reproductive management in small ruminants

Reproductive management in small ruminants

Feb 2012 M.A. Driancourt, MSD AH, R&D Pharmaceuticals

Backbone of the presentation

1. What are the main reproductive features of Middle East sheep and goat breeds?

2. What are the consequences on these physiological features on production?

3. What are the technical options to break seasonal anoestrus?

4. What are the technical options to synchronize estrus during the breeding season?

5. How can we improve fertility?

6. How can prolificacy be improved?

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What are the main reproductive features of Middle East sheep and goat breeds?

Awassi sheep• Display a seasonal pattern of

reproduction

• Tend to display a late puberty

• Commonly produce a single lamb (low prolificacy)

• Are good milk producers

4


Damascus goats• Display a seasonal pattern of

reproduction, with a variable breeding season (June to Oct in Jordan or Sept to Feb in Cyprus)

• Tend to display a late puberty

• Are mildly prolific (1.5 kid per litter)

• Are good milk producers (500kg/lactation)

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Links between month of the year and cyclicity in sheep and goats

Month of the year

% of females in estrus

100

50

0

Jan May Sept Dec

Very seasonal breed or female

Less seasonal breed or female

anoestrusBSBS

TransitionTransition

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What are the consequences on these physiological features on production?

The seasonal pattern of reproduction does not allow to have reproduction timed to generate milk or lamb meat when prices are highest.

The seasonal pattern of reproduction may not always fit with the periods when forage and feedstuffs are available to cover the production needs of the late pregnant and lactating ewes or the growth needs of the lambs

Low prolificacy negatively affects the income of the farmers

The random pattern of cyclicity between individual ewes of a flock does not allow to use AI (and the associated diffusion of genetic merit)

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What are the consequences on these physiological features on production?

• Breed during anoestrus (hence “break” anoestrus)

• Synchronize estrus during the breeding season (to use AI )

• Increase prolificacy

Technical needs triggered by these physiological features

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What are the technical options to break seasonal anoestrus?

• Use progestagen/progesterone impregnated vaginal devices

• Use the ram effect

• Use melatonin

9



Three types of devices are available: cronolone (20mg) impregnated sponges (Chronogest CR, MSD AH), MAP (60mg) impregnated sponges and CIDR(0.3g progesterone)

Typical treatment scheduleDay 0 Day 14 Day 17

Sponge insertion

Sponge removal and

PMSG injection

AI or mating

55h

SHEEP

If mating is used, preparation of the rams (flushing, light treatment or melatonin) and a

suitable ewe to ram ratio are needed

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•Use progestagen/progesterone impregnated vaginal devices (+ 400IU

PMSG and mating) in Awassi ewes

SHEEP

Ozyutlu et al 2010

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Three types of devices are available: cronolone (20mg) impregnated sponges (Chronogest CR, MSD AH), and CIDR


Sponge insertion

Sponge removal

AI or mating

44h

GOAT

Day 9

Prostaglandin injection and

PMSG administration

Bucks also need to be prepared!

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•Use progestagen/progesterone impregnated vaginal devices

GOAT

Parity 1

55.3%

Parity 2

73.7%

Parity 3

55.9%

Parity 4

75%

Parity 5

58.8%

400UI PMSG

50.9%

500UI PMSG

62.9%

600UI PMSG

68.1%

Prolificacy= 1.97+/- 0.8

Fertility Alpine & Saanen goats

Intervet registration files

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Pre-requisites: • Target a breed with a light anoestrus or females

during the transition period• Ewes/goats need to be away from the rams/bucks

for at least a month • The rams/bucks need to be prepared (light

treatment/melatonin)

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Chemineau et al 2006

Estrus and formation of normal corpora lutea do not happen immediately!

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•Use melatonin ear implants (18mg)

Control Sponge + PMSG (450IU)

Melatonin

Fertility 65% 78% 78%

Prolificacy 1.26 1.50 1.55

(Gomez et al 2006), Manchega ewes

I Implants need to be inserted between 50 and 70 days before breeding

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Submission rate

Fertility Prolificacy AI use

Progestagen sponges

+++ ++ +++ Yes

Ram effect + + + No!

Melatonin implant

++ ++ ++ No

(no synchro)

Take home message

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What are the technical options to synchronize estrus during the breeding season?


• Use of Ovsynch type protocols• Use of double prostaglandin protocols

SHEEP

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Three types of devices are available: cronolone (20mg) impregnated sponges (Chronogest CR, MSD AH), MAP (60mg) impregnated sponges and CIDR (0.3g)


Sponge insertion

Sponge removal and

PMSG injection

AI or mating

55h

SHEEP

If mating is used, a suitable ewe to ram ratio needs to be respected

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SHEEP

Dairy

(Lacaune)

Dairy

(Manech)

Meat

(Texel, Vendeen)

Fertility 71% 52.3% 63.2%

Prolificacy 1.69+/- 0.67 1.45+/- 0.77 1.62+/-0.68

Intervet registration files

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Sponges allow to obtain improved reproductive performance in Awassi ewes managed in a “3 lambings in 2 years” management system (6

breeding periods)

SHEEP

Zarkawi et al 2011

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Three types of devices are available: cronolone (20mg) impregnated sponges (Chronogest CR, MSD AH), and CIDR


Sponge insertion

Sponge removal

AI or mating

44h

GOAT

Day 9

Prostaglandin injection and

PMSG administration


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Damascus goats

GOAT

Al Merestani et al (2003)

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• Use of Ovsynch type protocols (Deligiannis et al 2005, Titi et al 2010)

SHEEP

Day 0 5 6.5 7

AIGnRHGnRH PGF2 a

50% fertility in

Greek ewes

60% fertility

in Awassi ewes

Day 0 5 6

GnRH PGF2 a Rams in

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•Use of Ovsynch type protocols (Holtz et al 2008) Boer goats

GOAT

N=24/group Sponge

+ prostaglandin and 250IU PMSG 48h before sponge removal (AI 43h

later)

Ovsynch ( 4µg Buserelin on d0,

prostaglandin on d 7 and 4µg buserelin on d 9 with

AI 16h later)

% goats in estrus 100% 96%

Fertility (day 30post AI)

50% 56%

Prolificacy 1.83 +/- 0.23 1. 86 +/- 0.14

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•Use of double prostaglandin protocols ( 7 to 11 days apart)

SHEEP

control Double PG

Conception (% US positive 30 days

post AI)

88% 63%

Prolificacy 1.58 1.27

Fierro et al 2011

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• Vaginal sponges are the best approach• Ovsynch may be an alternative in goats• Double prostaglandin treatment reduces fertility

Take home message

When a successful synchronization is obatined,

1. Diffusion of genetic merit becomes possible (AI)

2. Breeding can be focussed on a narrow part of the year (labor efficiency)

3. Lambing is limited to a narrow time period (labor efficacy)

4. An homogeneous lamb crop is ready to be sold at a set time every year

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How can we reach optimal prolificacy?

What is optimal prolificacy?• An homogeneous crop of twins! (no triplets)• If

1. maternal behavior of the ewe is OK!

2. Milk production of the ewe is adequate!

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How can prolificacy be improved?

• Use PMSG at removal of progestagen/progesterone impregnated vaginal devices

• Use Androvax, a vaccine against an ovarian steroid

• Use genetic introgression of a prolificacy gene (such as Fec B) into your sheep breed

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•Use PMSG at removal of progestagen/progesterone impregnated vaginal devices

0

0,5

1

1,5

2

2,5

3

3,5

4

4,5

5

0 375 750

Galway

Timadhite

romney

Dose of PMSG (IU)

Ovulation rate

Quirke et al 1986

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The recommended vaccination schedule is

First vaccination (2ml): 8 to 10 weeks before joining

Booster (2ml): 4 to 6 weeks before joining

The antibodies reduce negative feedback of the steroids on LH secretion. The increased frequency of LH pulses increases the proportion of double ovulations (by around 20%)

Not affecting seasonality (not inducing ovulation in anoestrous ewes)

Not synchronizing ovulation, hence compatible with mating by rams

A booster is needed every year to obtain the prolificacy increase, but may be skipped if the environment is too harsh

A vaccine against a steroid (androstenedione coupled to a carrier (bovine lactalbumin) in a DEAE adjuvant), applied as a primary and a booster on the first year of treatment.

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Prolificacy data from 27 farms in NZ

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• Use genetic introgression of a prolificacy gene (such as Fec B) into your sheep breed

The Booroola gene (Fec B) is a major gene that has large effects on prolificacy (but not on seasonality).

Homozygous ewes and heterozygous carrier ewes display over 5 and around 3 ovulations (vs 1 for the non carriers)

This gene acts by interfering with the signalling of bone morphogenic proteins

Its position in the sheep genome is known

By crossing a specific breed with homozygous rams and then backcrossing to the initial breed, it is possible to introgress the Fec B prolificacy gene in that breed, while keeping all the production features of the breed (was done with Awassi)

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How should fertility problems be analysed?

Questions to be asked when fertility is lower than expected

1. Is the problem physiological or pathological?

2. What evidence do I have that low fertility is only a female problem?

3. What evidence do I have that the ewes were indeed ready to be bred (i.e. cycling)

4. Was body condition of the ewes adequate for initiation and maintenance of pregnancy?

5. What were the climatic conditions in the days around ovulation and early embryonic development?

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Conclusion : the tools to work from…

Efficient breeding at all times of

the year

Improving prolificacy

Allowing early

breeding of ewe lambs

Allows easy diffusion of

genetic merit by AI

Allows matings by

rams

Sponges Yes Yes( 10-40%)

(depending on amount of PMSG)

Yes Yes Yes (ram to ewe

ratio adapted to the season)

Melatonin implants

No? Yes (15%) No No Yes

Androvax No Yes (25%) No No Yes

Genetics Not yet If prolificacy genes are

introgressed

No No Yes

Improved nutrition

No Yes (10%) No No Yes

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Conclusion: how to implement these tools according to your needs

• There are many tools that are available to move from extensive production systems towards more intensive ones (provided the farm technical management and food availability allow it)

• Several steps of intensification are possible (from mild such as the use of Androvax or melatonin implants to a more “European” production system using sponges to obtain three lambings in 2 years with increased prolificacy)

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Questions?

reproductive management in small ruminants

Documents

seasonal anoestrus

physiological features

technical options

femaleless seasonal

use progestagenprogesterone

goat breeds

production needs

reproductive management