Reproduction and Ultrasound. Examination in Cattle

T h e V e t e r i n a ry P u b l i s h i n g C o m pa n y Production animals

cattle

Reproduction and Ultrasound Examination in Cattle A new perspective on the oestrous cycle Author: Manuel Fernández Sánchez.

Format: 22 x 28 cm.

Number of Pages: 104.

Number of Images: 450.

Binding: Hardcover ISBN Spanish edition: 978-84-92569-77-9.

Year: 2012.

RRP: 55 e.

Manuel Fernández Sánchez, author of the best seller The Oestrus Cycle of the Cow. A Photographic Atlas, now brings us his second book Reproduction and ultrasound examination in cattle, published by Servet. It offers a detailed comparison of the uterine and ovarian structures in all phases of the oestrous cycle.

This publication is characterized by an original introduction to both photographic and ultrasound images of the different anatomical structures and their pathological conditions. In this way, the author succeeds in simplifying the interpretation of reproductive diagnosis using ultrasound, by guiding the reader and enabling him to visualise the structures on which ultrasonography is performed.

Centro Empresarial El Trovador, planta 8, oficina I - Plaza Antonio Beltrán Martínez, 1 • 50002 Zaragoza - España Tel.: 976 461 480 • Fax: 976 423 000 • pedidos@grupoasis.com • Grupo Asís Biomedia, S.L.

T h e V e t e r i n a ry P u b l i s h i n g C o m pa n y

Reproduction and Ultrasound Examination in Cattle A new perspective on the oestrous cycle

Table of Contents 1. Importance of the use of ultrasonography in dairy cattle

3. The oestrous cycle Introduction

Economic aspects

Follicular waves

Technical aspects

Recognition of structures

Uterus Foetus Ovaries

2. Ultrasound technology Principles of ultrasound technology What is ultrasound?

What is a sound wave?

What is a wave?

Examination procedure Recognition of ovarian structures Recognition of uterine structures Overall assessment of the cycle Recognition of structures Series of images for recognition of structures

4. Periodic examination and ultrasonography.

Practical use

Characteristics of waves

Periodic ultrasound examination

How are they propagated?

Routine procedures

Practical application of the technology Practical definition How is ultrasound produced?

How is it emitted?

Interpretation of the result of wavetissue interaction Acoustic impedance Attenuation The ultrasound scanner Structure of the ultrasound scanner Types of transducers or probes Ultrasound scanning modes Ultrasound gel Scanner controls

Postpartum examination/involution/infection (- days postpartum) Examination of the uterus, development of follicular waves and days open (- days) Detection of pregnancy (- days to days) Confirmation of pregnancy and foetal sexing (- days) Interpretation of the different ultrasound sections Transverse plane Horizontal plane Sagittal plane Foetal measurements Other non-routine uses of ultrasonography Embryo transfer

Appearance of artefacts Acoustic shadowing Posterior enhancement Edge shadowing

Centro Empresarial El Trovador, planta 8, oficina I - Plaza Antonio Beltrán Martínez, 1 • 50002 Zaragoza - España Tel.: 976 461 480 • Fax: 976 423 000 • pedidos@grupoasis.com • Grupo Asís Biomedia, S.L.

T h e V e t e r i n a ry P u b l i s h i n g C o m pa n y

5. Ultrasonography and pathological conditions Pathological conditions of the uterus Endometritis Pyometra Mucometra Embryo resorption Pathological conditions of the ovaries Ovarian cysts Follicular cysts Luteal cysts Anoestrus

6. Bibliography

Centro Empresarial El Trovador, planta 8, oficina I - Plaza Antonio Beltrán Martínez, 1 • 50002 Zaragoza - España Tel.: 976 461 480 • Fax: 976 423 000 • pedidos@grupoasis.com • Grupo Asís Biomedia, S.L.

IMPORTANCE OF THE USE OF ULTRASONOGRAPHY

REPRODUCTION AND ULTRASOUND EXAMINATION IN CATTLE

1

Importance of the use of ultrasonography in dairy cattle

Before turning to the presentation of ultrasound images, I believe it is important to place the applicability of this technology to the daily practice of reproductive examination in its true perspective.

Why should we forego an improvement in the quality of our reproductive service and fail to open the doors to such a valuable source of additional information such as that offered by ultrasound?

In order to allow the reader to make their own judgement of its value, the principal arguments, both economic and technical, which are normally put forward, will be listed, and as the author, I shall give my personal opinion on the matter.

Economic aspects Detail of an embryo aged 30 days and the corresponding ultrasound image

It is clear that the use of ultrasonography and hormone measurement have provided research with a basis for a greater understanding of the reproductive cycle. They can provide new techniques which can be applied in routine examination. Their cost therefore more than justifies their use in this area.

However, the majority of veterinary surgeons are not directly involved in research. The clinician therefore has to obtain the best return possible from a considerable investment in daily practice. With the use of ultrasonography, a veterinary surgeon is improving the quality of their service. Therefore it is the farmer who should bear an increased bill. As can be seen from this book, a dairy farmer should not assume that a cow is pregnant without having it confirmed on an ultrasound screen. There is no room for guesswork in an early positive diagnosis by palpation that may then be followed by an oestrus. Embryonic death does occur, and can be demonstrated by ultrasound imaging.

Furthermore, the correct use of an ultrasound scanner entails additional visits, as the initial diagnosis of gestation requires an ultrasound visit to confirm the pregnancy, which could coincide with foetal sexing, as

2

Male embryo aged 60 days (seen from behind) and the corresponding ultrasound image.

Detail of the head of the foetus.

Detail of the neck and spinal column.

we shall see later. All this results in a better service to the farmer, which should have economic benefits, as his business will be more profitable.

The veterinary surgeon should assume that the use of an ultrasound scanner will provide him, as an expert, with added value compared to other procedures, including the possibility of going into more detailed technical aspects of research to which he previously did not have access. With this in mind, there is little alternative but to accept that the veterinary surgeon, too, must bear a part of the cost, as it is very difficult to write off the equipment solely by means of passing on the cost to the farmer.

Consequently, it is the author’s opinion that it is a necessary investment for an expert who specializes in reproduction. Clinicians such as myself have no alternative but to accept this economic burden and its effects, as the day will come when our clients will expect and demand ultrasound imaging, and we have to be prepared for this.

3

IMPORTANCE OF THE USE OF ULTRASONOGRAPHY

REPRODUCTION AND ULTRASOUND EXAMINATION IN CATTLE

1

Importance of the use of ultrasonography in dairy cattle

Before turning to the presentation of ultrasound images, I believe it is important to place the applicability of this technology to the daily practice of reproductive examination in its true perspective.

Why should we forego an improvement in the quality of our reproductive service and fail to open the doors to such a valuable source of additional information such as that offered by ultrasound?

In order to allow the reader to make their own judgement of its value, the principal arguments, both economic and technical, which are normally put forward, will be listed, and as the author, I shall give my personal opinion on the matter.

Economic aspects Detail of an embryo aged 30 days and the corresponding ultrasound image

It is clear that the use of ultrasonography and hormone measurement have provided research with a basis for a greater understanding of the reproductive cycle. They can provide new techniques which can be applied in routine examination. Their cost therefore more than justifies their use in this area.

However, the majority of veterinary surgeons are not directly involved in research. The clinician therefore has to obtain the best return possible from a considerable investment in daily practice. With the use of ultrasonography, a veterinary surgeon is improving the quality of their service. Therefore it is the farmer who should bear an increased bill. As can be seen from this book, a dairy farmer should not assume that a cow is pregnant without having it confirmed on an ultrasound screen. There is no room for guesswork in an early positive diagnosis by palpation that may then be followed by an oestrus. Embryonic death does occur, and can be demonstrated by ultrasound imaging.

Furthermore, the correct use of an ultrasound scanner entails additional visits, as the initial diagnosis of gestation requires an ultrasound visit to confirm the pregnancy, which could coincide with foetal sexing, as

2

Male embryo aged 60 days (seen from behind) and the corresponding ultrasound image.

Detail of the head of the foetus.

Detail of the neck and spinal column.

we shall see later. All this results in a better service to the farmer, which should have economic benefits, as his business will be more profitable.

The veterinary surgeon should assume that the use of an ultrasound scanner will provide him, as an expert, with added value compared to other procedures, including the possibility of going into more detailed technical aspects of research to which he previously did not have access. With this in mind, there is little alternative but to accept that the veterinary surgeon, too, must bear a part of the cost, as it is very difficult to write off the equipment solely by means of passing on the cost to the farmer.

Consequently, it is the author’s opinion that it is a necessary investment for an expert who specializes in reproduction. Clinicians such as myself have no alternative but to accept this economic burden and its effects, as the day will come when our clients will expect and demand ultrasound imaging, and we have to be prepared for this.

3

REPRODUCTION AND ULTRASOUND EXAMINATION IN CATTLE

ULTRASOUND TECHNOLOGY

Types of transducers or probes

Sector

Linear

Convex

The ultrasound scanner Structure of the ultrasound scanner The ultrasound scanner consists of the following parts: Transducer or probe Any device which converts one type of energy to another is called a transducer. Thus, a sound transducer converts electrical energy into sound energy and vice versa (e.g. microphones).

The ultrasound transducer is responsible for converting an electrical signal with ultrasound-capable frequencies into an ultrasound pressure signal that is propagated through air.

There are three basic types of transducers (probes): ■■ Sector ■■ Linear ■■ Convex Photo courtesy of Ana Isabel Peña Martínez.

Transmitter Regulates the transmission of ultrasound by the transducer.

Signal receiver and amplifier Picks up the electrical impulses generated in the transducer.

Gives a triangular or fan-shaped

■■

Gives a rectangular image.

image.

■■

Wide interface.

■■

Broad paths are required.

■■

Operating frequencies are usually

■■

The window is small with a very

■■

wide scanning angle.

■■

The probe contains the piezoelectric crystals that emit the ultrasound wave towards the tissues and is based on what is known as the piezoelectric effect.

Oscilloscope or cathode ray tube Processes the echoes that arrive from the signal amplifier.

■■

■■

Operating frequencies are the same as for sector probes, between 3.5 and 5 MHz.

Ideal for small structures at a frequency of 7.5 MHz.

Has a curved shape and gives a trapezoid image.

between 5 and 7.5 MHz.

When used for the examination of more deeply situated structures,

■■

■■

Used for the examination of deeply

The majority of transrectal probes

situated structures and has a broad

the operating frequency is usually

for veterinary use are in this

window.

between 3.5 and 5 MHz.

category.

■■

Piezoelectric effect ■■

■■

The piezoelectric effect is a physical phenomenon which some

■■

The crystal expands and contracts with the same frequency

crystals display, as a result of which a difference in electrical

as the electrical signal. The mechanical movement produces

potential (voltage) appears between certain surfaces of the

an ultrasound of the same frequency as the signal (by this

crystal when it is subjected to pressure.

method, the transducer converts the electrical signal into a

In the case of the probe of the ultrasound scanner, a crystal-

mechanical movement and thus into ultrasound).

line material is electrically stimulated and the crystal expands.

■■

The waves are reflected back towards the probe in the

When the polarity of the electrical signal is reversed, the crystal

form of a return echo, depending on the different imped-

contracts.

ance of the tissues.

Electrical current off

Electrical current on ■■

12

The probe is very sensitive to possible damage.

13

REPRODUCTION AND ULTRASOUND EXAMINATION IN CATTLE

ULTRASOUND TECHNOLOGY

Types of transducers or probes

Sector

Linear

Convex

The ultrasound scanner Structure of the ultrasound scanner The ultrasound scanner consists of the following parts: Transducer or probe Any device which converts one type of energy to another is called a transducer. Thus, a sound transducer converts electrical energy into sound energy and vice versa (e.g. microphones).

The ultrasound transducer is responsible for converting an electrical signal with ultrasound-capable frequencies into an ultrasound pressure signal that is propagated through air.

There are three basic types of transducers (probes): ■■ Sector ■■ Linear ■■ Convex Photo courtesy of Ana Isabel Peña Martínez.

Transmitter Regulates the transmission of ultrasound by the transducer.

Signal receiver and amplifier Picks up the electrical impulses generated in the transducer.

Gives a triangular or fan-shaped

■■

Gives a rectangular image.

image.

■■

Wide interface.

■■

Broad paths are required.

■■

Operating frequencies are usually

■■

The window is small with a very

■■

wide scanning angle.

■■

The probe contains the piezoelectric crystals that emit the ultrasound wave towards the tissues and is based on what is known as the piezoelectric effect.

Oscilloscope or cathode ray tube Processes the echoes that arrive from the signal amplifier.

■■

■■

Operating frequencies are the same as for sector probes, between 3.5 and 5 MHz.

Ideal for small structures at a frequency of 7.5 MHz.

Has a curved shape and gives a trapezoid image.

between 5 and 7.5 MHz.

When used for the examination of more deeply situated structures,

■■

■■

Used for the examination of deeply

The majority of transrectal probes

situated structures and has a broad

the operating frequency is usually

for veterinary use are in this

window.

between 3.5 and 5 MHz.

category.

■■

Piezoelectric effect ■■

■■

The piezoelectric effect is a physical phenomenon which some

■■

The crystal expands and contracts with the same frequency

crystals display, as a result of which a difference in electrical

as the electrical signal. The mechanical movement produces

potential (voltage) appears between certain surfaces of the

an ultrasound of the same frequency as the signal (by this

crystal when it is subjected to pressure.

method, the transducer converts the electrical signal into a

In the case of the probe of the ultrasound scanner, a crystal-

mechanical movement and thus into ultrasound).

line material is electrically stimulated and the crystal expands.

■■

The waves are reflected back towards the probe in the

When the polarity of the electrical signal is reversed, the crystal

form of a return echo, depending on the different imped-

contracts.

ance of the tissues.

Electrical current off

Electrical current on ■■

12

The probe is very sensitive to possible damage.

13

ThE OESTROUS CyCLE

REPRODUCTION AND ULTRASOUND EXAMINATION IN CATTLE

First week of the cycle, possibly between days 1 and 2

First week of the cycle, possibly between days 1 and 2

Left ovary

Right ovary

Left ovary

Right ovary

Follicles are observed starting to grow. One stands out as being slightly more developed.

Possible follicle recruitment is observed which cannot be distinguished by palpation.

Possible follicle recruitment is observed. One of the follicles is more developed, as shown by ultrasonography.

An old corpus luteum is observed, together with developing follicles. One of them is shown by ultrasonography to be more pronounced.

Palpable structures Surface without

Surface without

palpable

palpable

structures.

structures.

Palpable structures

1

1 Small follicles (not palpable).

1

1 Small follicles (not palpable).

2 Old corpus luteum.

Ultrasound recognition

1

1 Follicle.

1 Small follicles.

2

1

1

2

Ultrasound recognition

1 Follicle.

2 Small follicles.

1 Follicles.

2 Old corpus

2

1

luteum.

Section of the ovary

1

Section of the ovary

1 1 Follicle.

1 Small follicles.

1 1 Follicles.

1

1 Follicle.

2 Old corpus luteum.

2

30

31

ThE OESTROUS CyCLE

REPRODUCTION AND ULTRASOUND EXAMINATION IN CATTLE

First week of the cycle, possibly between days 1 and 2

First week of the cycle, possibly between days 1 and 2

Left ovary

Right ovary

Left ovary

Right ovary

Follicles are observed starting to grow. One stands out as being slightly more developed.

Possible follicle recruitment is observed which cannot be distinguished by palpation.

Possible follicle recruitment is observed. One of the follicles is more developed, as shown by ultrasonography.

An old corpus luteum is observed, together with developing follicles. One of them is shown by ultrasonography to be more pronounced.

Palpable structures Surface without

Surface without

palpable

palpable

structures.

structures.

Palpable structures

1

1 Small follicles (not palpable).

1

1 Small follicles (not palpable).

2 Old corpus luteum.

Ultrasound recognition

1

1 Follicle.

1 Small follicles.

2

1

1

2

Ultrasound recognition

1 Follicle.

2 Small follicles.

1 Follicles.

2 Old corpus

2

1

luteum.

Section of the ovary

1

Section of the ovary

1 1 Follicle.

1 Small follicles.

1 1 Follicles.

1

1 Follicle.

2 Old corpus luteum.

2

30

31

PERIODIC EXAMINATION AND ULTRASONOgRAPhy

REPRODUCTION AND ULTRASOUND EXAMINATION IN CATTLE

Interpretation of the different ultrasound sections The ultrasound images may be taken from different section planes. This complicates their interpretation, but basically the following applies: ■■ Horizontal plain: this is the most practical, as it allows us to visualize all the necessary areas at once.

■■ Transverse plane.

■■ Sagittal plane.

In this way images can be obtained of different ultrasound sections, and selected to study the situation and reach a conclusion.

The detection of different structures can give an idea of the age of the foetus under examination (adapted from Curran et al. 1986)

The size of the foetus is a limiting factor, as the larger it is, the greater the difficulty in positioning the probe appropriately in order to obtain the desired image (after 90 days it is difficult to visualize).

As the probe is moved, the image is focussed.

Sometimes it is not possible to retract the uterus to a suitable position for this type of manipulation, as the location of the gravid horn is too ventral (especially in older cows).

It is therefore necessary to ensure that these three positions are properly recorded: ■■ The area adjacent to the umbilical cord.

■■ The area between the hind limbs.

■■ The area ventral to the tail.

Transverse plane

Horizontal plane

This section allows us to see the foetus from the rear. We can distinguish the tail and the limbs.

In this case, the section allows the foetus to be seen from above, so that the spinal column can be distinguished, along with the ribs and the intestinal contents.

No. of exams

Average (days)

Interval

Embryo

15

20

19-24

Heartbeat

15

21

19-24

Allantois

9

23

22-25

Curved appearance of the embryo

11

25

22-30

Spinal column

14

29

26-33

Outline of hind limbs

14

29

28-31

Amnion

14

29

28-33

Orbital cavities

14

30

29-33

Outline of fore limbs

13

31

30-33

L-shaped appearance of the embryo

12

33

29-39

Placentomes

6

35

33-38

Lens

12

40

37-44

Hooves

10

45

42-49

Foetal movements

9

45

42-50

Ribs

7

53

51-55

Sagittal plane The horizontal plane from below allows the foetus to be seen from another perspective, so that the legs and the abdomen can be distinguished.

The sagittal plane of this male allows the umbilical cord and the genital tubercle next to it to be distinguished.

Structures observed according to time of appearance.

The different structures that may be encountered, together with the use of foetal measurements, gives a very approximate idea of the foetal age.

Example: between 25-45 days: take foetal length in mm (head-rump) and add 18 (thus 15mm long + 18 = 33 days old).

Examples: 15 mm (30-35 days); 20-25 mm (40 days); 40 mm (50 days); 80 mm (60 days).

70

71

PERIODIC EXAMINATION AND ULTRASONOgRAPhy

REPRODUCTION AND ULTRASOUND EXAMINATION IN CATTLE

Interpretation of the different ultrasound sections The ultrasound images may be taken from different section planes. This complicates their interpretation, but basically the following applies: ■■ Horizontal plain: this is the most practical, as it allows us to visualize all the necessary areas at once.

■■ Transverse plane.

■■ Sagittal plane.

In this way images can be obtained of different ultrasound sections, and selected to study the situation and reach a conclusion.

The detection of different structures can give an idea of the age of the foetus under examination (adapted from Curran et al. 1986)

The size of the foetus is a limiting factor, as the larger it is, the greater the difficulty in positioning the probe appropriately in order to obtain the desired image (after 90 days it is difficult to visualize).

As the probe is moved, the image is focussed.

Sometimes it is not possible to retract the uterus to a suitable position for this type of manipulation, as the location of the gravid horn is too ventral (especially in older cows).

It is therefore necessary to ensure that these three positions are properly recorded: ■■ The area adjacent to the umbilical cord.

■■ The area between the hind limbs.

■■ The area ventral to the tail.

Transverse plane

Horizontal plane

This section allows us to see the foetus from the rear. We can distinguish the tail and the limbs.

In this case, the section allows the foetus to be seen from above, so that the spinal column can be distinguished, along with the ribs and the intestinal contents.

No. of exams

Average (days)

Interval

Embryo

15

20

19-24

Heartbeat

15

21

19-24

Allantois

9

23

22-25

Curved appearance of the embryo

11

25

22-30

Spinal column

14

29

26-33

Outline of hind limbs

14

29

28-31

Amnion

14

29

28-33

Orbital cavities

14

30

29-33

Outline of fore limbs

13

31

30-33

L-shaped appearance of the embryo

12

33

29-39

Placentomes

6

35

33-38

Lens

12

40

37-44

Hooves

10

45

42-49

Foetal movements

9

45

42-50

Ribs

7

53

51-55

Sagittal plane The horizontal plane from below allows the foetus to be seen from another perspective, so that the legs and the abdomen can be distinguished.

The sagittal plane of this male allows the umbilical cord and the genital tubercle next to it to be distinguished.

Structures observed according to time of appearance.

The different structures that may be encountered, together with the use of foetal measurements, gives a very approximate idea of the foetal age.

Example: between 25-45 days: take foetal length in mm (head-rump) and add 18 (thus 15mm long + 18 = 33 days old).

Examples: 15 mm (30-35 days); 20-25 mm (40 days); 40 mm (50 days); 80 mm (60 days).

70

71

REPRODUCTION AND ULTRASOUND EXAMINATION IN CATTLE

5

UltRasoNogRaphy aND pathological coNDitioNs

Ultrasonography and pathological conditions

As with rectal palpation, for the most complete examination of the uterus possible, it is recommended that it should be retracted before the probe is inserted.

Natural retention of liquid in the lumen of the uterus due to oestrus.

Pathological conditions of the uterus Generally speaking, visualization of a fluid accumulation could suggest a possible pathological condition of the uterus, but the following possibilities should always be considered: ■■ The uterus could have accumulated some liquid during oestrus and in the first half of the luteal phase of the cycle.

■■ Importantly, diagnosis of pregnancy during the earliest phases is based on the identification of liquid (black anechogenic image) in the lumen of the uterus.

Retention of liquid due to 26 days’ gestation, the time when the embryo can already be seen.

Therefore, it is essential to know how to assess the presence of liquid (quality and quantity), and in addition, the condition of the uterine wall.

The most common pathological conditions of the uterus are: endometritis, pyometra, mucometra and embryonic death.

The ability of ultrasonography to improve the detection of pathological ovarian and uterine conditions is doubtless one of its most highly valued applications.

74

then take the left horn, move it backwards to the base of the pelvis.

locate the intercornual ligaments and use these to locate the right horn.

Move the right horn towards the base of the pelvis.

Embryonic/foetal death at 56 days. Disorganized material and dots which correspond to the embryo/foetus and floccules of pus can be observed.

Dots

The use of ultrasonography allows any pathological condition to be observed directly, and therefore means greater diagnostic precision.

grasp the body of the uterus.

26 day embryo

Disorganized embryo Thickened wall

75

REPRODUCTION AND ULTRASOUND EXAMINATION IN CATTLE

5

UltRasoNogRaphy aND pathological coNDitioNs

Ultrasonography and pathological conditions

As with rectal palpation, for the most complete examination of the uterus possible, it is recommended that it should be retracted before the probe is inserted.

Natural retention of liquid in the lumen of the uterus due to oestrus.

Pathological conditions of the uterus Generally speaking, visualization of a fluid accumulation could suggest a possible pathological condition of the uterus, but the following possibilities should always be considered: ■■ The uterus could have accumulated some liquid during oestrus and in the first half of the luteal phase of the cycle.

■■ Importantly, diagnosis of pregnancy during the earliest phases is based on the identification of liquid (black anechogenic image) in the lumen of the uterus.

Retention of liquid due to 26 days’ gestation, the time when the embryo can already be seen.

Therefore, it is essential to know how to assess the presence of liquid (quality and quantity), and in addition, the condition of the uterine wall.

The most common pathological conditions of the uterus are: endometritis, pyometra, mucometra and embryonic death.

The ability of ultrasonography to improve the detection of pathological ovarian and uterine conditions is doubtless one of its most highly valued applications.

74

then take the left horn, move it backwards to the base of the pelvis.

locate the intercornual ligaments and use these to locate the right horn.

Move the right horn towards the base of the pelvis.

Embryonic/foetal death at 56 days. Disorganized material and dots which correspond to the embryo/foetus and floccules of pus can be observed.

Dots

The use of ultrasonography allows any pathological condition to be observed directly, and therefore means greater diagnostic precision.

grasp the body of the uterus.

26 day embryo

Disorganized embryo Thickened wall

75