Controlled reproduction of the pig: The benefits of P.G. 600
By Jan Baars, Annette Bonde Larsen and Marc Martens, Intervet. - P.G. 600 was developed in the beginning of the sixties and introduced on the Dutch market in 1965. Since then it has been registered in pig producing countries all over the world, including the US. Research in pig reproduction has always been an area of major interest. Since P.G. 600 was introduced several studies have been performed showing the benefits of the product and articles have been published from all over the world.
P.G. 600 is a unique combination of PMSG
and HCG (400/200 I.U.). This combination
has always proven to be the optimal one in
order to bring prepuberal gilts in oestrus.
Also in first litter sows it has proved to be
a unique help to avoid anoestrus. For
synchronisation purposes the product can
be used as well.
In 30 years much has changed. Breeding
companies changed the genetic potency
of the pigs. Feed companies keep on
changing formulations and feeding
schemes. Housing and management has
been altered etc.
Is P.G. 600 still a winner?
We think it is. At
the beginning of this year the book
Controlled Reproduction in Pigs appeared
(5). The author, Ian Gordon, referred to
literature about the use of P.G. 600 in
several chapters :
- More frequent farrowing in pigs
- Embryo transfer and associated techniques in pigs
- Breeding pigs at younger ages
The name P.G. 600 is even included in the
index of the book, demonstrating that this
product still is an up to date tool in
P.G. 600®: The Evergreen
Jan Baars, Annette Bonde Larsen and Marc Martens
controlled reproduction of the pig and
contributes to the profitability of the pig
enterprise.
However, there are also genetic and
environmental factors which influence the
reproductive efficacy. These may be the
reason that the results of different P.G.
600 trials sometimes vary.
The claim of the product has always been,
that it induces a fertile heat. This means it
reduces farrowing intervals, whereas
pregnancy rates and litter sizes are equal
or even better than those in control
animals.
P.G. 600 is often used in first litter sows at
day of weaning in order to reduce the
weaning to service interval.
To demonstrate that results of P.G. 600
treatment may vary, results of 2 recent
trials, one from Canada and one from
Germany, will be presented. So far the
results have not been published.
Canadian trial
The Canadian trial has been performed by
Kirkwood c.s. of the University of Alberta.
On four farms they treated ± 50% of
primiparous sows at day of weaning, the
remaining ones were untreated controls.
The total number of animals involved in
the trial varied per farm. On farms 1, 2, 3,
and 4 respectively 56, 424, 40, and 89
animals have been treated with P.G. 600,
while 62, 450, 34, and 95 animals have
been left as controls.
The effect on reproductive performance
of P.G. 600 treatment at weaning in all
four farms is given in Table 1.
Table 1: Effect on reproductive performance of
P.G. 600 treatment at weaning of primiparous sows
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The over-all results show a highly significant
reduction of W.O.I. with 2 days resulting in
± 22% more animals bred by 7 days after
weaning.
By 25 days after weaning ± 10% more
animals had been bred in the treated
group compared to the control group. The
results varied among the farms and the
decrease in W.O.I. in treated animals was
less outspoken in farms 3 and 4 than in
farms 1 and 2.
No difference in the over-all farrowing rate
was observed. Litter sizes were better in
the control animals, however, not at all
farms. In farm four 11.2 piglets were born
Table 2: The effect of P.G. 600 and 1 000 I.U. Folligon treatment in sows
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German trial
In the former East Germany oestrus
induction with 1 000 I.U. PMSG 24 hours
after weaning has been frequently used.
In order to compare results of treatments
with P.G. 600 and 1 000 I.U. Folligon
(PMSG) , Intervet GmbH initiated a one
year lasting trial in a 750 sow unit. The
trial has been performed by a research
team of the Institute for Animal Husbandry
and Genetics of the Georg August
University in Göttingen (FRG). One of the
researchers, W. Holtz, of this institute was
already involved in P.G. 600 trials in the
seventies (4).
The treatment was given 24 hours after
weaning. Three days after treatment
oestrus detection was performed every
12 hours with a teaser boar. A.I. was
applied at time of standing heat. In Table
2 the results are given irrespective of
parity, because the W.O.I. in the
primiparous sows in the control group
was less than one day longer than in the
multiparous sows.
Reproductive performance in treated sows
was better than in controls. The over-all
result becomes quite clear by calculating
the number of piglets born alive per treated
sow. In the P.G. 600 group 9.0 piglets
were born alive per treated sow, 7.7 piglets
in the Folligon treated group and only 6.9
in the control group.
There was no difference at all in the duration
of standing heat between the three groups.
Discussion and conclusions
More than thirty years after the development
of P.G. 600 it is evident that the
product is still an important tool in
controlled reproduction in pigs.
However, it is difficult to predict the
reproductive performance of the treated
animals. In the results above presented,
differences are seen on important
parameters. In the Canadian trial P.G. 600
reduced farrowing intervals and did not
improve litter size. On the other hand, in
the German trial there was hardly any
reduction of the weaning to service interval.
In this trial the big advantage of the product
was the increased number of piglets born
alive per treated sow, which was the
consequence of excellent farrowing rates
and litter sizes. Explanation for this is the
big influence of genetic and environmental
factors on reproductive performance.
In the German trial it is quite striking, that
in the control group of primiparous sows
there was no clear delay in the weaning to
oestrus intervals. In general this is just the
group for which P.G. 600 is indicated.
As already proven in the dose titration
study which has been performed to get
P.G. 600 registered in the US, it came out
that for oestrus induction P.G. 600 is
superior to Folligon and other combinations
of PMSG and HCG. Also in the
German trial the use of P.G. 600 appeared
to be superior to Folligon. PMSG has
frequently been used for this indication
in the (former) Eastern European countries
and this may still be the case, because
literature about the use of PMSG for
oestrus induction is abundant.
Further information
Click the links below for additional information:
- More information on P.G. 600
- More information on Intervet and their pig products
References
1. Schilling E. and Cerne F. (1972).
Induction and synchronization of oestrus
in prepuberal gilts and anoestrus sows
by a PMSG/HCG compound.
Vet. Rec., 91, 471-474.
2. Webster W.R. (1978).
Evaluation of a pregnant mare?s serum
and human chorionic gonadotrophin
mixture for alleviating summer infertility
in sows.
Australian Vet. J., 54, 26-29.
3. Britt J.H., Day B.N., Webel S.K. and
Brauer M.A. (1989).
Induction of fertile estrus in prepuberal
gilts by treatment with a combination of
pregnant mare?s serum gonadotrophin
and human chorionic gonadotrophin.
J. Anim. Sc., 67, 1148-1153.
4. Holtz W., Hermann F., Pich H.H. and
Polanco A. (1977).
Die Steuerung von Brunst und
Ovulationszeitpunkt bei Jungsauen.
Zuchthygiene, 12, 91-92.
5. Ian Gordon. Controlled reproduction in
pigs, Vol. 3 (1997).
ISBN 9851991165. CAB International.
Source: Intervet UK Ltd - November 2005