Heat Detection in the Cow

Floron C. Faries, Jr., DVM, MSProfessor and Extension Program Leader

Texas AgriLife Extension ServiceTexas A&M System

College Station, TX 77843http://extensionvetmed.tamu.edu

The Mechanics of Estrus

The basics of the estrous cycle

Why a cow cycles

Duration of heat: 1 day (6-30 hrs) Heat Estrus

Days between cycles: 20 days No heat Out of heat Between heats Diestrus

Cycling Estrous cycle is 21 days (18-24 days)

Not cycling Anestrus (no heat)

Cow in heat for 1 day Follicle and egg

Cow out of heat for 20 days CL develops for 5 days Mature CL for 11 days CL regresses for 4 days Cow comes in heat after CL regresses

Age cattle should cycle (puberty)

English breeds: 12-13 months

Continental breeds: 14-15 months

Brahman: 14-18 months

Cross breeds: puberty at least 1 month earlier

Determination of Timing for A.I.

Early Stage of Heat Bawling and walking Butting, trailing and mounting other cows Swollen vulva with redness inside Little if any, clear mucous discharge Cervix is open Uterus is rigid

Middle Stage of Heat Complacent and restless Very red and swollen vulva Abundant, clear mucous discharge Slightly matted hair on tail head Rides other cows Ridden by other cows Stands to be mounted (in standing heat)

Late Stage of Heat Mount other cows May still be ridden but will not stand Nervousness disappear Vulva swelling and mucus decrease Mucus becomes slightly rubbery Hair on tail head becomes matted

Ovulation occurs 14 hours (range 6 to 18 hours) after standing heat ends

Slightly bloody mucous discharge occurs about 24 to 48 hours after standing heat ends

Proper timing to increase conception rates Heat checks by an observer are 15 to 30

minute durations Repeated 3 to 4 times a day

Breed the cow 8 to 12 hours after first mounting (standing heat)

When standing heat begins in the morning, breed at night

When standing heat begins at night, breed in the morning

Health Concerns

Non-diseases Persistent heat

Persistent follicle Persistent no heat/anestrus

Persistent CL Embryonic/fetal deaths

Stress Malnutrition

Infertility Stress Malnutrition Low reproductive tract scores Low body condition scores Uterine trauma

Diseases Embryonic/fetal deaths

Vibriosis Trichomoniasis Neosporosis Brucellosis IBR BVD Hemophilus

Infertility Uterine infections