knights
14
Determining Late Embryonic and Fetal Loss in Ewes
Summer 2000 and 2001 (N 1400)Breeding -
May to September 1. Embryos / Fetuses on each
day of pregnancy diagnosis 2. Lambs at
term d25 45 65 85 Term Loss
Loss Loss Loss
15
Effect of Face Color On Embryo or Fetal Loss
During Several Stages of Gestation
a, b,c Columns with different letters are
different (P lt 0.05)
16
Ewes Losing Embryos Present at Day 25 of
Gestation By Type of Loss
Multiple Partial
Single Complete
Multiple Complete
17
Corpora Lutea (Ovulations) Not Represented By
Lambs Born in Ewes Treated With Three Dosages of
FSH
Knights et al., 2002
18
Effect of Mastitis on Reproductive Efficiency
Bacteria
Conception/ Pregnancy Failure
Mastitis
Inflammatory Mediators
Cell Wall Components (peptidoglycan,
lipopolysaccharide)
19
Mastitis and Reproduction in Dairy cowsAmanda
Barker Tennessee data

• Mastitis Caused
• Increased Number of Services
• Increased Interbreeding Interval
• Increased Days Open
• Increased Calving Interval

20
Cell Wall of Gram-Negative and Gram-Positive
Bacteria
Hurlbert, 1999
21
Sheep Model for Effects of Mastitis on
Reproduction (Amanda Stewart)

• Rationale
• Bacteria promote inflammation and infection after
  the host digests the bacterial cell wall
• Major component of cell wall is peptidoglycan
  (PTG)
• Majority of embryonic loss in cows is by days 6-
  8
• Method Inject PTG in ewes on day 5
  post-breeding
• Results - Induced transient fever
• - Reduce progesterone - Increased
  cortisol - Increased prostaglandin
  metabolite (PGFM)
• - Decreased pregnancy rate

22
Effect of Blocking Inflammatory Increase in PGF2a
on Pregnancy Rate (Amanda Stewart)

• Rationale PTG increased PGFM. Did increased
  PGF2? decrease pregnancy rate?
• Objective
• Does blocking PGF2? following PTG challenge
  result in increased embryo survival?
• Are other inflammatory mediators involved?
• Treatments
• 30 ?g PTG/kg body weight on day 5 plus saline (n
  10)
• PTG plus flunixin meglumine (fm) at 0, 6, and 12
  h (n 10)
• Saline plus fm (n 4)
• Saline alone (n 5)
• Jugular blood Progesterone, Inflammatory
  mediators TNF-?, IFN-?, TGF-?, IL-1, IL-2

23
Results - Pregnancy Rates

• Peptidoglycan plus saline 60
• Peptidoglycan plus FM 50
• Saline plus FM 75
• Saline 80
• Conclusion
• Increased PGF2a not solely responsible for
  pregnancy losses.

24
Effect of Peptidoglycan on Reproductive
Efficiency and Mastitis in Sheep (Holásková)

• Primary objective was to determine if
  immunization prevented
• 1. fever at bacterial challenge
• 2. early embryonic loss, and 3. mastitis in
  ewes.
• Five days after breeding, sheep were injected
  s.c. with PTG.

25
Results

Immunization did not prevent fever on day
5, enhance pregnancy maintenance, prevent
mastitis after weaning. In fact, increased
dosage of PG-PS lowered the probability of
successful pregnancy. This result fits earlier
finding by Coleman and Dailey that reproductive
disorders occurred more commonly in cows that
had previously experienced the
disorder. Mastitis tended to occur in fewer
immunized ewes.