Physiology of Estrous Cycle

Estrus detection: significance, signs, methods of detection, timing of insemination

1

Significance of ED

Lesser no. of repeat breeder cows Decreased no. of services per

conception Decreased calving interval Per cow/buffalo increase in the

productivity and income of the farmer Decreased culling percentage due to

reproductive reasons

2

Estrus Signs (cows & buffaloes)Primary Sign Stands to be mounted (Standing Heat)Secondary Signs Active (nervous, Licking other cows,

Excitement Clear Mucus discharge (best sign) Mounting on other females (she will come in

heat later) Vulvar swelling (general sign) Reduced feed intake (general sign) Raised Tail head, Roughened (late sign) Micturition, Bellowing Milk let down reappear just after milking

(“Dokey”) 1-2 (in buffaloes)3

Behavioral signs of estrus

•Economic Significance

•Calf a year

•Ideal 60-90 days postpartum successful rebreeding

4

STANDING HEAT IN COWS: A SURE SIGN OF

ESTRUS

Note: Buffaloes do not show homosexual

behavior

5

6

Note: Buffaloes don’t show homosexual behavior

7

8

CLEAR MUCUS DISCHARGE : A VERY GOOD SIGN OF ESTRUS

9

SIGNS OF ESTRUS: CHANGES IN THE VULVA

NO ESTRUS

AFTER ESTRUS

BEFORE ESTRUSMAIN ESTRUS

PREGNANCY

10

11

estrus

Day Before Day after

SIGNS OF ESTRUS: CHANGES IN THE APPEARANCE OF

CERVIX

PRE ESTRUS

POST ESTRUS PREGNANCY

MAIN ESTRUS

NO ESTRUS

12

MATURE FOLLICLE

13

34% 22%

21% 23%

Methods of DetectionTwo to three times a day heat check is needed (visual

method)Note: 66% Buffaloes show estrus activity during 6 pm

to mid night

•Efficient

•Accurate

14

Barn estrus and breeding chart

15

Chin-ball marker

16

•Penile deviated bulls

•Vasectomized bulls

•Androgenized cows

Aids to estrus detection in cow

P4 milk test

Penile deviated bulls

Uterine tone

17

Optimum time of insemination in relation to onset of (standing)

estrus (AM-PM rule)

•Fertilizable life of ova about 6 -12 hrs after ovulation

•Fertilizable life of sperm in female reproductive tract is 24-48 hrs 18

Duration after termination of standing oestrus (h)

16 18 20 22 24 26 28 30

19

Pre-standing oestrus (h)

9 -8 -6 -4 -2

0 2 4 6 8 10 12 14

Standing oestrus (h)

L.H ( Roelofs et al., 2004)

A.I

IMPLICATIONS FOR TIMING OF OVULATION IN RELATION TO OESTRUS

BEHAVIOUR IN BUFFALOES

Hours in relation to onset of standing oestrus

200

150

100

50

0

Oestr

us b

eh

avio

ral

scoreA.I

• Increased activity

• Vulvular swelling

• Frequent urination

• Mucous discharge clear and thin

Too early to breed

• Mucous thicker & cloudy

• Restless

• Will not stand

• Sniffing the vulva of another buffalo

Fair to poor fertilityBest time to breed

Managemental activities helpful for Better ED Clear identification (branding/ear tagging) Record keeping Only one man should be made responsible for this job He should know the primary & secondary signs of heat Accurate timing of AI Every heat detection aid should be accompanied with

visual observation Interval between milking and offering of fodder is ideal

time for visual observation Estrus activity chart of breeding females Observing heat signs after AI has the same

importance as before AI. Why??

20

Favorable conditions for cows to show estrus Free interaction of cows to show estrus

behavior especially mounting activity Adequate numbers of cows present in the

grouping Cows able to have good footing for successful

mounting in respect of ground conditions Cows should not have feet and leg problems

that discourage them from mounting

21

Mount detection aids

22

Pedometers: Measures walking activity

23 Thank you