THE EFFECTS OF DIETARY CLOVER SPECIES ON REPRODUCTION IN THE EWE LACEY BEAM DEPARTMENT OF ANIMAL SCIENCES OREGON STATE UNIVERSITY
Dec 22, 2015
THE EFFECTS OF DIETARY CLOVER SPECIES ON
REPRODUCTION IN THE EWE
LACEY BEAM
DEPARTMENT OF ANIMAL SCIENCES
OREGON STATE UNIVERSITY
BACKGROUND
Escalon, CA
BACKGROUND
• SAN JOAQUIN DELTA COLLEGE2000-2002
• OREGON STATE UNIVERSITY– B.S. IN ANIMAL
SCIENCE 2004
• OREGON STATE UNIVERSITY– M.Ag. GRADUATE
STUDENT
REPRODUCTION
• REPRODUCTIVE DIFFICULTIES IN SHEEP GRAZING CLOVER SPECIES WERE FIRST RECOGNIZED IN 1946 (Bennetts et al.)
• “CLOVER DISEASE”– SYNDROME OF ABNORMAL
REPRODUCTIVE FUNCTIONS OF EWES GRAZING CLOVER PASTURES
GRAZING
• LEGUMES ARE A WIDELY AVAILABLE FEEDSTUFF FOR MAINTAINING RUMINANT ANIMALS
• SHEEP ARE A USEFUL TOOL IN A GRAZING SYSTEM– SEED TO SOIL CONTACT– CREATES MORE TILLARS– CONTROLS PLANT SIZE– INEXPENSIVE FERTILIZER– LEGUMES ARE HIGH IN CP,
DIGESTIBILITY, INTAKE
CLOVER SPECIES
• SUBTERRANEAN CLOVER Trifolium subterraneum
Cultivars Formononetin % DM
Yarloop 1.5
Dwalganup 1.3
Dinninup 1.2
Geraldton .9
Tallarook .8
Daliak .2
Clare .15
Trikkala .15
Seaton Park .12
Bacchus Marsh .11
CLOVER SPECIES
• RED CLOVER Trifolium pratense
Cultivars Formononetin % DM
Broad .99
Tetraploid .90
Morocco .14
PHYTOESTROGENS
• DEFINITION: COMPOUND THAT EXERTS ESTROGENIC EFFECTS ON THE CNS, INDUCE ESTRUS, AND STIMULATE GROWTH OF THE GENITAL TRACT OF FEMALE ANIMALS
• CONTAINED IN MANY LEGUMES
• ESTROGENIC ACTIVITY DEPENDS ON POSITION OF 2 HYDROXYL GROUPS
PHYTOESTROGENS
• PHYTOESTROGEN CONTENT VARIES BETWEEN PLANT SPECIES, AND GROWING AND HARVESTING CONDITIONS
– EARLY SPRING:• PLANT STRESS DUE TO CHANGES IN AVAILABLE
NITROGEN OR PHOSPHORUS • TEMPERATURE
– DISEASE
– DROUGHT
– INCREASES PHYTOESTROGEN ACCUMULATION IN LEAVES
PHYTOESTROGENS
• PHYTOESTROGENS CONTAIN ESTROGENIC COMPOUNDS:
COUMESTANS
ISOFLAVONES
LIGNANS
PHYTOESTROGENS
COUMESTANS
• COUMESTROL– MOST COMMON
COUMESTAN– MOST ESTROGENIC
POTENCY OF ALL
PHYTOESTROGENS(ADAMS, 1995a)
PHYTOESTROGENS
ISOFLAVONES
• FORMONONETIN – MOST IMPORTANT
ISOFLAVONE PERTAINING TO RUMINANTS
– REDUCED AND DEMETHYLATED INTO THE MORE ESTRTOGENIC COMPOUND EQUOL
(Lundh, 1990)
EQUOL
• MORE ESTROGENIC THAN FORMONONETIN
• RAPIDLY ABSORBED THROUGH RUMINAL WALL
• MAJOR ESTROGENIC METABOLITE THAT INITIATES ESTROGENIC EFFECTS IN SHEEP
• CHEMICAL STRUCTURE RESEMBLES ESTRADIOL - ALLOWS BINDING TO THE ESTROGEN RECEPTOR
Equol Estradiol(Lundh, 1990) (ADAMS, 1995a)
RUMINANTS AND ISOFLAVONES
• DEGREDATION AND DETOXIFICATION OF ISOFLAVONES TAKES PLACE IN THE RUMEN
• RESULTING IN ESTROGENIC RUMEN CONTENTS
• RUMEN MICROBES BREAKDOWN ALL OTHER ISOFLAVONES INTO THEIR NONESTROGENIC METABOLITES
• FORMONONETIN EQUOL
EFFECTS ON SHEEP
• EWE INFERTILITY
TEMPORARY:• DECREASED FIRST SERVICE CONCEPTION
• IRREGULAR ESTRUS– DECREASED OVARIAN WEIGHTS– EXCESSIVE SMALL AND MEDIUM FOLLICLES
DEFICIENT OF ANTRUM FORMATION, EARLY ATRESIA
• REDUCED OVULATION AND CONCEPTION RATES– REDUCED LAMBING RATES AND MULTIPLE BIRTHS
EFFECTS ON SHEEP
PERMANENT:• REPEATED GRAZING:
– DECREASES RESPONSIVENESS TO ESTROGEN
– BARRENNESS
• CERVIX- SERVES AS A RESERVOIR FOR SPERM DURING INSEMINATION AND OVULATION
EFFECTS ON SHEEP
• PROLONGED EXPOSURE TO ESTROGEN LEADS TO DEFEMINIZATION OF CERVIX– BECOMES SHORTER
AND BROADER– INAPPROPRIATE MUCUS
VISCOSITY UNABLE SPERM
TO MIGRATE THROUGH CERVIX – LOSS OF ABILITY TO STORE
SPERMATOZOA
MEASUREMENTS OF ESTROGENIC FEEDS
• UDDER DEVELOPMENT AND MILK SECRETION IN UNBRED EWES
• WETHERS MAY ALSO SECRETE MILK
• INCREASED TEAT LENGTH– DIRECTLY CORRELATED TO
CONCENTRATIONS OF FORMONONETIN IN PASTURE
ADDITIONAL PROBLEMS
• DYSTOCIA
• UTERINE PROLAPSE
• ABORTIONS
• NEONATAL MORTALITY
RESEARCH
• RESEARCH PAPER
• AREAS OF INTEREST– SUBTERRANEAN CLOVER CAN ACCUMULATE UP
TO 5% WEIGHT OF ISOFLAVONES– ISOFLAVONES ARE ONLY PRESENT IN GREEN
CLOVER (ADAMS, 1995a)
– RAPIDLY DRIED HAY MAY RETAIN ISOFLAVONE CONCENTRATIONS
RESEARCH
• OBJECTIVES– TO DEFINE RAPIDLY DRIED HAY VS. SLOWLY
DRIED HAY– TO DETERMINE THE DIFFERENCES IN
ISOFLAVONE LEVELS BETWEEN RAPIDLY AND SLOWLY DRIED CLOVER HAY
– TO DETERMINE IF CUTTING AND HARVESTING CLOVER FOR EWE FEED HAS A NEGATIVE IMPACT ON REPRODUCTION
RESEARCH
• HYPOTHESIS– FEEDING SLOWLY DRIED CLOVER HAY
TO EWES WILL HAVE LOWER CONCENTRATIONS OF ISOFLAVONES AND LESS NEGATIVE REPRODUCTIVE EFFECTS THAN THE SAME GRAZED CULTIVAR
EXPECTED OUTCOMES
• SLOWLY DRIED CLOVER HAY WILL CONTAIN LOWER LEVELS OF ISOFLAVONES THAN RAPIDLY DRIED CLOVER HAY
• NEGATIVE REPRODUCTIVE EFFECTS ON THE EWE SHOULD BE REDUCED COMPARED TO GRAZED GREEN CLOVER
• SPECIFIC EVENTS DURING THE DRYING PROCESS THAT REDUCES/ELIMINATE ISOFLAVONE CONCENTRATIONS