Reproductive Physiology of Beef and Cattle Suporn Katawatin Department of Animal Science Khon Kaen University

Reproduction is one of the most important consideration determining the profit of cattle production

(85 days) HERD HEALTH ARTIFICIAL INSEMINATION DAYS OPEN RECORD NUTRITION ESTROUS DETECTION MANAGEMENT HERD HEALTH DAYS OPEN (85 days) FEMALE FERTILITY REDUCE AGE AT 1ST CALVING INCREASE % COWS CYCLING TREAT PROBLEM COWS CONTROL GENITAL DISEASE PREGNANCY DIAGNOSIS ARTIFICIAL INSEMINATION IMPROVE AI TECHNIQUE USE GOOD QUALITY SEMEN BREED COWS IN STANDING HEAT

to show regular cyclic breeding activity Good reproduction is … to show regular cyclic breeding activity

Reproductive Physiology Male and Female Reproductive Anatomy Puberty : age or body weight Sexual maturity Estrous Cycle Mating or Breeding Calving Lactation Recycling

Female Reproductive Characteristics of Cattle and Buffalo Parameters Cattle Buffalo Age at puberty (mth) 15 (10-24) 21 (15-36) Estrous cycle Length (d) Estrus (h) 21 (14-29) 18 (12-30) 21 (18-22) 21 (17-24) Ovulation Type Time from onset (h) Spontaneous 30 (18-48) 32 (18-45)

Female Reproductive Characteristics of Cattle and Buffalo Parameter Cattle Buffalo Life span of CL (d) 16 Fertilizable life of ova (h) (20 – 24) ?? Entry of ova into uterus (h after ovulation) 90 (64-96) Gestation length (d) 280 (278-293) 315 (305-330)

Female Reproductive Characteristics of Cattle and Buffalo Parameter Cattle Buffalo Age at 1st calving (months) 30 (24-36) 42 (36-56) Postpartum interval (days) Uterine involution First ovulation 45 (32-50) 30 (10-110) 35 (16-60) 75 (35-180) Calving interval (months) 13 (12-14) 18 (15-21)

Areas of controlled reproduction in female cattle Control estrus Suppression of estrus Breeding cattle at younger ages Controlled reproduction in cattle Pregnancy testing Induction of twin births Control calving Embryo transfer & in vitro fertilization Control postpartum interval

Heat Detection or Estrous Detection Estrous behavior

Before heat (6-10 h) Smells other cows Attempts to ride other cows Vulva moist, red slightly swollen

Standing heat (18 h) Stand to be ridden Bawls frequently Nervous & excitable Off feed and milk Vulva moist and red Clear mucous discharge Eye pupil dilated

Clear mucous discharge from vulva After heat (10 h) Will not stand Clear mucous discharge from vulva

Hours from the start of estrus Egg released Life of egg (6-10 h) Standing heat (18 h) After heat (10 h) Before heat (6-10 h) Estrus in cow and associated featured

Approaches to estrus detection in the cow Tail-painting & use of chalk Heat-mount detectors Use of closed circuit television Techniques used in estrous detection Chin-ball devices Cow activity changes Use of teaser animals Progesterone tests Vaginal probes

Hormonal Pattern During Estrous Cycle in Cow

Hormones Used for Induction of Estrus and Ovulation Type of hormones Method Biologic Activity Gonadotropins eCG or PMSG Single injection Mimics FSH and stimulates follicular growth; long half-life FSH Single/multiple injections Stimulates follicular growth; short half-life hCG Mimics LH and induce ovulation

Hormones Used for Induction of Estrus and Ovulation Type of hormones Method Biologic Activity Gonadotropin Releasing Hormone Agonist GnRH-buselerin Single injection Induces release of LH and FSH from the anterior pituitary gland; recruitment and selection of new dominant follicle

Hormones Used for Induction of Estrus and Ovulation Type of hormones Method Biologic Activity Progestogens Progesterone Multiple injections Inhibits ovulation by suppressing LH; mimics action of CL Synthetic progestogens Oral, subcutaneous implant, intravaginal device

Method of Administration Hormones Used for Induction of Estrus and Ovulation Type of hormones Method of Administration Biologic Activity Estrogens Estradiol conjugates Injection, implant Induce premature regression of CL, and enhances response to progestrogens Prostaglandins PGF2 or synthetic analogs Single intramuscular injection Induces regression of CL during responsive phases

End of Treatment to Estrus Protocols for Inducing Estrus and Ovulation in Acyclic Cattle and Buffalo Treatment End of Treatment to Estrus Prepubertal or postpartum suckled cows Estrogen on day 1 followed by 7 -12 days of progesterogen, eCG given on last day (optional) Within 5 days Postpartum milked cows GnRH on day 14 postpartum GnRH (day 0) and PGF (day 6) 1 day 2-4 days

End of treatment to estrus Techniques for Synchronizing Estrus in Cyclic Cattle Method Treatment Regimen End of treatment to estrus PGF Two injections (11-12 days apart) 3-5 days: AIDE/TAI GnRH + PGF Inject GnRH (day 0), PGF (day 6) 2-4 days: TAI GnRH + PGF + GnRH Inject GnRH (day 0), PGF (day 7), GnRH (day 8 or 9)

End of treatment to estrus Techniques for Synchronizing Estrus in Cyclic Cattle. Method Treatment Regimen End of treatment to estrus Progestogen + estrogen Estrogen injection (day 1), CIDR (day 1-9X 3-5 days : AIDE/TAI Progestogen +PGF Progestogen (days1-7), PGF (day 6) 2-3 days: AIDE/TAI

Ovulate follicle Start new follicle wave OVSync Breed (cows) GnRH (100ug) PGF2 (35mg) GnRH (100ug) 7 days 48 h 24 h Ovulate follicle Start new follicle wave Ovulate follicle Regress corpora lutea Timing and purpose of hormones to synchronize ovulation in lactating dairy cow (Pursley et al., 1995)

Days calving to conception Calving interval (days) Measure Reproductive Efficiency Trait Definition First calving Age (months) Days open Days calving to conception Calving interval (days) Days between successive calving Total cows First service conception rate (%) No. pregnant 1st service X 100 No. bred 1st service

No. of services in all cows Measure Reproductive Efficiency Trait Definition Services per conception No. of services in all cows Total conceptions Pregnancy rate (%) No. of cows pregnant X 100 Total cows in herd Calving rate (%) No. of calves born X 100 Net calf crop (%) Total calves weaned X 100

Book Suggestion Hafez, E.S.E. and B. Hafez. 2000. Reproduction in Farm Animals. 7th ed. Lippincott Williams & Wilkins, New York. Gordon, I. 1996. Controlled Reproduction in Cattle & Buffaloes. CAB International. Bearden, H.J. and J.W. Fuquay. 1997. Applied Animal Reproduction 4th ed. Prentice Hall.

Approximate Values for Selected Reproductive Events in Female Domesticated Mammals  Species  Length of cycle (days)  Duration of estrus (hours)  Approximate time of ovulation  Normal breeding season  Cow Mean=20.5  Range 17 - 23 Mean < 10  Range 1 - 24  30 h after beginning of estrus   All year  Buffalo Mean=21  Range 18 - 22 Mean < 15  Range 4 - 24  32 h after beginning of estrus  All year   Mare Mean=21  Range 12 - 35 Mean=120  Range 24 - 240  Near end of estrus  Spring & summer  Ewe Mean=16  Range 12 - 19 Mean=30  Range 20 -48  26 h after beginning of estrus   Fall (variable with breed)  Doe Mean=20  Range 16 - 22 Mean=40  Range 24 - 72  On 2nd day of estrus  Fall  Sow Mean=48  Range 24 - 90  36 h after beginning of estrus