Artificial insemination and hormonal management of the sow

PRESENTATION

BROCHURE

ESSENTIAL GUIDES ON SWIN

HEALTH AND PRODUCTION

Artificial Ins mination and Hormone Management in the Sow María Victoria Falceto Recio

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ESSENTIAL GUIDES ON SWINE HEALTH AND PRODUCTION

Artificial Insemination and Hormone Management in the Sow

ESSENTIAL GUIDES ON SWIN

HEALTH AND PRODUCTION

Artificial Ins mination and Hormone Management in the Sow María Victoria Falceto Recio

P67190_Artificial_insemination_cover_SERVET.indd 1

22/6/18 13:52

AUTHOR: María Victoria Falceto Recio.

FORMAT: 17 x 11 cm.

NUMBER OF PAGES: 88.

BINDING: Softcover, wire-o.

RETAIL PRICE

€35

This guide is a visual and practical explanation of what should happen from the moment when you receive the semen from the artificial insemination centre, until the moment when the sow is inseminated, with a focus on the use of refrigerated semen: conservation and management of seminal doses, oestrus detection, identification of the best time for insemination, insemination methods, and hormonal control of oestrus and ovulation.

Aleksandar Malivuk/shutterstock.com

Artificial Insemination and Hormone Management in the Sow

Presentation of the book Pigs are the only production animals to produce a large number of offspring, in particular since the appearance of hyperprolific lines, which have increased the number of piglets born alive per litter over the past decades. Artificial insemination of the sow has long been a common and even necessary practice on commercial farms.

This guides takes a visual and practical approach to explaining what should happen from the moment semen is received from the artificial insemination centre, until the moment when the sow is inseminated, with a focus on artificial insemination using refrigerated semen: storage and management of semen doses, oestrus detection, identification of the best time for insemination, insemination methods, and hormonal control of oestrus and ovulation. All this is explained with a special emphasis on the sow.

A chapter is dedicated to justifying one of the main tasks on the farm: oestrus detection, where the use of teaser boars and the need for qualified personnel is essential. Failure in this task results not only in direct economic losses, but can also cause the unnecessary euthanasia of animals.

One of today’s current objectives is to reduce the number of sperm used in seminal doses and the number of inseminations performed per sow in heat. To do so, not only must semen quality be improved, but oestrus synchronisation must also be achieved. A chapter therefore focuses on how to determine the best time to inseminate a sow, and also outlines the consequences of carrying out forced insemination when the sow is no longer in heat (dirty sow syndrome). All the insemination technique options are explained, and the advantages and disadvantages of depositing the semen in the papillary tubercles of the cervix (imitating the natural mating process) or directly in the uterus of the sow are also discussed. The importance of the use of appropriate insemination materials and of ensuring adequate hygiene during the process are emphasised. The book also includes basic information about techniques that are not widely used yet in the pig industry (artificial insemination with frozen or sexed semen and embryo transfer), which can be performed on commercial farms using deep intrauterine catheters.

Finally, the book reviews the hormonal induction and synchronisation of both oestrus and ovulation, which will optimise the use of time and productivity on farms.

Artificial Insemination and Hormone Management in the Sow

The author María Victoria Falceto Recio María Victoria Falceto Recio is professor of Reproduction and Obstetrics at the Faculty of Veterinary Medicine of the University of Zaragoza (UZ) and academic coordinator of Pig Production as part of the undergraduate programme in veterinary medicine.

She has been head of the Reproductive Consultancy Service at the Faculty of Veterinary Medicine (UZ) since 2003, and codirector of the Joint Master’s Degree Programme in Pig Health and Production organised by the universities of Lleida, Zaragoza, Barcelona and Madrid since 2006.

She has authored or coauthored numerous scientific articles published in Spanish and international journals and is the author of the handbook Essential guides on swine health and production. Ovarian pathophysiology in the sow, published by Servet.

hkeita/shutterstock.com

María Victoria has vast experience in the pig production industry, both from an academic and scientific perspective, as well as from a practical one. For this reason, she is secretary of the Spanish Association of Swine Veterinary Practitioners (ANAVEPOR), a member of the Board of Directors of the Aragon Association of Swine Veterinary Practitioners (AVPA) and a member of the Spanish Scientific Pig Farming Association (ANAPORC).

ESSENTIAL GUIDES ON SWIN

HEALTH AND PRODUCTION

Artificial Ins mination and Hormone Management in the Sow María Victoria Falceto Recio

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Table of contents 1. AI in pigs: current approach 2. Oestrus detection in the sow Oestrous cycle Signs of oestrus Detection of oestrus Choice of staff and boar Frequency of detection of oestrus Sows requiring detection of oestrus Methods for oestrus detection

Consequences of poor oestrus detection

3. Timing of artificial insemination When to inseminate Insemination based on estimating the moment of ovulation Duration of oestrus Measuring luteinising hormone (LH) Temperature of the vulva Vaginal cytology Electrical resistance of the vaginal mucus Ultrasound examination of the ovary

Fixed-time artificial insemination Using hormones to induce and synchronise ovulation Use of encapsulated semen

When to stop inseminating

4. Methodology of artificial insemination Preparation of the semen Microscopic evaluation of the semen before artificial insemination Management of semen doses on the farm

Preparing the equipment required for artificial insemination Catheters

Common features of all AI techniques Hygiene during AI Introducing the catheter into the sow’s vagina

Intracervical insemination Catheters for IC-AI IC-AI method Semen dose characteristics for IC-AI Duration of intracervical insemination Backflow from the vulva Stimulation of the sow during IC-AI

Postcervical intrauterine insemination Catheters for PC-AI PC-AI method Semen dose characteristics for PC-AI Advantages of PC-AI

Deep intrauterine insemination Catheters for DIU–AI DIU-AI method Semen dose characteristics for DIU-AI Advantages and disadvantages

Use of seminal additives during artificial insemination

5. Hormonal control of oestrus Induction of oestrus Differentiating between anoestrus and pseudoanoestrus Hormones that stimulate the ovaries Absence of oestrus after hormonal induction

Synchronising oestrus Hormones for synchronisation of oestrus Absence of oestrus after synchronisation Duration of treatment Other uses for altrenogest on the farm

Induction and synchronisation of ovulation When to induce ovulation during the oestrous cycle Hormones for induction of ovulation Advantages of a single fixed-time insemination

References

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Timing of artificial insemination

AI and Hormone Management in the Sow

Insemination based on estimating the moment of ovulation Despite research into many methods of detecting the moment of ovulation, there is still no truly effective, cheap method that is easy for farm personnel to use. The techniques investigated so far are based on changes in various parameters during oestrus: luteinising hormone (LH) levels, temperature of the vulva, vaginal cytology, electrical resistance of the vaginal mucus, etc. Diagnosis by ultrasound examination of the ovary is extremely precise, but it requires highly skilled personnel and lengthy evaluation. The most common technique currently used by farms to estimate the moment of ovulation (AI) is based on the determination of the onset and end of oestrus.

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Figure 2. Insemination and the standing reflex in the sow.

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TIMING OF ARTIFICIAL INSEMINATION

Duration of oestrus Oestrus starts with the appearance of the standing reflex in the sow and ends when is ceases. It lasts approximately two days (between one and five days). Ovulation occurs 70 % of the way through oestrus (Kirkwood and Kauffold, 2015).

The main problem when estimating the interval between the start of oestrus and ovulation is that the end of the standing reflex is unknown. The duration of oestrus and the moment of ovulation also vary significantly between sows. This variability depends on the following factors:

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◗ Genetics. ◗ Age: gilts or multiparous sows. ◗ Start of oestrus after weaning. ◗ Time of year. ◗ Farm: temperature, humidity, ventilation, lighting, welfare, stress, nutrition, lactation length, ‘boar effect’, protocol for detection of oestrus, etc.

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Timing of artificial insemination

AI and Hormone Management in the Sow

Every farm should record the start and end of oestrus in their sows and calculate the average duration (Table 1). However, this information can be subjective, as it depends on operator training and the method and frequency of detection of oestrus on the farm.

Table 1. Average duration of oestrus (hours) in multiparous sows.

Week of the year

Average

Range

Week of the year

Average

Range

1 2 3 4 5

56.2 59.4 60.4 54.7 63.6

(42–72) (36–84) (36–72) (36–84) (36–72)

6 7 8 9 10

55.2 62.1 56.2 61.3 61.5 59.06 (n=400)

(42–72) (36–84) (36–72) (36–84) (48–72)

Overall farm average

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(36–84)

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TIMING OF ARTIFICIAL INSEMINATION

Effect of age on the duration of oestrus and the timing of insemination Oestrus is very short in some gilts and ovulation can occur on the first day, so insemination is recommended as soon as the standing reflex is seen. The gilt should be inseminated again 24 hours later. This behaviour is caused by immaturity of the hypothalamic–pituitary–ovarian axis related to age.

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The duration of oestrus in multiparous sows is very variable. Hypothalamic–pituitary–ovarian axis functioning in these sows is related to the lactation period that has just ended. Recommendations for inseminating postweaning females mainly depend on the interval between weaning and oestrus (Table 2).

Figure 3. The duration of oestrus varies between sows, depending on the interval between weaning and oestrus.

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Methodology of artificial insemination

AI and Hormone Management in the Sow

Preparation of the semen Microscopic evaluation of the semen before artificial insemination The causes of infertility are equally shared between the boar and the sow. On arrival at the farm, it is essential to assess the sperm motility of the dose immediately before insemination to verify that it has not been affected by temperature changes during transport or by semen preservation methods. The steps to follow are: Step 1. Turn on the external warming plate or the microscope stage 38 °C warmer. When the temperature reaches 38 °C, place the slide and coverslip on the warmer to come up to temperature (Fig. 1).

15 °C Caution! Temperatures <37 °C do not allow true sperm motility to be assessed and >39 °C can kill the sperm.

Step 2. Remove a dose for each boar from which semen will be used that day for AI on the farm from the semen storage unit Figure 1. Warming plate (left). The thermometer shows (15–17 °C). Warm the doses in a water bath at 37 °C. the difference between the storage temperature and the correct temperature to evaluate motility (right).

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METHODOLOGY OF ARTIFICIAL INSEMINATION

Step 3. Check that the dose has not passed its expiry date.

Step 4. Gently rotate 2–3 times to mix the contents (Fig. 2).

Step 5. Using a Pasteur pipette, place one drop of semen on the slide and cover it with the coverslip, both already at a temperature of 38 °C. The drop should be big enough to fill the coverslip area so that no air bubbles remain to make observation difficult.

Step 6. Assess the sample with a light microscope: ◗ View at 100, 200 and 400 times magnification (10× eyepiece and 10×, 20× and 40× objectives). ◗ Obtain the percentage of sperm with motility (0–100 %) by counting at least 4 different optical fields. ◗ Do not include sperm that are clumped together (Fig. 3).

BOA R332 102/ 09

09 102/ R332 BOA

Figure 2. Rotation of the dose to mix.

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Figure 3. Clumped sperm.

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Methodology of artificial insemination

AI and Hormone Management in the Sow

Introducing the catheter into the sow’s vagina The protocol employed by all artificial insemination techniques to introduce the catheter into the sow’s vagina is as follows: Step 1. When the sow is in oestrus, clean the vulva with a disposable wipe moistened with a nonspermicidal disinfectant and dry with a disposable paper towel.

Step 2. Lubricate the tip of the catheter with 1–2 ml of a sterile, nonspermicidal gel to facilitate introduction and prevent the catheter injuring the vaginal mucosa. Avoid plugging the catheter opening from where the semen will come out.

Step 3. Part the lips of the vulva and, while drawing them outwards, move the catheter towards the vaginal vestibule (Fig. 6).

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Figure 6. Opening the lips of the vulva and introducing the catheter.

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METHODOLOGY OF ARTIFICIAL INSEMINATION

Step 4. Gently introduce the catheter upwards towards the roof of the vagina at an angle of 45° to prevent damage to the external opening of the urethra (Fig. 7).

If urine flows out of the free end of the catheter, it means that the catheter has been fed into the urethra. If this occurs, a new catheter should be used, as urine is spermicidal.

Step 5. Continue inserting the catheter in a more horizontal position.

Figure 7. The catheter should be aimed at entry towards the roof of the vagina at an angle of 45°.

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After this point, each insemination technique has its own peculiarities with regard to the part of the uterus where the semen is deposited: cervix, body or horn.

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Methodology of artificial insemination

AI and Hormone Management in the Sow

DIU-AI method The protocol for DIU-AI is as follows: 1. After the intracervical guide catheter is inserted, wait a few minutes for the cervix to relax.

2. Introduce the inner catheter and press forward sufficiently to overcome the resistance of the interdigitating pads of the cervix until the uterine body is reached.

3. Continue to press forward, and it will pass into one of the uterine horns.

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4. Continue to press very slowly to introduce the full length of the catheter into the uterine horn.

5. Introduce the semen dose in one go (Fig. 15).

6. Once insemination is complete, remove the deep intrauterine (inner) catheter very slowly. Then twist the intracervical catheter several times to activate mechanical stimulation of the cervix and encourage uterine contractions and passage of the sperm.

7. Remove the intracervical guide catheter.

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METHODOLOGY OF ARTIFICIAL INSEMINATION

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Figure 15. Deep intrauterine insemination.

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Hormonal control of oestrus

AI and Hormone Management in the Sow

Duration of treatment

Cycle (days)

When the date of the previous oestrus is unknown

1

In this case, altrenogest should be administered for 18 days.

Sow 1

The corpora lutea last 16–18 days in dioestrus.

Altrenogest blocks oestrus but does not affect luteolysis.

Administered for at least 18 consecutive days, it ensures that no progesterone is produced that could block oestrus. When the progestogen is withdrawn, a new follicular phase starts, leading to oestrus.

5

9

13

17 21 25 Altrenogest (18 days)

29

33

37

Sow 2 Sow 3

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Sow 4 Last oestrus

Synchronised oestrus

Follicular phase

Luteal phase

Even though there are no corpora lutea in the ovary, the sow does not come into oestrus while altrenogest is being administered.

Figure 12. Administration of altrenogest for 18 consecutive days when the date of the previous cycle is unknown (Falceto, 2015).

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Oral administration of altrenogest (18 days)

The corpora lutea mature and regress physiologically ◗ No follicular growth ◗ No ovulation ◗ No oestrus

No GnRH

Hypothalamus

GnRH

No FSH No LH

Pituitary gland

FSH LH

Ovary

◗ ◗ ◗

Altrenogest withdrawn

Positive feedback: activation of the HPO axis

Negative feedback: HPO axis blocked

HORMONAL CONTROL OF OESTRUS

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Terminal follicular growth Oestrus: 3–5 days (gilts) and 2–3 days (sows) Ovulation

Figure 13. Hypothalamic–pituitary–ovarian (HPO) axis blocked after altrenogest administration. Activated after withdrawal.

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Hormonal control of oestrus

Pituitary gland LH peak

AI and Hormone Management in the Sow

Administration of 10 μg buserelin (IM/SC) ◗ ◗

115–120 h after altrenogest1 86 ± 3 h after weaning2

Figure 18. Hormonal induction of ovulation using buserelin.

1 Driancourt, 2013.

2 Martinat Botte et al., 2010.

3 Van Kaufmann and Holtz, 1982.

Ovary ◗

◗

Single fixed-time insemination: 30–33 h after buserelin Ovulation: 42 ± 2 h after buserelin3

It is still advisable to tease the sow to make sure that she is in oestrus before insemination, even though it is not strictly necessary.

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GnRH analogues will fail to induce ovulation if the timetables for hormone administration and insemination are not adhered to.

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HORMONAL CONTROL OF OESTRUS

Advantages of a single fixed-time insemination ◗ The weekly workload can be organised more effectively when the day and time at which all the sows should be inseminated is known. This also reduces the staffing levels required. ◗ Using a single semen dose per sow in oestrus allows all the sows in a group to be inseminated with semen from the same boar, reducing birth weight variability between litters.

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◗ When ovulation and insemination are synchronised, fertilisation is also synchronised and farrowing is grouped more closely. Piglet birth weight is also more uniform across the same litter. ◗ Despite only inseminating each sow once, fertility and prolificacy reach similar levels to those obtained with multiple inseminations (Falceto et al., 2014). ◗ Inseminating more sows with semen from the same boar enables progeny to be evaluated sooner and genetics to be improved more rapidly.

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