This Lecture is belonging to The Course VHM 154 For students in The First level in Faculty of Veterinary Medicine, Cairo University, Egypt

1. By
Dr. Rabie Hassan Fayed
Prof. of Animal & Poultry Management
Faculty of Veterinary Medicine
Cairo University, Egypt

2.  Estrus
Estrus, or standing heat, is defined as a
regularly occurring state of sexual
receptivity during which the female will
accept the male.
This is indicated in cattle by the cow
standing to be mounted by a bull or other
cows. Standing heat typically lasts for about
12 -18 hours, but some cows may stand as
short as four hours or as long as 24 hours.
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3. The term “estrous cycle” refers to the
whole sequence of hormonal and
reproductive changes that take place
from one heat period to the next. The
length of the estrous cycle average is
21 days, but may vary among
individuals, with 17 - 24 day cycle
lengths being common.
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4.  Good heat detection is an essential part of
good fertility.
 Poor heat detection leads to cows on heat
being missed and cows being served when they
are not on heat
 The only definitive sign of heat is a cow
standing to be mounted when it is free to move
 Other signs, such as restless behaviour, a
bulling string, and mounting other cows,
suggest a cow is around oestrus but are not
definitive
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5.  Having a well-planned heat detection
strategy and well trained staff are
crucial
 Even in the best herds, heat detection
aids can improve detection
 Whatever system you use ensure that
you record heats effectively, assess
how effective your heat detection and
use these records to constantly
improve fertility
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7.  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 the
number of heats observed
 Always observe cows quietly
 Return cows to the milking herd as soon as
possible after AI – these cows will act as detectors
 Ensure all staff record all observations using the
same system
 Training of staff is critical
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8.  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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16.  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 or
down the sides from the mounting cow’s front
hooves
 heat detector device rubbed
 Cows will stand to be mounted for 12-24 hours
(less than this for heifers), and during this time
they may be jumped 50-80 times by various other
cows (often the ones who are about to stand later
that day, or by a more dominant female).
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20.  1) An older steer / bullock that was
castrated later in life will certainly
show you who is cycling, in much the
same was as a bull might.
 2) A side-winder bull will do the same
job (this is an entire bull that has had
his sheath operated on by a vet to
make it point out to the side so that
he can never effectively serve a cow).
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21. A-Chemical Communication
(Olfaction & gustatory)
B- Tactile communication
C- Auditory communication
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22. 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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27. 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 on
the rump of the cow and then smeared if the cow is
ridden .
 (2) Pressure-sensitive pads which glue to the rump
of the cow and (a) emit a red liquid when the pad is
mounted or trigger a computer-linked response to
indicate the cow has been ridden (Heat Watch)
 (3) Chin-ball markers

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34. One of the most effective ways of
determining heat is to attach this halter
device under the chin of a vasectomized
bull. The marker consists of a paint
reservoir with a steel ball valve, similar
to a ballpoint pen. When bull rides
another animal, the chin ball marker is
activated, and paint marks are left on
the in-heat animal’s back
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37. Many believe these to be the most
reliable, especially on the long hair of
Highlands. Take care with their
placement as per the directions, and
second Kamar can be placed over the
top of ones that have gone off. They do
not go fully off until the cow has been
mounted 3-4 times.
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41. Also useful but may not stick as
well to hairy animals. Also need to
pay attention to application
technique to be sure the glue gets
sticky enough. Some will cut these
in half & get two uses from a
single patch, thus halving the
cost.
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43. some have used this in Highlands
and tail paint is generally useful
but there are more potential for
‘false alarms’ with this method.
Certainly the cheapest heat
detection aid.
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50.  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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51.  drop in milk production
 clear, glistening mucous discharge from vagina
 redness and swelling of vulva
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52.  A characteristic of standing heat that is often
mentioned refers to a somewhat reddened
and swollen, loose vulva. Practical experience
suggests that this may be very subject to
interpretation and difficult to view, and is
thus of limited value as a heat detection aid.
 a bloody discharge at the end of estrus
usually indicates a missed heat; observe this
animal for return to heat in 18–24 days
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53. 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.