By

Dr. Rabie Hassan Fayed

Prof. of Animal & Poultry Management

Faculty of Veterinary Medicine

Cairo University, Egypt

EstrusEstrus, or standing heat, is defined as aregularly occurring state of sexualreceptivity during which the female willaccept the male.

This is indicated in cattle by the cowstanding to be mounted by a bull or othercows. Standing heat typically lasts for about12 -18 hours, but some cows may stand asshort as four hours or as long as 24 hours.

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The term “estrous cycle” refers to thewhole sequence of hormonal andreproductive changes that take placefrom one heat period to the next. Thelength of the estrous cycle average is21 days, but may vary amongindividuals, with 17 - 24 day cyclelengths being common.

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Good heat detection is an essential part ofgood fertility.

Poor heat detection leads to cows on heatbeing missed and cows being served when theyare not on heat

The only definitive sign of heat is a cowstanding to be mounted when it is free to move

Other signs, such as restless behaviour, abulling string, and mounting other cows,suggest a cow is around oestrus but are notdefinitive

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Having a well-planned heat detectionstrategy and well trained staff arecrucial

Even in the best herds, heat detectionaids can improve detection

Whatever system you use ensure thatyou record heats effectively, assesshow effective your heat detection anduse these records to constantlyimprove fertility

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Ensure all cows are identifiable at a distance

Check two hours after morning milking

Check two hours after afternoon milking

Add an early afternoon check to maximize thenumber of heats observed

Always observe cows quietly

Return cows to the milking herd as soon aspossible after AI – these cows will act as detectors

Ensure all staff record all observations using thesame system

Training of staff is critical

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Restless behaviour Attempting to mount other cows Mounting head-to-head (rare but cows are

usually in heat if they do this) Bellowing when isolated Small increase in body temperature Poor milk let-down Clear mucus discharge from the vulva.

‘bulling string’ (mucus discharge with blood suggests heat 48 hours ago)

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Turning the tail to one side.

Abducted hind legs

ruffled hair on the tail head

scruff marks or dirt/mud half way up their back ordown the sides from the mounting cow’s fronthooves

heat detector device rubbed

Cows will stand to be mounted for 12-24 hours(less than this for heifers), and during this timethey may be jumped 50-80 times by various othercows (often the ones who are about to stand laterthat day, or by a more dominant female).

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1) An older steer / bullock that wascastrated later in life will certainlyshow you who is cycling, in much thesame was as a bull might.

2) A side-winder bull will do the samejob (this is an entire bull that has hadhis sheath operated on by a vet tomake it point out to the side so thathe can never effectively serve a cow).

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A-Chemical Communication

(Olfaction & gustatory)

B- Tactile communication

C- Auditory communication

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Through sniffing and licking to◦ The female genital opening ◦ or urine ◦ or the bedding to detect chemical substance called Pheromones

● Response of the male◦ Chin resting behaviour◦ Flehmen phenomenon

●Response of female◦ Standing behaviour

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The male raise its head

Extends the neck

Curling upper lip( exposing of the teeth)

Opening of the nostrils

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(1) Marking crayons (e.g. Chalk) which are used onthe rump of the cow and then smeared if the cow isridden .

(2) Pressure-sensitive pads which glue to the rumpof the cow and (a) emit a red liquid when the pad ismounted or trigger a computer-linked response toindicate the cow has been ridden (Heat Watch)

(3) Chin-ball markers

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One of the most effective ways ofdetermining heat is to attach this halterdevice under the chin of a vasectomizedbull. The marker consists of a paintreservoir with a steel ball valve, similarto a ballpoint pen. When bull ridesanother animal, the chin ball marker isactivated, and paint marks are left onthe in-heat animal’s back

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Many believe these to be the mostreliable, especially on the long hair ofHighlands. Take care with theirplacement as per the directions, andsecond Kamar can be placed over thetop of ones that have gone off. They donot go fully off until the cow has beenmounted 3-4 times.

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Also useful but may not stick aswell to hairy animals. Also need topay attention to applicationtechnique to be sure the glue getssticky enough. Some will cut thesein half & get two uses from asingle patch, thus halving thecost.

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some have used this in Highlandsand tail paint is generally usefulbut there are more potential for‘false alarms’ with this method.Certainly the cheapest heatdetection aid.

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a-dirty rump and flank

b-ruffled hair on tail head and

patches of hair are removed

c-streaks of saliva on the back

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drop in milk production

clear, glistening mucous discharge from vagina

redness and swelling of vulva

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A characteristic of standing heat that is oftenmentioned refers to a somewhat reddenedand swollen, loose vulva. Practical experiencesuggests that this may be very subject tointerpretation and difficult to view, and isthus of limited value as a heat detection aid.

a bloody discharge at the end of estrususually indicates a missed heat; observe thisanimal for return to heat in 18–24 days

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Pedometer for heat detection

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This device is used

along with a computer to

determine how far an

animal has walked.

Animals in heat are

usually restless and may

walk long distances.